Unmasking hepatopulmonary syndrome: the 6-min walk test as a key to a missed diagnosis.

Hepatopulmonary syndrome (HPS) is an under-recognised complication of chronic liver disease, affecting 10%-30% of patients with cirrhosis. It involves intrapulmonary vascular dilatations, arterial hypoxaemia and an elevated alveolar-arterial gradient, causing impaired functional status and increased peri-transplant morbidity. Early recognition is crucial for timely liver transplantation referral.We report a woman in her mid-50s with alcohol-related liver disease admitted for a urinary tract infection, in whom severe exertional hypoxaemia was incidentally revealed. She developed positional dyspnoea and marked desaturation on the 6-min walk test (6MWT). Arterial blood gas confirmed hypoxaemia with an elevated alveolar-arterial gradient. DLCO was reduced, and contrast transthoracic echocardiography confirmed intrapulmonary shunting; other causes of hypoxaemia were excluded by relevant investigations.She was referred for transplant assessment; however, ongoing alcohol use precluded listing. Symptomatic treatment was initiated. This case underscores the 6MWT and posture assessment in unmasking HPS and informing appropriate clinical decision-making, without implying therapeutic impact.