Light micrograph section through a human tissue showing liver edema. Edema is swelling caused by excess fluid trapped in the body's tissue. Severe liver disease, such as cirrhosis, causes fluid retention and also leads to low levels of albumin and other proteins in the blood. Fluid leaks into the abdomen and can also cause edema in the legs. The increased pressure in the portal vein can cause fluid to accumulate in the legs known as edema and in the abdomen (ascites).