Cerebral venous sinus thrombosis after intrathecal administration of nusinersen

Cerebral venous sinus thrombosis is an uncommon sequela of low intracranial pressure, which may result from a lumbar puncture (LP). We describe a case of a patient in their 40s presenting with 48 hours of persistent headache following intrathecal administration of nusinersen for spinal muscular atrophy (SMA) type 3. There were no focal neurological signs or symptoms apart from baseline symmetrical proximal limb weakness attributed to SMA. Initial investigations revealed radiological evidence of an acute cerebral venous sinus thrombus (CVST). The patient was promptly started on anticoagulation. Partial recanalisation was seen as soon as 48 hours after commencement of anticoagulation, with almost full resolution of the thrombus at follow-up in 2 months. Awareness of CVST as a potential complication of intrathecal therapies and diagnostic LP allows for early identification, management and prevention of serious neurological consequences.