Differentials
Epidural haematoma
SIGNS / SYMPTOMS
'Lucid interval', younger patients, usually an associated skull fracture.
Rarer in older patients (>60 years).
INVESTIGATIONS
CT of the brain shows lenticular shape that does not normally cross suture lines.
Intracerebral haematoma
SIGNS / SYMPTOMS
There may be no differences in symptoms and signs.
INVESTIGATIONS
CT of the brain shows haematoma within brain parenchyma.
Diffuse axonal injury (DAI)
SIGNS / SYMPTOMS
History of trauma involving shear or acceleration/deceleration force; high-grade diffuse axonal injury typically results in coma.
INVESTIGATIONS
Absence of subdural collection on CT of the brain; small hyperdense lesions may be seen. MRI of the brain with gradient-recalled echo or susceptibility-weighted imaging shows small regions of susceptibility artefact in the cortex, corpus callosum, or brainstem.
Stroke
SIGNS / SYMPTOMS
No history of preceding trauma (though a fall may have resulted from the stroke). May have a history of atrial fibrillation, cardiac arrhythmia, or prothrombotic disorder. May have had a previous transient ischaemic attack.
INVESTIGATIONS
Ischaemic stroke: Non-contrast CT can shows hypoattenuation (darkness) of the brain parenchyma and loss of grey matter/ white matter differentiation; hyperattenuation (brightness) in an artery indicates a clot within the vessel lumen.
Haemorrhagic stroke: Non-contrast CT shows hyperattenuation suggestive of acute blood, often with surrounding hypoattenuation due to oedema.
Seizure
SIGNS / SYMPTOMS
After postictal state, patient typically returns to baseline. There may be a lingering Todd's paralysis for up to 48 hours after a focal motor seizure.
INVESTIGATIONS
Electroencephalogram may show seizure activity.
Substance abuse
SIGNS / SYMPTOMS
Usually no history of trauma.
Known history of substance misuse.
INVESTIGATIONS
Toxicology screen may be useful in differentiating causes of altered mental status.
Use of this content is subject to our disclaimer