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A lucid interval after a blow to the head
A 19-year-old is struck on the right side of the head by a baseball. He is knocked out briefly, then talks normally. Two hours later he has a severe headache, vomits and becomes drowsy.
Step 1 of 4
Which vessel is most likely bleeding?
Correct answer: E
Brief loss of consciousness, a lucid interval and then rapid decline is the classic story of an epidural hematoma — arterial bleeding from the middle meningeal artery torn by a temporal bone (pterion) fracture.
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E
Brief loss of consciousness, a lucid interval and then rapid decline is the classic story of an epidural hematoma — arterial bleeding from the middle meningeal artery torn by a temporal bone (pterion) fracture.
Step 2 of 4
What would the noncontrast CT most likely show?
Correct answer: C
Arterial blood strips the dura from the skull and is stopped at the sutures, giving a biconvex bleed. A crescent crossing sutures is subdural (bridging veins); cisternal blood is subarachnoid; the empty delta sign is venous sinus thrombosis (see cranial meninges and intracranial hemorrhage).
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C
Arterial blood strips the dura from the skull and is stopped at the sutures, giving a biconvex bleed. A crescent crossing sutures is subdural (bridging veins); cisternal blood is subarachnoid; the empty delta sign is venous sinus thrombosis (see cranial meninges and intracranial hemorrhage).
Step 3 of 4
His right pupil is now fixed and dilated.
What does this sign indicate?
Correct answer: C
An expanding supratentorial mass pushes the uncus over the tentorium, compressing the ipsilateral oculomotor nerve (CN III). Its parasympathetic fibers lie on the surface, so the pupil blows first. Contralateral hemiparesis follows from compression of the cerebral peduncle.
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C
An expanding supratentorial mass pushes the uncus over the tentorium, compressing the ipsilateral oculomotor nerve (CN III). Its parasympathetic fibers lie on the surface, so the pupil blows first. Contralateral hemiparesis follows from compression of the cerebral peduncle.
Step 4 of 4
What is the definitive management?
Correct answer: A
An epidural hematoma with herniation needs emergency craniotomy. Lumbar puncture with a mass lesion risks herniation; nimodipine is for subarachnoid hemorrhage; heparin treats venous sinus thrombosis.
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A
An epidural hematoma with herniation needs emergency craniotomy. Lumbar puncture with a mass lesion risks herniation; nimodipine is for subarachnoid hemorrhage; heparin treats venous sinus thrombosis.
Key points
- Epidural = arterial (middle meningeal), biconvex, stops at sutures, lucid interval.
- Ipsilateral blown pupil after head injury → uncal herniation compressing CN III.
Study: Middle meningeal artery, Cranial meninges and intracranial hemorrhage, Oculomotor nerve (CN III), Midbrain