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🏥 PEDIATRICS INTERNAL EXAM — COMPLETE STUDY NOTES

All 17 Topics Covered

Sources: Harriet Lane Handbook (23rd ed.), Tintinalli's Emergency Medicine, Brenner & Rector's The Kidney, Campbell-Walsh-Wein Urology, Robbins Pathology, Rosen's Emergency Medicine, Essentials of Forensic Medicine & Toxicology

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PART 1: RENAL TOPICS

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1. URINARY TRACT INFECTION (UTI) IN CHILDREN

Definition & Classification

Etiology

• E. coli - most common in ALL age groups
• Klebsiella, Proteus (alkaline urine, stones in males)
• Staphylococcus saprophyticus (adolescent females)
• Group B Streptococcus (neonates - hematogenous route)
• Route: Ascending (most common); Hematogenous in neonates

Risk Factors

• Uncircumcised males - 10x higher risk
• Female sex (short urethra)
• VUR, urinary stasis, constipation, voiding dysfunction
• Age <1 year (highest incidence)

Clinical Features by Age

⚠️ "Smelly urine" is NOT a reliable sign of UTI

Investigations

• Nitrite: Sensitivity 53%, Specificity 98% (highly specific)
• Leukocyte esterase: Sensitivity 83%, Specificity 78%
• Both positive together = best diagnostic value

• Renal/Bladder Ultrasound (RBUS) - after first febrile UTI
• VCUG - ONLY if RBUS is abnormal (not routine)
• DMSA scan - cortical scarring

Management

Complications

• Renal scarring → hypertension, CKD
• Sepsis (especially infants)
• Recurrence (2x risk after first UTI)

High-Yield Points ⭐

1. Most common organism = E. coli
2. Neonatal UTI = hematogenous (NOT ascending)
3. Never use bag specimen for culture
4. Pyelonephritis can be treated ORALLY if not toxic
5. VCUG not routine - only if RBUS abnormal

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2. VESICOURETERAL REFLUX (VUR)

Definition & Grading

Pathophysiology

• Primary VUR: Short intravesical ureteral tunnel (congenital) - most common
• Secondary VUR: Bladder dysfunction (BBD), obstruction, neurogenic bladder
• VUR allows infected urine to reach kidney → pyelonephritis → renal scarring
• BBD (Bladder & Bowel Dysfunction) - most critical modifiable factor (51% recurrent UTIs with BBD+VUR vs 20% VUR alone)

Two Phenotypes

Investigations

Management

• Antibiotic prophylaxis (CAP): TMP-SMX; reduces recurrence ~50%
• BBD treatment FIRST (oxybutynin for overactive bladder, constipation treatment)
• Circumcision in males - markedly reduces UTI risk

• Indication: Failed medical management, recurrent febrile UTIs, high-grade VUR (IV-V) persisting, declining renal function
• Endoscopic injection (DEFLUX) - bulking agent; ~85% success
• Open ureteral reimplantation - gold standard; 95-99% success

Spontaneous Resolution Rates

High-Yield Points ⭐

1. VCUG grades VUR; DMSA detects scarring - complementary roles
2. VUR is NOT a cause of UTI, it accelerates upper tract infection
3. BBD is the most important modifiable variable - treat FIRST
4. Grade I-III: likely spontaneous resolution; Grade IV-V: surgery often needed
5. Sibling screening: ~30% risk of VUR in siblings

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3. GLOMERULONEPHRITIS (ACUTE & CHRONIC)

Nephritic Syndrome Features (remember with PHAROH)

• Hematuria (RBC casts - PATHOGNOMONIC)
• Hypertension
• Edema (periorbital, mild-moderate)
• Oliguria / Azotemia
• Proteinuria (subnephrotic, <3.5 g/day)
• RBC casts in urine

Post-Streptococcal GN (PSGN) - Most Common Pediatric GN

• Group A β-hemolytic Streptococcus (nephritogenic strains)
• After pharyngitis (M types 1, 4, 12) or impetigo/skin infection (M types 49, 55)

• Throat infection: 7-15 days
• Skin infection: 2-4 weeks (14-21 days)

• Streptococcal antigen + host antibody → immune complexes in glomeruli
• Complement activation (alternative pathway) → ↓C3, normal C4
• EM: Subepithelial "humps" (pathognomonic)
• IF: Granular IgG + C3 ("lumpy-bumpy"/"starry sky")

• Age: 4-12 years (peak); Male:Female = 2:1
• Abrupt onset: cola/tea-colored urine + periorbital edema + hypertension + oliguria
• 2 weeks after sore throat OR 3-4 weeks after skin infection

• Fluid and sodium restriction
• Diuretics (furosemide) for edema
• Antihypertensives (CCB, beta-blockers)
• Penicillin 10 days (to eradicate active infection - does NOT change renal outcome)
• Dialysis for severe AKI, uncontrolled hyperkalemia, fluid overload
• Prognosis: >95% of children recover completely

IgA Nephropathy (Berger's Disease)

• Mesangial IgA deposits (poorly glycosylated IgA)
• Hematuria concurrent with URI (within 24-48 hours) - "synpharyngitic"
• C3 = NORMAL
• Can progress to ESRD (25-50% over 20 years)

Differentiation Table

RPGN (Rapidly Progressive GN)

High-Yield Points ⭐

1. PSGN = most common pediatric GN globally
2. Low C3 + Normal C4 = PSGN (alternative pathway activation)
3. RBC casts = pathognomonic of glomerular bleeding
4. C3 normalizes by 4-8 weeks; if not → think MPGN or lupus
5. IgA nephropathy: hematuria concurrent with URTI (NOT 2 weeks later)
6. PSGN treatment is SUPPORTIVE

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4. NEPHROTIC SYNDROME

Definition - TETRAD (PHHE)

1. Proteinuria >40 mg/m²/hr OR urine protein:creatinine >2
2. Hypoalbuminemia <3 g/dL
3. Hyperlipidemia (↑cholesterol, ↑triglycerides)
4. Edema (anasarca)

Classification in Children

⭐ Age 2-6 years + nephrotic = 80-90% MCD

Pathophysiology

• T-cell dysfunction → podocyte foot process effacement (EM finding in MCD)
• Loss of charge barrier → massive albuminuria
• Hypoalbuminemia → ↓oncotic pressure → edema ("underfill")
• Liver compensates → ↑lipoproteins → hyperlipidemia
• Loss of immunoglobulins + complement → infection risk
• Loss of antithrombin III, protein C/S → thrombosis risk

Clinical Features

• Periorbital edema (morning - often mistaken for allergy!) - FIRST sign
• Pitting edema, ascites, pleural effusion, scrotal/labial edema
• Frothy urine (proteinuria)
• Oliguria in severe cases

Investigations

• Age <1 year or >10 years (atypical age for MCD)
• Steroid-resistant
• Persistent hematuria or elevated creatinine
• Hypocomplementemia

Management

• Prednisone 2 mg/kg/day (max 60 mg) daily × 4-6 weeks → then alternate-day taper

• Cyclophosphamide: 2 mg/kg/day × 8-12 weeks
• Cyclosporine: 3-5 mg/kg/day
• Mycophenolate mofetil (MMF)
• Rituximab (anti-CD20) - for complicated cases

• Salt restriction + furosemide 0.5-1 mg/kg
• Caution: Do NOT aggressively diurese hypovolemic NS patients

Response Definitions

Complications

• Infections: SBP (S. pneumoniae, E. coli) - LEADING cause of morbidity/mortality
• Thromboembolism: Renal vein thrombosis, sagittal sinus, PE
• Hypovolemia/shock (with aggressive diuresis)
• Steroid toxicity (Cushing's, growth retardation, cataracts, osteoporosis)
• AKI (from hypovolemia)

Nephrotic vs Nephritic Comparison

High-Yield Points ⭐

1. MCD = steroid-responsive; 2-6 years; NORMAL light microscopy; only foot process effacement on EM
2. Normal complement in MCD/FSGS; low C3+C4 → MPGN/Lupus
3. Periorbital edema - cardinal sign, mistaken for allergy
4. Infections (SBP) = leading cause of mortality
5. Vaccinate against pneumococcus + varicella BEFORE steroids

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5. ACUTE RENAL FAILURE (ARF) / AKI

KDIGO Staging

Classification

HUS - Most Common Cause of AKI in Young Children ⭐

• Triad: Microangiopathic hemolytic anemia (MAHA) + Thrombocytopenia + AKI = MAT
• Caused by Shiga toxin producing E. coli O157:H7 (bloody diarrhea history)
• Age: children <5 years most susceptible
• ANTIBIOTICS CONTRAINDICATED in STEC-HUS (worsens severity!)
• Treatment: Supportive (fluids, dialysis if needed)

Differentiating Pre-renal vs Intrinsic AKI

Management

• Acidosis (pH <7.2, refractory)
• Electrolytes (severe hyperkalemia, hyperphosphatemia)
• Intoxication
• Overload (fluid, pulmonary edema)
• Uremia (encephalopathy, pericarditis, bleeding)

High-Yield Points ⭐

1. FENa <1% = prerenal; FENa >1-3% = intrinsic
2. HUS triad = MAHA + thrombocytopenia + AKI; NO antibiotics in STEC-HUS
3. Muddy brown casts = ATN; RBC casts = GN
4. Calcium gluconate FIRST in hyperkalemia (membrane stabilization)
5. ECG mandatory in AKI (hyperkalemia detection)

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6. CHRONIC RENAL FAILURE (CKD)

Definition & Staging

eGFR = 0.413 × Height (cm) / Serum Cr (mg/dL)

Causes of CKD in Children (Different from Adults!)

⭐ CAKUT = #1 cause of pediatric CKD (contrast: adults = diabetes/hypertension)

Multi-System Manifestations

Management

• ACE inhibitors (ramipril 6 mg/m²/day) - FIRST-LINE for hypertension + proteinuria
• Target BP: <50th percentile for age (ESCAPE Trial - 30% fewer patients reached endpoint)

• ESAs (Epoetin alfa, Darbepoetin) - target Hb 10-12 g/dL
• Iron supplementation (IV preferred in CKD)

• Phosphate restriction + phosphate binders (calcium carbonate, sevelamer)
• Active Vit D: Calcitriol (suppresses PTH)

• Recombinant Growth Hormone (rhGH) - SC injection daily
• Indicated if height <2 SD below mean
• Does NOT accelerate CKD progression (safe long-term)

• Sodium bicarbonate to maintain HCO₃ ≥22 mEq/L

• Peritoneal dialysis (PD) - preferred in infants/young children
• Hemodialysis - older children
• Renal transplantation - BEST long-term option; pre-emptive transplant has best outcomes

High-Yield Points ⭐

1. CAKUT = most common cause (~50%)
2. Growth failure = hallmark of pediatric CKD (not seen in adult CKD)
3. Schwartz formula: eGFR = 0.413 × H/Cr (k values: 0.33, 0.45, 0.55, 0.70)
4. LVH = 50-75% of children on dialysis; cardiovascular disease = leading cause of death
5. rhGH is safe and effective; does NOT worsen CKD
6. ACE inhibitor = first-line antihypertensive

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PART 2: RESPIRATORY TOPICS

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7. ASTHMA IN CHILDREN

Definition

Pathophysiology (Pediatric Specific)

• Children: compliant chest walls, horizontal ribs → limited thoracic expansion
• Ventilation is diaphragm-dependent in infants
• Oxygen consumption 2× adults → rapid fatigue → hypoxemia → bradycardia → arrest

NAEPP Classification (Ages 5-11 years)

Common Triggers

• URI - most common in children
• Allergens (dust mites, cockroaches, mold, pet dander)
• Cold air, exercise, cigarette smoke
• GERD, emotional stress

Severity of Acute Attack

⭐ Rising pCO₂ in acute asthma = impending respiratory failure (normally ↓pCO₂ due to hyperventilation)

Management - Acute Exacerbation (ED)

Stepwise Long-Term Management

High-Yield Points ⭐

1. "Silent chest" = NO air movement = most severe (critical emergency)
2. Rising pCO₂ = impending arrest
3. SpO₂ ≤92% = supplemental O₂ needed
4. Avoid β-blockers (precipitate bronchospasm)
5. Asymmetric wheeze → think foreign body, pneumothorax
6. Step up if SABA needed >2 days/week for symptoms

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8. PNEUMONIA IN CHILDREN

Etiology by Age (KEY EXAM TABLE)

⭐ S. pneumoniae = most common BACTERIAL cause beyond neonatal period ⭐ Mycoplasma = "walking pneumonia" in school-age children (headache, GI symptoms, arthralgia + cough)

Clinical Features

• Tachypnea - most sensitive sign in young children
• Nasal flaring, retractions, grunting
• Cough, fever, reduced breath sounds, rales
• "Head nodding" - highly specific for severe hypoxia
• Pulse oximetry - most important investigation

Management by Age

Complications

• Parapneumonic effusion/empyema
• Pneumatocele (especially S. aureus)
• Lung abscess
• Respiratory failure, sepsis

High-Yield Points ⭐

1. Pneumonia = ~20% of childhood deaths globally
2. CXR does NOT reliably differentiate bacterial vs viral
3. ALL neonates <3 weeks with respiratory symptoms = ADMIT
4. PCV-13 vaccine dramatically reduced S. pneumoniae pneumonia

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9. BRONCHIOLITIS

Definition

Etiology

RSV season: December-March (late winter) 90% of children exposed to RSV by age 2 years RSV does NOT confer lasting immunity - reinfections common

Pathophysiology

Clinical Features (Progression)

1. Rhinitis (runny nose)
2. Cough → tachypnea
3. Wheeze, rales (fine crackles)
4. Retractions, nasal flaring, grunting
5. Transient apnea (especially premature infants - RED FLAG)

Management - SUPPORTIVE CARE IS MAINSTAY

Criteria for Hospital Admission

• RR >70/min
• SpO₂ <92% on room air
• Apnea
• Unable to maintain oral hydration
• Age <12 weeks with moderate-severe symptoms
• High-risk: CHD, prematurity, immunodeficiency

High-Yield Points ⭐

1. Most common cause = RSV (not Mycoplasma)
2. CXR and viral testing NOT routinely obtained
3. Bronchodilators + steroids + antibiotics = NOT routinely recommended
4. Palivizumab = anti-RSV monoclonal antibody (NOT a vaccine)
5. Breastfeeding is protective (3× higher hospitalization in non-breastfed)

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10. LOWER RESPIRATORY TRACT INFECTIONS (LRTI)

Classification

Bacterial Tracheitis - Important Special Entity

• Pathogen: S. aureus/MRSA (+ mixed flora)
• Age: 3-5 years
• 3× more likely to cause respiratory failure than epiglottitis + croup combined
• Starts as croup-like illness → sudden toxic deterioration
• Biphasic (inspiratory + expiratory) stridor - distinguishes from croup
• X-ray: Shaggy tracheal air column
• Poor/no response to racemic epinephrine
• Management: Intubation (often in OR) + Vancomycin + 3rd-gen cephalosporin × 7-10 days

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11. STRIDOR

Classic Comparison Table

Management of Viral Croup

• Oral dexamethasone 0.15-0.6 mg/kg (single dose)

• Dexamethasone +
• Nebulized epinephrine (L-epinephrine 1:1000, 0.5 mL/kg max 5 mL in 2 mL NS)
• Observe 2-3 hours after epinephrine (rebound risk)

• Heliox (80:20) + consider intubation (ETT ½ size smaller)

Foreign Body Aspiration

• Most common: Toddlers 6 months-3 years; round foods (peanuts, grapes, hot dogs)
• Right main bronchus most commonly affected
• Signs: Witnessed choking + unilateral wheeze + asymmetric breath sounds
• Management:
  • Infant (<1 yr): 5 back blows + 5 chest thrusts (NO abdominal thrusts)
  • Child (>1 yr): Heimlich maneuver (abdominal thrusts)
  • Unconscious: Chest compressions; look in mouth before each breath
  • NO blind finger sweeps
  • Definitive: Rigid bronchoscopy

High-Yield Points ⭐

1. Croup = most common infectious cause of stridor (>90%)
2. "Steeple sign" = Croup (subglottic narrowing on AP neck X-ray)
3. "Thumbprint sign" = Epiglottitis (on lateral neck X-ray)
4. NEVER lay down a child with epiglottitis - risk of complete obstruction
5. Balloons = most lethal aspirated foreign body in children
6. No abdominal thrusts in infants - risk of organ injury

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PART 3: EMERGENCY / CRITICAL CARE

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12. SHOCK IN CHILDREN

Types

⭐ Sepsis = leading cause of death in children worldwide; mortality ~25%

Clinical Features

• Tachycardia - MOST SENSITIVE early sign
• Prolonged capillary refill >2 seconds
• Mottled/cool skin (cold shock) OR warm/flushed (warm/distributive)
• Normal BP maintained

• Hypotension (LATE sign in children - they compensate well!)
• Altered mental status
• Oliguria (<1 mL/kg/hr)
• Cyanosis, respiratory failure

PALS Management - First Hour Bundle

Epinephrine > Dopamine as first-line vasopressor in pediatric septic shock

High-Yield Points ⭐

1. Hypotension is LATE - children maintain BP via tachycardia + vasoconstriction
2. Tachycardia = most sensitive early indicator of shock
3. IO route = acceptable for ALL drugs/fluids if IV fails
4. Fluid bolus = 20 mL/kg LR each time
5. Antibiotics within 1 hour reduces mortality

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13. ANEMIA IN CHILDREN

Classification by MCV

Iron Deficiency Anemia (IDA) - Most Common

• Pallor, fatigue, irritability
• Pica (craving ice, dirt, paper) - PATHOGNOMONIC of iron deficiency
• Koilonychia (spoon nails), cheilosis, glossitis
• Tachycardia, murmur in severe cases

• Ferrous sulfate 3-6 mg/kg/day elemental iron orally
• Dietary modification (reduce cow's milk to ≤500 mL/day)
• Reticulocytosis within 5-7 days confirms response
• Treat for 3 months after Hb normalizes (replenish stores)

Sickle Cell Disease

Thalassemia

High-Yield Points ⭐

1. IDA = most common anemia and nutritional deficiency worldwide
2. Pica = pathognomonic for iron deficiency
3. Ferritin = best single test for iron stores
4. Hb electrophoresis diagnoses sickle cell + thalassemia
5. Thalassemia trait vs IDA: both microcytic; Hb electrophoresis differentiates
6. Parvovirus B19 → aplastic crisis in sickle cell children
7. Universal Hb screening at 1 year (AAP)

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14. CPR (CARDIOPULMONARY RESUSCITATION) - PEDIATRIC

Key Principles

• Pediatric cardiac arrest: usually from progressive respiratory/circulatory failure (NOT sudden cardiac arrest like adults)
• Brain ATP depleted after 4-6 minutes without blood flow
• Pediatric in-hospital cardiac arrest survival: ~40% (better than adults ~25%)
• Bystander CPR can more than double survival

Compression Technique

⭐ With advanced airway: continuous compressions + 1 breath every 6 seconds

Shockable vs Non-Shockable

Drug Doses in Cardiac Arrest

Reversible Causes - H's and T's

High-Yield Points ⭐

1. CAB order (Compressions → Airway → Breathing) since 2010
2. Epinephrine IV dose: 0.01 mg/kg (NOT 0.1 mg/kg)
3. ETT epinephrine = 10× the IV dose (0.1 mg/kg)
4. Do NOT interrupt compressions >10 seconds
5. Allow full chest recoil between compressions
6. Pediatric VF/pVT is less common than in adults

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15. BLS (BASIC LIFE SUPPORT) - PEDIATRIC

AHA Pediatric BLS Sequence (CAB Order)

1. CHECK RESPONSIVENESS + Activate EMS simultaneously
2. C — COMPRESSIONS (START FIRST)
   - Rate: 100-120/min
   - Depth: ≥1/3 AP chest diameter
   - Allow FULL RECOIL between compressions
3. A — AIRWAY (Head-tilt chin-lift; Jaw thrust if trauma)
4. B — BREATHING (2 rescue breaths, 1 sec each, visible chest rise)
5. Continue: 30:2 (1 rescuer) OR 15:2 (2 rescuers)
6. AED: Apply as soon as available → Analyze → Shock if indicated

Key Parameters

CAB vs ABC - Why Changed in 2010?

• Compressions generate immediate perfusion
• Most arrests are cardiac in origin → compressions most critical
• Exception: NEWBORNS still use ABC (neonatal arrests are almost always respiratory)

Foreign Body in BLS

High-Yield Points ⭐

1. BLS = no equipment required (except AED)
2. CAB since 2010; Newborns = ABC (exception)
3. Infants: 2-thumb encircling technique preferred (2 rescuers)
4. NO abdominal thrusts in infants (organ injury risk)
5. 15:2 ratio ONLY with 2 rescuers + child/infant victim

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16. POISONING IN CHILDREN

General Approach (ABCDE)

A - Airway: Open; intubate if GCS ≤8 or declining
B - Breathing: O₂, SpO₂ monitor
C - Circulation: IV access × 2, cardiac monitor, 12-lead ECG
D - Disability: GCS + FINGERPRICK GLUCOSE (IN ALL!) + pupils
E - Exposure: Full skin exam; decontamination; remove clothing

Gastric Decontamination

Specific Poisons

A. Organophosphate Poisoning

• Diarrhea, Urination, Miosis, Bronchorrhea/Bronchospasm, Bradycardia, Emesis, Lacrimation, Salivation

Atropinization ENDPOINT: Secretions dry + chest clear + HR ≥80 (NOT pupil dilation - miosis may persist) AVOID: Succinylcholine (prolonged paralysis), β-blockers

B. Paracetamol (Acetaminophen) Overdose

• IV: 150 mg/kg over 1 hr (loading) → 50 mg/kg over 4 hr → 100 mg/kg over 16 hr
• Most effective if given <8-10 hours post-ingestion
• Use Rumack-Matthew nomogram (4-hr level)

C. Organophosphate vs Paracetamol - Key Difference

• Organophosphate: cholinergic crisis → DUMBBELS
• Paracetamol: may be asymptomatic initially then liver failure on days 3-4

D. Salicylate Poisoning

• Features: Tinnitus, hyperventilation (respiratory alkalosis early), fever, metabolic acidosis
• Reye's Syndrome: Aspirin + viral illness (chickenpox/flu) → liver failure + encephalopathy
• Management: Urinary alkalinization (NaHCO₃) + hemodialysis for severe cases

E. Iron Poisoning

• Phases: GI phase → latent phase → systemic toxicity → hepatic necrosis
• Treatment: Deferoxamine 15 mg/kg/hr IV (for serum iron >500 μg/dL)
• WBI for radiopaque tablets on X-ray

Master Antidote Table

High-Yield Points ⭐

1. Fingerprick glucose IN ALL unconscious/altered children
2. DUMBBELS = organophosphate (muscarinic features)
3. Pralidoxime must be given EARLY before "aging" of AChE
4. NAC most effective within 8-10 hours for paracetamol
5. Syrup of ipecac is OBSOLETE
6. Reye's syndrome = aspirin + viral illness (chickenpox/flu) in children

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17. UNCONSCIOUS CHILD MANAGEMENT

Rapid Assessment Scales

GCS ≤8 = Severe; INTUBATE Min GCS = 3; Max GCS = 15

Causes of Unconsciousness - AEIOU TIPPS

Immediate Management (ABCDE)

A - Airway: Position; jaw thrust if trauma; suction
B - Breathing: O₂; BVM if inadequate; INTUBATE if GCS ≤8
C - Circulation: IV access × 2; cardiac monitor; 12-lead ECG
D - Disability:
    ★ FINGERPRICK GLUCOSE FIRST (most critical immediate test)
    ★ Treat hypoglycemia: 5 mL/kg D10W IV OR 1-2 mL/kg D50W
    ★ Pupils (equal, reactive)
    ★ GCS/AVPU
E - Exposure: Temperature; trauma signs; RASH (petechiae = meningococcemia!)

Investigations

• Bedside immediate: Glucose, SpO₂, ECG
• Blood: CBC, electrolytes, glucose, BUN/Cr, LFTs, ammonia, Ca, Mg, ABG, blood cultures, TFTs, toxicology screen
• CT head (before LP if signs of raised ICP)
• LP (CSF): After CT, if meningitis/encephalitis suspected - DO NOT delay antibiotics for LP
• EEG: Non-convulsive status epilepticus
• Ophthalmology: Retinal hemorrhages (non-accidental injury/shaken baby)

Signs of Raised ICP (Cushing's Triad)

• ↑ Blood pressure (hypertension)
• ↓ Heart rate (bradycardia)
• Irregular respirations (Cheyne-Stokes)

• Papilledema + Unilateral dilated pupil (uncal herniation)

High-Yield Points ⭐

1. ALWAYS check glucose FIRST in unconscious child
2. Petechial rash + fever + altered consciousness = meningococcemia → Benzylpenicillin IM IMMEDIATELY
3. GCS ≤8 = intubate for airway protection
4. Cushing's triad = raised ICP
5. CT head BEFORE LP if any signs of raised ICP

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18. MENINGITIS - TUBERCULAR AND BACTERIAL

CSF Findings - Master Comparison Table

⭐ Bacterial = Neutrophils + ↑Protein + ↓Glucose ⭐ TBM = Lymphocytes + ↑↑Protein + ↓Glucose (ratio <0.5) ⭐ Viral = Lymphocytes + Normal/slight ↑Protein + Normal Glucose

Bacterial Meningitis

Organisms by Age

Top 3 organisms = S. pneumoniae + N. meningitidis + H. influenzae = 80% of community-acquired cases

Clinical Features

• Fever + Headache + Neck stiffness

• Kernig's sign: Unable to extend knee when hip flexed at 90°
• Brudzinski's sign: Passive neck flexion → involuntary hip/knee flexion

Empiric Antibiotic Therapy

Adjunctive Dexamethasone

• 0.15 mg/kg every 6 hours × 2-4 days
• Give 10-20 minutes BEFORE or WITH first antibiotic dose
• Strongly recommended for Hib meningitis (reduces sensorineural hearing loss)
• Consider for pneumococcal meningitis
• Do NOT give if antibiotics already started

Tubercular Meningitis (TBM)

Pathogenesis

• Hematogenous spread of M. tuberculosis → often follows miliary TB
• Subpial caseous foci rupture into subarachnoid space → meningeal inflammation

Clinical Features

• Gradual/insidious onset (days to weeks)
• Low-grade fever initially
• Cranial nerve palsies (III, VI, VII most common) - due to basal meningitis
• Communicating hydrocephalus (common complication)
• Lymphocytic CSF with low glucose + high protein

Additional Investigations

• ADA (Adenosine Deaminase) - elevated in TBM
• AFB smear + culture (weeks to grow)
• CSF PCR (improving sensitivity)
• CT head: Basal meningeal enhancement, hydrocephalus, infarcts
• Mantoux test, Chest X-ray (miliary pattern), Gastric lavage for AFB

ATT Treatment Regimen for TBM

• Dexamethasone 0.15 mg/kg q6h OR prednisolone 1-2 mg/kg/day × 4-6 weeks → taper over 6-8 weeks
• Reduces mortality and neurological complications

Meningitis Prophylaxis

• Rifampicin 10 mg/kg (max 600 mg) q12h × 2 days
• OR Ceftriaxone IM single dose (125 mg if ≤15 yr; 250 mg if >15 yr)

• Rifampicin 20 mg/kg (max 600 mg) once daily × 4 days

High-Yield Points ⭐

1. Bacterial = neutrophils; TBM/Viral = lymphocytes (most important CSF differentiator)
2. TBM: CSF glucose ratio <0.5; protein ↑↑; "spider web clot" formation
3. NEVER delay antibiotics for LP - give after blood cultures
4. Petechial rash + fever = meningococcemia → Benzylpenicillin IM IMMEDIATELY
5. Dexamethasone BEFORE antibiotics (maximize benefit)
6. Bulging fontanelle in infants = equivalent of papilledema (raised ICP)
7. TBM treatment: 2 months HRZE → 7-10 months HR (total 9-12 months)
8. Cranial nerve palsies (III, VI, VII) = hallmark of TBM (basal meningitis)
9. Hib vaccine has virtually eliminated H. influenzae meningitis

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MASTER QUICK-REFERENCE SUMMARY

Critical Drug Doses at a Glance

Top High-Yield Exam Mnemonics

Key X-ray Signs

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