Neurology — 5-min cram sheet
_Built from the neuro disease index. Deck-faithful._
Buzzword → answer (the vignette reflex)
- Kayser-Fleischer rings (slit lamp) + low ceruloplasmin → Wilson's disease (ATP7B, autosomal recessive)
- Caudate atrophy on MRI + chorea + CAG >40 repeats → Huntington's (autosomal dominant, anticipation)
- Albuminocytologic dissociation (CSF) → Guillain-Barré (steroids DO NOT help — vs CIDP)
- Thunderclap "worst of my life", occipital + xanthochromia on LP → subarachnoid haemorrhage (aneurysm 70%)
- Lucid interval + biconvex/lens-shaped CT, doesn't cross sutures → epidural haematoma (middle meningeal artery at pterion)
- Crescent-shaped CT, crosses suture lines, bridging veins, elderly + atrophy → subdural haematoma
- Hyperdense MCA sign → early ischaemic stroke thrombosis
- Oligoclonal bands (IgG CSF > serum) + Lhermitte's / Uhthoff's / INO → multiple sclerosis
- RAPD + red desaturation + pain on eye movement → optic neuritis (often first MS presentation)
- AQP4-IgG + longitudinally extensive myelitis (>3 vertebral segments) → NMO (Devic's)
- Heliotrope rash + Gottron's papules + proximal weakness → dermatomyositis (adults → screen malignancy)
- Jaw claudication + scalp tenderness + ESR >50 mm/h, >50 y → giant cell arteritis (ophthalmic emergency)
- Young woman, high BMI + papilloedema + pulsatile tinnitus → idiopathic intracranial hypertension
- Restlessness/agitation + unilateral autonomic (lacrimation, ptosis, miosis) → cluster headache (TAC)
- Gowers sign + calf hypertrophy + CK up to 10,000 → Duchenne (X-linked, absent dystrophin)
- Fatigable weakness + ptosis/diplopia, sensory + reflexes normal → myasthenia gravis (ACh-R Ab, thymoma)
Lesion site / sign → deficit or diagnosis
| Localisation / sign | Deficit / diagnosis (index wording) |
| Subthalamic nucleus (contralateral) infarct | Hemiballismus — violent large-amplitude flinging |
| Substantia nigra pars compacta degeneration | Parkinson's — dopamine depletion, α-synuclein Lewy bodies |
| Caudate + putamen atrophy | Huntington's |
| ACA territory | Contralateral lower limb weakness |
| MCA territory | Contralateral UL/face/trunk + aphasia (dominant) |
| PCA territory | Homonymous hemianopia with macular sparing |
| PICA / lateral medulla (Wallenberg) | 4 lateral "S": ipsi ataxia, contra pain/temp, ipsi facial pain/temp, ipsi Horner's; CN IX/X → dysphagia/dysarthria |
| Anterior spinal artery | Medial medullary syndrome |
| Lenticulostriate artery rupture | Hypertensive ICH — basal ganglia + internal capsule |
| ACA-MCA / MCA-PCA border zone | Watershed infarct (prolonged hypotension; proximal > distal weakness) |
| Hippocampus + cerebellum (selective vulnerability) | Hypoxic brain injury |
| MLF lesion | Internuclear ophthalmoplegia (INO) |
| Frontal eye field (destructive lesion) | Eyes deviate towards lesion |
| Broca's (frontal) / Wernicke's (temporal) | Expressive / receptive dysphasia |
| Parietal optic radiation / temporal Meyer's loop | Inferior quadrantanopia / superior quadrantanopia ("pie in the sky") |
| Dominant parietal | Gerstmann — finger agnosia, acalculia, agraphia, R-L disorientation |
| Bilateral parieto-occipital / striate cortex | Cortical blindness; + denial (anosognosia) = Anton's; pupillary light reflex intact |
| Bilateral occipito-temporal | Prosopagnosia (face blindness) |
| Cord hemisection | Brown-Séquard — ipsi UMN + proprioception loss below, contra pain/temp loss |
| Central cord (syringomyelia) | Cape-like dissociated pain/temp loss, UL > LL |
| Anterior cord syndrome | Pain/temp loss below; vibration/proprioception spared |
| Uncal (transtentorial) herniation | Ipsilateral fixed dilated pupil (CN III) + PCA compression + Duret haemorrhages |
| Subfalcine (cingulate) herniation | ACA compression |
| Median nerve at wrist (Tinel/Phalen, thenar wasting) | Carpal tunnel — most common mononeuropathy |
| Ulnar nerve (cubital tunnel) | Claw hand / benediction sign |
| Radial nerve (spiral groove) | Wrist drop / Saturday-night palsy |
| Lateral femoral cutaneous under inguinal ligament | Meralgia paresthetica (pure sensory, oval lateral thigh) |
| HSV predilection | Temporal lobes (viral encephalitis) |
Criteria / staging / scores at a glance
- McDonald (MS): DIS + DIT + no better explanation. 2010 DIS = 4 regions (periventricular, juxtacortical, infratentorial, spinal cord); 2017 = OCBs can substitute for DIT in CIS; 2024 = optic nerve as 5th DIS site + kFLC + CVS + PRL.
- Migraine (IHS): 4–72 h; ≥2 of 4 (unilateral, throbbing, mod/severe, aggravated by movement); ≥1 of 2 (N/V or photo+phonophobia); chronic if ≥15 days/month.
- TTH (IHS): 30 min–7 days; ≥2 of 4 (bilateral, non-throbbing, mild/mod, not aggravated); no N/V; one or neither photo/phonophobia.
- MOH: headache ≥15 days/month; triptans/opioids/combos ≥10 days/month OR simple analgesics ≥15 days/month; ≥3 months overuse; resolves within 2 months.
- Tourette: ≥2 motor tics + ≥1 vocal tic; duration >1 y; onset <18 y (typical 5–10 y).
- Huntington's genetics: AD; HTT gene, CAG repeat expansion; normal 9–36; disease threshold >40; anticipation.
- GBS (functional): AIDP; symmetric ascending weakness + areflexia; CSF albuminocytologic dissociation; nadir by 4 weeks in 90%.
- NIHSS: 0 no stroke · 1–4 minor · 5–15 moderate · 16–20 mod-severe · 21–42 severe (max 42).
- ABCD2 (TIA): Age >60 (1), BP ≥140/90 (1), unilateral weakness (2), speech w/o weakness (1), duration 10–59 min (1) / ≥60 min (2), DM (1). Score 0–3 low (1.0%), 4–5 mod (4.1%), 6–7 high (8.1%) 2-day stroke risk.
- MS disease courses: RIS, CIS, RRMS, SPMS, PPMS; modifiers RAW (relapse-associated worsening) vs PIRA (progression independent of relapse activity).
- Intracranial haemorrhage classification: extradural (skull–dura), subdural (dura–arachnoid), subarachnoid (arachnoid–pia), intracerebral (parenchyma).
- DAI grades: I widespread corpus callosum/WM/brainstem; II + focal haemorrhage in corpus callosum; III + rostral brainstem. Histology = axonal spheroids ("retraction balls").
- Cerebral oedema: vasogenic (BBB breakdown; tumour/abscess/contusion; dexamethasone) vs cytotoxic (Na/K pump failure; ischaemia/hypoxia; mannitol).
- SOL herniation grades: I <2 cm from lesion; II >2 cm, <½ hemisphere; III >2 cm, >½, no midline shift; IV >2 cm, >½, with midline shift (subfalcine).
- Hyperkinetic movement disorders: chorea, dystonia, myoclonus, tremor, tic (less common: ballism, athetosis, stereotypy).
- Dystonia distribution: focal, segmental (≥2 contiguous), hemidystonia, multifocal (≥2 non-contiguous), generalised (trunk + ≥2 parts).
- Dystonia aetiology: primary (isolated), dystonia-plus (+parkinsonism/myoclonus), secondary (lesion/drug/tardive).
- CMT (HMSN) classification: groups HMSN/HMN/HSN-HSAN; onset early-infantile <2 y, childhood 2–10, juvenile 10–20, adult 20–50, late adult >50; demyelinating vs axonal; PMP22 CNV most common.
- Muscular dystrophies: congenital, Duchenne, Becker, limb girdle, myotonic, FSHD, Emery-Dreifuss, occulopharyngeal, distal.
- Myopathy umbrella: hereditary (congenital, dystrophy, distal) vs idiopathic/acquired (inflammatory, immune, infection/HIV, endocrine-metabolic, drugs/toxins, malignancy).
- Aphasia: Broca = expressive; Wernicke = receptive.
- Dysarthria: cerebellar, bulbar (LMN flaccid), pseudobulbar (UMN spastic), extrapyramidal.
- Watershed areas: ACA-MCA = high parasagittal cortex; MCA-PCA = posterior parietal/occipital; setting = prolonged hypotension.
- ICP thresholds: normal 7–15 mmHg; borderline 20–25; raised >25; IIH LP opening pressure >25 cm H₂O; CPP target >70 mmHg.
- Cushing triad: ↑BP + bradycardia + irregular respiration (± pupil dilation) = late sign of impending herniation.
- Rule of 4 (brainstem): 4 midline structures (motor pathway, medial lemniscus, MLF, motor nucleus) + 4 lateral "S"; 4 midline CNs = III, IV, VI, XII; 4 lateral CNs = V, VII, IX, XI.
- UMN vs LMN: tone spastic vs flaccid; reflexes brisk/clonus vs absent; plantar upgoing vs downgoing; fasciculations absent vs present; atrophy late vs early/marked.
- VITAMIN CD: Vascular, Infection/Inflammatory, Traumatic, Autoimmune, Metabolic, Idiopathic/Iatrogenic, Neoplastic, Congenital, Degenerative/Drug.
- CSF meningitis: bacterial = ↑↑ opening pressure, neutrophils, ↓ glucose, ↑↑ protein · viral = normal/mild ↑, lymphocytes, normal glucose, ↑ protein · fungal = ↑, lymphocytes, ↓ glucose, ↑ protein.
- SNOOP red flags: Systemic, Neurologic, Onset (thunderclap <1 min), Onset age (<5 or >65 y), Pattern change, Precipitated by Valsalva, Postural, Papilledema, Pregnancy, Phenotype of rare headache.
- Syncope DDx: structural (aortic stenosis, cardiomyopathy, RV dysplasia), arrhythmia (VT, Brugada, long QT, AV block), reflex (vasovagal, carotid), situational (cough, micturition), postural (orthostatic/POTS), OSA.
- rt-PA windows: NINDS 1996 = 3 h; ECASS 3 (2008) = 4.5 h. Dose 0.9 mg/kg (max 90), 10% bolus then rest over 1 h; door-to-needle ≤60 min.
- Mechanical thrombectomy: up to 6 h (extended windows possible); targets Carotid, M1/M2, A1/A2.
- IIH ladder: weight loss (first-line) → acetazolamide/topiramate/furosemide → repeated LP (15–25 mL/session) → CSF shunt if vision threatened.
- Meningitis empiric: IV cefotaxime/ceftriaxone 2 g qds; add IV ampicillin 2 g qds if >55 y (Listeria); dexamethasone 10 mg qds ×4 d; prophylaxis single-dose ciprofloxacin OR rifampicin 600 mg bd ×2 d.
- GCA treatment: long-term oral steroids 1 mg/kg; monitor ESR.
- TBI initial management: 12 steps (GCS → wound exam → elevate head → ABC → repeat GCS → neuro exam → anticonvulsants → osmotic diuretics if ↓GCS → C-spine imaging → CT brain → polytrauma survey → labs).
- Brainstem death: flat EEG + loss of corneal reflex; if not dead → craniectomy.
- Duroplasty grafts: autograft (fascia lata), xenograft (bovine pericardium), allograft (artificial).
- Post-stroke complications to prevent: painful shoulders, pressure sores, contractures, incontinence, malnutrition, aspiration pneumonia.
- Rehab DON'Ts: don't pull hemiparetic arm, don't squeeze fingers, don't leave in one position, don't catheterise if possible.
- Brain plasticity: dendritic growth + axonal arborisation post-stroke; rehab starts day 1 via MDT; "never too late".
Discriminators that decide questions
- UMN vs LMN: UMN = ↑tone (spastic), brisk reflexes/clonus, upgoing plantar (Babinski), no fasciculations, late/disuse atrophy. LMN = ↓tone (flaccid), absent reflexes, downgoing plantar, fasciculations present, early/marked atrophy.
- EDH vs SDH: EDH = biconvex/lens-shaped, does NOT cross sutures, arterial (middle meningeal at pterion), classic lucid interval. SDH = crescent-shaped, crosses suture lines, venous (bridging veins), elderly + dementia + atrophy; chronic SDH mimics stroke.
- GBS vs CIDP: GBS = nadir <4 weeks, cranial/respiratory involvement, steroids DO NOT help. CIDP = slowly progressive >8 weeks, spares cranial/respiratory muscles, steroids DO work.
- Migraine vs TTH: migraine = featureful (unilateral, throbbing, N/V, photo+phonophobia, aggravated by movement). TTH = featureless (bilateral, non-throbbing, no N/V, one or neither photo/phonophobia).
- Syncope vs GTCS: duration <30 s vs 1–2 min; jerks multifocal/non-rhythmic vs rhythmic; tongue bite tip vs lateral; post-ictal <30 s vs 2–30 min; pale vs cyanosed. (Jerks during syncope do NOT make it a seizure.)