Multicystic kidney dysplasia is a congenital kidney disease, but it is not hereditary. The degree of expression of the disease varies. A cystic kidney forms.
What is multicystic kidney dysplasia?
Multicystic kidney dysplasia is classified as part of the polycystic kidney disease (PKD) group. However, unlike the classic polycystic kidney diseases, it is not hereditary. It occurs sporadically during embryonic development and, like the polycystic kidney diseases, results in a cystic kidney. Often, the renal pelvic caliceal system is absent. There are unilateral and bilateral forms of the disease. While only one kidney is affected in unilateral multicystic kidney dysplasia, both kidneys are affected in the bilateral form. In the unilateral form, the course of the disease is usually asymptomatic because the healthy kidney takes over all functions. If left untreated, the bilateral form leads to death due to the complete regression of both kidneys. Cystic kidney disease is initially classified into genetically heritable and non-heritable forms. According to Potter’s classification, cyst formation is based on the nephron segment. Thus, multicystic kidney dysplasia is classified as a non-heritable kidney disease and Potter classification as Potter IIa. Multicystic renal dysplasia is considered the most common abdominal tumor or cystic disease of the kidneys in the neonatal period. The probability of the disease is 1 per 4300 live births.
Causes
The causes of multicystic kidney dysplasia are not known. All that is known is that the kidney changes occur sporadically during embryonic development and are not inherited. There are also no familial clusters. In contrast, there are polycystic kidney diseases, which are genetically determined and can be inherited in an autosomal recessive or autosomal dominant manner. In multicystic kidney dysplasia, there is a disturbed interaction between the ureteral and renal anlagen during embryogenesis. As a result, the individual nephrons cannot be properly laid down. According to one theory, the metanephritic blastema is abnormally induced by the ureteric bud. Viral infections as a cause of the malformation are also discussed.
Symptoms, complaints, and signs
Symptoms of multicystic renal dysplasia vary among patients. In addition to asymptomatic courses, severe renal disease, including renal failure requiring dialysis, may occur. The course depends decisively on whether only one or both kidneys are affected. In most cases, unilateral kidney involvement occurs. Only one kidney is affected. In the further course of the disease, the kidney recedes completely. However, since a healthy kidney is still present, no symptoms occur. The healthy kidney takes over full kidney function. Bilateral multicystic kidney dysplasia is much rarer. However, it leads to complete renal failure in the setting of cystic kidney disease. Initial manifestations of the disease occur between birth and infancy. Unilateral manifestations are often asymptomatic, but may be manifested by frequent urinary tract infections in childhood. In the bilateral form, renal failure requiring dialysis already occurs in young children. In the further course, spontaneous involution occurs in both forms. This means that one or both kidneys spontaneously regress. This often leads later to the misdiagnosis of renal agenesis (hereditary absence of a kidney). The ureter is also sometimes characterized by malformations, so that difficulties in urination may occur. Sometimes there is cystic dysplasia of the testes. In bilateral multicystic renal dysplasia, death can occur within eight weeks without dialysis as part of a fatal Potter syndrome.
Diagnosis and course of the disease
The finding of multicystic kidney dysplasia can only be clearly determined by various diagnostic procedures. Thus, a hereditary component must first be excluded as part of a family history. Sonography and, if necessary, CT are used as imaging procedures. In the case of suspicious changes, laboratory tests may be considered. It is important to examine creatinine clearance and blood count.Furthermore, urine diagnostics and long-term blood pressure measurement must be performed. The excretory function of the kidneys is determined by a urinary excretion program. However, differential diagnosis must exclude medullary sponge kidney and renal cyst.
Complications
This condition does not necessarily cause particular symptoms or complications in every case. It can also be asymptomatic in some cases and thus does not lead to any particular complications or limitations. In a malignant course, however, renal insufficiency occurs, so that the affected person usually dies without treatment. Those affected are then dependent on either a donor kidney or dialysis for survival. Life expectancy is significantly reduced in a negative progression of the disease and quality of life is reduced. Similarly, infections or inflammations of the urinary tract of the affected person may occur, which in most cases are associated with pain and other unpleasant symptoms. The testicles are also affected by the disease in some cases. If the position of the kidney in the body is altered, this complaint can also lead to the death of the affected person. In the course of treatment, transplantation of the kidney is usually performed. Various complications may occur during this process. However, if the transplant is successful, the outcome is positive. Whether or not life expectancy will be limited cannot be generally predicted.
When should you see a doctor?
If urinary irregularities are noticed in infants or children, a physician should be consulted immediately. In many cases, obstetricians or pediatricians can detect disturbances during the first postnatal examinations. They will automatically initiate further steps to ensure adequate health care for the infant so that no complications arise. If in the further development and growth process of the newborn child there are abnormalities in the amount of urine, the color of the urine or an unusual odor, a doctor is needed. General peculiarities of toileting or changes must be observed. If they are acute, persist over a long period of time, or increase in intensity, a doctor’s visit is needed. If there is pain, swelling on the body or changes in the appearance of the skin, there is a health condition that needs to be investigated and treated. If the affected person suffers from inner restlessness, apathy, sleep disorders or general vegetative abnormalities, a visit to the doctor is recommended. Refusal of fluid intake, increased incidence of urinary tract infections, and cramps must be presented to a physician. If an acute health condition occurs, emergency medical services are required. An emergency physician must be alerted and first aid measures must be initiated, as the premature demise of the affected person is imminent. If disinterest in social activities is evident or other behavioral abnormalities are noted, consultation with a physician is advised.
Treatment and therapy
Unfortunately, treatment of multicystic kidney dysplasia can only be symptomatic. A cure for the disease is impossible. Prevention and early detection of severe renal insufficiency are the main factors. Therefore, it is necessary to carry out regular controls of laboratory values. This applies to sonographic examinations, constant determination of creatinine clearance, excretory functions of kidneys and ureters, and examination of urine for blood and protein components. If arterial hypertension occurs, it must be treated quickly. If permanent renal insufficiency develops, regular dialysis must first be provided. Kidney transplantation may also be necessary. Very important is the treatment of constant urinary tract infections. If the pain is severe, laparoscopic cystostomies are still performed. In this case, cysts filled with fluid are opened via a reflection. However, this treatment has no effect on the course of the disease. In the unilateral forms of the disease, symptomatic treatments are usually sufficient, if symptoms occur at all. In bilateral multicystic kidney dysplasia, kidney transplantation is often required.
Outlook and prognosis
Doctors rate the outlook for multicystic kidney dysplasia as favorable.The causes of the disease remain obscure to this day. Nor can it be prevented from developing in the embryonic stage. Nevertheless, the kidneys usually shrink on their own during the first years of life, eliminating the risk of renal insufficiency. Regular check-ups are therefore necessary during the first years of life. Only in the case of a severe course and a large extent of symptoms, surgery is necessary. Multicystic kidney dysplasia occurs in one out of 4,300 newborns. Most infants develop the unilateral form, which has the best chance of cure. The bilateral form is rarer and progresses with a great need for action on the part of physicians. This is especially true for malignant tumors. Very often children have to undergo dialysis procedures at a young age. The question of transplantation also arises. In the case of bilateral tumors, failure to treat the disease leads to death within a few weeks. Basically, life expectancy is shortened insofar as a tumor cannot be completely removed. There is also often a risk of recurrence.
Prevention
Multicystic kidney dysplasia cannot be prevented. It is a congenital kidney disease, but it is not hereditary. Only the progression of the disease can be permanently monitored by laboratory tests and imaging techniques to adjust further treatments. Regular therapy of urinary tract infections and the correct start of dialysis treatment can be life-saving and postpone the time for a kidney transplant.
Follow-up
Even if no treatment is given, regular kidney checks should be performed to detect urinary tract infections or the development of renal failure early. There is an increased risk of both because of renal dysplasia. Also, annual checkups should be done to detect renal anemia based on blood counts. Whether the malformed kidney has been removed or not, some behavioral tips should be followed. These will help to care for and protect the remaining kidney. As a rule, the amount of drinking should be consistently kept high, but sometimes there are contraindications. In such cases, an individually tailored daily drinking quantity can be agreed with the doctor. Particular attention should be paid to fluid intake, especially in hot weather and during sporting activity. In addition, all substances that unnecessarily burden the kidneys should be avoided. These include over-the-counter painkillers such as ibuprofen, diclofenac or aspirin. There is nothing to prevent occasional use, but other drugs should be used for permanent pain therapy. Especially in the period directly after surgical removal of the dysplastic kidney, the corresponding part of the body should be spared. This includes no heavy lifting and limited sports activities.
What you can do yourself
The right diet can already provide more well-being in everyday life. Since a change in diet must not only pay attention to nutrients, but rather to the severity of the disease, it is advisable not to do this on your own. A mistake regarding the amount of protein and fluids would be fatal, depending on the severity of the disease. Instead, it is advisable to contact a nutritionist to obtain an individually tailored diet plan. This should be optimized so as not to affect kidney function, particularly with regard to salt, protein, potassium, phosphate and sodium. The goal is a balanced, healthy diet that is also gentle on the kidneys. To minimize damage to the kidneys from frequent urinary tract infections, it is often not enough to avoid sitting on cold surfaces. Rather, it is important to pay attention to good intimate hygiene, which does not only refer to regular washing. The choice of contraceptive and quick toilet use after sexual intercourse already play a major role. In women, a lowered estrogen level can lead to an increased risk of infection, so it is advisable to have this checked at the latest during menopause and to discuss further treatment options with the gynecologist. If dialysis is not required, regular consumption of bladder tea from the pharmacy is also possible.
