Dental surgery reveals a vascular anomaly

A right-to-left shunt is thought to be caused by a patent foramen ovale - or was it?

Michelle is 59 and has a past history of a transient ischaemic attack (TIA) 10 years ago.

She presents to ED with headache, vomiting, and right retro-orbital pain. She is systemically well with no signs of meningism.

Further history reveals a constellation of subtle subacute neurological symptoms, including non-specific speech disturbance, left arm inco-ordination and altered left lower limb sensation.

Three weeks ago she had dental surgery to drain a left maxillary abscess. The previous TIA is her only significant past medical history.