A 60-year-old man with known cirrhosis presents with progressive dyspnea on exertion and platypnea. Physical examination reveals cyanosis and multiple spider nevi on the chest. Pulse oximetry shows oxygen saturation of 88% that worsens to 82% when moving from supine to upright position (orthodeoxia). Which diagnosis best explains these findings?

• A Hepatopulmonary syndrome ✓
• B Portopulmonary hypertension
• C Hepatic hydrothorax
• D Spontaneous bacterial peritonitis

Explanation

Hepatopulmonary syndrome (HPS) is characterized by the triad of liver disease, intrapulmonary vascular dilatations, and impaired oxygenation (PaO2 <80 mmHg or A-a gradient >15 mmHg). Platypnea (dyspnea worsened by upright position) and orthodeoxia (desaturation worsened by upright position) are classic findings due to preferential blood flow through dilated vessels at the lung bases in the upright position. Portopulmonary hypertension causes pulmonary arterial hypertension without hypoxemia. Hepatic hydrothorax causes pleural effusion.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.