Portal hypertension and hypoalbuminemia promote the formation of ascites. In addition, the cirrhotic patient is vasodilated because of endotoxins, vasodilatory prostaglandins, nitric oxide, various gut hormones, and other mediators. Idiopathic edema is a benign disorder of young menstruating women who have no cardiac, hepatic, or renal disease. Fluid retention often begins premenstrually and then becomes persistent. Depression and neurotic symptoms are commonly present, and affected patients are often weight conscious and markedly concerned about even minor degrees of edema.
Some patients episodically fast for days at a time and then accumulate edema on refeeding.
In many others, diuretics play an important role in the pathogenesis. When the diuretic is stopped, marked sodium retention occurs because the sodium-retaining forces cannot be shut off rapidly. The patient thus becomes convinced of the need for diuretics, and the cycle continues. Dyspnea on exertion and orthopnea provoked by pulmonary interstitial edema are prominent features in patients with left ventricular failure or nephritic edema, but these symptoms are usually absent when edema is caused by right heart failure, nephrotic syndrome, or cirrhosis. Mild peripheral edema collects in the dependent portions of the anatomy and is usually asymptomatic.