Makindo Medical Notes

Related Subjects: |Subdural haematoma

🩸 A Subdural Haematoma (SDH) = bleeding between the dura mater and arachnoid. 🧠 Usually venous (bridging veins) → slower onset than extradural bleeds. ⚠️ Classic in the elderly, alcoholics, and anticoagulated patients. Can present acutely (coma) or chronically (confusion, delirium).

💡 Mechanism

• Tear in bridging veins, often after acceleration–deceleration injury.
• Can cause altered mental state (delirium → coma).
• Worsened by cerebral atrophy (elderly, alcoholics).
• CT head + cervical spine = essential in trauma.

📌 Top Tips

• 💻 SDH may appear isodense on CT and be missed → MRI helpful.
• 👨‍⚕️ Neurosurgeons often delay evacuation until clot liquefies → easier removal via burr holes.

🧬 Aetiology & Causes

• Bridging vein rupture (main mechanism).
• Risk factors:
  • Falls (esp. elderly 👴)
  • Alcohol abuse 🍺
  • Anticoagulation (e.g. warfarin) 💊
  • Seizures, assaults, RTA
  • Low CSF pressure post-LP or shunt

🩺 Clinical Features

• Acute: ↓ GCS, headache, drowsiness, seizures.
• Chronic: Insidious confusion, delirium, gait disturbance.
• Focal neurology: hemiparesis/hemisensory loss.
• Pupil changes (fixed, dilated, CN III palsy) → herniation.
• Signs of ↑ ICP: Cheyne–Stokes breathing, bradycardia, hypertension.

📷 Imaging Examples

Large Left Subacute SDH with Midline Shift

Large Left Acute SDH with Midline Shift

🔬 Investigations

• Bloods: FBC, U&E, clotting screen (check INR if on warfarin; platelets >100 × 10⁹/L if surgical).
• CT Head: Crescent-shaped, extra-axial collection; crosses suture lines (unlike extradural).
• MRI: Helpful if haematoma is isodense on CT.
• CT Cervical Spine: Rule out associated fractures.

⚠️ Complications

• Recurrent SDH
• Seizures (often focal → generalized)
• Raised ICP & brain herniation
• Infection (subdural empyema)
• ACA infarction (from falx compression)

⚡ Management

• Acute SDH: ABC stabilisation, urgent neurosurgical referral, reverse anticoagulation, anticonvulsants if seizures.
• Surgery:
  • Acute: Trauma craniotomy if large clot.
  • Chronic: Burr holes once clot liquefies (preferred). Evacuate if >10 mm thick or midline shift >5 mm.
• Conservative: Small, stable SDH monitored with repeat imaging.
• Palliative: Consider in frail patients with severe brain injury.

📋 Key Exam Tips

✅ EDH vs SDH: - EDH = arterial, biconvex (lens-shaped), does NOT cross sutures, lucid interval. - SDH = venous, crescent-shaped, CAN cross sutures, insidious/chronic course.

✅ Think SDH in elderly, alcoholics, or anticoagulated with confusion after a fall. ✅ Always check INR and reverse if anticoagulated.