Pulmonary arteriovenous malformation (PAVM) with hereditary haemorrhagic telangiectasia (HHT): a rare cause of paradoxical embolic stroke

Pulmonary arteriovenous malformation (PAVM), a manifestation of hereditary haemorrhagic telangiectasia (HHT), is rarely encountered but a significant cause of seemingly cryptogenic strokes. In cases of PAVM, there is an abnormal connection between pulmonary arteries and veins which leads to right-to-left shunting, resulting in mainly hypoxaemia and dyspnoea but more dangerously can cause paradoxical embolic strokes.We present a woman in her 40s with no prior known medical comorbidities attending with a right-sided hemiparesis and diffusion-weighted MRI sequence of the brain confirming a left thalamic infarction. After detailed investigation, she was found to have PAVM and HHT, explaining her stroke. She was successfully treated with transcatheter embolisation and continued on single antiplatelet therapy with no further recurrence of strokes since then. This case highlights the importance of thorough investigation of young strokes when no immediate or apparent cause is found, especially in the absence of risk factors.