A subarachnoid hemorrhage (SAH) occurs when blood leaks into the space between the brain and the arachnoid membrane — an area normally filled with cerebrospinal fluid (CSF).
This bleeding irritates the brain and increases intracranial pressure, leading to sudden, severe headache and neurological symptoms.
SAH can be traumatic (after head injury) or spontaneous, most often due to the rupture of a cerebral aneurysm.
It is a neurosurgical emergency, and rapid diagnosis with modern imaging and prompt intervention can save lives and prevent complications.
Causes
- Ruptured intracranial aneurysm (≈ 80% of non-traumatic cases)
- Arteriovenous malformation (AVM) rupture
- Trauma-related bleeding after skull or vascular injury
- Coagulopathy or anticoagulant use
- Rarely, vasculitis or tumor-related hemorrhage
Symptoms
Subarachnoid hemorrhage typically presents abruptly, often described by patients as the “worst headache of my life.”
Common symptoms include:
- Sudden, severe headache (thunderclap headache)
- Neck stiffness and photophobia (light sensitivity)
- Nausea, vomiting, or loss of consciousness
- Seizures at onset in some cases
- Double vision or drooping eyelid (from third nerve palsy in posterior communicating artery aneurysm)
- Neurological deficits such as weakness, speech disturbance, or confusion
In severe bleeding, coma or respiratory arrest may occur within minutes.
Diagnosis
Rapid evaluation is vital.
- Non-contrast CT scan is the first-line investigation — it shows diffuse blood in the basal cisterns, sulci, and ventricles.
- If CT is negative but suspicion remains high, lumbar puncture detects xanthochromia (yellow discoloration of CSF).
- Once SAH is confirmed, CT or MR angiography (CTA/MRA) identifies the source of bleeding (e.g., aneurysm, AVM).
- In selected cases, digital subtraction angiography (DSA) provides high-resolution vascular detail for surgical or endovascular planning.
Early diagnosis minimizes rebleeding and secondary brain injury.
Treatment Options
1. Emergency Stabilization
Initial management focuses on maintaining airway, breathing, and circulation.
Blood pressure is carefully controlled to prevent rebleeding while ensuring adequate brain perfusion.
Patients are transferred to a neuro-intensive care unit (NICU) for monitoring and management.
2. Aneurysm Securing (Definitive Treatment)
If an aneurysm is detected, it must be secured as soon as possible to prevent rebleeding:
- Microsurgical Clipping: The aneurysm is surgically exposed and a titanium clip is applied across its neck to isolate it from the circulation. Ideal for accessible aneurysms and younger patients.
- Endovascular Coiling: A minimally invasive technique where platinum coils are placed inside the aneurysm via a catheter to induce clotting and seal it off. Preferred for deep or complex aneurysms and elderly patients.
Treatment choice depends on aneurysm anatomy, patient condition, and available expertise.
3. Management of Secondary Complications
- Vasospasm prevention: Nimodipine (a calcium channel blocker) is administered for 21 days to prevent delayed cerebral ischemia.
- Hydrocephalus management: Temporary external ventricular drainage (EVD) or permanent shunt placement may be required.
- Seizure control and ICP management: Antiepileptic drugs and osmotic therapy are used as needed.
- Rehabilitation: Early mobilization and neurorehabilitation improve recovery and reduce complications.
Recovery & Follow-Up
Recovery depends on the severity of bleeding, neurological grade at presentation, and speed of treatment.
Hospitalization typically lasts 1–3 weeks, including intensive monitoring.
Follow-up CTA or MRA ensures that the aneurysm remains sealed.
Long-term rehabilitation addresses motor, cognitive, and emotional effects of brain injury.
Patients are advised to control blood pressure, stop smoking, and maintain healthy vascular habits to prevent recurrence.
Prognosis
Outcome varies widely:
- Good prognosis with early aneurysm treatment and no secondary ischemia.
- Poor prognosis in cases with coma, rebleeding, or vasospasm-induced infarction.
Modern treatment has significantly improved survival and reduced disability compared to past decades.
When to Seek Emergency Care
Seek immediate medical help if you experience:
- Sudden, severe headache unlike any before
- Vomiting, neck stiffness, or loss of consciousness
- Double vision, drooping eyelid, or weakness on one side
Subarachnoid hemorrhage is a true emergency — early neurosurgical evaluation saves lives and preserves brain function.