HEPATO-PULMONARY SYNDROME: LOOK CLOSELY OR YOU MIGHT MISS IT

ABSTRACT

CASE A Hispanic-speaking 63-year-old lady presented with left shoulder pain and dyspnea since two weeks. Past history was significant for cirrhosis due to autoimmune hepatitis and portal hypertension diagnosed 1.5 years prior. Upon further questioning, she revealed that she had exertional dyspnea for 2 years, which got progressively worse after her COVID-19 infection, 14 months prior. On initial exam, her hemoglobin levels were unchanged with previous. Troponin and BNP levels were unremarkable. CT Pulmonary Embolus scan and shoulder X-ray were negative. However, her SpO2 which was 90% on lying flat, fell to 84% on walking and she was admitted for further workup. On exam, she had a loud S2, spider angioma, and clubbing. ABG showed an alveolar-arterial oxygen gradient of 54.7 mm and PO2 of 61.7 mm. A contrastenhanced transthoracic echo with saline showed significant shunting with dilated pulmonary veins. Upon close inspection, she had a small right to left intracardiac shunt through an incidental PFO and a rather large intrapulmonary shunt. This was confirmed on trans-esophageal echo. Right heart catheterization showed a high cardiac index (5.3 L/min) suggestive of a high-output state, as typically seen with cirrhosis. It also revealed increased right-sided oxygen saturations, confirming the presence of a significant left to right shunt. Finally, pulmonary CT angiography was negative for AVMs. These findings were congruent with hepato-pulmonary syndrome (HPS) and based on her presenting symptoms she was referred to hepatology for consideration of liver transplantation. IMPACT/DISCUSSION: HPS is characterized by abnormal oxygenation due to intrapulmonary vascular dilations (IPVD) in the setting of advanced liver disease. Diagnosis needs an elevated A-a gradient (≥ 15mm or ≥ 20 mm if >64 years). IPVDs may not be seen on CT scans and are optimally detected on CE-TTE. The delayed appearance of injected microbubbles in the left heart, 3 or more cardiac cycles after visualization in the right heart signifies abnormally dilated pulmonary capillaries which don't trap the bubbles. TTE can help differentiate intracardiac and intrapulmonary shunts, by revealing the source of the microbubbles entering into the left atrium (across the atrial septum vs pulmonary veins). Shunting classically causes platypnea-orthodexia (worsening dyspnea on standing or sitting, alleviated by lying down). Alterations in lung parenchyma due to COVID-19 could have increased the flow through intrapulmonary AVMs and contributed to the worsening of symptoms. Management of HPS is supportive. Liver transplantation improves survival. CONCLUSION: Evaluation and management of HPS involves multiple modalities of testing and specialists in gastroenterology, cardiac imaging, interventional cardiology, interventional radiology, and transplant surgery. The diagnosis of HPS should escalate referral to a liver transplant center. Engaging medical interpreters can help elicit more detailed history and improve clinical outcomes.