CASE PRESENTATION: A 25-year-old female with liver cirrhosis complicated with portal vein thrombosis and PH (figure 1) presented with breathlessness on exertion over 1 year. On examination, the patient was cyanotic with presence of finger clubbing. She was hypoxic on room air with an SpO2 84%. Respiratory and cardiovascular examinations otherwise were unremarkable. ABG analysis showed type 1 respiratory failure (pO2 7.34 kPa). Erect PA chest x-ray was normal. Due to a history of thrombosis, a CTPA was performed but no abnormalities were found. Subsequent HRCT of the lung was also normal. Contrasted echocardiography was positive with bubbles noted in the left atrium and ventricle after 3 seconds of injection (figure 2). There was however no intracardiac shunt or anomalous pulmonary veins. A cardiac magnetic resonance study did not reveal any structural abnormality. CTA of pulmonary vasculature did not reveal any arterial-venous fistula or malformation. In view of the type 1 respiratory failure and right to left shunt without evidence of intracardiac lesions, a diagnosis of hepatopulmonary syndrome was made. She was started on LTOT and currently is on a waiting list for liver transplant.