Subdural haemorrhage

A subdural haematoma is a collection of blood deep to the dural layer of the meninges. The blood is not within the substance of the brain and is therefore called an 'extra-axial' or 'extrinsic' lesion. They can be unilateral or bilateral.

Subdural haematomas can be classified in terms of their age:

• Acute: Symptoms usually develop within 48 hours of injury, characterised by rapid neurological deterioration
• Subacute: Symptoms manifest within days to weeks post-injury, with a more gradual progression.
• Chronic: Common in the elderly, developing over weeks to months. Patients may not recall a specific head injury.

The typical presentation of a subdural haematoma (SDH) often involves a history of head trauma, which may range from minor to severe. Patients frequently exhibit a lucid interval followed by a gradual decline in consciousness. This pattern is particularly common in chronic SDH. Other hallmark features include headache, confusion, and lethargy.

Clinical Features

Neurological Symptoms:

• Altered Mental Status: Ranging from mild confusion to deep coma. Fluctuations in the level of consciousness are common.
• Focal Neurological Deficits: Weakness on one side of the body, aphasia, or visual field defects, depending on the haematoma's location.
• Headache: Often localised to one side, worsening over time.
• Seizures: May occur, particularly in acute or expanding hematomas.

Physical Examination Findings:

• Papilloedema: Indicates raised intracranial pressure.
• Pupil Changes: Unilateral dilated pupil, especially on the side of the haematoma, indicating compression of the third cranial nerve.
• Gait Abnormalities: Including ataxia or weakness in one leg.
• Hemiparesis or Hemiplegia: Reflecting the mass effect and midline shift.

Behavioural and Cognitive Changes:

• Memory Loss: Especially in chronic SDH.