Abstract
A 43 year-old man presented with 18 months of gait ataxia and sensorineural hearing loss. He described frequent gait imbalance over 18 months, and several years of bilateral hearing loss. There was no head trauma or headaches. He had a past medical history of a gastric sleeve 6 months prior, and was an ex smoker. He took no regular medications, and consumed minimal alcohol.
Examination revealed bidirectional nystagmus, and an ataxic gait. There was appendicular ataxia affecting only the lower limbs, and the remainder of the neurological examination was normal.
MRI brain and spine demonstrated extensive superficial siderosis of the infratentorial compartment, with haemosiderin deposition involving the posterior fossa structures, vestibulocochlear nerves, and spinal cord. A ventral epidural collection was seen, and CT myelogram confirmed CSF leak at T1/2 due to a dural tear. The patient was diagnosed with infratentorial superficial siderosis, due to cerebrospinal fluid leak, from a spinal dural tear. This was repaired with a T1/2 laminectomy.
Infratentorial superficial siderosis is characterised by progressive sensorineural hearing loss, gait ataxia, and sometimes myelopathy, and commonly results from a spinal CSF leak. MRI brain and spine shows hemosiderin deposition involving the superior cerebellar vermis, vestibulocochlear nerves, brainstem and spinal cord. Classical infratentorial superficial siderosis is most often due to a spinal, or less often, cranial dural defect. It should be investigated with MRI brain and whole spine, followed by CT myelogram or digital subtraction myelography, to assess for dural leak. Repairing the defect offers the best chance of preventing progression.
