Midbrain infarction in inherited protein S deficiency: a rare association

Inherited thrombophilic disorders are well-established predisposing factors for venous thromboembolism, but their role in arterial ischaemic stroke is uncertain. The exact mechanism of arterial thrombosis in thrombophilias remains elusive. Herein, we report a case of a 30-year-old woman who was admitted to our facility with sudden-onset right-sided ptosis and ophthalmoplegia. Detailed clinical features, neuroimaging and laboratory evaluation clinched the diagnosis of ischaemic stroke in midbrain due to microvascular obstruction associated with isolated protein S deficiency. She was treated with oral anticoagulant (warfarin) and physiotherapy; without any improvement of her symptoms at 2 months of follow-up. A high index of clinical suspicion is needed in any case of young ischaemic stroke in absence of common cardiac and vascular risk factors, to recognise the presence of inherited thrombophilia.