Definition of medullary sponge kidney

Definition of medullary sponge kidney

Medullary sponge kidney (MSK) is a congenital disorder that can affect one or both kidneys, or only part of one kidney. There are ectatic and cystic changes of the medullary and papillary collecting ducts. The names tubular ectasia and cystic dilatation of the collecting ducts have been suggested as alternatives for this condition because the medulla does not actually appear like a sponge. It is bilateral in 70% of cases. Cysts can be 1-7 mm in diameter. Cyst formation is commonly associated with the development of small calculi within the cyst. The rest of the kidney is usually normal unless affected by complications such as pyelonephritis or obstruction secondary to renal calculi.

Causes of medullary sponge kidney

Although some cases of this disorder seem to be inherited, usually the cause is not known.

Complications of medullary sponge kidney

About one person in every 10 with medullary sponge kidney has complications. Some of the complications associated with the condition include:

● Calcium deposits in the kidneys

● Kidney stones

● Kidney infection

● Abscess (pocket of pus) within the kidney

● Kidney failure as a result of repeated kidney infections or kidney stones.

The symptoms associated with medullary sponge kidney are those related to infection and stone passage. Because many patients with MSK develop no symptoms and remain undiagnosed, reliable data on how many will form stones is not available.

● The first sign that a person has MSK is usually a UTI or kidney stone. UTIs and kidney stones share many of the same symptoms:

● Burning or painful urination

● Pain in the back, lower abdomen, or groin

● Foul-smelling urine

● Fever and chills

● General discomfort

● Vomiting

● Stones cause pain in the flank or groin as they pass. They usually cause some bleeding. The bleeding may not be visible in the urine, but it is apparent under a microscope.

People who experience these symptoms should see a doctor as soon as possible.

Many people never have trouble with this disorder. For those that do, infections and stones will need periodic treatment. Medullary sponge kidney in these patients must be treated aggressively until the urine is clear. Proteus infection can lead to the formation of struvite stones and requires aggressive antibacterial therapy.

● Infections should be treated with antibiotics early in order to prevent kidney damage. Stones 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.The particles can then pass easily through the urinary tract with the flow of urine. Another way to remove stones is to insert a thin tube called a ureteroscope through the urethra and bladder to catch the stone and retrieve it. A person with MSK may be able to prevent more stones from forming through diet changes or taking medicine.

● No treatment can get rid of cysts in the affected kidneys. Once a doctor is sure that a person has MSK, treatment focuses on curing existing infection, removing any stones, and preventing future infection and stone formation.

● UTIs. To treat UTIs, the doctor may prescribe a medicine called an antibiotic that kills bacteria. A person with MSK may need to continue taking a low-dose antibiotic to prevent recurrent infections.

There is no cure for medullary sponge kidney. Treatment may include:

Long-term, low-dose antibiotics to prevent urinary tract infections Medications to discourage the formation of kidney stones.

● Dietary changes such as reducing salt, protein, cholesterol and caffeine.

● Avoiding non-steroidal anti-inflammatory (NSAIDs) medications, since these drugs can worsen kidney function in people with kidney disease.

A short course of high-dose antibiotics to treat abscesses.

The diagnosis of medullary sponge kidney is made with imaging studies, either with an intravenous pyelogram (an older type of x-ray) or with a contrast CT scan. These imaging studies will show a characteristic distribution of stones or calcifications in the location of the medullary pyramids and contrast pooling in dilated tubules. In order to confirm the diagnosis, the imaging study should include intravenous contrast in order to demonstrate the dilated tubules that are the hallmark of MSK. However, most CT scans for kidney stones are performed without contrast and in this case the diagnosis, while likely, is not considered definitive because other stone related conditions can also lead to an appearance similar to MSK on a non-contrast CT scan.

Recurring kidney infections, bleeding, or stones will prompt x rays of the kidneys. The appearance of medullary sponge kidney on an intravenous pyelogram (x rays of the upper urinary system) is characteristic.

Tests used to diagnose medullary sponge kidney may include:

● Renal ultrasound – scan of the kidneys. This is normal in medullary sponge kidney unless stones have formed.

● Computed tomography (CT) scan – to detect the presence of cysts, if other tests are inconclusive or if more information is needed.

● Excretory urogram – the kidneys are injected with a special dye that shows up on x-ray examination and can reveal abnormalities.

● Kidney stones may be seen in the bladder, ureters (tubes that drain urine from the kidneys to the bladder) or kidneys. In severe cases, imaging may reveal multiple large cysts and clusters of broad kidney stones
● Surgery to drain abscesses, if they are particularly large or do not respond to antibiotic therapy.

Prognosis

Ignoring symptoms can result in progressive damage to the kidneys and ultimate kidney failure, but attentive early treatment will preserve kidney function.

● Normally a benign condition that does not affect life expectancy.

● Recurrent stones and pyelonephritis affect about 10%.

● Renal impairment can occur in 10% of patients.

Prevention

Diligent monitoring for infection at regular intervals and at the first symptom will give the best long-term results. 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).

Hope through research

Researchers are exploring the genetic and molecular mechanisms that control kidney development in a fetus. These studies will point the way to more effective treatments for MSK and other kidney defects that are present at birth.

Participants in clinical trials can play a more active role in their own health care, gain access to new research treatments before they are widely available, and help others by contributing to medical research.

Kidney is one of the most important organs in human body. Here are some tips for you to protect your kidney hoping it may useful to you.

● Do not eat or drink too much or intake too much salt and protein. For the things mentioned above will burden the kidney and the sports drink contain extra electrolyte and salt that the patients should pay attention.

● In winter, patients should keep warm. The research shows that the illness easily get worse in winter and the reason is the cold weather shrink the blood vessel. As a result, the blood pressure will rise and the blood coagulability rise accordingly. In this condition, the kidney is likely to become out of control.

● Drink water properly and do not Suppresses the urine. The urine stays in the bladder which likes the drainage full of dirty water and the bacteria will breed. The infection of the ureter will damage the kidney.

● Do not drink the water right from the wells or rivers. The water may contain too much heavy metal such as lead, chrome and others.

● Keep yourself in a good mood. Try to control your anger because the anger will damage your liver. Thus the function of expelling toxicant will transfer from liver to kidney. Anger is the biggest enemy of the kidney.