Hereditary haemorrhagic telangiectasia as a cause of exertional dyspnoea.

Hereditary haemorrhagic telangiectasia (HHT) is an uncommon autosomal dominant vascular disorder, most frequently associated with pathogenic variants in ENG or ACVRL1, resulting in multisystem arteriovenous malformations (AVMs). We report a middle-aged woman with primary antiphospholipid syndrome on chronic enoxaparin therapy who presented with exertional dyspnoea. CT demonstrated bilateral pulmonary AVMs (PAVMs), and clinical evaluation revealed mucocutaneous telangiectasias. Genetic testing identified an ENG mutation, confirming HHT type 1 according to the three Curaçao criteria. Selective microcoil embolisation of PAVMs with feeding arteries >3 mm led to marked improvement in functional capacity. HHT1 is predominantly associated with pulmonary and cerebral AVMs, whereas HHT2 and juvenile polyposis-hereditary haemorrhagic telangiectasia syndrome involve hepatic and gastrointestinal manifestations. Diagnostic assessment relies on echocardiographic contrast studies and CT angiography. Embolisation represents the standard of care for significant PAVMs with periodic radiological surveillance recommended. This case underscores the importance of early recognition and multidisciplinary management to mitigate HHT-associated complications.