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BL Hand Muscle Wasting — Does Everything on This Diagram Cause It?

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LEFT BRANCH: UMN Signs (+) → Mixed UMN + LMN

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RIGHT BRANCH: Pure LMN Type

Anterior Horn Cell

Root (C8–T1 Radiculopathy)

Plexus

Peripheral Nerve

Muscle

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Bottom Left: Disuse Atrophy → RA

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Summary

1. Typically unilateral (unless bilateral disease): Pancoast tumour, lower trunk plexopathy, TOS, C8–T1 radiculopathy, ulnar neuropathy
2. Characteristically unilateral/asymmetric: Hirayama disease, MMN (multifocal motor neuropathy)
3. Bilateral but primarily proximal (hand wasting not a main feature): LGMD

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History to Ask — Structured Approach

🔴 The Working Diagnosis: Paraneoplastic Cerebellar Degeneration (PCD)

"Paraneoplastic cerebellar degeneration associated with breast and gynecologic (ovaries, uterus) carcinomas — anti-Yo, anti-Ri antibodies" — Localization in Clinical Neurology, 8e

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1. History of Presenting Illness — Cerebellar Symptoms

• Onset and progression — subacute onset over weeks to months is a red flag for PCD (vs. slow years-long course of hereditary ataxia)
• Sequence — which came first: gait unsteadiness, limb ataxia, slurred speech, double vision, oscillopsia?
• Any nystagmus / oscillopsia noticed?
• Dysphagia or dysphonia — brainstem involvement (paraneoplastic encephalomyelitis overlap)
• Cognitive changes / memory problems — limbic encephalitis component?
• Sensory symptoms in limbs — sensory neuronopathy (anti-Hu)
• Autonomic symptoms — postural dizziness, constipation, gastroparesis (anti-Hu PEM)

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2. Gynecological / Oncological History ← Most Critical in a 60F

• Last Pap smear / cervical screening — when was it done?
• Postmenopausal bleeding — endometrial/uterine carcinoma
• Breast lump, nipple discharge, last mammogram — breast cancer (anti-Yo)
• Ovarian symptoms — bloating, early satiety, pelvic fullness (ovarian carcinoma)
• Family history of breast, ovarian, or colorectal cancer (BRCA risk)

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3. Weight Loss Characterisation

• Duration — how long for 10 kg loss?
• Associated anorexia vs. normal appetite (anorexia + weight loss = malignancy)
• Night sweats — lymphoma (Hodgkin's → anti-Tr cerebellar degeneration)
• Dysphagia / odynophagia — oesophageal/gastric malignancy
• Haemoptysis / chronic cough / smoker — SCLC (anti-Hu)
• Change in bowel habits, rectal bleeding — colorectal cancer

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4. Smoking & Substance History

• Smoking pack-years — SCLC most associated with PCD via anti-Hu; also risk for paraneoplastic encephalomyelitis
• Alcohol — chronic alcohol use is a major non-paraneoplastic cause of cerebellar degeneration (vermis predominant, but can be pancerebellar)
• Alcohol quantity and duration — vermis atrophy, thiamine deficiency (Wernicke's)

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5. Medication & Toxic History

• Phenytoin — classic cause of cerebellar atrophy/toxicity
• Chemotherapy (prior cancer treatment) — cytarabine, 5-FU, methotrexate can cause cerebellar syndrome
• Lithium toxicity
• Heavy metals — mercury, lead

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6. Family History

• Hereditary ataxias (SCA — spinocerebellar ataxia types): onset at 60 is late but possible for SCA3/SCA6
• Family history of ataxia, Parkinson's, tremor

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7. Past Medical History

• Prior malignancy (even if "cured" — recurrence can present with PCD, including Hodgkin's)
• Hypothyroidism — cause of cerebellar syndrome (ask about fatigue, cold intolerance, constipation)
• Coeliac disease — ask about chronic diarrhoea, bloating (gluten ataxia)
• Diabetes — non-ketotic hyperglycaemia can cause cerebellar signs; also peripheral neuropathy
• Autoimmune disease — SLE, Sjögren's (anti-Ro antibodies linked to cerebellar ataxia)

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8. Systems Review

• Rash — dermatitis herpetiformis (gluten ataxia), or paraneoplastic
• Uveitis / vision changes
• Myoclonus / jerks — opsoclonus-myoclonus (anti-Ri, breast/gynaecological)
• Psychiatric symptoms — depression, anxiety, personality change (limbic involvement)

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Bottom Line for Exam

1. Gynaecological cancer (ovary/uterus → anti-Yo) — most likely in this demographic
2. Breast cancer screening history
3. Smoking/SCLC (anti-Hu)
4. Lymphoma (night sweats, nodes → anti-Tr)
5. Alcohol (non-paraneoplastic cause to exclude)
6. Subacute onset (weeks–months) — confirms paraneoplastic pattern vs. hereditary (years)

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Temporal Lobe Hyperintensity on MRI — Differentials & Approach

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DIFFERENTIALS

🔴 Category 1: Infectious / Inflammatory

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🟠 Category 2: Autoimmune / Paraneoplastic Limbic Encephalitis

"Typical MRI findings include unilateral or bilateral mesial temporal lobe abnormalities best seen on T2-weighted and FLAIR images. The temporal-limbic regions may be hypointense on T1 and rarely enhance with contrast." — Bradley & Daroff's Neurology

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🟡 Category 3: Vascular

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🟢 Category 4: Tumour

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🔵 Category 5: Metabolic / Toxic / Genetic

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APPROACH

Step 1 — Characterise the MRI Signal

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Step 2 — Clinical Context (History + Exam)

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Step 3 — Investigations

• FBC, CRP, ESR
• Electrolytes (hyponatraemia → LGI1)
• Serum autoimmune encephalitis panel: Anti-NMDAR, LGI1, CASPR2, AMPAR, GABA-B, Hu, Ma2
• Paraneoplastic screen (Anti-Hu, Yo, Ri)
• Lactic acid (MELAS)
• Thyroid (Hashimoto encephalopathy)

• Opening pressure, cells, protein, glucose
• HSV PCR ← start empirical aciclovir BEFORE result
• VZV, EBV, HHV-6, CMV PCR
• Oligoclonal bands
• CSF autoimmune antibodies (more sensitive than serum for some)
• Cytology (if malignancy suspected)

• Temporal lobe epileptiform activity supports limbic encephalitis or TLE
• Periodic lateralising discharges (PLEDs) → HSE

• MRI with contrast — enhancement pattern
• MR spectroscopy — if tumour vs. inflammation unclear
• PET/CT whole body — if autoimmune/paraneoplastic (find hidden primary)
• CT chest/abdomen/pelvis — tumour screen

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Step 4 — Management Principle

Temporal lobe hyperintensity → fever/acute onset?
        ↓ YES → Start IV Aciclovir immediately (HSE treatment)
        ↓ NO → Subacute? → Autoimmune workup + paraneoplastic screen
                        → Seizures only? → Consider status/postictal change
                        → Structural/chronic? → Tumour / hippocampal sclerosis workup

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CSF Findings: HSE vs Limbic Encephalitis

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Key Differentiating Points

1. RBCs in CSF — the single most useful bedside discriminator

"Up to 500 red cells/mm³ are common [in HSE], and the CSF protein content is usually elevated." — Plum & Posner's Diagnosis & Treatment of Stupor and Coma

2. Pleocytosis is variable in both — but more marked in HSE

• HSE: typically 50–200 WBC/µL, can be up to 1,000
• Limbic encephalitis: mild or absent — the CSF can be entirely normal in up to 50% of autoimmune cases

"CSF often demonstrates findings consistent with inflammation (protein >50 mg/dL or lymphocytic pleocytosis >5 cells/µL) but can be normal." — Washington Manual of Medical Therapeutics

3. HSV PCR — definitive test, but timing matters

• Sensitivity 96%, specificity 99% when tested at 48–72 hrs after symptom onset
• Can be falsely negative in the first 24–48 hours — a negative early PCR does NOT rule out HSE
• If strong clinical suspicion + negative PCR < 72 hrs → repeat LP at 72–96 hrs
• Never stop aciclovir based on a single negative early PCR

4. Antibody testing in CSF vs serum

• For autoimmune encephalitis, CSF antibodies are more sensitive than serum for some (e.g., anti-NMDAR)
• Must be sent specifically; not part of routine CSF biochemistry
• Some antibodies (Anti-LGI1, CASPR2) are more reliably detected in serum than CSF

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Practical Algorithm

CSF Result
    │
    ├─ RBCs present + lymphocytic pleocytosis + elevated protein
    │        → HSE most likely → CONTINUE aciclovir, await PCR
    │
    ├─ Lymphocytic pleocytosis, NO RBCs, normal glucose
    │        → HSE still possible (early) OR autoimmune
    │        → Send HSV PCR + autoimmune antibody panel
    │
    └─ Completely NORMAL CSF
             → Does NOT exclude autoimmune limbic encephalitis
             → Does make HSE less likely (but not impossible early)
             → Send serum + CSF antibody panel

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Important Caveat — Post-HSE Autoimmune Encephalitis

"Late autoimmune encephalitis can occur 1 to 7 weeks after herpes simplex encephalitis, associated with NMDA-receptor antibodies in the spinal fluid." — Goldman-Cecil Medicine

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MRI Images: HSE vs Limbic Encephalitis

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🔴 Herpes Simplex Encephalitis (HSE)

• A & B (Case 1): Axial + coronal FLAIR — hyperintense signal in the left medial temporal lobe and insula (arrows), with cortical swelling. Classic HSE territory.
• C (Case 2): T1 non-contrast — swollen left temporal lobe with faint cortical hyperintensity indicating haemorrhage (black arrows).
• D: T1 post-contrast — gyriform enhancement (white arrows) — a pattern highly suggestive of HSE.

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• (A) FLAIR: massive bilateral temporal lobe hyperintensity — confluent and asymmetric, consistent with fulminant HSE. Note the left temporal lobe is more severely affected.
• (B) Post-contrast T1: bilateral enhancement pattern with associated swelling.

Key radiological hallmarks of HSE: medial temporal + insula + cingulate + orbitofrontal involvement; haemorrhagic component; gyriform enhancement; grey matter > white matter.

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🟠 Autoimmune / Limbic Encephalitis

• A — Limbic Encephalitis (anti-Hu, Ma2, AMPAR, GABA-B, LGI1, Caspr2): Bilateral medial temporal lobe FLAIR hyperintensity — confined, symmetric, no haemorrhage, no gyriform enhancement. Clean signal restricted to hippocampus/amygdala.
• B — Anti-NMDAR encephalitis: Often normal MRI or only mild, subtle FLAIR changes — despite severe clinical syndrome.
• C — Anti-GABA-B encephalitis: Multiple cortical-subcortical FLAIR changes, more widespread than classic limbic encephalitis.
• D — MOG-antibody encephalitis (paediatric): Extensive cortical T2 signal, diffuse cortical involvement.

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Side-by-Side Differentiating Features on MRI

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Memory Hook

HSE = Haemorrhage + Swelling + Enhancement (gyriform) + Insula involved
Limbic Encephalitis = Limited to mesial temporal, Enhancement absent, Bilateral and symmetric

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Painful Vision Loss — Causes

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🔴 Category 1: Eye/Orbital Pain + Vision Loss

1. Acute Angle-Closure Glaucoma

• Most dramatic — excruciating periorbital/frontal pain, nausea, vomiting
• Sudden vision loss + coloured halos around lights
• Signs: red eye, hazy/steamy cornea, mid-dilated non-reactive pupil, rock-hard globe, shallow anterior chamber
• RAPD variable; fundus difficult to visualise due to corneal oedema
• Emergency — requires immediate IOP reduction

"Distinguishing characteristics include the severity of pain (which can be excruciating), presence of visual halos, and an injected eye with an enlarged, nonreactive pupil." — Bradley & Daroff's Neurology

2. Optic Neuritis

• Periorbital/retrobulbar pain, worse on eye movement — in ~90% of cases
• Subacute monocular vision loss over hours–days (nadir at ~1 week)
• RAPD present; colour desaturation (red desaturation earliest finding)
• Young female; strongly associated with MS
• Disc may appear normal (retrobulbar) or swollen (papillitis)
• Pain with eye movement is the clinical hallmark distinguishing it from other causes

3. Anterior Uveitis (Iritis/Iridocyclitis)

• Deep aching eye pain + photophobia + blurred vision
• Ciliary flush (perilimbal injection), cells and flare in anterior chamber, consensual photophobia
• Miosis (not mydriasis)
• Associated with HLA-B27 conditions (AS, reactive arthritis, psoriatic arthritis), sarcoidosis, Behçet's

4. Scleritis

• Severe boring/boring pain — often worst at night, may radiate to face/jaw
• Deep red/violaceous hue (not relieved by topical vasoconstrictors)
• Necrotising scleritis: may cause vision loss through secondary uveal or corneal involvement
• Strongly associated with rheumatoid arthritis, ANCA vasculitis, SLE

5. Endophthalmitis

• Severe pain + profound vision loss + hypopyon
• Post-operative (most common) or endogenous (haematogenous — IV drug users, immunocompromised)
• Vitritis, anterior chamber cells, swollen lids — ocular emergency

6. Corneal Pathology (Ulcer / Keratitis)

• Sharp, surface pain + photophobia + tearing
• Herpes simplex keratitis: dendritic ulcer on fluorescein
• Acanthamoeba keratitis: contact lens wearer, disproportionate pain
• Bacterial corneal ulcer: hypopyon possible

7. Orbital Cellulitis

• Periorbital pain + proptosis + restricted painful eye movements + chemosis
• Vision loss if optic nerve compressed (surgical emergency)
• Fever + signs of sinusitis
• Distinguish from preseptal (periorbital) cellulitis — the latter does not threaten vision

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🟠 Category 2: Headache/Retro-orbital Pain + Vision Loss

8. Giant Cell Arteritis (Temporal Arteritis)

• Age >50 (usually >70), female predominance
• Jaw claudication + scalp tenderness + temporal headache — then sudden, profound, painless or mildly painful vision loss
• Ischaemic optic neuropathy: swollen pale disc, RAPD
• Contralateral eye involved in days if untreated
• ESR >50, CRP elevated — start high-dose steroids immediately, before biopsy

9. Pituitary Apoplexy

• Sudden severe headache ("thunderclap") + bitemporal visual field loss + diplopia (CN III palsy)
• Haemorrhage/infarction into pituitary adenoma
• Cavernous sinus involvement → III, IV, VI nerve palsies

10. Cavernous Sinus Thrombosis

• Periorbital pain + proptosis + chemosis + ophthalmoplegia + fever
• Vision loss from optic nerve/retinal vein compromise
• Post-septal spread from sinusitis (sphenoid/ethmoid)

11. Migraine (Retinal/Ocular Migraine)

• Retro-orbital pain + transient monocular vision loss (scintillating scotoma)
• Fully reversible; younger patients; personal/family history of migraine
• Rare but can cause permanent retinal infarction

12. Carotid-Cavernous Fistula

• Pulsatile proptosis + ocular bruit + chemosis + elevated IOP → vision loss
• High-flow (post-traumatic) or low-flow (spontaneous, dural)

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🟡 Category 3: Acute Retinal Necrosis / Inflammatory

• Acute Retinal Necrosis (ARN): retinal arteriolar sheathing + peripheral retinal opacification + uveitis + pain
• Caused by VZV (>HSV) in immunocompetent; CMV in immunocompromised

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Summary Table

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Memory Framework

PAINFUL Vision Loss
        │
        ├── Eye pain → ACG, Uveitis, Scleritis, Keratitis, Endophthalmitis, Orbital cellulitis
        │
        ├── Pain on eye movement → OPTIC NEURITIS (MS)
        │
        └── Headache + pain → GCA, Pituitary apoplexy, Cavernous sinus thrombosis, Migraine

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Mild Painful Vision Loss Over 4–5 Days — Differential Diagnosis

The Clinical Profile Points To:

• Subacute onset (days, not seconds/minutes) → excludes vascular (CRAO, AION)
• Pain present → excludes most retinal pathology
• No fever → makes infection/endophthalmitis less likely
• No trauma → excludes traumatic causes
• No seizures → not post-ictal cortical visual loss
• Mild → not fulminant (not angle-closure crisis)

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Top Differentials

🥇 1. Optic Neuritis — Most Likely

• Pain: retrobulbar/periorbital, worse on eye movement — present in >90%
• Pain typically precedes or accompanies vision loss and lasts a few days
• Vision loss progresses over several days to 3 weeks, nadir at ~1 week
• Usual VA: 6/18–6/60 (mild to moderate)
• Colour desaturation (red colour looks washed out) — often more impaired than acuity suggests
• RAPD present
• Disc: normal in 2/3 (retrobulbar) OR swollen in 1/3 (papillitis)
• Age 20–50 years, female predominance

"Discomfort or pain in or around the eye is present in over 90% and typically exacerbated by ocular movement. It may precede or accompany the visual loss and usually lasts a few days." — Kanski's Clinical Ophthalmology

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🥈 2. Anterior Uveitis (Iritis)

• Deep aching eye pain + photophobia + blurred vision over days
• No fever typically in idiopathic/HLA-B27 associated forms
• Ciliary flush (ring of injection around limbus)
• Cells and flare in anterior chamber on slit lamp
• Posterior synechiae (iris stuck to lens)
• Consensual photophobia (shining light in good eye hurts the bad eye)
• Vision loss is usually mild-moderate; rarely severe unless complicated by cataract, macular oedema, or hypopyon

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🥉 3. Posterior Uveitis / Intermediate Uveitis

• Less prominent external pain but dull ache + vitreous floaters + blurred vision
• Progressive over days–weeks
• Vitritis on fundoscopy; may see choroidal/retinal lesions
• Causes: sarcoidosis, toxoplasmosis (reactivation), TB, syphilis, idiopathic

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4. Scleritis (Posterior)

• Posterior scleritis can be deceptive — less visible redness but significant dull, boring pain, often worse at night or on eye movement
• Proptosis, choroidal effusion, reduced motility, subretinal fluid
• Vision loss from retinal/choroidal involvement
• Associated with RA, vasculitis

"Posterior scleritis is more difficult to diagnose because some patients do not have anterior signs of inflammation." — Rosen's Emergency Medicine

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5. Acute Angle-Closure Glaucoma (Subacute/Intermittent form)

• The intermittent/subacute variant presents less dramatically than the acute crisis
• Episodes of mild pain, coloured halos, mildly blurred vision — coming and going over days
• No nausea/vomiting in mild form
• Narrow anterior chamber on exam; IOP elevated during episodes
• Risk: hypermetropes, Asian ethnicity, elderly females, dim-light exposure, mydriatics

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6. Corneal Pathology (Keratitis)

• Surface/foreign body pain (sharp, gritty) + photophobia + lacrimation
• Herpes simplex keratitis: recurrent, dendritic ulcer on fluorescein staining
• Vision blurred by corneal oedema/opacity
• No fever unless bacterial superinfection

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7. Optic Perineuritis

• Inflammation of the optic nerve sheath (not the nerve itself)
• Pain on eye movement similar to optic neuritis but vision relatively preserved
• Usually idiopathic; also with sarcoidosis, IgG4 disease, GPA
• Disc may be swollen; MRI shows nerve sheath enhancement ("tram-track" sign)

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8. Leber's Hereditary Optic Neuropathy (LHON) — Atypical Presentation

• Usually painless, but mild periocular discomfort occasionally reported
• Young male (maternal inheritance), subacute central visual loss
• Typically bilateral (fellow eye affected weeks–months later)
• Central scotoma, disc hyperaemia/pseudoedema in early phase
• If mild pain present: easy to confuse with optic neuritis

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Ranked by Probability for This Scenario

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Bedside Examination Steps

1. Visual acuity (each eye separately)
2. Colour vision (Ishihara — red desaturation in optic neuritis)
3. RAPD (swinging torch test) — present in optic neuritis, absent in uveitis
4. IOP — elevated in ACG
5. Slit lamp — anterior chamber cells/flare (uveitis), corneal staining, depth of anterior chamber
6. Fundoscopy — disc swollen (papillitis) vs normal (retrobulbar neuritis) vs vitritis (posterior uveitis)
7. Pain on eye movement — strongly suggests optic neuritis

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Unilateral Hand Muscle Weakness — Differentials

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Anatomical Framework

Cortex → Corticospinal tract → Cervical cord (C8/T1 segments)
                                        ↓
                              Anterior horn cell
                                        ↓
                              C8/T1 nerve roots
                                        ↓
                              Lower trunk of brachial plexus
                                        ↓
                      Medial cord → Ulnar nerve
                                  → Median nerve (partly)

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Level 1: Cortical / UMN

Contralateral Cortex / Corticospinal Tract

• Stroke (MCA territory — hand knob area)
• Brain tumour (cortical/subcortical)
• Cortical vein thrombosis
• Multiple sclerosis (cervical cord or cortical lesion)

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Level 2: Cervical Cord

C8/T1 Cord Segment

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Level 3: Anterior Horn Cell (LMN Pure)

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Level 4: C8/T1 Nerve Root

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Level 5: Brachial Plexus (Lower Trunk / Medial Cord)

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Level 6: Peripheral Nerve

Ulnar Nerve

Median Nerve

Radial Nerve

• Wrist drop (extensor weakness) ± finger drop; sensory loss dorsum hand
• Saturday night palsy (spiral groove), posterior interosseous nerve syndrome (no sensory loss, finger/thumb extension weak)

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Summary Localisation Table

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High-Yield Unilateral Causes to Remember

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Causes of Strictly Unilateral Hand Wasting

1. Anterior Horn Cell

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2. C8/T1 Nerve Root (Radiculopathy)

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3. Brachial Plexus — Lower Trunk / Medial Cord

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4. Peripheral Nerve

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5. Disuse Atrophy (Non-neurological)

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Memory Scaffold

UNILATERAL hand wasting — level by level:

CORD:         Hirayama ← young male, most important cause
              Syringomyelia (early/asymmetric)
              ALS focal onset

ROOT (C8/T1): Cervical disc C7-T1
              Cervical spondylosis
              Cervical rib

PLEXUS:       Pancoast (+ Horner's)
              Klumpke's (trauma)
              Neuralgic amyotrophy
              Radiation plexopathy
              TOS / cervical rib

NERVE:        Ulnar (elbow > wrist) → hypothenar/interossei
              Median (CTS) → thenar only
              Leprosy → combined

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The Single Most Important Discriminator

• No sensory loss → anterior horn cell (Hirayama, ALS, PMA, polio)
• Medial forearm + 4/5 fingers → lower trunk plexus or C8 root (Pancoast, disc, cervical rib)
• 4/5 fingers only (no forearm) → ulnar nerve at wrist
• Lateral 3½ fingers → median nerve (CTS)
• Dissociated (pain/temp lost, touch preserved) → cord (syringomyelia)

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Leprosy (Hansen's Disease) — Complete Crisp Summary

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Classification

• Paucibacillary (PB) = 1–5 lesions, no bacilli on smear → TT + BT
• Multibacillary (MB) = >5 lesions OR nerve trunk involvement OR bacilli on smear → BB + BL + LL

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Clinical Features by Type

Tuberculoid Leprosy (TT)

• 1–3 well-defined hypopigmented or erythematous plaques
• Raised edges sloping inward (punched-out appearance)
• Skin: dry, scaly, anhidrotic, anaesthetic, hairless
• One peripheral nerve thickened (commonly ulnar)
• Good prognosis; self-limiting in some

Lepromatous Leprosy (LL)

• Innumerable, symmetric, poorly defined lesions — macules, papules, nodules
• Skin: shiny, "succulent" texture
• Leonine facies — diffuse facial skin infiltration, thickened ear lobes, nodules (see image below)
• Madarosis — loss of lateral eyebrows and eyelashes
• Nasal involvement — saddle nose deformity, epistaxis, nasal stuffiness
• Gynecomastia, testicular atrophy, sterility (in males)
• Lagophthalmos — inability to close eyelids → corneal exposure → blindness
• Bilateral, symmetric peripheral neuropathy (both sensory and motor)
• High bacterial load — smear teeming with acid-fast bacilli

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Facies of Leprosy

• Diffuse facial infiltration → skin folds deepened → lion-like face
• Earlobe nodules (pathognomonic — earlobe hangs low, succulent)
• Madarosis — loss of lateral eyebrows (outer 1/3 first)
• Saddle-nose deformity (nasal cartilage collapse)
• Supraorbital ridging
• Lagophthalmos → corneal exposure → blindness
• Greater auricular nerve visible/palpable as thickened cord

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Hand Wasting in Leprosy

Nerves Commonly Affected

Hand Deformities

• Claw hand (Griffe) — ulnar claw (4th/5th fingers clawed due to interossei weakness)
• Ape/simian hand — thenar flat, thumb adducted (median nerve)
• Drop wrist — radial nerve
• Trophic ulcers — anaesthetic palm + pressure + trauma → perforating ulcers
• Absorption of digits — longstanding untreated LL — bones resorb
• Lagophthalmos from facial nerve involvement

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Diagnosis

Cardinal Signs (any ONE = diagnose leprosy)

1. Hypopigmented/erythematous skin lesion with loss of sensation
2. Thickened peripheral nerve (ulnar, common peroneal, great auricular, posterior tibial, radial cutaneous, supra-orbital, facial nerve)
3. Acid-fast bacilli (AFB) in slit-skin smear

Investigations

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Lepra Reactions (Immunological Emergencies)

Type 1 Reaction — Reversal Reaction (RR)

• Occurs in borderline types (BT, BB, BL)
• Sudden upgrade in cell-mediated immunity
• Existing lesions become acutely inflamed — erythematous, oedematous, warm, may ulcerate
• Neuritis — acute painful nerve swelling → may cause sudden motor/sensory loss
• Triggered by: pregnancy, MDT, infections, stress
• Treatment: Prednisolone 40–60 mg/day, tapered over 3–6 months; MDT continued

Type 2 Reaction — Erythema Nodosum Leprosum (ENL)

• Occurs in LL and BL (multibacillary, high antigen load)
• Immune complex (Type III hypersensitivity) — Ag-Ab complexes, complement activation
• New painful red nodules (not pre-existing lesions) over face, limbs, trunk
• Systemic features: fever, malaise, lymphadenopathy, iridocyclitis, orchitis, arthritis, neuritis, nephritis
• Treatment: Thalidomide (drug of choice — 100–400 mg/day; teratogenic — not in women of childbearing age) OR prednisolone; MDT continued
• Clofazimine also has anti-ENL activity (used for chronic/recurrent ENL)

Comparison

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Treatment — WHO MDT Regimens

Paucibacillary (PB) — 1–5 lesions

Multibacillary (MB) — >5 lesions or nerve involvement

Drug Side Effects

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Memory Framework

LEPROSY

Spectrum:  TT ←→ BT ←→ BB ←→ BL ←→ LL
            ↑ CMI              ↓ CMI
           Paucibacillary    Multibacillary

Diagnosis = ANY 1 of 3 cardinal signs

Hand:      Ulnar → claw hand (4,5)
           Median → ape hand (thenar flat)
           Both → pan-intrinsic wasting

Facies:    LL = Leonine + Madarosis + Earlobe nodules + Saddle nose

Reactions:
  Type 1 (RR) = Borderline → existing lesions inflame → Steroids
  Type 2 (ENL) = LL/BL → new painful red nodules + systemic → Thalidomide

MDT:
  PB = Rifampicin + Dapsone × 6 months
  MB = Rifampicin + Dapsone + Clofazimine × 12 months

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Wilson's Disease — Complete Neurology Viva Guide

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1. Basics (Viva Opener)

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2. Clinical Features

Neurological (40–50% present neurologically first)

• Tremor — "wing-beating tremor" (coarse, proximal, intention tremor with arms outstretched)
• Dysarthria — often the first sign; slurred, scanning speech
• Dystonia — generalised or focal; grimacing, abnormal postures
• Rigidity — Parkinsonian type
• Chorea / athetosis
• Dysphagia
• Gait ataxia
• Seizures (rare)

Psychiatric (20% present psychiatrically)

• Personality change (irritability, aggression)
• Depression, anxiety
• Psychosis (rare)
• Declining school/work performance in adolescents

Hepatic

• Jaundice, hepatomegaly, splenomegaly
• Chronic hepatitis → cirrhosis
• Acute liver failure with Coombs-negative haemolytic anaemia — classic/emergency presentation

Systemic

• Renal: Fanconi syndrome — aminoaciduria, phosphaturia, haematuria, nephrolithiasis
• Haematological: Coombs-negative haemolytic anaemia (copper → RBC oxidative damage)
• Musculoskeletal: osteoporosis, arthritis (large joints), rickets
• Endocrine: amenorrhoea, infertility, hypoparathyroidism

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3. Kayser-Fleischer (KF) Ring

"Most patients with a neurologic or psychiatric presentation of Wilson disease have Kayser-Fleischer rings; only 5% do not." — Sleisenger & Fordtran

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4. MRI of Wilson's Disease

Image 1 — Full spectrum of basal ganglia and brainstem changes:

Image 2 — Midbrain signs and pontine involvement:

MRI Findings — Summary

MRI Hallmarks — Viva Points

• T2 hyperintensity in putamen = most common MRI finding in Wilson's
• "Face of Giant Panda" sign = T2 hyperintense midbrain tegmentum + dark red nuclei (eyes) + dark substantia nigra pars reticulata (ears) = pathognomonic for Wilson's
• T1 hyperintensity in basal ganglia = seen in some cases (copper/manganese deposition)
• MRI abnormalities may partially/fully reverse with treatment

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5. Differential Diagnosis

For Bilateral Basal Ganglia T2 Hyperintensity

For Young-Onset Movement Disorder + Liver Disease

• Wilson's (AR, copper), Niemann-Pick type C (NPC1/NPC2, sphingomyelinase), Gaucher disease, Westphal variant Huntington's (rigid juvenile), NBIA

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6. Diagnosis

Leipzig Scoring System (Viva must-know)

Key Lab Values

Trick question: Serum ceruloplasmin can be normal in acute liver failure (acute phase reactant) and low in normal neonates — do not use alone

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7. Treatment

Chelating Agents (First-Line for Symptomatic)

Zinc Acetate (Maintenance / Presymptomatic)

• Mechanism: Induces metallothionein in intestinal cells → blocks copper absorption → copper lost in faeces
• Uses: Presymptomatic patients, maintenance after initial chelation, pregnancy (safest in pregnancy)
• Dose: 50 mg elemental zinc TDS
• Side effect: Dyspepsia; risk of hepatic decompensation if used as sole initial therapy
• Takes 4–6 months to achieve copper balance

Liver Transplant

• Indicated: Acute liver failure unresponsive to medical therapy; end-stage cirrhosis
• Corrects both hepatic failure AND neurological disease (provides normal ATP7B enzyme)

Dietary Restriction

• Avoid: shellfish, liver, nuts, chocolate, mushrooms, drinking water with copper >1.3 mg/L

Treatment is lifelong — stopping causes relapse and liver failure

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8. High-Yield Viva Questions

250 µg/g dry weight (normal 20–50 µg/g)

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Wilson's Disease MRI — Full Explanation

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Image 1 — Axial T2: Bilateral Basal Ganglia Hyperintensity (Most Common Finding)

• Bright (hyperintense) caudate nuclei bilaterally — the curved structures flanking the lateral ventricles
• Bright putamen bilaterally — the lateral part of the lentiform nucleus
• Bright thalami bilaterally
• Midbrain tegmentum bright — the region around the aqueduct
• No mass effect — this is not oedema from a tumour, it is diffuse copper-induced cytotoxic injury and gliosis

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Image 2 — The Three Classic MRI Signs Together

• Symmetrical bright signal in bilateral thalami, basal ganglia and dorsal mesencephalon (midbrain)
• FLAIR suppresses CSF — so the bright areas here are genuine parenchymal signal, not CSF
• This confirms bilateral deep grey matter involvement — characteristic of Wilson's

• Bright background = T2 hyperintense midbrain tegmentum (the region of copper/gliosis)
• Dark dots in the centre = red nuclei — they appear DARK because they are relatively spared and contain iron normally → form the "eyes" of the panda
• Dark outline laterally = substantia nigra pars reticulata → forms the "ears"
• Dark region inferiorly = superior colliculi → forms the "mouth"
• Net result: the midbrain looks like a panda's face → pathognomonic for Wilson's disease

• Bilateral frontal > parietal white matter hyperintensity — diffuse leukoencephalopathy in severe/late Wilson's
• This reflects demyelination and gliosis from copper toxicity spreading into white matter tracts

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Image 3 — Giant Panda Sign Close-up (Single Axial T2 at Midbrain Level)

• Level: midbrain at the level of the superior colliculi
• You can see the bright (white) tegmentum surrounding the central structures
• The dark red nuclei (round, symmetrical, flanking the midline) = the panda's eyes
• The dark substantia nigra laterally = the panda's ears
• The whole midbrain takes on a face-shaped appearance at this level

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Image 4 — Full Series: All Six Wilson's MRI Patterns

• Blue arrow → caudate nucleus bright
• Green arrows → putamen bright bilaterally
• White arrow → splenium of corpus callosum bright (copper deposits in posterior commissural fibres)
• Red arrow → thalamus bright

• Green arrows → midbrain tegmentum hyperintensity bilaterally at different cuts through the midbrain
• The relative dark regions (red nuclei) can be identified against this bright background

• Green arrow → "Bright claustrum" sign — the claustrum (a thin grey matter layer lateral to the putamen and medial to the insula) appears bright; this is highly specific for Wilson's disease
• Red asterisk → T2-hypointense globus pallidus — in contrast to the hyperintense putamen/caudate; GP hypointensity = heavy iron/copper mineralisation (copper itself is diamagnetic but associated iron causes T2 shortening)

• Green arrow → Classic "central hypointensity surrounded by hyperintensity" in putamen
• This "eye within eye" or "target" pattern reflects: outer ring = gliosis/oedema (bright) + inner core = copper/iron deposition (dark)

• Green arrow → Face of Giant Panda sign — clearest demonstration, with bright tegmentum and dark central structures forming the face pattern

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Image 5 — Pontine Signs: Face of Panda Cub + Trident Sign

• "Face of Panda Cub" sign — T2 hyperintensity in pontine tegmentum with relative sparing of the central tegmental tracts (which appear dark) → smaller panda face at pons level
• "Trident sign" — T2 hyperintensity in the basis pontis in a trident shape, sparing the corticospinal tracts

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Summary: Wilson's MRI Signs in Order of Importance

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Why Do Different Structures Show Different Signals?