Monday June 4, 2007
Triad of Hepato-Pulmonary Syndrome
Q: What is the triad of hepatopulmonary syndrome ?
A: The triad of hepatopulmonary syndrome
- liver disease,
- increased A-a gradient, and
- evidence of intrapulmonary vascular dilitations
(providing intrinsic cardiopulmonary disease is excluded)
About 8-10% of cirrhotics manifest clinical features of the hepatopulmonary syndrome. 2 major clinical signs are
Platypnea: Dyspnea improves when lying flat (opposite of orthopnea) and
Orthodeoxia: hypoxemia worsens upon sitting up and improves when lying flat.
Platypnea and orthodeoxia occur because the pulmonary AVMs (arterio-venous malformations) occur in the bases of the lung. Therefore, when sitting up or standing, blood pools at the bases of the lung and increase AV shunting and V/Q mismatch. Increasing the oxygen level can overcome this problem.
Note: Hepatopulmonary syndrome and Portopulmonary hypertension are 2 different conditions. Portopulmonary hypertension also occurs in end stage liver disease but pathphysiology is more similar to primary pulmonary hypertension with intense vasoconstriction of pulmonary capillaries and thickened pulmonary vasculature.
Refer to nice review article
