Zebras Masquerading As Horses: A Case of Spinal Subarachnoid Haemorrhage

A previously independent 83-year-old lady presents with acute confusion, decreased mobility, urinary retention, and constipation, having recently received a course of oral acyclovir for shingles. The patient was noted to have extensive bruising to her upper limbs, and blood tests showed raised inflammatory markers with low platelet count, although this remained above 75 × 10⁹/L. Her confusion on a background of shingles raised the differential diagnosis of varicella-zoster virus (VZV) encephalitis. CT head and MRI brain showed no acute intracranial abnormality. Lumbar puncture yielded frankly haemorrhagic cerebrospinal fluid (CSF), but viral polymerase chain reaction (PCR) testing was negative for the varicella-zoster virus. She later developed further right shoulder pain and right lower limb weakness three days post-initial lumbar puncture. Repeat CT head was unremarkable. MRI spine showed extensive spinal subarachnoid haemorrhage, with possible cervical arteriovenous malformation and L5/S1 spinal nerve compression. The patient was managed conservatively with dexamethasone and inpatient physiotherapy support. She was discharged after a long hospital stay at a new mobility baseline requiring hoist transfers.