Multicystic dysplastic kidney is a common condition that occurs when one kidney doesn't get put together correctly as it's forming in the womb. The kidneys begin to develop at around 5-6 weeks gestation, and the process by which they form is complicated. If something goes wrong during development, it is possible to end up with a non-functioning kidney full of cysts and scar tissue. Fortunately, the remaining kidney is usually able to take over all kidney function.
If both kidneys are affected, a spontaneous abortion would occur. This is because the kidneys are responsible for the production of amniotic fluid which is required to maintain a normal pregnancy. Amniotic fluid is also important for proper lung development.
Multicystic dysplastic kidney is thought to affect 1 in every 3,500 people, but that number may be higher because some people who have it are never diagnosed with the condition.
There are rare cases when multicystic dysplastic kidney runs in families because of a genetic trait. However, the vast majority occur as a sporadic event. The proper formation of a kidney is complex with hundreds of thousands of steps that must execute correctly. If there is a hiccup in just one step, an abnormal kidney may form. Some studies suggest certain viral infections and some drugs might also play a role if exposure occurs at a critical stage of development.
Multicystic dysplastic kidney does not cause any symptoms at all. The condition is usually found during a prenatal ultrasound or when a doctor discovers an abdominal mass during a routine physical examination. The diagnosis of multicystic dysplastic kidney is usually made with an ultrasound examination. Sometimes a nuclear scan is required to differentiate a multicystic dysplastic kidney from a blocked kidney.
A blocked kidney may have a similar appearance on ultrasound, and tumors are another possibility for asymptomatic abdominal masses. Other imaging techniques, such as CT scans, MRIs, and nuclear scans can help distinguish between the possibilities.
The multicystic dysplastic kidney requires no specific treatment. Over time, the abnormal kidney regresses and just goes away. Many people know someone who "only has one kidney." These are often individuals who had a multicystic dysplastic kidney that shrank and vanished before a doctor could diagnose it.
The multicystic dysplastic kidney is not typically associated with any significant complications, and in most cases there are no associations between it and disease in any other organ system. In some cases, there may be treatable structural abnormalities in the remaining kidney, which can result in reflux or blockage of urine. This makes it important for patients with multicystic dysplastic kidney to continue following up with a kidney doctor even though the dysplastic kidney is unlikely to ever be a problem.
The multicystic dysplastic kidney has an excellent long-term prognosis, and an affected patient will most likely have one normally functioning kidney for the remainder of their life.
There is no way to prevent multicystic dysplastic kidney from occurring early in a baby's development, and there is no known way to prevent it from happening.
It is important not to confuse multicystic dysplastic kidney and polycystic kidney disease. Polycystic kidney disease is an inherited disease that affects both kidneys. Affected individuals are born with normal kidneys, and the cysts develop over time. Age of onset and severity are variable and depends on the genetic pattern of the disease in a given family. Polycystic kidney disease is associated with significant complications such as hypertension (high blood pressure) and decreased kidney function or kidney failure. Sometimes dialysis or kidney transplant are required.
There is no known relationship between multicystic dysplastic kidney and autism. Because these are common conditions, lots of kids have both problems, but this does not mean one caused the other.
In children with multicystic dysplastic kidney, the non-dysplastic kidney usually functions properly and easily does the work of two kidneys. Therefore, there is no reason to limit drugs or supplements in doses appropriate for a person with two kidneys. As always, it is recommended parents talk to their child's doctor and only use drugs and supplements in accordance to their guidance.