Medullary Sponge Kidney Disease

Medullary sponge kidney disease is a rare kidney disorder that affects approximately 1 in every 200 persons. Although some cases of this disorder seem to be inherited, usually the cause is not known.

Basically, this disease causes pools of urine to remain in the kidneys. This is caused mainly by structural defects within the kidneys' anatomy.

Healthy kidneys with normally structured anatomy can efficiently extract toxins and other waste products from the blood and expel them from the body, in the form of urine.

If wastes are allowed to accumulate in the body, the results can be deadly.

It is, therefore, important for waste products to be eliminated from the body, relatively quickly. Through a sophisticated process called excretion, the kidneys continuously remove wastes products from the body.

Nephron

The job of removing unwanted substances from the blood is performed mainly by tiny structures in the kidneys, known as nephrons.

Once waste substances are removed from the blood, they are transported out of the kidneys by tiny collecting tubules. These tiny tubules gradually join together until they reach the renal pelvis, where the ureters begin.

As the tiny tubules within the kidneys join together, they are supposed to get progressively larger as they get fewer in numbers. With Medullary sponge kidney disease, however, this is not the case. The tubules are irregular in diameter, which allows pools of urine to form and remain in the kidneys as urine is transported out of the kidneys, by these irregular tubules. These pools of urine encourage stone formation and kidney infection.

Symptoms of Sponge Kidney Disease

There are little or no symptoms directly related to this condition. Symptoms are those related to, or caused by infections and kidney stones. Infections cause fever; back and flank pains; cloudy, frequent, and burning urine; and general discomfort. Stones can cause severe pain in the flank or groin area, as they pass out of the body. They usually cause some bleeding. The bleeding may not be visible in the urine, but it is apparent under a microscope.

Diagnosis & Treatment

In most cases, this condition is only diagnosed after a patient is affected with recurring kidney infections, bleeding, or kidney stones. This will prompt the physician to check for this kidney disorder.

A series of x-rays taken after injecting iodine dye into a vein usually reveals the disorder, characterized by tubules that are irregular in diameter.

This procedure is known as intravenous pyelogram (IVP).

The dye is like a highlighter, which makes it easier to see the anatomy of the kidney.

Many people never have trouble with this disorder. For those who do, however, the primary treatment relates to kidney infections and kidney stones. Infections are usually treated with antibiotics early, in order to prevent kidney damage. Sometimes, kidney stones pass out in the urine without medical intervention. If, however, they do not pass out on their own, they may need to be surgically removed.

Often, removal can be accomplished without an incision but rather by reaching up with instruments through the lower urinary tract to grab the stones. There is also a new method of stone treatment called shock wave lithotripsy. A special machine delivers a focused blast of shock waves that breaks stones into sand so that they will pass out naturally. It is considered reasonably safe and usually effective.

Kidney infection and kidney stones can result in progressive damage to the kidneys and, ultimately, kidney failure. By drinking extra liquids, most stones can be prevented. The most common kind of stones, calcium stones, can be deterred by regularly taking a medication that encourages urine production (thiazide diuretic).

Persons with Medullary sponge kidney disease should constantly monitor their health for early signs of kidney infections or kidney stones. This will allow for early treatment that provides the best long-term results.