A 65 year old female was transferred to the Hyperacute Stroke Unit after a routine L5/S1 laminectomy. She suffered a small dural tear. 3 hours post procedure, her GCS dropped to 3. CT scan showed a bi-cerebellar haemorrhage and MRI brain the next day revealed a convexity subarachoid haemorrhage. Imaging was reviewed with neuroradiologists and neurosurgeons. They recognised this as a typical case of post-dural puncture remote cerebellar haemorrhage. In surgical literature there are many cases reported since 1981 of “the Zebra sign”. Patients can become obtunded up to 72 hours after the injury. The mechanism of the haemorrhage is not fully understood. There are no cases reported after a lumbar puncture, which suggests a rapid loss of CSF is required for the pressure shift. Sudden caudal shift of brain with traction of arachnoid matter and venous structures on brain surface during ‘cerebellar sag’ may result in venous bleeding and sometimes infarction. Usually bleeding is bilateral near upper vermis and cerebellar sulci in close proximity to cerebellar draining veins giving rise to the ‘Zebra sign’. Remote cerebellar haemorrhage is an unknown known for a neurologist but with the increased access to stroke services, we are likely to see more cases.
Zebra sign (cerebellum)
