Nephrotic syndrome can be caused by a number of different diseases.

　　Nephrotic syndrome can be caused by a number of different diseases. The common mechanism which seems to cause damage involves the immune system. For some reason, the immune system seems to become directed against the person’s own kidney. The glomeruli become increasingly leaky as various substances from the immune system are deposited within the kidney. A number of different kidney disorders are associated with nephrotic syndrome, including:
　　• minimal change disease or MCD (responsible for about 80% of nephrotic syndrome in children, and about 20% in adults) MCD is a disorder of the glomeruli
　　• focal glomerulosclerosis
　　• membranous glomerulopathy
　　• membranoproliferative glomerulonephropathy Other types of diseases can also result in nephritic syndrome. These include diabetes, sickle-cell anemia, amyloidosis, systemic lupus erythematosus, sarcoidosis, leukemia, lymphoma, cancer of the breast, colon, and stomach, reactions to drugs (including nonsteroidal anti-inflammatory drugs, lithium, and street heroine), allergic reactions (to insect stings, snake venom, and poison ivy), infections (malaria, various bacteria, hepatitis

　　B, herpes zoster, and the virus which causes AIDS), and severe high blood pressure. The first symptom of nephrotic syndrome is often foamy urine. As the syndrome progresses, swelling (edema) is noticed in the eyelids, hands, feet, knees, scrotum, and abdomen. The patient feels increasingly weak and fatigued. Appetite is greatly decreased. Over time, the loss of protein causes the muscles to become weak andsmall (called muscle wasting). The patient may note abdominal pain and difficulty breathing. Because the kidneys are involved in blood pressure regulation, abnormally low or abnormally high blood pressure may develop.