INI-CET 2010 — Internal Medicine

Question 1: Commonest cause of thunderclap headache:

• A. Basilar migraine
• B. Extradural hemorrhage
• C. Subdural hemorrhage
• D. Aneursymal SAH (Correct Answer)

Explanation: ***Aneursymal SAH*** - An **aneurysmal subarachnoid hemorrhage (SAH)** is the most common and often life-threatening cause of a **thunderclap headache**, characterized by a sudden, severe headache reaching maximum intensity within one minute [1]. - The sudden rupture of a cerebral aneurysm leads to blood spilling into the subarachnoid space, causing a rapid increase in intracranial pressure and meningeal irritation. *Basilar migraine* - While basilar migraine can cause severe headaches, it typically presents with neurological symptoms like **vertigo**, **ataxia**, and **diplopia** preceding the headache phase, and its onset is usually less abrupt than a thunderclap headache. - Basilar migraines usually have a **recurrent pattern** and are associated with a history of similar migraine episodes, unlike the abrupt, singular nature of an SAH-related thunderclap headache. *Extradural hemorrhage* - An **extradural (epidural) hemorrhage** is usually caused by **head trauma** and often presents with a **lucid interval** followed by a progressive neurological decline, rather than an immediate thunderclap headache [2]. - It involves bleeding between the **dura mater** and the skull, which typically develops more slowly than the catastrophic onset of an SAH. *Subdural hemorrhage* - A **subdural hemorrhage** is usually caused by **venous bleeding** and can be acute, subacute, or chronic, often presenting with a gradual onset of symptoms like headache, confusion, and neurological deficits [2]. - While an acute subdural hematoma can be severe, its headache is generally not as instantaneously explosive or universally described as a thunderclap as that seen with SAH.