Presentation
Two-week history of general decline and increasing falls, on a background of Huntington disease. On initial presentation to a rural hospital patient was GCS 10, with CT brain showing bilateral subdural hematomas. He was subsequently transferred urgently to a tertiary hospital where on arrival he was GCS 7 with fixed and dilated pupils. Bilateral burr holes evacuated 300 mL of hematoma. Presented CT brain here was acquired 1 hour post-burr hole surgery.
Patient Data
Bilateral frontal and parietal burr holes.
Bilateral tension pneumocephalus causing frontal and parietal lobe compression, with 7 mm midline shift to the right.
Ischemia in both occipital lobes extending into the posterior temporal lobes, consistent with bilateral PCA territory infarcts.
Bilateral basal ganglia infarcts.
Midline brainstem hemorrhage.
Nil cerebellar herniation.
Case Discussion
The above CT series demonstrates two classical signs:
The Mount Fuji sign of tension pneumocephalus.
The classical appearance of Duret hemorrhage, with hemorrhage of the brainstem in the midline.
Tension pneumocephalus is a known but rare complication of subdural hematoma evacuation. Air enters through the dural defect but is unable to escape, often known as a “ball-valve” mechanism. The subsequent increase in intracranial pressure produces a mass effect on the frontal and parietal lobes.
Additionally, this case illustrates the sequelae of tension pneumocephalus. The raised supratentorial pressure has resulted in caudal shift of the brainstem, with the associated injury to the basilar artery resulting in the Duret hemorrhage. Ischemia of the branches of the basilar artery would account for the PCA territory infarcts.
Acknowledgement is made to Dr David Preston who initially reported the film.
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