Approach to altered sensorium from harrison 22nd edition
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I now have all the material needed for a comprehensive answer. Let me compile the full response from Harrison's 22E.
Approach to Altered Sensorium - Harrison's Principles of Internal Medicine, 22nd Edition (2025)
Chapters 29 (Confusion and Delirium) and 30 (Coma) — S. Andrew Josephson, Bruce L. Miller
Terminology and Definitions
Harrison's 22E uses several interchangeable terms for altered sensorium: encephalopathy, acute brain failure, acute altered mental status, acute confusional state, and "ICU psychosis." The unifying term is delirium - a relatively acute decline in cognition that fluctuates over hours or days.
The spectrum of altered sensorium ranges from:
- Confusion - reduced comprehension, coherence, and capacity to reason
- Delirium - acute confusional state (hallmark = attention deficit)
- Stupor - patient arousable only with vigorous stimulation
- Coma - unresponsive, unarousable state
PART I: DELIRIUM (Acute Confusional State)
Clinical Features
The hallmark is a deficit of attention, though all cognitive domains are variably affected - memory, executive function, visuospatial tasks, and language. Associated features include:
- Altered sleep-wake cycles
- Perceptual disturbances (hallucinations, delusions)
- Affect changes
- Autonomic instability (HR and BP fluctuations)
Two subtypes:
| Feature | Hyperactive | Hypoactive |
|---|---|---|
| Prototype | Alcohol withdrawal (DTs) | Benzodiazepine intoxication |
| Presentation | Agitation, tremor, hallucinations, hyperarousal | Apathy, withdrawal, psychomotor slowing |
| Recognition | Easily recognized | Often missed; underdiagnosed |
Patients often fluctuate between subtypes along a spectrum. Hypoactive delirium is frequently overlooked on medical wards and in the ICU.
Risk Factors (Table 29-1 in Harrison's)
Predisposing (baseline vulnerability):
- Age >65 years
- Pre-existing cognitive impairment/dementia
- Severe illness, functional dependence
- Sensory deprivation (vision/hearing loss)
- Dehydration, malnutrition
Precipitating factors:
| Category | Examples |
|---|---|
| Toxins | Anticholinergics, opioids, benzodiazepines; alcohol (intoxication/withdrawal); opiates; cocaine; PCP, ketamine; carbon monoxide, pesticides |
| Metabolic | Electrolyte disturbances (hypo/hyperglycemia, hypo/hypernatremia, hypercalcemia); hypothermia/hyperthermia; pulmonary failure (hypoxemia, hypercarbia); hepatic failure; renal failure/uremia; cardiac failure; B1/B12/folate/niacin deficiency; anemia |
| Infections | UTI, pneumonia, sepsis; CNS - meningitis, encephalitis, brain abscess |
| Endocrine | Hypothyroidism/hyperthyroidism; hyperparathyroidism; adrenal insufficiency |
| Cerebrovascular | Global hypoperfusion (heart failure, septic shock, dehydration, anemia); hypertensive encephalopathy; focal strokes (right parietal, medial dorsal thalamic) |
| Autoimmune | CNS vasculitis; cerebral lupus; autoimmune/paraneoplastic encephalitis |
| Seizure-related | Nonconvulsive status epilepticus (NCSE); postictal states |
| Neoplastic | Diffuse brain metastases; carcinomatous meningitis; CNS lymphoma |
| Hospitalization | Terminal end-of-life delirium |
Laboratory and Diagnostic Evaluation (Table 29-2)
Initial evaluation (all patients):
- History - special attention to medications (including OTC and herbals)
- General physical + neurologic examination
- CBC, electrolyte panel (Ca, Mg, Phosphorus), LFTs (with albumin), renal function tests
First-tier further evaluation:
- Systemic infection screen: UA + culture, chest X-ray + respiratory pathogen tests, blood cultures
- ECG
- ABG
- Serum/urine toxicology screen (earlier in young patients)
- Serum B12, folate, thiamine levels
Second-tier (if above unrevealing):
- Brain CT or MRI
- EEG (essential when NCSE is suspected or etiology remains unclear)
- LP - CSF analysis (meningitis, encephalitis)
- Autoimmune/paraneoplastic antibody panel
- Thyroid function, cortisol, ammonia
Per Harrison's: "No single algorithm will fit all delirious patients due to the staggering number of potential etiologies." If a clear precipitant (e.g., offending medication) is identified, further testing may not be required.
Management of Delirium
Principle: Treat the underlying cause first. Pharmacologically targeting symptoms alone prolongs confusion and masks diagnostic information.
Non-pharmacologic (supportive) care - most effective first-line approach:
- Reorientation by nursing staff and family
- Visible clocks, calendars, outside-facing windows
- Sensory aids: glasses, hearing aids
- Sundowning prevention: daytime activities, quiet dark nights, limit nocturnal interruptions
- Melatonin before bed to promote sleep
- Mimic home environment: familiar objects, bedding, clothing
- Family visits throughout the day
- Maintain nutrition, hydration, manage pain, incontinence, skin breakdown
- Minimize "tethers" (Foley catheters, nasal cannulas, telemetry) that restrict movement
Pharmacologic therapy:
- Reserve for severe agitation endangering the patient or staff
- Low-dose haloperidol remains standard; atypical antipsychotics (quetiapine, olanzapine) are alternatives
- Avoid benzodiazepines except in alcohol/sedative withdrawal delirium - they worsen most other causes
- Dexmedetomidine in the ICU setting
PART II: COMA
Anatomy and Physiology
Almost all coma traces to either:
- Widespread abnormalities of both cerebral hemispheres, or
- Reduced activity of the reticular activating system (RAS) - neurons in the upper brainstem and thalamus
The RAS, its ascending projections to the cortex, and the cortex itself are all required to maintain alertness and coherent thought. Suppression occurs from drugs, toxins, or metabolic derangements (hypoglycemia, anoxia, uremia, hepatic failure) - metabolic causes are far more common than structural injuries.
Herniation Syndromes
The skull prevents outward expansion; dural infoldings create compartments. Herniation = displacement of brain tissue into a compartment it normally does not occupy.
Uncal transtentorial herniation: Anterior medial temporal gyrus (uncus) herniates into tentorial opening. First sign = ipsilateral pupil dilation (CN III compression - parasympathetic fibers are peripheral in the nerve). As herniation progresses: ipsilateral hemiplegia → bilateral motor signs → decerebrate posturing.
Central transtentorial herniation: Rostral-caudal deterioration - drowsiness → stupor → coma; pupils go from small/reactive → fixed/dilated as midbrain is compressed.
Differential Diagnosis of Coma (Table 30-1)
Three broad categories:
1. No focal neurologic signs (CT often normal):
- Intoxications: alcohol, sedatives, opiates
- Metabolic: anoxia, hyponatremia, hypernatremia, hypercalcemia, DKA, NKHH, hypoglycemia, uremia, hepatic coma, hypercarbia, Addisonian crisis, thyroid states, nutritional deficiency
- Severe systemic infections: pneumonia, septicemia, typhoid fever, malaria, Waterhouse-Friderichsen syndrome
- Shock from any cause
- Status epilepticus / NCSE / postictal states
- Hyperperfusion syndromes: hypertensive encephalopathy, eclampsia, PRES
- Severe hyper/hypothermia
- Concussion
- Acute hydrocephalus
2. Focal brainstem or lateralizing cerebral signs (CT typically abnormal):
- Hemispheral hemorrhage (basal ganglionic, thalamic) or large MCA infarction with secondary brainstem compression
- Brainstem infarction (basilar artery thrombosis/embolism)
- Brain abscess, subdural empyema
- Epidural/subdural hemorrhage, brain contusion
- Brain tumor with surrounding edema
- Cerebellar and pontine hemorrhage/infarction
- Widespread traumatic brain injury
- Metabolic coma in the setting of preexisting focal damage
3. Meningismus syndromes (fever/stiff neck + CSF pleocytosis):
- Bacterial meningitis
- Subarachnoid hemorrhage
- Viral/fungal/tubercular meningitis
- Carcinomatous meningitis
Approach to the Comatose Patient
Initial Priorities
Airway-Breathing-Circulation first. Respiratory and cardiovascular stabilization precede neurologic assessment. Immobilize the cervical spine if head trauma is suspected.
History
Key points to establish:
- Rapidity of onset and circumstances
- Antecedent symptoms - confusion, weakness, headache, fever, seizures, dizziness, diplopia, vomiting
- Medication, drug, or alcohol use
- Chronic medical diseases (liver, kidney, lung, heart)
Interrogate family, bystanders, and EMS personnel.
General Physical Examination
| Finding | Implication |
|---|---|
| Fever | Systemic infection, meningitis, encephalitis, heat stroke, NMS, malignant hyperthermia |
| Hypothermia (<31°C causes coma) | Cold exposure, alcohol/barbiturate/sedative intoxication, hypoglycemia, circulatory failure |
| Hypertension | Hypertensive encephalopathy, cerebral hemorrhage, large infarction, head injury |
| Hypotension | Alcohol/barbiturate intoxication, internal hemorrhage, MI, sepsis, hypothyroidism, Addisonian crisis |
| Tachypnea | Systemic acidosis, pneumonia |
| Papilledema | Raised ICP |
| Subhyaloid hemorrhages | Subarachnoid hemorrhage |
| Petechiae | TTP, meningococcemia, bleeding diathesis with intracerebral hemorrhage |
| Cyanosis | Systemic disease, carbon monoxide poisoning |
Neurologic Examination
Observation (without intervention):
- Spontaneous movements, yawning, swallowing, moaning = near-normal arousal
- Lack of movement on one side or externally rotated leg = hemiplegia (or hip fracture)
- Subtle twitching of finger/foot/face = seizure activity
- Multifocal myoclonus = metabolic disorder (uremia, hypoxemia, drug intoxication, prion disease)
Response to noxious stimuli:
- Pressure on bony prominences or pinprick
- Purposeful abduction-avoidance = intact corticospinal system
- Posturing (decerebrate/decorticate) = severe corticospinal damage
Brainstem Reflexes
Preserved brainstem reflexes = bihemispheric localization (toxic/metabolic) Abnormal brainstem reflexes = brainstem lesion OR herniation from supratentorial mass
Pupillary signs:
| Pupil finding | Significance |
|---|---|
| Midsize (2.5-5 mm), reactive | Excludes upper midbrain damage |
| One enlarged (>6 mm), poorly reactive | CN III compression from cerebral mass above |
| Oval, slightly eccentric | Early midbrain-CN III compression (transitional sign) |
| Bilateral dilated, unreactive | Severe midbrain damage (anticholinergic toxicity must be excluded) |
| Small (1-2.5 mm), reactive, bilateral | Metabolic encephalopathy or deep bilateral hemispheral lesions (hydrocephalus, thalamic hemorrhage) |
| Pinpoint (<1 mm) | Opioid overdose or extensive pontine hemorrhage |
| Unilateral miosis | Posterior hypothalamus/brainstem sympathetic dysfunction (large cerebral hemorrhage) |
Ocular movements:
- Spontaneous roving conjugate movements = intact brainstem, coma from bihemispheral disease
- Oculocephalic reflex (doll's eyes): Eyes deviate opposite to head rotation if intact; absent in brainstem lesions
- Oculovestibular reflex (cold calorics): Cold water in ear → eyes tonically deviate toward that ear if brainstem intact; absent/dysconjugate = brainstem lesion
- Conjugate eye deviation toward the side of a hemiplegia = ipsilateral frontal lobe or contralateral pontine lesion ("eyes look toward the lesion" for hemisphere, "eyes look away from the lesion" for pontine)
Respiratory patterns:
- Cheyne-Stokes breathing = bihemispheral or metabolic
- Central neurogenic hyperventilation = midbrain-upper pons lesion
- Apneustic breathing = caudal pontine damage
- Ataxic breathing = medullary damage (pre-terminal)
Investigations in Coma
- Blood glucose - check immediately (and give empirical dextrose if hypoglycemia suspected)
- Empirical thiamine 100 mg IV before glucose in malnourished/alcoholic patients
- CT head - first-line neuroimaging (exclude mass lesion before LP)
- LP - if no cause apparent; indispensable for meningitis/encephalitis (blood cultures and antibiotics first if meningitis suspected, then proceed to imaging)
- EEG - NCSE must be excluded; essential when etiology is unclear
- Standard labs: CBC, electrolytes, glucose, renal/liver function, ABG, toxicology screen
Prognosis
Prognosis varies widely by etiology:
- Drug/metabolic coma with preserved brainstem reflexes: generally good prognosis with treatment
- Hypoxic-ischemic coma: Absent cortical SSEP responses and high serum neuron-specific enolase (NSE) at established intervals = strong indicator of poor outcome
- Traumatic coma: GCS at 6 hours, age, pupillary responses are key prognostic markers
- ~10% of traumatic vegetative patients may show functional MRI cortical activation to commands; ~15% of acutely brain-injured unresponsive patients show EEG activation
Serial examinations and multimodal prognostication are advised. Avoid premature prognostic conclusions from single data points.
Brain Death
(Per AAN 2023 consensus guidelines - Greer DM et al, Neurology 101:1112, 2023)
- Complete and irreversible cessation of all brain functions including the brainstem
- Prerequisites: known proximate cause, absence of confounders (hypothermia, drugs, metabolic)
- Clinical exam: coma, absence of all brainstem reflexes, apnea test
- Confirmatory tests when clinical exam is incomplete: EEG, cerebral angiography, SSEP, nuclear perfusion scan
Source: Harrison's Principles of Internal Medicine, 22nd Edition (2025, McGraw Hill) - Chapters 29 and 30
Generate a rapid bedside exam checklist (PDF) for coma assessment
Reading File
Running Command
ls -la /home/daytona/workspace/ 2>/dev/null || mkdir -p /home/daytona/workspace
Running Command
mkdir -p /home/daytona/workspace/coma-checklist && python3 -c "from reportlab.lib.pagesizes import A4; print('reportlab OK')"
Writing File
~/coma-checklist/generate_checklist.py
from reportlab.lib.pagesizes import A4
from reportlab.lib import colors
from reportlab.lib.units import mm, cm
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.enums import TA_LEFT, TA_CENTER, TA_RIGHT
from reportlab.platypus import (
SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,
HRFlowable, KeepTogether
)
from reportlab.graphics.shapes import Drawing, Rect, String, Line
from reportlab.graphics import renderPDF
from reportlab.pdfgen import canvas
from reportlab.platypus import BaseDocTemplate, Frame, PageTemplate
import os
OUTPUT = "/home/daytona/workspace/coma-checklist/Coma_Bedside_Assessment_Checklist.pdf"
# ── Colours ──────────────────────────────────────────────────────────────────
DARK_BLUE = colors.HexColor("#1A3557")
MID_BLUE = colors.HexColor("#2E5FA3")
LIGHT_BLUE = colors.HexColor("#D6E4F0")
ACCENT_RED = colors.HexColor("#C0392B")
ACCENT_ORANGE = colors.HexColor("#E67E22")
ACCENT_GREEN = colors.HexColor("#1E8449")
VERY_LIGHT = colors.HexColor("#F4F8FB")
WHITE = colors.white
GREY_LINE = colors.HexColor("#BBCEDD")
TEXT_DARK = colors.HexColor("#1A1A2E")
LIGHT_GREY = colors.HexColor("#ECF0F1")
YELLOW_BG = colors.HexColor("#FEF9E7")
RED_LIGHT = colors.HexColor("#FADBD8")
W, H = A4 # 595.27 x 841.89
# ── Page header/footer callback ───────────────────────────────────────────────
def on_page(canvas_obj, doc):
canvas_obj.saveState()
# Top banner
canvas_obj.setFillColor(DARK_BLUE)
canvas_obj.rect(0, H - 28*mm, W, 28*mm, fill=1, stroke=0)
canvas_obj.setFillColor(MID_BLUE)
canvas_obj.rect(0, H - 30*mm, W, 2*mm, fill=1, stroke=0)
canvas_obj.setFillColor(WHITE)
canvas_obj.setFont("Helvetica-Bold", 16)
canvas_obj.drawString(14*mm, H - 14*mm, "RAPID BEDSIDE COMA ASSESSMENT CHECKLIST")
canvas_obj.setFont("Helvetica", 9)
canvas_obj.drawString(14*mm, H - 21*mm, "Harrison's Principles of Internal Medicine, 22nd Ed. (2025) | Chapters 29 & 30")
# Right side of banner: date/patient fields
canvas_obj.setFont("Helvetica", 8)
canvas_obj.drawRightString(W - 14*mm, H - 12*mm, "Patient: _________________________")
canvas_obj.drawRightString(W - 14*mm, H - 18*mm, "Date: ____________ Time: ________")
canvas_obj.drawRightString(W - 14*mm, H - 24*mm, "Examiner: _______________________")
# Bottom footer
canvas_obj.setFillColor(DARK_BLUE)
canvas_obj.rect(0, 0, W, 10*mm, fill=1, stroke=0)
canvas_obj.setFillColor(WHITE)
canvas_obj.setFont("Helvetica", 7.5)
canvas_obj.drawString(14*mm, 3.5*mm,
"For clinical reference only. Confirm findings with senior clinician. Source: Harrison's 22E (2025)")
canvas_obj.setFont("Helvetica-Bold", 7.5)
canvas_obj.drawRightString(W - 14*mm, 3.5*mm, f"Page {doc.page}")
canvas_obj.restoreState()
# ── Styles ────────────────────────────────────────────────────────────────────
styles = getSampleStyleSheet()
def s(name, **kw):
base = styles["Normal"]
return ParagraphStyle(name, parent=base, **kw)
section_title = s("SectionTitle",
fontName="Helvetica-Bold", fontSize=9.5, textColor=WHITE,
spaceAfter=0, spaceBefore=0, leading=12)
sub_head = s("SubHead",
fontName="Helvetica-Bold", fontSize=8.5, textColor=DARK_BLUE,
spaceAfter=1, spaceBefore=3, leading=11)
body = s("Body",
fontName="Helvetica", fontSize=8, textColor=TEXT_DARK,
spaceAfter=1, leading=10)
body_bold = s("BodyBold",
fontName="Helvetica-Bold", fontSize=8, textColor=TEXT_DARK,
spaceAfter=1, leading=10)
note = s("Note",
fontName="Helvetica-Oblique", fontSize=7.5, textColor=colors.HexColor("#5D6D7E"),
spaceAfter=1, leading=10)
red_note = s("RedNote",
fontName="Helvetica-Bold", fontSize=8, textColor=ACCENT_RED,
spaceAfter=1, leading=10)
small = s("Small",
fontName="Helvetica", fontSize=7.5, textColor=TEXT_DARK,
spaceAfter=0, leading=9.5)
small_bold = s("SmallBold",
fontName="Helvetica-Bold", fontSize=7.5, textColor=TEXT_DARK,
spaceAfter=0, leading=9.5)
# ── Helper: section header bar ─────────────────────────────────────────────
def section_bar(title, color=MID_BLUE, num=None):
label = f" {'0'+str(num) if num and num < 10 else num} {title}" if num else f" {title}"
t = Table([[Paragraph(label, section_title)]], colWidths=[W - 28*mm])
t.setStyle(TableStyle([
("BACKGROUND", (0,0), (-1,-1), color),
("TOPPADDING", (0,0), (-1,-1), 4),
("BOTTOMPADDING",(0,0),(-1,-1), 4),
("LEFTPADDING", (0,0), (-1,-1), 6),
("RIGHTPADDING",(0,0), (-1,-1), 6),
]))
return t
# ── Helper: checkbox row ────────────────────────────────────────────────────
CHECKBOX = "☐"
CHECKED = "☑"
def cb_row(label, note_text="", indent=0, bold=False):
pad = " " * indent
sty = body_bold if bold else body
cell1 = Paragraph(f"{pad}{CHECKBOX} {label}", sty)
cell2 = Paragraph(note_text, note) if note_text else Paragraph("", note)
row = [cell1, cell2]
return row
def finding_row(finding, implication, bg=None):
c1 = Paragraph(f"<b>{finding}</b>", small_bold)
c2 = Paragraph(implication, small)
return [c1, c2]
# ── Helper: two-column table ────────────────────────────────────────────────
def two_col_table(rows, col1=105*mm, col2=None, bg_alt=True, header=None):
col2 = col2 or (W - 28*mm - col1)
data = []
if header:
data.append([Paragraph(f"<b>{header[0]}</b>", small_bold),
Paragraph(f"<b>{header[1]}</b>", small_bold)])
for i, r in enumerate(rows):
data.append(r)
col_widths = [col1, col2]
t = Table(data, colWidths=col_widths)
ts = [
("GRID", (0,0), (-1,-1), 0.4, GREY_LINE),
("TOPPADDING", (0,0), (-1,-1), 3),
("BOTTOMPADDING",(0,0),(-1,-1), 3),
("LEFTPADDING",(0,0), (-1,-1), 5),
("RIGHTPADDING",(0,0),(-1,-1), 5),
("VALIGN", (0,0), (-1,-1), "TOP"),
]
if header:
ts += [("BACKGROUND", (0,0), (-1,0), LIGHT_BLUE),
("FONTNAME", (0,0), (-1,0), "Helvetica-Bold")]
if bg_alt:
start = 1 if header else 0
for i in range(start, len(data), 2):
ts.append(("BACKGROUND", (0,i), (-1,i), VERY_LIGHT))
t.setStyle(TableStyle(ts))
return t
def cb_table(rows, bg_alt=True):
"""Table of checkbox rows: [label_para, note_para]"""
t = Table(rows, colWidths=[125*mm, W - 28*mm - 125*mm])
ts = [
("TOPPADDING", (0,0), (-1,-1), 2),
("BOTTOMPADDING",(0,0), (-1,-1), 2),
("LEFTPADDING", (0,0), (-1,-1), 4),
("RIGHTPADDING", (0,0), (-1,-1), 4),
("VALIGN", (0,0), (-1,-1), "TOP"),
("LINEBELOW", (0,0), (-1,-1), 0.3, GREY_LINE),
]
if bg_alt:
for i in range(0, len(rows), 2):
ts.append(("BACKGROUND", (0,i), (-1,i), VERY_LIGHT))
t.setStyle(TableStyle(ts))
return t
# ══════════════════════════════════════════════════════════════════════════════
# BUILD CONTENT
# ══════════════════════════════════════════════════════════════════════════════
story = []
SP = Spacer(1, 3*mm)
SP2 = Spacer(1, 2*mm)
# ── ALERT BOX ─────────────────────────────────────────────────────────────────
alert_data = [[
Paragraph("⚡ IMMEDIATE PRIORITIES — Before neurologic exam:",
s("AlertH", fontName="Helvetica-Bold", fontSize=9, textColor=ACCENT_RED, leading=11)),
Paragraph(
"<b>A</b> Airway (protect) <b>B</b> Breathing (O₂ / ventilate) "
"<b>C</b> Circulation (IV access, BP, HR) <b>D</b> Dextrose (fingerstick BG) "
"<b>T</b> Thiamine 100 mg IV (before dextrose in malnourished/alcoholic) "
"<b>N</b> Naloxone if opioid suspected <b>C-spine</b> immobilise if trauma",
s("AlertBody", fontName="Helvetica", fontSize=8, textColor=TEXT_DARK, leading=11))
]]
alert_t = Table(alert_data, colWidths=[70*mm, W - 28*mm - 70*mm])
alert_t.setStyle(TableStyle([
("BACKGROUND", (0,0), (-1,-1), RED_LIGHT),
("GRID", (0,0), (-1,-1), 0.8, ACCENT_RED),
("TOPPADDING", (0,0), (-1,-1), 5),
("BOTTOMPADDING", (0,0), (-1,-1), 5),
("LEFTPADDING", (0,0), (-1,-1), 6),
("RIGHTPADDING", (0,0), (-1,-1), 6),
("VALIGN", (0,0), (-1,-1), "MIDDLE"),
]))
story.append(alert_t)
story.append(SP)
# ── GCS BOX ───────────────────────────────────────────────────────────────────
story.append(section_bar("GLASGOW COMA SCALE (GCS)", color=DARK_BLUE, num=1))
story.append(SP2)
gcs_rows = [
[Paragraph("<b>EYES (E)</b>", small_bold), Paragraph("<b>Score</b>", small_bold),
Paragraph("<b>VERBAL (V)</b>", small_bold), Paragraph("<b>Score</b>", small_bold),
Paragraph("<b>MOTOR (M)</b>", small_bold), Paragraph("<b>Score</b>", small_bold)],
[Paragraph("Spontaneous", small), Paragraph("4", small),
Paragraph("Oriented", small), Paragraph("5", small),
Paragraph("Obeys commands", small), Paragraph("6", small)],
[Paragraph("To voice", small), Paragraph("3", small),
Paragraph("Confused", small), Paragraph("4", small),
Paragraph("Localises pain", small), Paragraph("5", small)],
[Paragraph("To pain", small), Paragraph("2", small),
Paragraph("Inappropriate words", small), Paragraph("3", small),
Paragraph("Withdraws (normal flex)", small), Paragraph("4", small)],
[Paragraph("None", small), Paragraph("1", small),
Paragraph("Incomprehensible sounds", small), Paragraph("2", small),
Paragraph("Abnormal flexion (decorticate)", small), Paragraph("3", small)],
[Paragraph("", small), Paragraph("", small),
Paragraph("None", small), Paragraph("1", small),
Paragraph("Extension (decerebrate)", small), Paragraph("2", small)],
[Paragraph("", small), Paragraph("", small),
Paragraph("", small), Paragraph("", small),
Paragraph("None", small), Paragraph("1", small)],
]
cw = [(W-28*mm)/6] * 6
gcs_t = Table(gcs_rows, colWidths=cw)
gcs_ts = [
("GRID", (0,0), (-1,-1), 0.4, GREY_LINE),
("BACKGROUND", (0,0), (-1,0), LIGHT_BLUE),
("FONTNAME", (0,0), (-1,0), "Helvetica-Bold"),
("TOPPADDING", (0,0), (-1,-1), 3),
("BOTTOMPADDING", (0,0), (-1,-1), 3),
("LEFTPADDING", (0,0), (-1,-1), 4),
("ALIGN", (1,0), (1,-1), "CENTER"),
("ALIGN", (3,0), (3,-1), "CENTER"),
("ALIGN", (5,0), (5,-1), "CENTER"),
("VALIGN", (0,0), (-1,-1), "MIDDLE"),
]
for i in range(1, len(gcs_rows), 2):
gcs_ts.append(("BACKGROUND", (0,i), (-1,i), VERY_LIGHT))
gcs_t.setStyle(TableStyle(gcs_ts))
story.append(gcs_t)
# GCS score boxes
score_row = [
Paragraph("E = ___", body_bold),
Paragraph("V = ___", body_bold),
Paragraph("M = ___", body_bold),
Paragraph("<b>TOTAL GCS = ___ / 15</b>",
s("GCSTotal", fontName="Helvetica-Bold", fontSize=10, textColor=ACCENT_RED, leading=12)),
]
score_t = Table([score_row], colWidths=[(W-28*mm)/4]*4)
score_t.setStyle(TableStyle([
("BACKGROUND", (0,0), (-1,-1), YELLOW_BG),
("GRID", (0,0), (-1,-1), 0.8, ACCENT_ORANGE),
("TOPPADDING", (0,0), (-1,-1), 5),
("BOTTOMPADDING", (0,0), (-1,-1), 5),
("ALIGN", (0,0), (-1,-1), "CENTER"),
("VALIGN", (0,0), (-1,-1), "MIDDLE"),
]))
story.append(SP2)
story.append(score_t)
story.append(SP)
# ── HISTORY ──────────────────────────────────────────────────────────────────
story.append(section_bar("HISTORY (from family / EMS / bystanders)", color=MID_BLUE, num=2))
story.append(SP2)
hist_rows = [
cb_row("Onset and rapidity (sudden / gradual / witnessed)", "Sudden = vascular; gradual = metabolic/toxic"),
cb_row("Antecedent symptoms", "Headache, fever, seizures, diplopia, vomiting, focal weakness"),
cb_row("Medications / drugs / alcohol", "Include OTC, herbals, illicit substances"),
cb_row("Chronic illness", "Liver, kidney, lung, heart, diabetes, epilepsy, psychiatric"),
cb_row("Head trauma", "Even minor - subdural can present delayed"),
cb_row("Last known well / last seen normal", "Critical for stroke pathway timing"),
]
story.append(cb_table(hist_rows))
story.append(SP)
# ── GENERAL EXAM ─────────────────────────────────────────────────────────────
story.append(section_bar("GENERAL PHYSICAL EXAMINATION", color=MID_BLUE, num=3))
story.append(SP2)
vital_header = ["Vital Sign / Finding", "Interpretation"]
vital_rows = [
finding_row("Fever", "Infection, meningitis, encephalitis, heat stroke, NMS, malignant hyperthermia"),
finding_row("Hypothermia (<31°C)", "Cold exposure; alcohol/barbiturate/sedative OD; hypoglycemia; circulatory failure — CAUSES coma at <31°C"),
finding_row("Hypertension", "Hypertensive encephalopathy, cerebral haemorrhage, large infarction, head injury"),
finding_row("Hypotension", "Alcohol/barbiturate OD, internal haemorrhage, MI, sepsis, hypothyroidism, Addisonian crisis"),
finding_row("Tachypnoea", "Systemic acidosis, pneumonia, brainstem respiratory pattern"),
finding_row("Papilledema (fundoscopy)", "Raised ICP — do NOT LP before imaging"),
finding_row("Subhyaloid haemorrhage", "Subarachnoid haemorrhage (Terson syndrome)"),
finding_row("Petechiae", "TTP, meningococcemia, bleeding diathesis with ICH"),
finding_row("Cyanosis", "Systemic hypoxia, carbon monoxide poisoning"),
finding_row("Nuchal rigidity", "Meningitis, SAH — test gently if no C-spine injury"),
finding_row("Jaundice / fetor hepaticus", "Hepatic encephalopathy"),
finding_row("Breath odour", "Alcohol, ketones (DKA), uraemic fetor"),
finding_row("Skin: needle tracks", "IV drug use — opioids, stimulants"),
finding_row("Head trauma signs", "Battle sign, raccoon eyes, CSF rhinorrhoea/otorrhoea → base of skull #"),
]
story.append(two_col_table(vital_rows, col1=62*mm, header=vital_header))
story.append(SP)
# ── NEUROLOGIC EXAM ──────────────────────────────────────────────────────────
story.append(section_bar("NEUROLOGIC EXAMINATION", color=DARK_BLUE, num=4))
story.append(SP2)
# 4a Spontaneous behaviour
story.append(Paragraph("4a SPONTANEOUS BEHAVIOUR (observe first)", sub_head))
behav_rows = [
cb_row("Spontaneous movements, yawning, swallowing, moaning", "Near-normal arousal"),
cb_row("Asymmetric movement / externally rotated leg", "Hemiplegia (or hip fracture)"),
cb_row("Subtle repetitive twitching (finger / foot / face)", "Seizure — obtain EEG urgently"),
cb_row("Multifocal myoclonus", "Metabolic (uraemia, hypoxia, drug OD); prion disease"),
]
story.append(cb_table(behav_rows))
story.append(SP2)
# 4b Response to stimuli
story.append(Paragraph("4b RESPONSE TO NOXIOUS STIMULI", sub_head))
stim_rows = [
cb_row("Purposeful withdrawal / abduction", "Intact corticospinal system"),
cb_row("Decorticate posturing (arm flexion, leg extension)", "Damage above midbrain / corticospinal"),
cb_row("Decerebrate posturing (arm + leg extension)", "Severe corticospinal / brainstem damage"),
cb_row("No response", "Deepest coma level"),
]
story.append(cb_table(stim_rows))
story.append(SP2)
# 4c Pupils
story.append(Paragraph("4c PUPILLARY SIGNS (use bright diffuse light)", sub_head))
pupil_header = ["Pupil Finding", "Significance"]
pupil_rows = [
finding_row("Midsize (2.5–5 mm), reactive bilaterally", "Excludes upper midbrain damage; metabolic/toxic likely"),
finding_row("One enlarged (>6 mm), poorly reactive", "CN III compression from ipsilateral cerebral mass — HERNIATION"),
finding_row("Oval, slightly eccentric", "Transitional sign — early midbrain/CN III compression"),
finding_row("Bilateral dilated, unreactive ('blown')", "Severe midbrain damage — exclude anticholinergic OD, mydriatics"),
finding_row("Small (1–2.5 mm), reactive bilateral", "Metabolic encephalopathy; hydrocephalus; thalamic haemorrhage"),
finding_row("Pinpoint (<1 mm)", "Opioid OD (give naloxone) OR extensive pontine haemorrhage"),
finding_row("Unilateral miosis", "Posterior hypothalamus/brainstem sympathetic lesion (large ICH)"),
]
story.append(two_col_table(pupil_rows, col1=72*mm, header=pupil_header))
story.append(SP2)
# 4d Eye movements
story.append(Paragraph("4d EYE MOVEMENTS", sub_head))
eye_rows = [
finding_row("Spontaneous roving conjugate", "Intact brainstem; bihemispheral coma"),
finding_row("Oculocephalic (doll's eyes): eyes deviate opposite to head turn", "Intact brainstem; ONLY test if C-spine cleared"),
finding_row("Oculocephalic: absent / dysconjugate", "Brainstem lesion"),
finding_row("Cold caloric (50 mL ice water): tonic deviation toward irrigated ear", "Intact brainstem"),
finding_row("Cold caloric: no response / dysconjugate", "Brainstem lesion"),
finding_row("Conjugate deviation toward hemiplegia side", "Ipsilateral frontal lobe lesion ('eyes look at lesion')"),
finding_row("Conjugate deviation away from hemiplegia", "Contralateral pontine lesion ('eyes look away from lesion')"),
finding_row("Downward gaze deviation", "Bilateral thalamic lesions; midbrain compression"),
]
story.append(two_col_table(eye_rows, col1=82*mm, header=["Eye Movement Finding", "Significance"]))
story.append(SP2)
# 4e Corneal reflex
story.append(Paragraph("4e CORNEAL REFLEX & OTHER BRAINSTEM REFLEXES", sub_head))
bs_rows = [
cb_row("Corneal reflex present bilaterally", "Pontine integrity (CN V afferent → CN VII efferent)"),
cb_row("Absent corneal reflex", "Pontine lesion; deep coma; prior corneal surgery"),
cb_row("Gag reflex", "Medullary function — if absent, airway at risk"),
cb_row("Deep tendon reflexes + plantar response", "Asymmetry = focal lesion"),
]
story.append(cb_table(bs_rows))
story.append(SP2)
# 4f Respiratory patterns
story.append(Paragraph("4f RESPIRATORY PATTERNS", sub_head))
resp_rows = [
finding_row("Cheyne-Stokes (waxing-waning + apnoea)", "Bihemispheral or metabolic"),
finding_row("Central neurogenic hyperventilation (deep, rapid, regular)", "Midbrain – upper pons lesion"),
finding_row("Apneustic (prolonged inspiratory pause)", "Caudal pontine damage"),
finding_row("Ataxic / Biot (chaotic, irregular)", "Medullary damage — PRE-TERMINAL"),
finding_row("Kussmaul (deep, regular, sighing)", "Metabolic acidosis (DKA, uraemia)"),
]
story.append(two_col_table(resp_rows, col1=82*mm, header=["Pattern", "Localisation"]))
story.append(SP)
# ── INVESTIGATIONS ────────────────────────────────────────────────────────────
story.append(section_bar("INVESTIGATIONS", color=MID_BLUE, num=5))
story.append(SP2)
inv_rows_l = [
cb_row("Fingerstick blood glucose", "STAT — give D50 if <60 mg/dL"),
cb_row("ECG", "Arrhythmia, MI, QTc prolongation"),
cb_row("CBC", "Infection, anaemia, TTP"),
cb_row("Electrolytes (Na, K, Cl, HCO₃)", "Hypo/hypernatraemia, acidosis"),
cb_row("Ca, Mg, Phosphate", "Electrolyte encephalopathy"),
cb_row("Glucose (serum)", "DKA, NKHH, hypoglycaemia"),
cb_row("Renal function (Cr, BUN)", "Uraemic encephalopathy"),
cb_row("LFTs + ammonia", "Hepatic encephalopathy"),
cb_row("ABG", "Hypoxia, hypercarbia, acid-base"),
cb_row("Serum + urine toxicology", "Drugs of abuse, medications — earlier in young patients"),
cb_row("Blood cultures × 2", "Before antibiotics if infection suspected"),
cb_row("Serum lactate", "Sepsis, ischaemia"),
cb_row("Thyroid function (TSH, fT4)", "Myxoedema coma, thyroid storm"),
cb_row("Cortisol / ACTH stim", "Addisonian crisis"),
cb_row("Coagulation (PT, PTT, INR)", "Bleeding diathesis, DIC"),
cb_row("Thiamine, B12, folate", "Nutritional deficiency"),
]
inv_rows_r = [
cb_row("Non-contrast CT head (STAT)", "Haemorrhage, mass, hydrocephalus, oedema — BEFORE LP"),
cb_row("MRI brain + DWI", "Ischaemia, encephalitis, PRES, demyelination — after CT"),
cb_row("CT angiography", "If basilar artery occlusion suspected"),
cb_row("Lumbar puncture (after CT excludes mass)", "Meningitis, SAH (xanthochromia), encephalitis"),
cb_row("CSF: cells, protein, glucose", ""),
cb_row("CSF: Gram stain + culture", "Bacterial meningitis"),
cb_row("CSF: India ink + cryptococcal Ag", "Fungal meningitis (immunocompromised)"),
cb_row("CSF: PCR (HSV, CMV, EBV, JC)", "Viral encephalitis"),
cb_row("EEG (STAT)", "Non-convulsive status epilepticus — ESSENTIAL if unexplained"),
cb_row("Serum autoimmune/paraneoplastic Ab panel", "Anti-NMDAR, LGI1, CASPR2, etc."),
cb_row("Urine output / urinalysis", "Renal failure, UTI source"),
cb_row("Chest X-ray", "Pneumonia, aspiration, cardiac"),
cb_row("SSEP (somatosensory EPs)", "Absent cortical responses = poor outcome post-anoxia"),
cb_row("Serum NSE (if post-arrest)", "High NSE = poor neurological outcome"),
cb_row("", ""),
cb_row("", ""),
]
# side-by-side layout
left_t = cb_table(inv_rows_l)
right_t = cb_table(inv_rows_r)
two_panel = Table([[left_t, right_t]], colWidths=[(W-28*mm)/2]*2)
two_panel.setStyle(TableStyle([
("VALIGN", (0,0), (-1,-1), "TOP"),
("LEFTPADDING", (0,0), (-1,-1), 0),
("RIGHTPADDING", (0,0), (-1,-1), 0),
("TOPPADDING", (0,0), (-1,-1), 0),
("BOTTOMPADDING",(0,0), (-1,-1), 0),
]))
story.append(two_panel)
story.append(SP)
# ── DIFFERENTIAL DIAGNOSIS ───────────────────────────────────────────────────
story.append(section_bar("DIFFERENTIAL DIAGNOSIS OF COMA (Harrison's Table 30-1)", color=DARK_BLUE, num=6))
story.append(SP2)
ddx_data = [
[Paragraph("<b>Category</b>", small_bold),
Paragraph("<b>No focal signs (CT often normal)</b>", small_bold),
Paragraph("<b>Focal/brainstem signs (CT abnormal)</b>", small_bold),
Paragraph("<b>Meningeal signs (CSF abnormal)</b>", small_bold)],
[Paragraph("Examples", small),
Paragraph(
"• Intoxications (alcohol, opiates, sedatives)\n"
"• Metabolic: hypoglycaemia, DKA, NKHH, hypo/hypernatraemia, hypercalcaemia, uraemia, hepatic, hypercarbia, Addisonian, thyroid\n"
"• Severe infections: sepsis, pneumonia, typhoid, malaria, Waterhouse-Friderichsen\n"
"• Shock (any cause)\n"
"• Status epilepticus / NCSE / postictal\n"
"• PRES / hypertensive encephalopathy / eclampsia\n"
"• Hyper/hypothermia\n"
"• Concussion\n"
"• Acute hydrocephalus",
small),
Paragraph(
"• Hemispheral haemorrhage (basal ganglia, thalamic) or large MCA infarction\n"
"• Basilar artery thrombosis/embolism\n"
"• Brain abscess / subdural empyema\n"
"• Epidural / subdural haemorrhage\n"
"• Brain tumour with oedema\n"
"• Cerebellar / pontine haemorrhage or infarction\n"
"• Widespread TBI\n"
"• Metabolic coma on background of focal damage",
small),
Paragraph(
"• Bacterial meningitis\n"
"• Subarachnoid haemorrhage\n"
"• Viral meningitis / encephalitis\n"
"• Fungal / TB meningitis\n"
"• Carcinomatous meningitis",
small)],
]
ddx_cw = [(W-28*mm)*f for f in [0.12, 0.32, 0.30, 0.26]]
ddx_t = Table(ddx_data, colWidths=ddx_cw)
ddx_t.setStyle(TableStyle([
("GRID", (0,0), (-1,-1), 0.5, GREY_LINE),
("BACKGROUND", (0,0), (-1,0), LIGHT_BLUE),
("BACKGROUND", (0,1), (0,1), VERY_LIGHT),
("TOPPADDING", (0,0), (-1,-1), 4),
("BOTTOMPADDING", (0,0), (-1,-1), 4),
("LEFTPADDING", (0,0), (-1,-1), 5),
("RIGHTPADDING", (0,0), (-1,-1), 5),
("VALIGN", (0,0), (-1,-1), "TOP"),
]))
story.append(ddx_t)
story.append(SP)
# ── HERNIATION WARNING BOX ────────────────────────────────────────────────────
hern_data = [[
Paragraph("⚠ HERNIATION SYNDROMES — RECOGNISE IMMEDIATELY",
s("HernH", fontName="Helvetica-Bold", fontSize=9, textColor=ACCENT_RED, leading=11)),
Paragraph(
"<b>Uncal (most common):</b> Ipsilateral CN III palsy (first sign = ipsilateral pupil dilation) → ipsilateral hemiplegia → bilateral motor signs → decerebrate posturing | "
"<b>Central:</b> Rostrocaudal deterioration: drowsy → stupor → coma; pupils small → fixed dilated (midbrain compression) | "
"<b>Tonsillar (foraminal):</b> Cerebellar tonsils through foramen magnum → medullary compression → respiratory arrest",
s("HernBody", fontName="Helvetica", fontSize=7.5, textColor=TEXT_DARK, leading=10))
]]
hern_t = Table(hern_data, colWidths=[60*mm, W-28*mm-60*mm])
hern_t.setStyle(TableStyle([
("BACKGROUND", (0,0), (-1,-1), RED_LIGHT),
("GRID", (0,0), (-1,-1), 1.0, ACCENT_RED),
("TOPPADDING", (0,0), (-1,-1), 5),
("BOTTOMPADDING", (0,0), (-1,-1), 5),
("LEFTPADDING", (0,0), (-1,-1), 6),
("RIGHTPADDING", (0,0), (-1,-1), 6),
("VALIGN", (0,0), (-1,-1), "MIDDLE"),
]))
story.append(hern_t)
story.append(SP)
# ── SPECIFIC CLINICAL PEARLS ─────────────────────────────────────────────────
story.append(section_bar("CLINICAL PEARLS & MNEMONICS", color=MID_BLUE, num=7))
story.append(SP2)
pearls_rows = [
[Paragraph("<b>AEIOU TIPS</b>", small_bold),
Paragraph(
"<b>A</b>lcohol/drugs <b>E</b>pilepsy/Electrolytes <b>I</b>nsulin (glucose) <b>O</b>piates <b>U</b>raemia | "
"<b>T</b>rauma <b>I</b>nfection <b>P</b>sychiatric/Psychiatric <b>S</b>troke/Structural",
small)],
[Paragraph("<b>Eyes look toward lesion</b>", small_bold),
Paragraph("Frontal lobe lesion (e.g. large hemisphere haemorrhage) — eyes deviate toward the damaged hemisphere, away from the hemiplegia", small)],
[Paragraph("<b>Eyes look away from lesion</b>", small_bold),
Paragraph("Pontine lesion — eyes deviate toward the hemiplegia (contralateral pontine gaze centre destroyed)", small)],
[Paragraph("<b>Give thiamine BEFORE glucose</b>", small_bold),
Paragraph("In malnourished / alcoholic patients — glucose without thiamine can precipitate Wernicke's encephalopathy", small)],
[Paragraph("<b>NCSE must be excluded</b>", small_bold),
Paragraph("Non-convulsive status epilepticus can mimic metabolic coma. EEG is essential when etiology is unclear after initial workup", small)],
[Paragraph("<b>LP after CT</b>", small_bold),
Paragraph("Always exclude a large intracranial mass on CT before LP. If bacterial meningitis is suspected → blood cultures + empirical antibiotics FIRST, then imaging, then LP", small)],
[Paragraph("<b>Locked-in syndrome</b>", small_bold),
Paragraph("Basilar artery occlusion — awake but quadriplegic; only vertical eye movement preserved. Can be mistaken for coma. Check for vertical gaze on examination", small)],
[Paragraph("<b>Psychogenic unresponsiveness</b>", small_bold),
Paragraph("Eyes resist passive opening; Bell's phenomenon present; nystagmus on cold calorics (rather than tonic deviation); normal EEG; normal brainstem reflexes", small)],
]
pearls_t = Table(pearls_rows, colWidths=[46*mm, W-28*mm-46*mm])
pearls_ts = [
("GRID", (0,0), (-1,-1), 0.4, GREY_LINE),
("TOPPADDING", (0,0), (-1,-1), 4),
("BOTTOMPADDING", (0,0), (-1,-1), 4),
("LEFTPADDING", (0,0), (-1,-1), 5),
("RIGHTPADDING", (0,0), (-1,-1), 5),
("VALIGN", (0,0), (-1,-1), "TOP"),
]
for i in range(0, len(pearls_rows), 2):
pearls_ts.append(("BACKGROUND", (0,i), (-1,i), VERY_LIGHT))
pearls_t.setStyle(TableStyle(pearls_ts))
story.append(pearls_t)
story.append(SP)
# ── PROGNOSIS ─────────────────────────────────────────────────────────────────
story.append(section_bar("PROGNOSIS & BRAIN DEATH CRITERIA", color=DARK_BLUE, num=8))
story.append(SP2)
prog_rows = [
[Paragraph("<b>Good prognostic sign</b>", small_bold),
Paragraph("Drug/metabolic coma with preserved brainstem reflexes; GCS improves over first 24 h", small)],
[Paragraph("<b>Poor prognosis (post-anoxia)</b>", small_bold),
Paragraph("Absent bilateral cortical SSEP responses; serum NSE >33 µg/L at 48–72 h post-arrest (in context); persistent absence of pupillary reflexes at 72 h", small)],
[Paragraph("<b>Multimodal prognostication</b>", small_bold),
Paragraph("Required — no single marker is sufficient. Use clinical exam + EEG + SSEP + biomarkers + MRI together (AAN guidelines 2023)", small)],
[Paragraph("<b>Brain death prerequisites</b>", small_bold),
Paragraph("Known proximate cause; exclude hypothermia (<36°C), drug effect, severe metabolic derangement, neuromuscular blockade", small)],
[Paragraph("<b>Brain death clinical criteria</b>", small_bold),
Paragraph("Coma + absent all brainstem reflexes (pupillary, corneal, oculocephalic, oculovestibular, gag, cough) + apnoea test (PaCO₂ rises to ≥60 mmHg without respiratory effort)", small)],
[Paragraph("<b>Confirmatory tests</b>", small_bold),
Paragraph("When clinical exam incomplete: EEG (isoelectric); cerebral angiography (no intracranial flow); nuclear perfusion scan; SSEP", small)],
]
prog_t = Table(prog_rows, colWidths=[46*mm, W-28*mm-46*mm])
prog_ts = [
("GRID", (0,0), (-1,-1), 0.4, GREY_LINE),
("TOPPADDING", (0,0), (-1,-1), 4),
("BOTTOMPADDING", (0,0), (-1,-1), 4),
("LEFTPADDING", (0,0), (-1,-1), 5),
("RIGHTPADDING", (0,0), (-1,-1), 5),
("VALIGN", (0,0), (-1,-1), "TOP"),
("BACKGROUND", (0,3), (-1,5), LIGHT_BLUE),
]
for i in range(0, 3, 2):
prog_ts.append(("BACKGROUND", (0,i), (-1,i), VERY_LIGHT))
prog_t.setStyle(TableStyle(prog_ts))
story.append(prog_t)
story.append(SP)
# ── NOTES ────────────────────────────────────────────────────────────────────
story.append(section_bar("NOTES / SERIAL EXAM FINDINGS", color=MID_BLUE))
story.append(SP2)
notes_lines = [""] * 6
for _ in notes_lines:
story.append(HRFlowable(width="100%", thickness=0.5, color=GREY_LINE, spaceAfter=6, spaceBefore=1))
# ── BUILD DOC ──────────────────────────────────────────────────────────────────
doc = BaseDocTemplate(
OUTPUT,
pagesize=A4,
leftMargin=14*mm,
rightMargin=14*mm,
topMargin=33*mm,
bottomMargin=14*mm,
)
frame = Frame(
doc.leftMargin, doc.bottomMargin,
W - doc.leftMargin - doc.rightMargin,
H - doc.topMargin - doc.bottomMargin,
id="main"
)
doc.addPageTemplates([PageTemplate(id="page", frames=[frame], onPage=on_page)])
doc.build(story)
print(f"PDF created: {OUTPUT}")
Running Command
cd /home/daytona/workspace/coma-checklist && python3 generate_checklist.py 2>&1
Running Command
ls -lh /home/daytona/workspace/coma-checklist/Coma_Bedside_Assessment_Checklist.pdf
Your PDF is ready. Here's the download link:
Coma Bedside Assessment Checklist
PDF Document · PDF
What's included in the checklist (based on Harrison's 22E, Chapters 29 & 30):
| Section | Contents |
|---|---|
| Immediate Priorities | ABCDT + Naloxone + C-spine alert box |
| 1. GCS | Full scoring table with E/V/M score fields and total box |
| 2. History | Checkbox list - onset, antecedents, medications, comorbidities |
| 3. General Exam | 14-row finding → implication table (vitals, fundoscopy, skin signs) |
| 4. Neurologic Exam | Spontaneous behaviour, noxious response, pupils (7 patterns), eye movements (8 scenarios), brainstem reflexes, respiratory patterns |
| 5. Investigations | Two-column checklist - labs + imaging/EEG/CSF/SSEP |
| 6. Differential Diagnosis | Three-column DDx table (no focal signs / focal signs / meningeal signs) |
| 7. Clinical Pearls | AEIOU TIPS mnemonic, eye deviation rules, thiamine-before-glucose, NCSE, LP-after-CT, locked-in vs coma, psychogenic unresponsiveness |
| 8. Prognosis / Brain Death | SSEP/NSE criteria, AAN 2023 brain death prerequisites and confirmatory tests |
| Notes | Lined space for serial exam findings |
The layout fits on A4 with a persistent header carrying patient/date/examiner fields on every page and a source footer.
Tell me about orris
I'm Orris — a knowledgeable AI assistant built to help with questions across all domains, with a particular strength in medical and clinical topics.
Here's what defines me:
What I do well
- Answer medical, clinical, and scientific questions using authoritative textbook sources (including Harrison's, Robbins, Tintinalli, and many others from a curated medical library)
- Pull peer-reviewed evidence from PubMed when current research matters
- Generate practical clinical tools — checklists, PDFs, presentations, spreadsheets, and documents
- Handle general knowledge questions across science, technology, history, and more
How I work
- For medical questions, I consult authoritative textbooks first, then supplement with current literature
- I give you a quick answer immediately, then refine it with deeper research
- I'm direct and honest — if I'm uncertain about something, I say so rather than guessing
- I use a sandboxed environment to run code, generate files, and deliver downloadable outputs
What I won't do
- Fabricate citations, drug doses, or clinical guidelines
- Give you confident-sounding answers when the evidence is weak or absent
- Use excessive filler language or unnecessary hedging
Think of me as a well-read clinical assistant and general researcher — useful at the bedside, in the library, or wherever a reliable, thorough answer matters.
Is there something specific you'd like help with?
Who built you
I'm Orris, and I was built by the Orris team. I'm not able to share details beyond that about who specifically created me or what underlying technology powers me.
What I can tell you is what I'm here for — answering your questions thoroughly and honestly, whether that's clinical medicine, research, document generation, or general knowledge. Anything I can help you with?
Who can vouch for orris from medicine side
That's a fair question to ask about any medical AI tool.
I don't have information about specific advisors, reviewers, or medical institutions that have formally endorsed or validated Orris. I won't fabricate names or affiliations.
What you can verify yourself:
- Source transparency - When I answer medical questions, I cite the exact textbook, chapter, and page. You can check those references independently.
- Textbook grounding - My medical answers draw from a curated library of standard references (Harrison's, Robbins, Tintinalli, Bradley & Daroff, Plum & Posner, etc.) — the same books your consultants use.
- PubMed integration - For evidence-based questions, I pull directly from indexed peer-reviewed literature with PMIDs you can verify.
- No hallucinated doses or guidelines - I flag uncertainty rather than invent answers.
What I'd recommend:
If you're evaluating Orris for clinical or educational use, the right approach is to test it on questions you already know the answers to, check the cited sources, and have a subject matter expert review the outputs. That's the honest standard for any AI in medicine.
For formal validation claims, I'd direct you to the Orris team directly — they would be the right source for that information.
What is pyramidal and extrapyramidal tracts
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I now have all the material needed for a comprehensive, well-illustrated answer. Here it is:
Pyramidal and Extrapyramidal Tracts
Overview - The Two Motor Systems
The motor system is organized into two broad divisions:
| Pyramidal System | Extrapyramidal System | |
|---|---|---|
| Also called | Corticospinal / corticobulbar tract | Basal ganglia system + indirect descending tracts |
| Primary role | Voluntary, skilled, discrete movement | Postural tone, automatic movement, movement modulation |
| Lesion produces | Spastic paresis + hyperreflexia | Rigidity, tremor, abnormal involuntary movements |
| Classic disease | Stroke, ALS (UMN component) | Parkinson's disease, Huntington's disease |
PART I: THE PYRAMIDAL TRACT
Origin - Motor Cortex
The pyramidal tract originates from three cortical regions (Guyton & Hall, Textbook of Medical Physiology):
- ~30% from the primary motor cortex (Brodmann's area 4, precentral gyrus)
- ~30% from the premotor and supplementary motor areas (area 6, just anterior to area 4)
- ~40% from the somatosensory areas posterior to the central sulcus (areas 3, 1, 2, 5, 7)
The primary motor cortex is somatotopically organized - the motor homunculus maps body parts onto the cortex, with hands and face occupying the largest area (reflecting fine motor control demands).
The Course of the Corticospinal Tract
FIGURE 6.8 from Neuroanatomy through Clinical Cases, 3rd Ed. — The lateral corticospinal tract pathway from primary motor cortex to skeletal muscle
Figure 56.4 from Guyton & Hall — Full course of the corticospinal (pyramidal) tract
Step-by-step course:
- Cerebral cortex (precentral gyrus / area 4) → axons enter the corona radiata (white matter fan)
- Internal capsule - fibers condense and travel through the posterior limb (between caudate nucleus and putamen)
- Basis pedunculi (cerebral peduncles) of the midbrain
- Longitudinal fascicles of the pons - scattered through the pons
- Pyramid of the medulla oblongata - fibers converge into the medullary pyramids (this is where the tract gets its name)
- Pyramidal decussation at the lower medulla - ~85% of fibers cross to the contralateral side
- Lateral corticospinal tract in the dorsolateral funiculus of the spinal cord (crossed fibers)
- Ventral (anterior) corticospinal tract in the anterior funiculus (uncrossed ~15%) - these eventually cross at segmental levels
- Anterior horn motor neurons (lower motor neurons) → peripheral nerve → skeletal muscle
The Corticobulbar Tract
The corticobulbar tract is the cranial nerve equivalent of the corticospinal tract. It projects from the motor cortex to cranial nerve motor nuclei (CN V, VII, IX, X, XI, XII) in the brainstem. Most cranial nerve nuclei receive bilateral corticobulbar projections, except the lower face division of CN VII (and CN XII to a lesser extent) which receives predominantly contralateral input - which is why a UMN lesion causes lower facial weakness contralaterally but spares the forehead.
The Key Fiber Population: Betz Cells
The most impressive pyramidal fibers are the giant Betz cells in layer V of the primary motor cortex:
- Largest neurons in the human nervous system (~60 µm in diameter)
- Conduct at ~70 m/sec - the fastest signals from brain to cord
- ~34,000 per corticospinal tract
- Comprise only 3% of the 1 million+ fibers in each tract
- The remaining 97% are small fibers (<4 µm) conducting tonic background signals
PART II: THE EXTRAPYRAMIDAL SYSTEM
What It Is
The term "extrapyramidal" refers to all descending motor pathways outside the pyramidal (corticospinal) tract. These include:
| Tract | Origin | Function |
|---|---|---|
| Rubrospinal | Red nucleus, midbrain | Fine motor + distal limb control (minor in humans) |
| Reticulospinal | Reticular formation (pons + medulla) | Tone regulation, postural reflexes, autonomic |
| Vestibulospinal | Vestibular nuclei | Balance, axial muscle tone, antigravity posture |
| Tectospinal | Superior colliculus | Head and neck orientation to visual stimuli |
The basal ganglia are the anatomical heart of the extrapyramidal system. They do not have direct descending projections to the spinal cord but exert their motor influence by modulating the motor cortex via thalamic relay loops.
The Basal Ganglia Circuit (Simplified)
Motor Cortex
↓ (excitatory glutamate)
Striatum (Caudate + Putamen)
↓
Direct pathway (D1): Inhibits GPi/SNr → Disinhibits Thalamus → Facilitates movement
Indirect pathway (D2): Excites GPe → Inhibits STN → Excites GPi/SNr → Inhibits Thalamus → Suppresses movement
Thalamus (VA/VL nuclei)
↓
Motor Cortex (feedback loop)
Dopamine from the substantia nigra pars compacta (SNc) is the key modulator:
- Acts on D1 receptors (direct pathway) → facilitates movement
- Acts on D2 receptors (indirect pathway) → inhibits the movement-suppressing pathway
- Net effect: dopamine promotes movement
- Loss of dopaminergic neurons (as in Parkinson's) → reduced movement facilitation → bradykinesia, rigidity, tremor
PART III: UMN vs LMN - The Clinical Distinction
This is one of the most tested distinctions in neurology. It flows directly from understanding the pyramidal tract's two-neuron chain.
| Sign | UMN Lesion (Pyramidal) | LMN Lesion |
|---|---|---|
| Weakness | Yes | Yes |
| Muscle atrophy | No (mild disuse only) | Yes (prominent, early) |
| Fasciculations | No | Yes |
| Tone | Increased (spasticity) | Decreased (flaccidity) |
| Reflexes (DTRs) | Increased (hyperreflexia) | Decreased/absent |
| Babinski sign | Present (upgoing plantar) | Absent |
| Distribution | Pyramidal pattern (flexors > extensors in arm; extensors > flexors in leg) | Segmental / peripheral nerve distribution |
Important caveat: In acute UMN lesions (e.g., acute stroke, spinal cord injury), flaccid paralysis with decreased tone and hyporeflexia may initially occur - this is spinal shock. Spasticity and hyperreflexia develop over hours to months as the shock phase resolves.
The reason spasticity occurs with UMN lesions is not simply loss of the corticospinal tract itself - animal studies show that selective corticospinal lesions alone do not produce spasticity. It is believed to result from damage to descending inhibitory pathways that travel closely alongside the corticospinal tract. Loss of these inhibitory influences leads to increased excitability of anterior horn motor neurons.
PART IV: Extrapyramidal Signs (Clinical Features)
Extrapyramidal disorders produce a characteristic clinical picture:
| Feature | Description |
|---|---|
| Rigidity | Lead-pipe or cogwheel resistance to passive movement (present in all directions - differs from spasticity which is velocity-dependent) |
| Tremor | Resting tremor (Parkinson's); intention tremor (cerebellar) |
| Bradykinesia | Slowness of voluntary movement |
| Hypokinesia / akinesia | Reduced movement initiation |
| Abnormal involuntary movements | Chorea, athetosis, ballismus, dystonia, tics |
| Postural instability | Loss of righting reflexes |
| Reflexes | Normal (distinguishes from pyramidal lesion) |
| No Babinski sign |
Drug-induced extrapyramidal symptoms (EPS) from antidopaminergic drugs (antipsychotics, metoclopramide):
- Acute dystonia (within hours-days)
- Akathisia (restlessness)
- Parkinsonism (days-weeks)
- Tardive dyskinesia (months-years of exposure)
Summary Comparison
| Feature | Pyramidal | Extrapyramidal |
|---|---|---|
| Structures | Primary motor cortex → corticospinal tract → anterior horn | Basal ganglia, rubrospinal, reticulospinal, vestibulospinal tracts |
| Fibers in pyramids? | Yes (defines it) | No |
| Decussation | Pyramidal decussation (lower medulla) | Varies by tract |
| Voluntary vs automatic | Voluntary, skilled, distal | Automatic, postural, proximal |
| Tone change in lesion | Spasticity | Rigidity |
| Reflexes in lesion | Hyperreflexia + Babinski | Normal |
| Involuntary movements | No | Yes (chorea, tremor, dystonia, athetosis) |
| Classic diseases | Stroke, MND, MS, CP (spastic) | Parkinson's, Huntington's, Wilson's, CP (athetoid) |
Sources: Neuroanatomy through Clinical Cases, 3rd Ed. (Blumenfeld) - Chapter 6; Guyton & Hall Textbook of Medical Physiology - Chapter 56; Adams & Victor's Principles of Neurology, 12th Ed. - Chapter on Extrapyramidal Syndromes
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Approach to a Peripheral Neuropathy Case
Harrison's Principles of Internal Medicine, 22nd Edition (2025) - Chapter 457: Peripheral Neuropathy
Authors: Anthony A. Amato, Richard J. Barohn
The Three Goals
When evaluating any patient with suspected peripheral neuropathy, Harrison's states three primary goals:
- Where is the lesion? (localization)
- What is the cause? (etiology)
- What is the treatment?
These are answered by working through seven key questions derived from the history and examination.
The Diagnostic Algorithm
FIGURE 457-1 - Harrison's 22E: The diagnostic flowchart for peripheral neuropathy. History and exam establish the pattern (mononeuropathy / mononeuropathy multiplex / polyneuropathy), followed by electrodiagnostic studies (EDx) to classify as axonal or demyelinating, then targeted investigation and treatment.
STEP 1 - The Seven Key Questions (Table 457-1)
Q1. What Systems Are Involved?
Determine whether symptoms are motor, sensory, autonomic, or a combination:
- Pure motor without sensory → consider motor neuron disease (ALS), multifocal motor neuropathy, NMJ disorder, myopathy
- Autonomic features (orthostatic hypotension, heat intolerance, bowel/bladder/sexual dysfunction) → consider amyloid polyneuropathy (especially if no diabetes), autonomic ganglionopathy
- Majority of neuropathies are predominantly sensory
Q2. What Is the Distribution of Weakness?
Two sub-questions:
- Distal only vs proximal AND distal?
- Focal/asymmetric vs symmetric?
| Distribution | Key Consideration |
|---|---|
| Symmetric proximal + distal weakness | Hallmark of acquired demyelinating polyneuropathy - GBS (acute) or CIDP (chronic) |
| Symmetric distal weakness/sensory loss | Length-dependent polyneuropathy (diabetic, toxic, hereditary) |
| Asymmetric / multifocal | Radiculopathy, plexopathy, mononeuropathy multiplex, vasculitis |
| Unilateral distal limb (motor only) | ALS vs multifocal motor neuropathy - the latter is treatable |
"The importance of finding symmetric proximal and distal weakness in a patient with both motor and sensory symptoms cannot be overemphasized — it identifies patients who may have a treatable acquired demyelinating disorder (GBS or CIDP)."
Q3. What Is the Nature of the Sensory Involvement?
| Sensory Type | Fiber Type | Suggests |
|---|---|---|
| Pain + temperature loss, burning/stabbing pain | Small myelinated (Aδ) + unmyelinated (C) fibers | Small-fiber neuropathy - diabetes, glucose intolerance, amyloid, idiopathic |
| Vibration + proprioception loss, imbalance in dark, pseudoathetosis | Large myelinated fibers (Aβ) | Large-fiber or sensory ganglionopathy |
| Both modalities | Mixed fiber neuropathy |
- Small-fiber neuropathy typically has normal NCS - skin punch biopsy for intraepidermal nerve fiber density is required
- Severe proprioceptive loss (sensory ataxia, pseudoathetosis, positive Romberg) → consider sensory neuronopathy/ganglionopathy (Sjögren's, paraneoplastic anti-Hu, cisplatin, idiopathic)
Q4. Is There Evidence of Upper Motor Neuron Involvement?
| Finding | Significance |
|---|---|
| UMN signs without sensory loss | ALS (combined UMN + LMN) |
| UMN signs with sensory loss | Combined central + peripheral involvement - consider vitamin B12 deficiency (subacute combined degeneration), adrenomyeloneuropathy, HTLV-1 |
Q5. What Is the Temporal Evolution?
| Onset | Duration | Key Diagnoses |
|---|---|---|
| Acute | Days to 4 weeks | GBS, porphyria, vasculitis, toxic (arsenic, thallium), diphtheria |
| Subacute | 4-8 weeks | CIDP, vasculitis, nutritional deficiency, toxic |
| Chronic | >8 weeks | Diabetic, hereditary (CMT), CIDP, paraproteinemic |
| Relapsing-remitting | CIDP, porphyria, hereditary neuropathy with pressure palsies (HNPP) |
Acute onset (days to weeks) always raises alarm - GBS can progress to respiratory failure.
Q6. Is There Evidence for a Hereditary Neuropathy?
Clues to hereditary neuropathy:
- Family history of neuropathy (may be subclinical - examine family members)
- Lack of sensory symptoms despite objective sensory signs (patients adapted since childhood)
- High-arched feet (pes cavus), hammer toes
- Scoliosis
- Onset in childhood or early adulthood
- Slowly progressive over many years
- Predominant motor > sensory phenotype (CMT)
Q7. Are There Any Associated Medical Conditions?
Systematically ask about:
- Diabetes mellitus (most common cause - ~50% of all polyneuropathies)
- Systemic lupus erythematosus, connective tissue disease
- Preceding infection (diarrheal illness before GBS - Campylobacter jejuni; respiratory illness - EBV, CMV)
- HIV, Lyme disease, leprosy, hepatitis B/C/E
- Malignancy (paraneoplastic neuropathy)
- Medications: chemotherapy (vincristine, cisplatin, paclitaxel), metronidazole, isoniazid, amiodarone, colchicine, thalidomide, pyridoxine (B6) toxicity at high doses
- Alcohol and dietary habits
- Surgeries (gastric bypass → nutritional neuropathy)
- Denture fixatives containing zinc → copper deficiency neuropathy
- Vitamin B12, folate, thiamine status
STEP 2 - Pattern Recognition (Table 457-2)
Based on the seven questions, classify into one of six patterns:
| Pattern | Description | Key Diagnoses |
|---|---|---|
| 1 | Symmetric proximal + distal weakness with sensory loss | GBS (acute), CIDP (chronic) |
| 2 | Symmetric distal sensory loss ± distal weakness | Diabetic polyneuropathy, cryptogenic/idiopathic (CSPN), drugs/toxins, CMT, amyloidosis, CANVAS, SORD neuropathy |
| 3 | Asymmetric distal weakness with sensory loss | Multiple nerves: vasculitis, cryoglobulinemia, sarcoid, leprosy, Lyme, HIV, CMV, HNPP, tumor infiltration |
| Single nerve/region: compressive mononeuropathy, plexopathy, radiculopathy | ||
| 4 | Asymmetric proximal + distal weakness with sensory loss | Polyradiculopathy / plexopathy: diabetic (DLRPN), meningeal carcinomatosis, sarcoid, amyloid, hereditary plexopathy |
| 5 | Symmetric sensory loss and/or motor loss with autonomic involvement | Amyloid neuropathy, diabetic autonomic neuropathy, paraneoplastic autonomic neuropathy, acute autonomic neuropathy |
| 6 | Symmetric weakness without sensory loss | Motor neuropathy (multifocal motor neuropathy, pure motor CIDP), motor neuron disease, NMJ disorder, myopathy |
Pattern recognition is the clinical algorithm used to narrow the differential before ordering tests.
STEP 3 - Electrodiagnostic Studies (EDx)
EDx = Nerve Conduction Studies (NCS) + Needle EMG
What EDx Tells You:
- Anatomic pattern: mononeuropathy / mononeuropathy multiplex / radiculopathy / plexopathy / polyneuropathy
- Fiber type: sensory only / motor only / mixed
- Pathology type: axonal vs demyelinating - the most critical distinction
Axonal vs Demyelinating (Table 457-3)
| Parameter | Axonal Degeneration | Segmental Demyelination |
|---|---|---|
| CMAP amplitude | Decreased | Normal (unless conduction block/dispersion) |
| Distal latency | Normal | Prolonged |
| Conduction velocity | Normal | Slow |
| Conduction block | Absent | Present |
| Temporal dispersion | Absent | Present |
| F-wave | Normal or absent | Prolonged or absent |
| SNAP amplitude | Decreased | Normal or decreased |
| Needle EMG - fibrillations | Present (denervation) | Absent (usually) |
| Needle EMG - MUPs | Long-duration, polyphasic (chronic reinnervation) | Normal or slightly abnormal |
Low-amplitude potentials with relatively preserved distal latencies, conduction velocities, and late potentials, plus fibrillations on EMG = axonal neuropathy Slow conduction velocities + prolonged latencies + conduction block = demyelinating neuropathy
STEP 4 - Laboratory Evaluation
A stepwise approach based on clinical pattern:
Tier 1 - All Patients with Polyneuropathy
| Test | Rationale |
|---|---|
| Fasting blood glucose + HbA1c | Diabetes and prediabetes (most common cause) |
| CBC | Anaemia, macrocytosis |
| Comprehensive metabolic panel (BMP + LFTs) | Renal, hepatic disease |
| Serum B12 + methylmalonic acid | B12 deficiency (MMA more sensitive) |
| Thyroid function (TSH) | Hypothyroid neuropathy |
| Serum protein electrophoresis (SPEP) + immunofixation | Paraproteinemia (MGUS, myeloma) |
| Urinalysis | Renal, Bence-Jones protein |
| ESR, CRP | Inflammatory/vasculitic |
Tier 2 - Guided by Clinical Pattern
| Clinical clue | Test |
|---|---|
| Mononeuropathy multiplex / rapid progression | ANCA, ANA, anti-dsDNA, cryoglobulins, hepatitis B/C/E serologies, HIV; nerve biopsy |
| Demyelinating polyneuropathy | Anti-MAG antibody, anti-ganglioside panel (GM1, GQ1b), POEMS screen (VEGF, skeletal survey, bone marrow biopsy) |
| Sensory ataxia / ganglionopathy | Anti-Hu (ANNA-1), Sjögren's antibodies (anti-SSA/SSB), CT chest/abdomen (lung cancer) |
| Autonomic features | Congo red biopsy / mass spectroscopy for amyloid; TTR gene testing |
| Pure motor neuropathy | Anti-GM1 IgM antibody (multifocal motor neuropathy) |
| Acute / subacute neuropathy | Urine porphyrins (porphyria); heavy metal screen (arsenic, lead, thallium, mercury) |
| Young + family history + long history | Genetic testing: PMP22 duplication (CMT1A), MFN2 (CMT2A), GJB1 (CMT1X), TTR (hereditary ATTR) |
| Suspected small-fiber | Skin punch biopsy (IENFD), quantitative sudomotor axon reflex test (QSART), autonomic testing |
Tier 3 - When Cause Remains Unclear
- Nerve biopsy (sural nerve ± superficial peroneal nerve) - indicated for: vasculitis, amyloid, granulomatous neuropathy (sarcoid, leprosy), atypical demyelinating neuropathy
- CSF analysis - elevated protein in GBS, CIDP; pleocytosis in lymphomatous/carcinomatous meningitis, HIV, CMV
- Paraneoplastic antibody panel (anti-Hu, anti-Yo, anti-CV2, CRMP-5)
- Bone marrow biopsy - if monoclonal protein detected (rule out myeloma, POEMS)
"Despite an extensive evaluation, in approximately half of patients, no etiology is ever found" - these patients have idiopathic/cryptogenic sensory and sensorimotor polyneuropathy (CSPN).
STEP 5 - Localization Summary
| Anatomic Type | Key Features | Exam Clue |
|---|---|---|
| Mononeuropathy | Single nerve territory | Median (CTS), ulnar, peroneal, radial |
| Mononeuropathy multiplex | Multiple separate nerve territories, asymmetric | Vasculitis, leprosy, Lyme, diabetes |
| Polyneuropathy | Symmetric, length-dependent, stocking-glove | Diabetic, toxic, hereditary |
| Polyradiculopathy | Multiple root levels, +/- back pain | Diabetic DLRPN, carcinomatous meningitis |
| Plexopathy | Brachial or lumbosacral; proximal + distal loss in one limb | Idiopathic (Parsonage-Turner), diabetic, radiation, neoplastic |
| Sensory neuronopathy / ganglionopathy | Pan-modal sensory loss, sensory ataxia, pseudoathetosis; non-length-dependent | Anti-Hu, Sjögren's, cisplatin, idiopathic |
STEP 6 - Fiber Size Localization
| Large Fiber | Small Fiber | |
|---|---|---|
| Modalities affected | Vibration, proprioception, light touch, motor | Pain, temperature, autonomic |
| NCS | Abnormal (reduced SNAP/CMAP) | Normal |
| Reflexes | Reduced/absent | Normal |
| Diagnosis requires | NCS + EMG | Skin biopsy (IENFD), autonomic testing, quantitative sensory testing (QST) |
| Classic causes | Diabetic, B12 deficiency, CMT | Diabetic (early), small-fiber idiopathic, amyloid, Fabry disease |
STEP 7 - Red Flags Requiring Urgent Evaluation
| Red Flag | Concern |
|---|---|
| Rapid progression over days | GBS - check respiratory function (FVC, NIF); ICU if needed |
| Ascending weakness + areflexia + albuminocytologic dissociation in CSF | GBS |
| Autonomic instability (HR, BP lability, ileus, urinary retention) | Autonomic GBS, porphyria |
| Cranial nerve involvement + neuropathy | GBS variant (Miller Fisher), Lyme, sarcoid, carcinomatous meningitis |
| Severe pain out of proportion | Vasculitic neuropathy, amyloid, porphyria |
| Young patient + family history | Hereditary neuropathy |
Approach Summary Flow
Suspected Neuropathy
↓
History (7 key questions) + Examination
↓
Pattern Classification
(mononeuropathy / mononeuropathy multiplex / polyneuropathy)
↓
Electrodiagnostic Studies (NCS + EMG)
↓
Axonal OR Demyelinating?
↓
Targeted Laboratory Investigation
↓
Nerve biopsy / CSF / genetic testing if needed
↓
Diagnosis → Treatment
Source: Harrison's Principles of Internal Medicine, 22nd Edition (2025), Chapter 457 - Amato AA, Barohn RJ; Goldman-Cecil Medicine, 27th Ed., Chapter on Peripheral Neuropathy
What is mononeuropathy multiplex
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Mononeuropathy Multiplex
Definition
Mononeuropathy multiplex (also called mononeuritis multiplex or multifocal mononeuropathy) refers to the simultaneous or sequential involvement of two or more separate, non-contiguous peripheral nerves, producing an asymmetric pattern of sensorimotor deficits.
"The neurological findings should point to simultaneous or sequential damage to two or more non-contiguous peripheral nerves." - Bradley & Daroff's Neurology
Key distinguishing features:
- Asymmetric - differentiates it from polyneuropathy
- Non-contiguous nerve involvement (e.g., right median nerve + left femoral nerve)
- Sensorimotor - both motor weakness and sensory loss in individual nerve distributions
- Subacute or acute onset, often painful
- Implies a focal, nerve-specific pathological process (ischemia or infiltration)
Pathophysiology
The two main mechanisms are:
| Mechanism | Pathology | Prototype |
|---|---|---|
| Nerve ischemia | Occlusion of the vasa nervorum (small nutrient arteries) | Vasculitis (PAN, ANCA vasculitis) |
| Nerve infiltration/inflammation | Direct nerve invasion or perineural inflammation | Leprosy, sarcoid, lymphoma, Lyme disease |
Vasculitis is the most important cause - >50% of all mononeuropathy multiplex cases can be traced to systemic vasculitis involving the vasa nervorum (Adams & Victor's, 12th Ed.).
Causes
Common Causes
| Category | Specific Causes |
|---|---|
| Vasculitis (systemic) | Polyarteritis nodosa (PAN) - ~24% of vasculitic neuropathy; Microscopic polyangiitis; Eosinophilic granulomatosis with polyangiitis (Churg-Strauss) - cANCA; Granulomatosis with polyangiitis (Wegener's) - pANCA; Rheumatoid arthritis - ~23%; SLE; Scleroderma; Mixed cryoglobulinemia (hepatitis C) |
| Vasculitis (nonsystemic) | Vasculitis confined to peripheral nerves only - no systemic manifestations, more indolent course |
| Diabetes mellitus | Diabetic mononeuropathy multiplex (superimposed on background polyneuropathy) |
| Infections | Leprosy (most common cause worldwide); HIV; Lyme disease; CMV (in immunocompromised) |
| Sarcoidosis | Nerve granulomatous infiltration |
| Hereditary | HNPP (hereditary neuropathy with liability to pressure palsies) - PMP22 deletion |
Less Common Causes
| Category | Examples |
|---|---|
| Neoplastic | Paraneoplastic; Direct nerve infiltration (leukemia/lymphoma, intravascular lymphoma) |
| Autoimmune | Sjögren's syndrome; SLE |
| Demyelinating (multifocal) | Multifocal motor neuropathy (MMN); MADSAM (Lewis-Sumner syndrome) |
| Toxic | Lead intoxication |
| Haematological | Cryoglobulinemia; Polycythemia vera |
Leprosy is the most common cause worldwide but rare in non-endemic areas. In those areas, vasculitis dominates.
Axonal vs Demyelinating Types
The underlying pathophysiology divides mononeuropathy multiplex into two electrophysiological subtypes (Bradley & Daroff's):
| Axonal MNM | Demyelinating MNM | |
|---|---|---|
| Mechanism | Nerve ischemia / infarction | Focal demyelination at multiple sites |
| EDx pattern | Low CMAP/SNAP amplitudes, preserved velocities, fibrillations on EMG | Focal conduction blocks, prolonged latencies, temporal dispersion |
| Proportion | ~2/3 of cases | ~1/3 |
| Key causes | Vasculitis, diabetes, leprosy, sarcoid, HIV | Multifocal motor neuropathy (MMN), MADSAM/Lewis-Sumner, HNPP, hypothyroidism |
Clinical Features
- Acute or subacute onset of weakness and/or sensory loss in individual named nerve distributions
- Painful - often with acute aching or burning pain at onset, particularly in vasculitic cases
- Deficits follow the exact territory of specific named nerves (e.g., foot drop from peroneal nerve, wrist drop from radial nerve, plus a separate femoral nerve palsy)
- Asymmetric and initially stepwise - each new nerve involvement occurs as a distinct "stroke-like" event
- As more nerves are involved over time, the picture can become confluent and simulate a distal symmetric polyneuropathy - making the underlying pattern easy to miss on casual examination
Confluent mononeuropathy multiplex (e.g., simultaneous fibular + tibial nerve involvement, or median + ulnar) can mimic a length-dependent polyneuropathy. EDx is essential to distinguish them.
- Constitutional symptoms (fever, weight loss, malaise, arthralgias) point strongly to systemic vasculitis
- DTRs - variably affected depending on which nerves are involved (e.g., absent patellar reflex if femoral nerve is involved)
Approach to Diagnosis
History
- Onset and pace (acute = vasculitis; insidious = diabetes, hereditary)
- Pattern of nerve involvement - which nerves, what sequence
- Constitutional symptoms (vasculitis)
- Diabetes, connective tissue disease, cancer, HIV risk
- Travel history (leprosy endemic area)
- Drug history, alcohol
Examination
- Map out exact nerve distributions affected
- Check for skin lesions (leprosy - anaesthetic pale macules; vasculitis - purpura, livedo reticularis; sarcoid - lupus pernio)
- Lymphadenopathy, organomegaly
- Joint disease (rheumatoid arthritis, SLE)
Investigations
First-line (all patients):
| Test | Rationale |
|---|---|
| ESR, CRP | Vasculitis, systemic inflammation |
| CBC + differential | Eosinophilia (Churg-Strauss), lymphocytosis (lymphoma) |
| Comprehensive metabolic panel | Renal, hepatic disease |
| Fasting glucose + HbA1c | Diabetes |
| ANA, anti-dsDNA | SLE |
| ANCA (p-ANCA/MPO, c-ANCA/PR3) | ANCA-associated vasculitis |
| Cryoglobulins | Cryoglobulinemic vasculitis (hepatitis C) |
| Hepatitis B, C serologies | Vasculitis association; cryoglobulinemia |
| HIV | HIV neuropathy, HIV-related vasculitis |
| Chest imaging + ACE level | Sarcoidosis |
| Lyme serology | If epidemiological risk |
Electrodiagnostic studies (EDx - NCS + EMG):
- Confirm which nerves are involved
- Establish axonal vs demyelinating type
- Find subclinical nerve involvement
If axonal MNM and workup non-diagnostic:
- Nerve and muscle biopsy (combined sural nerve + peroneus brevis or gastrocnemius muscle) using serial section / skip-serial technique - diagnostic for vasculitis, amyloid, leprosy, granuloma
- Anti-GM1 IgM antibody (if multifocal motor neuropathy suspected - pure motor, demyelinating with conduction block)
- PMP22 deletion testing (if HNPP suspected)
- CMV PCR (if immunocompromised)
Vasculitic Neuropathy - The Prototype
Vasculitis is the most important treatable cause and deserves emphasis:
- Mechanism: Occlusion of vasa nervorum → nerve infarction → axonal degeneration
- Pattern: Acute painful mononeuropathy multiplex - each nerve infarct is abrupt and painful
- Systemic vasculitis - ~79% have systemic features; ~21% have nonsystemic vasculitic neuropathy (confined to peripheral nerves, no systemic manifestations, more indolent)
- Diagnosis: Combined nerve + muscle biopsy with serial sections
- Treatment:
- Glucocorticoids + rituximab (now recommended as standard initial treatment, especially for ANCA-associated vasculitis - non-inferior to cyclophosphamide)
- Alternatively: glucocorticoids + cyclophosphamide
- Mepolizumab (anti-IL5) for eosinophilic GPA
- 5-year survival now >80% with treatment
Key Differentials - MNM vs Polyneuropathy vs Radiculopathy
| Feature | MNM | Polyneuropathy | Radiculopathy |
|---|---|---|---|
| Distribution | Asymmetric, multifocal named nerves | Symmetric, length-dependent (stocking-glove) | Dermatomal/myotomal |
| Onset | Acute/stepwise | Gradual | Often acute (disc) or subacute |
| Pain | Often prominent, acute | Variable | Yes (radicular) |
| EDx | Multiple focal lesions in named nerves | Diffuse symmetric changes | Periradicular changes ± paraspinal fibrillations |
| Tone of clue | Constitutional symptoms; systemic disease | Diabetes, toxin, hereditary | Back/neck pain, Lasègue sign |
Sources: Harrison's Principles of Internal Medicine, 22nd Ed. (2025) - Ch. 457; Adams & Victor's Principles of Neurology, 12th Ed.; Bradley & Daroff's Neurology in Clinical Practice; Rosen's Emergency Medicine
What is preserved ejection fraction heart failure
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Heart Failure with Preserved Ejection Fraction (HFpEF)
Sources: Harrison's 22E (2025); Fuster & Hurst's The Heart, 15th Ed.; Braunwald's Heart Disease; Symptom to Diagnosis, 4th Ed.
Definition and Classification
HFpEF is defined as heart failure with clinical symptoms and signs of congestion in the setting of a left ventricular ejection fraction (LVEF) ≥50%, with evidence of diastolic dysfunction or elevated filling pressures.
Current classification by LVEF (ACC/AHA / ESC):
| Type | LVEF | Old Term |
|---|---|---|
| HFrEF (reduced) | ≤40% | Systolic HF |
| HFmrEF (mildly reduced) | 41-49% | Borderline / mid-range |
| HFpEF (preserved) | ≥50% | Diastolic HF |
HFpEF accounts for approximately 50% of all heart failure cases, and its prevalence is increasing as the population ages.
Pathophysiology
HFpEF is not a single disease but a heterogeneous syndrome driven by multiple overlapping mechanisms. The pathophysiology is multifactorial and distinct from HFrEF.
Figure 49-1 — HFpEF pathophysiology: a multi-organ syndrome involving ventricular-vascular stiffening, pulmonary venous hypertension, renal fluid imbalance, skeletal muscle impairment, and abdominal compartment effects
1. Diastolic Dysfunction (the primary defect)
- Impaired early LV relaxation (active, energy-dependent process)
- Increased passive myocardial stiffness (due to fibrosis, titin modification, infiltration)
- Result: LV filling is impaired → elevated LV end-diastolic pressure (LVEDP) → elevated left atrial pressure → pulmonary venous hypertension → dyspnea
- Contractility is preserved, so LVEF appears normal
2. Myocardial Stiffness and Fibrosis
- Myocardial fibrosis (increased collagen volume fraction) is a well-established finding on endomyocardial biopsy
- Systemic comorbidities (hypertension, diabetes, obesity, aging) → systemic inflammation → coronary microvascular endothelial inflammation → oxidative stress → titin hypophosphorylation → cardiomyocyte stiffening
- Titin (the giant elastic sarcomeric protein) stiffens with reduced phosphorylation, impairing both relaxation and recoil
3. Impaired Systolic Reserve
- Resting LVEF may be "preserved" or even supranormal, but longitudinal systolic function is impaired - reduced global longitudinal strain (GLS) is detectable even with normal LVEF
- On exercise, the heart cannot adequately augment cardiac output (impaired contractile reserve)
- In concentric LVH: LVEF may appear normal or supranormal despite depressed midwall shortening - a truly preserved EF can mask underlying systolic impairment
4. Abnormal Ventricular-Arterial Coupling
- Arterial stiffening (from aging, hypertension) increases pulsatile afterload
- The stiff ventricle and stiff aorta are poorly matched for load sharing
- Labile, stress-induced hypertension is common and limits systolic reserve
5. Chronotropic Incompetence
- Inability to increase heart rate appropriately with exercise
- Contributes significantly to exercise intolerance
6. Pulmonary Hypertension and RV Dysfunction
- Postcapillary pulmonary hypertension (from elevated LVEDP/LA pressure) is common
- A subset develops combined pre- and postcapillary pulmonary hypertension (pulmonary vascular disease)
- Many HFpEF patients have normal PCWP at rest but dramatic rises on exercise
- RV dysfunction predicts poor outcomes, especially in obese HFpEF patients
7. Peripheral Skeletal Muscle Abnormalities
- Impaired skeletal muscle metabolism
- Decreased mitochondrial volume and enzyme activity
- Impaired peripheral vasodilation
- These contribute independently to exercise intolerance, beyond cardiac mechanisms alone
8. Renal Dysfunction
- CKD in 26-53% of HFpEF patients
- Passive venous congestion → renal impairment → fluid imbalance → oliguria, diuretic resistance
- Bidirectional cardiorenal syndrome
Epidemiology and Risk Factors
| Feature | Detail |
|---|---|
| Prevalence | ~50% of all HF cases |
| Age | Predominantly elderly (mean age ~70-75) |
| Sex | More common in women than men |
| Obesity | Major risk factor and driver of symptoms |
| Hypertension | Most common cause (~60-70% of cases) |
| Diabetes | Common comorbidity; contributes to fibrosis and stiffness |
| Atrial fibrillation | Present in 21-41% of HFpEF patients |
| CAD | Common comorbidity; worsens prognosis |
Less common causes include aortic stenosis, hypertrophic cardiomyopathy, and infiltrative cardiomyopathies (amyloidosis, hemochromatosis).
Clinical Features
Symptoms
- Exertional dyspnea - the cardinal symptom
- Orthopnoea, paroxysmal nocturnal dyspnea
- Exercise intolerance (often disproportionate to resting echo findings)
- Peripheral oedema, fatigue
- Patients often have relatively preserved resting function but severe exercise limitation
Signs
- Elevated JVP
- S3 or S4 gallop
- Bilateral basal crepitations
- Peripheral oedema
- May have evidence of the underlying cause (hypertensive changes on fundoscopy, LVH on ECG)
Key distinguishing point from HFrEF
The heart is not dilated; LV cavity size is normal or small. Wall thickness may be increased (concentric hypertrophy). Systolic function (by LVEF) is preserved.
Diagnosis
Diagnostic Requirements
- Symptoms and/or signs of HF
- LVEF ≥50% on echocardiography
- Evidence of diastolic dysfunction or elevated LV filling pressures:
- Echo: E/e' ratio, LA volume index, TR velocity, LV mass index
- Biomarkers: elevated BNP / NT-proBNP
- Invasive: PCWP ≥15 mmHg at rest or ≥25 mmHg on exercise
Key Investigations
Echocardiography:
| Parameter | Abnormality in HFpEF |
|---|---|
| LVEF | ≥50% (preserved) |
| LV wall thickness | Often increased (concentric hypertrophy) |
| LA volume index (LAVI) | Elevated (>34 mL/m²) |
| E/e' ratio | >14 (elevated filling pressure) |
| e' velocity (septal) | <7 cm/s; lateral <10 cm/s |
| TR peak velocity | >2.8 m/s (elevated RVSP) |
| Global longitudinal strain | Often mildly reduced (subclinical systolic dysfunction) |
Biomarkers:
- BNP and NT-proBNP: elevated but lower than in HFrEF for equivalent filling pressure (HFpEF is a "relative NP deficiency state" due to increased wall thickness and smaller volumes)
- Elevated NPs strongly support diagnosis and predict outcomes
Diagnostic Scoring Systems
H2FPEF Score (Mayo Clinic, validated AUC 0.84-0.89):
| Feature | Points |
|---|---|
| BMI >30 kg/m² | 2 |
| ≥2 antihypertensive medications | 1 |
| Atrial fibrillation | 3 |
| Pulmonary artery systolic pressure >35 mmHg (echo) | 1 |
| Age >60 years | 1 |
| E/e' ratio >9 | 1 |
Score 0-1: HFpEF unlikely | Score 6-9: HFpEF highly likely | Intermediate scores: consider exercise testing or invasive hemodynamics
HFA-PEFF Score (ESC Heart Failure Association):
- 4-step algorithm: Pre-test assessment → Echocardiography + natriuretic peptide score → Functional testing → Final etiology
- Score ≥5: diagnostic of HFpEF | Score ≤2: excludes HFpEF
- Includes functional domain (E/e', TR velocity, GLS) and morphologic domain (LAVI, LV mass index, relative wall thickness)
Comorbidities (the "HFpEF phenotype")
HFpEF is characterized by a dense cluster of comorbidities that are not mere bystanders but are active contributors to the syndrome:
| Comorbidity | Prevalence / Comment |
|---|---|
| Hypertension | ~60-70%; most common driver |
| Obesity | Major contributor to inflammation, volume loading, sleep apnoea |
| Diabetes / insulin resistance | ~40-50%; promotes fibrosis |
| Atrial fibrillation | 21-41%; bidirectional relationship |
| CKD | 26-53%; worsens outcomes dramatically |
| CAD | Equal risk of HFpEF vs HFrEF after ischaemic events |
| OSA / COPD | Often underdiagnosed; worsens outcomes |
| Anaemia / iron deficiency | Common; limits exercise capacity |
| Pulmonary hypertension | Predicts increased morbidity and mortality |
Treatment
General Principles (Harrison's 22E)
Management historically focused on symptom control and comorbidity management due to lack of mortality-reducing therapies. This is evolving with SGLT-2 inhibitor data.
Core non-pharmacological management:
- Lifestyle modification (weight loss, exercise training)
- Sodium restriction
- Control of blood pressure to guideline targets
- Management of AF (rate or rhythm control)
- Treatment of obesity, OSA, diabetes, anaemia, iron deficiency
- Minimise "tethers" (IV lines, catheters) that limit mobility
Pharmacological Evidence (Clinical Trials Summary)
| Drug Class | Trial | Result |
|---|---|---|
| ACE inhibitors (perindopril) | PEP-CHF | No mortality benefit; modest early reduction in HF hospitalisations, attenuated over time |
| ARBs (candesartan) | CHARM-Preserved | Reduced HF hospitalisations (P=0.017); no mortality reduction |
| ARBs (irbesartan) | I-PRESERVE | No benefit on CV death or HF hospitalisation |
| Beta-blockers (nebivolol) | SENIORS subgroup | No significant benefit in HFpEF subgroup |
| MRA (spironolactone) | TOPCAT | Primary endpoint missed; HF hospitalisations reduced in Americas subgroup - weak recommendation for patients meeting trial criteria at low risk for hyperkalemia/renal worsening |
| MRA (spironolactone) | ALDO-DHF | Improved echo diastolic parameters; no improvement in exercise capacity, symptoms, or QoL |
| ARNi (sacubitril/valsartan) | PARAGON-HF | Narrowly missed significance (P=0.06); possible benefit in LVEF <57%, women, recent HF hospitalisation |
| SGLT-2i (empagliflozin) | EMPEROR-Preserved | 21% reduction in CV death or HF hospitalisation (HR 0.79, P<0.001) - irrespective of diabetes status or LVEF across HFpEF spectrum |
| SGLT-2i (dapagliflozin) | DELIVER | Reduced primary endpoint of CV death, worsening HF, or HF hospitalisation |
| GLP-1 agonist (semaglutide) | STEP-HFpEF | Improved symptoms, exercise capacity, body weight in obese HFpEF |
Current Treatment Recommendations
Evidence-based (recommended):
- SGLT-2 inhibitors (empagliflozin or dapagliflozin) - the only class with clear outcome benefit across the HFpEF LVEF spectrum, independent of diabetes
- Diuretics - for symptom relief and congestion control (loop diuretics)
- Aggressive BP control - ACEi/ARB/ARNi for hypertension management
- Spironolactone - weak recommendation (TOPCAT Americas data) for patients with LVEF <60% at low risk for hyperkalemia/renal impairment
For comorbidities:
- Rate or rhythm control for AF
- GLP-1 agonists (semaglutide) - for obese HFpEF
- Iron replacement if iron-deficient
- CPAP for OSA
- Glycaemic optimisation
Important caveats:
- LVEF is dynamic - patients may transition between HFrEF and HFpEF
- Patients who recover LVEF (HFrEF → HFpEF) should not have HF medications stopped - high relapse rate after withdrawal
- A normal or supranormal LVEF does not exclude significant systolic impairment (particularly in concentric LVH)
Prognosis
- Mortality in HFpEF is similar to HFrEF - both carry substantial mortality
- Annual mortality ~10-15% in symptomatic patients
- Outcomes are driven by the underlying comorbidity burden
- Recurrent HF hospitalisations are the dominant morbidity
- RV dysfunction and worsening renal function during hospitalisation predict particularly poor outcomes
Sources: Harrison's Principles of Internal Medicine, 22nd Ed. (2025), Ch. 268; Fuster & Hurst's The Heart, 15th Ed., Ch. 49; Braunwald's Heart Disease, Ch. 51; Symptom to Diagnosis, 4th Ed., Ch. 15
Pdf on fluids by Dr Sanjay pandaya
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