A patient has a fixed dilated pupil on the right, left-sided weakness after head trauma, and a biconvex lesion on CT. Diagnosis?

A patient has a fixed dilated pupil on the right, left-sided weakness after head trauma, and a biconvex lesion on CT. Diagnosis?

• A. Right sided epidural hematoma
• B. Left sided epidural hematoma
• C. Right subdural hematoma
• D. Diffuse axonal injury

Answer: (A)

A lens-shaped (biconvex) hyperdense collection on CT after head trauma points to an epidural hematoma, usually from rupture of the middle meningeal artery and often with a temporal bone fracture. The fixed, dilated pupil on the right indicates pressure on the right oculomotor nerve from the expanding hematoma, a classic sign of impending herniation on that side. The left-sided weakness fits with a lesion in the right hemisphere, since motor pathways cross to control the opposite side of the body. This pattern helps distinguish it from a subdural hematoma, which is typically crescent-shaped and can cross suture lines, and from diffuse axonal injury, which presents with widespread brain injury and does not usually produce a well-defined lens-shaped lesion on CT. The findings together best fit a right-sided epidural hematoma.

A lens-shaped (biconvex) hyperdense collection on CT after head trauma points to an epidural hematoma, usually from rupture of the middle meningeal artery and often with a temporal bone fracture. The fixed, dilated pupil on the right indicates pressure on the right oculomotor nerve from the expanding hematoma, a classic sign of impending herniation on that side. The left-sided weakness fits with a lesion in the right hemisphere, since motor pathways cross to control the opposite side of the body.

This pattern helps distinguish it from a subdural hematoma, which is typically crescent-shaped and can cross suture lines, and from diffuse axonal injury, which presents with widespread brain injury and does not usually produce a well-defined lens-shaped lesion on CT. The findings together best fit a right-sided epidural hematoma.