Cryptogenic stroke in a young adult due to pulmonary arteriovenous malformation

Pulmonary arteriovenous malformations (PAVMs) are rare vascular anomalies that create a right-to-left intrapulmonary shunt, allowing embolic material to bypass the pulmonary capillary filter and enter the systemic circulation. This predisposes affected individuals to paradoxical embolic events, including transient ischaemic attack and ischaemic stroke. Although uncommon, PAVMs represent an important and potentially treatable cause of cryptogenic stroke in young adults.We report a young woman in her early 20s with a 4-year history of intermittent central cyanosis, digital clubbing and exertional dyspnoea who presented with transient perioral paraesthesia, dysarthria and aphasia. Brain MRI demonstrated subacute infarcts in the right paraventricular region and a lacunar infarct in the left caudate nucleus. In the context of chronic hypoxaemia and clinical features of right-to-left shunt physiology, a paradoxical embolic mechanism was suspected.CT pulmonary angiography revealed multiple PAVMs, which were successfully treated with transcatheter embolisation, resulting in normalisation of oxygen saturation.