Makindo Medical Notes

Related Subjects: |Subarachnoid Haemorrhage |Perimesencephalic Subarachnoid haemorrhage |Haemorrhagic stroke |Cerebellar Haemorrhage |Putaminal Haemorrhage |Thalamic Haemorrhage |ICH Classification and Severity Scores |Saccular aneurysms

⚡ Note: Any new, severe headache with onset to maximum severity within 5 minutes, lasting ≥60 minutes, should be treated as a possible Subarachnoid Haemorrhage (SAH). ❗ 50% of patients die within 48 hours irrespective of therapy. 🧠 Early clipping or coiling, ideally within 72 hours, is now the goal for all grades of SAH. Also see Saccular aneurysms.

🚑 Initial Management of Suspected Aneurysmal SAH (on CT)

🧾 About

• Definition: Bleeding into the subarachnoid space from ruptured vessels.
• Distribution: Blood tracks into sulci, ventricles, and cisterns. Convexity SAH may mimic trauma or RCVS.

📊 Incidence

• 1–2% of population harbour unruptured aneurysms.
• SAH incidence ≈ 6 per 100,000/year, mostly <60 yrs.

🔎 Tip: Differentiating traumatic vs aneurysmal SAH is vital. 👉 Traumatic bleeds: external signs, convexity blood, no thunderclap headache. 👉 Aneurysmal bleeds: sudden headache, basal cistern blood, CTA needed.

🩸 Causes

• Aneurysmal rupture: 85% (berry/saccular aneurysm).
• Perimesencephalic SAH: 10%, often benign course.
• Traumatic SAH: Common in elderly post-fall.
• Dissection: Vertebral artery dissection ± lateral medullary signs.
• AVM/vascular malformations: Rare, usually with parenchymal bleed.
• Others: RCVS, vasculitis, amyloid angiopathy, infections.

🧬 Berry/Saccular Aneurysms

• Sites: Ant. communicating (35%), ICA–PCom (35%), MCA bifurcation (20%), basilar tip (5%), PICA.
• Risk factors: Smoking 🚬, binge alcohol 🍺, cocaine/illicit drugs, ADPKD, Marfan, Ehlers–Danlos, sickle cell, SLE.

🩺 Clinical Presentation

• Sudden thunderclap headache (“worst ever”).
• Peak within 60s; collapse then transient recovery possible.
• Photophobia, meningism, ↓GCS/coma.
• CN III palsy or monocular blindness = local aneurysm compression.

⚠️ Complications

• Vasospasm: 3–12 days; delayed infarction → Nimodipine + fluid balance.
• Re-bleeding: 20% within 2 weeks; especially day after bleed.
• Hydrocephalus: Obstructed CSF outflow → EVD or VP shunt.
• Seizures: ~6% at presentation.
• Hyponatraemia: Renal salt wasting/SIADH.

🔍 Investigations

• CT Head: 95% sensitive within 6h; sensitivity drops thereafter.
• LP (xanthochromia): If CT negative but suspicion persists, do ≥6h after onset.
• CTA/MRA: Localises aneurysm; DSA if equivocal.
• TCD: Daily monitoring for vasospasm.

🧠 Treatment

• Vasospasm: Nimodipine 60 mg q4h × 21d. ICU may use Triple-H (HTN, hypervolaemia, haemodilution) but balance re-bleeding risk.
• Aneurysm repair:
  • Endovascular coiling = preferred (esp. high surgical risk).
  • Clipping = neurosurgical alternative if anatomy unsuitable.
  • Timing: ideally <72h to reduce re-bleed risk.
• Hydrocephalus: EVD acutely; VP shunt for chronic cases.
• Seizures: Treat if they occur (levetiracetam preferred). No routine prophylaxis.
• BP control: SBP 140–160 mmHg pre-treatment.
• Supportive: Maintain euvolaemia, prevent hyponatraemia, ICU/HDU monitoring.

📌 Exam Pearls

✅ Thunderclap headache + meningism = SAH until proven otherwise. ✅ If CT negative → LP after 6h for xanthochromia. ✅ Nimodipine reduces vasospasm risk, not re-bleeding. ✅ Early coiling/clipping <72h saves lives.

📚 References

• van Gijn & Rinkel. Subarachnoid haemorrhage. Brain 2001
• Subarachnoid haemorrhage. Lancet 2007