Pulmonary Arteriovenous Malformation Unmasking Hereditary Haemorrhagic Telangiectasia in Pregnancy: A Diagnostic Dilemma in a Patient with Bronchial Asthma

Abstract

Aims: To report a case of pulmonary arteriovenous malformation (PAVM) that unmasked hereditary haemorrhagic telangiectasia (HHT) in pregnancy, highlighting the diagnostic pitfalls when PAVM coexists with bronchial asthma, and to outline the importance of multidisciplinary delivery planning. Presentation of Case: A 26-year-old woman (G2P1) with a history of childhood asthma presented repeatedly during her second pregnancy with dyspnoea and oxygen-refractory hypoxaemia. On subsequent admissions, she was treated for acute asthma exacerbations attributed to community-acquired pneumonia and required intensive care on one occasion. Contrast-enhanced computed tomography (CECT) of the thorax revealed right upper lobe PAVMs. Reassessment identified longstanding epistaxis and tongue telangiectasia, and flexible nasendoscopy revealed multiple mucosal telangiectatic spots, fulfilling three Curaçao criteria for definite HHT. Cerebral and spinal imaging was performed to exclude additional malformations, and repeat third-trimester thoracic CECT showed that the lesion remained stable. Discussion: The repeated attribution to asthma and pneumonia illustrates diagnostic anchoring. A true anatomical right-to-left shunt is refractory to oxygen, unlike the ventilation–perfusion mismatch in cases of asthma or pneumonia. Pregnancy, acting as a physiological stress test, unmasked the previously silent malformation. Conclusion: Following multidisciplinary planning, the patient underwent elective caesarean section under regional anaesthesia at a centre with cardiothoracic standby. A healthy neonate was delivered, and maternal recovery was uneventful. A staged lobectomy was planned. Disproportionate, oxygen-refractory hypoxaemia necessitates a search for a right-to-left shunt.