After a fall, a teenager loses consciousness briefly but recovers fully. If his condition deteriorates two hours later, what is the most likely diagnosis?

In this scenario, the most likely diagnosis is an extradural haematoma. After a head injury such as a fall, it is common for initial symptoms to appear mild or for the patient to experience a brief loss of consciousness, followed by a full recovery. However, the critical point is that the teenager's condition deteriorated two hours later, which is typical for an extradural haematoma.

An extradural haematoma often occurs due to a tear of the middle meningeal artery, which can lead to a rapid accumulation of blood between the skull and the dura mater. Initially, the individual may feel fine or only show minimal symptoms as the brain can accommodate the sudden increase in pressure. However, as the haematoma expands, it can create increasing intracranial pressure, leading to a rapid decline in neurological status characterized by confusion, headache, or loss of consciousness after a period of lucidity.

In contrast, cerebral oedema and diffused axonal injury typically present with more immediate and ongoing symptoms following the injury, not a delayed deterioration. Subdural haematomas, while they can exhibit delayed symptoms, usually occur in a different pattern, often presenting days to weeks after a fall, especially in cases involving bridging vein injury.