Medullary sponge kidney

Under the Medullary sponge kidney nephrology understands a cystic medullary kidney disease that affects the renal medulla. Although the disease is present from birth, it remains partly asymptomatic for life. Possible symptoms are urinary stones and kidney stones in the form of calcium deposits.

What is a medullary sponge kidney?

The Medullary sponge kidney is a cystic kidney disease. From birth, both or, less often, only one of the kidneys show cystic changes in the medullary pyramids and papillae in the renal medulla, which are connected to the collecting ducts of the kidneys. The renal medulla and its pyramid are impaired by the cystic enlargements in the ability of the urine to concentrate.

The kidneys of those affected often excrete too little acids or too much calcium and form kidney stones. Urinary stones can also develop. In extreme cases, renal tubular acidosis develops. Although the medullary spongy kidney is congenital, it is not considered an hereditary kidney disease. The following are to be distinguished from the disease:

• the cystic medullary kidney diseases type I and II

• the nephronophthisis, which are largely genetic.

A prevalence of 1: 5000 to 1: 20000 is given for the symptomatic medullary sponge kidney. The prevalence for asymptomatic medullary spongy kidneys is 1: 200.

causes

The disease of the medullary spongy kidney usually occurs spontaneously. The original cause of the cystic changes is so far unknown. So far, no specific gene or chromosomal mutations have been associated with the disease. The transmission of the disease does not appear to be predictable. Due to the unpredictability, scientists assume that instead of a genetic basis, a complication in pregnancy is the more likely cause of the disease.

A combination of genetic and environmental factors is also considered. If such a combination exists, an autosomal dominant inheritance is assumed for the genetic factors. Even if the susceptibility is hereditary in the sense of a genetic disposition, in this case the disease only breaks out when the person concerned comes into contact with the environmental factors.

Symptoms, ailments & signs

Congenitally, the medullary sponge kidney has cystic enlargements in one or both kidneys. The cysts do not have to affect the entire renal medulla. Locally limited changes also occur. A cystic enlargement occurs mainly in the terminal collecting ducts of the renal medulla. The cysts often also form in the tips of the papillae. The cysts contain calcium oxalate concretions.

Although a person's kidneys retain their physiological shape, they appear spongy. In most cases, they are also enlarged. The cysts create obstructions that change the parenchyma. As a rule, kidney failure does not occur. The medullary spongy kidney usually remains symptom-free for a long time. A good half of those affected even remain without symptoms for a lifetime. If symptoms occur at all, they are usually urinary and kidney stones, recurrent renal colic, urinary tract infections or hematuria.

Diagnosis & course of disease

The medullary sponge kidney is diagnosed using x-ray imaging. Pyelography can also be used to confirm the diagnosis. With this procedure, it is not the calyxes that fill up first, but the papillary cavities of the kidneys. Although the changes are innate, diagnosis is usually made late. In most cases, a diagnosis can only be expected from young adulthood and is then mostly an incidental finding.

In many cases, the diagnosis is not made until the age of five or even after death. The prognosis is relatively favorable. A reduced life expectancy does not apply to the medullary sponge kidney, for example. Kidney and urinary stones made of calcium can cause severe pain and thus reduce the quality of life, but they can just as easily remain silent. How great the suffering is in the context of the medullary sponge kidney depends on the individual case.

Complications

The medullary spongy kidney causes cysts to form in the kidneys and around the kidneys. This enlarges them and there is no self-healing. In the worst case scenario, kidney failure can sometimes occur, which, without treatment, can also lead to patient death. The affected person is then dependent on a donor kidney or dialysis in order to survive.

However, the medullary sponge kidney does not have to lead to complications or complaints in every case, so that many patients live their entire life with the medullary sponge kidney without restrictions and complaints. Furthermore, kidney stones or urinary stones can develop more intensely. Other infections of the kidneys or urinary tract are also possible.

Due to the increased supply of fluids and various therapies, the symptoms of the medullary spongy kidney can be limited relatively well. There are usually no complications. However, it is not uncommon for patients to be dependent on taking medication. If the treatment is successful, the patient's life expectancy will not be reduced and there will be no further complications.

When should you go to the doctor?

Most patients have no symptoms or irregularities in the medullary spongy kidney. This leads to the fact that in some cases no diagnosis is made in the course of life. Everyone should take part in the regular check-ups and routine examinations, even if they have no symptoms. These take place in the first few years of life and are offered to adults from the age of 35. The need to consult a doctor arises as soon as the person concerned notices irregularities or complaints in the kidney area. If the kidney function changes or if the feeling is diffuse, a doctor should be consulted.

If there are problems urinating, blood in the urine, abnormal fluid intake or if ulcers in the kidney area can be felt, a doctor should be consulted. Swelling or a feeling of pressure in the upper body are indications of existing cysts that should be clarified by a doctor. A persistent urge to urinate immediately after going to the toilet, repeated infections of the urinary tract or the formation of urinary and kidney stones indicate the presence of a medullary spongy kidney. If colic occurs, a doctor must be consulted as soon as possible. Since there is a risk of organ failure, an ambulance service should be alerted immediately in the event of cramps and severe pain in the kidneys.

Treatment & Therapy

A causal treatment for the medullary sponge kidney is not yet available. The therapy is therefore exclusively symptomatic. Both drug therapies and interventions can take place as symptomatic treatment. Stone disintegration is carried out especially in the case of stones in the urinary tract or kidneys. Smaller stones are shattered by shock waves.

Without any operation or anesthesia, shock wave devices transmit shocks to the tissue water, which shatter the calcium calculus. The patient excretes the broken stones with the urine. Larger calculus cannot be removed in this way. Surgical removal is the treatment of choice even with a large number of stones. In order to avoid stone formation or to reduce the risk of recurrence after fragmentation, patients with medullary spongy kidney should drink as much water as possible.

A drinking amount of 2.5 liters per day is the minimum. The formation of stones can, however, also be prevented with medication. To treat hypercalciuria and as a prophylaxis for nephrolithiasis, those affected receive thiazides, for example, which also reduce the risk of urinary and kidney stones. Urinary tract infections are usually countered with antibiotic therapy.

Outlook & forecast

The prognosis of the medullary sponge kidney is based on the individual characteristics of the disease. However, no spontaneous healing is to be expected. Cysts form on the kidney that require medical attention. Otherwise, there is a risk of the disease spreading and thus an increase in health impairments.

In the case of a very unfavorable course of the disease and an intense expression of the genetically determined disease, the affected person can also die prematurely. The functional activity of the kidney is limited due to the new tissue formation. If there is no timely medical treatment, irreversible damage to the organ can occur. In addition, a failure of the organ activity is possible. In these cases there is a life-threatening disorder. The person concerned is threatened with premature death.

If medical care is initiated as soon as the first irregularities in the formation of new tissue, the symptoms can often be completely cured. A disintegration of the cysts or stones is initiated. The foreign bodies are then transported away and excreted by the organism. In addition, surgical interventions can be carried out that also track the removal of the foreign body. This treatment method increases the risk of complications. Nevertheless, it often represents the only prospect of recovery. In the further course of life, the foreign bodies can form new ones at any time.

prevention

The medullary spongy kidney cannot be prevented so far, as the causes of the disease have not been conclusively clarified. Nonetheless, the risk of symptoms can be reduced by drinking enough fluids, for example.

Aftercare

Since the disease and the treatment of the medullary spongy kidney are relatively complex, follow-up care is aimed at trying to deal with the situation well. This can lead to psychological upsets, which should sometimes be clarified by a psychologist. Therapy or contact with other people affected can help to better accept the disease. This can increase well-being regardless of the fact that the treatment continues.

A medullary spongy kidney can lead to various complications and complaints for the patient if left untreated. Those affected should regularly visit their doctor and strictly follow the instructions in their own interest. This also includes the diet, which is supposed to relieve the kidneys during regeneration. In this respect, aftercare aims to adjust to the unfamiliar situation and promote a healthy lifestyle. The further course depends very much on the severity of this disease, so that a general prediction is usually not possible. In some cases, the life expectancy of the patient is also limited.

You can do that yourself

If symptoms of kidney disease occur, a doctor should be consulted first. The medullary spongy kidney can be treated symptomatically by those affected, but requires a comprehensive clarification by a doctor.

A strict diet must be followed in addition to drug therapy, which is used to reduce pain. A lot of fluids should be consumed (at least three liters per day), especially before going to bed and after meals. The daily diet should mainly consist of light foods. Depending on how severe the medullary spongy kidney is, foods such as vegetables, fruits and low-salt foods are recommended. Meat and sausage should be avoided as far as possible. Coffee and alcohol should also be avoided as they put additional strain on the kidneys.

In general, care must be taken to ensure that the intestinal flora is intact. In consultation with the doctor, detoxification or a fast can be carried out to strengthen the health of the intestines and kidneys. General measures such as exercise and the avoidance of stress have a positive effect on the entire body and thus also on the diseased kidney. If the symptoms increase despite all measures, it is best to speak to the responsible doctor again.