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|Anti-NMDA (NMDAR) receptor encephalitis
|Herpes Simplex Encephalitis (HSV)
|Acute Encephalitis
|Limbic Encephalitis
|Paraneoplastic Limbic Encephalitis (Dementia)
|Hashimoto's (Steroid responsive) Encephalopathy
|Acute Disseminated Encephalomyelitis
|Measles
|Lumbar Puncture
|CSF Interpretation
🚨 Acute Hydrocephalus is a neurological and neurosurgical emergency requiring rapid recognition and intervention.
🔎 Aetiology
- Normal CSF volume ≈ 200 mL, produced mainly by the choroid plexus (~500 mL/day; ~20 mL/hr).
- CSF pathway: Lateral ventricles → Third ventricle → Fourth ventricle → Subarachnoid space via foramina of Luschka & Magendie.
- Absorbed via arachnoid granulations into venous sinuses.
- Hydrocephalus: Excess CSF accumulation → ventricular dilation → brain compression.
- Incidence: 1–2 per 1,000 live births.
- Types:
- Communicating hydrocephalus: Blockage beyond ventricles (e.g., SAH, meningitis, carcinomatous meningitis).
- Obstructive hydrocephalus: Blockage within CSF pathway (e.g., colloid cyst, aqueduct stenosis, tumours, Chiari malformations, Dandy-Walker).
🧠 Diagram of Ventricles
👶 Clinical Features in Infants
- Rapid head enlargement (due to open fontanelles).
- “Sun-setting eyes” 👀 (limited upward gaze due to tectal pressure).
- Irritability, poor head control, thin shiny scalp, tense fontanelle.
- Delayed milestones, breathing difficulty, cognitive impairment.
👩🦳 Clinical Features in Adults
- Severe headache, nausea, vomiting, blurred vision (papilloedema).
- Gait disturbance, truncal ataxia, UMN signs.
- Pituitary dysfunction (if suprasellar pressure).
- False-localising VI nerve palsy, impaired upward gaze (3rd ventricle enlargement).
- In severe cases: coma, pupillary changes, Cheyne-Stokes breathing.
🧪 Investigations
- CT/MRI: Dilated ventricles, mass lesion, obstructive vs communicating pattern.
- Communicating hydrocephalus → symmetrical ventricular dilation.
📸 Classical Imaging Signs
- Expansion of temporal horns.
- Convex third ventricular walls.
- Rounded frontal horns.
- Effacement of sulci.
- Ventricular enlargement out of proportion to cortical sulcal widening.
⚡ Management
- Emergency referral to neurosurgery.
- Surgical options:
- Ventriculoperitoneal (VP) shunt: Most common. Diverts CSF to peritoneal cavity or pleural space.
- External Ventricular Drain (EVD): Temporary drainage in acute cases.
- Endoscopic Third Ventriculostomy (ETV): Alternative in obstructive hydrocephalus.
- Medications (bridging only): Acetazolamide, furosemide to reduce CSF production.
- Complications: Infection (ventriculitis, shunt colonisation), shunt obstruction, subdural haematoma, shunt fracture/disconnection.
🖼️ Imaging Examples
