On non-contrast CT brain of a comatose road traffic accident victim, there are multiple small petechial haemorrhages at the grey-white matter junctions of the frontal lobes and in the corpus callosum, with ventricles of normal size. What is the most likely diagnosis?

• A Fat embolism syndrome
• B Traumatic subarachnoid haemorrhage
• C Cerebral venous sinus thrombosis
• D Diffuse axonal injury ✓

Explanation

Multiple punctate haemorrhages at grey-white interfaces, corpus callosum and dorsolateral brainstem in a comatose patient after high-energy deceleration are typical of diffuse axonal injury. Traumatic SAH appears as hyperdensity within sulci and cisterns rather than discrete parenchymal foci. Fat embolism produces diffuse white matter oedema and hypodensities, not focal junctional haemorrhages, and follows long bone fractures with a lucid interval.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.