**Question:** Extradural haemorrhage is caused by

A. Trauma to the skull or brain parenchyma
B. Infection
C. Intracranial aneurysm rupture
D. Intracerebral haemorrhage

**Correct Answer:** A. Trauma to the skull or brain parenchyma

**Core Concept:** Extradural haemorrhage (EDH) is a type of intracranial bleeding that occurs between the skull and the dura mater. It is often caused by trauma to the skull or brain parenchyma, leading to the disruption of blood vessels and subsequent bleeding.

**Why the Correct Answer is Right:** Trauma to the skull or brain parenchyma is the primary cause of extradural haemorrhage. The trauma can result from high-energy injuries such as falls, motor vehicle accidents, or assaults. When the skull is fractured or the brain tissue is injured, it can lead to the rupture of blood vessels, causing bleeding between the skull and dura mater.

**Why Each Wrong Option is Incorrect:**

B. Infection: Intracranial infections, such as meningitis, are associated with subdural or intracerebral haemorrhage, not extradural haemorrhage. Infection does not directly cause extradural haemorrhage.

C. Intracranial aneurysm rupture: While aneurysm rupture can result in subarachnoid haemorrhage (SAH), extradural haemorrhage is primarily caused by trauma to the skull or brain tissue, not aneurysm rupture.

D. Intracerebral haemorrhage: Intracerebral haemorrhage is a type of intracerebral haemorrhage, distinct from extradural haemorrhage. This option is incorrect as it does not address the specific cause of extradural haemorrhage.

**Clinical Pearl:** Extradural haemorrhage is an important diagnosis to consider in patients presenting with altered mental status, focal neurological deficits, and a tense or pulsatile mass on the skull. Immediate imaging and management are crucial in these cases, as extradural haemorrhage can lead to significant neurological impairment and, in severe cases, cause brain herniation and death if not promptly diagnosed and treated.