Question Title: Multicystic Dysplastic Kidney (MCDK)

During a level 2 ultrasound at 28 weeks our unborn child was diagnosed with multicystic dysplastic kidney (MCDK). The radiologist (doctor, not technician) explained the cause and the potential problems after birth, but we have been unable to find much plain-language information on these problems. Of particular concern to us is a statement he made that MCDK is an indicator of possible chromosomal abnormalities, which could indicate Down's Syndrome, mental retardation, etc. Of all the information we've been able to locate (and its not much) there has been no mention of any of the deformities the radiologist discussed with us. Did he give us some bad information? The alpha-theta protein test was negative and we were told that test was a good indicator because of the low incidence of false negatives.

Also, the other kidney shows no cysts whatsoever and the amniotic fluid levels are good. What is the possibility of the remaining kidney developing cysts?

I really need to find some information in "plain English" concerning MCDK. Even the info the National Kidney Foundation sent us was really technical in nature.

Appreciate any help we can get.

Thanks,
Dave

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Dear Dave,

I am sorry that you received upsetting news during your pregnancy; preparing for a baby's arrival is a time of happy anticipation normally, but now you must make some adjustments in your expectations. I hope my answer helps you understand the diagnosis in somewhat "plain English".
I cannot confirm a positive association between MSKD and Down Syndrome.

The finding of cysts on one side in a prenatal ultrasound most likely will be one of two things.
The most common causes are 1)what is referred to as "multicystic kidney", and 2) hydronephrosis (swollen kidney). Both conditions are diagnosed more frequently nowadays due to the widespread use of ultrasound during pregnancies, thus allowing the condition to be diagnosed prenatally rather than after the baby is born. The benefit of prenatal diagnosis is obvious--for one thing, you will already be somewhat aware of what to anticipate rather than noticing unexpected symptoms after the baby is born. Because you mention that cysts were only found on one kidney, I will respond to that finding and not discuss bilateral cysts.

Multi-cystic kidney is a benign (non-cancerous) condition which could stay clinically silent throughout life. No definite cause has been described. However, it is theorized that it may be associated with 1) an obstruction of the urinary tract on the involved side, or 2) perhaps the blood supply to the developing kidney was somehow diminished. If multi-cystic kidney is severe and bilateral, the fetus would not survive after birth; this occurs in approximately 20% of the diagnosed cases. When only one kidney is involved, the affected kidney may cease functioning over time. The prognosis for patients is dependent on the status of the unaffected kidney. Humans need only one functioning kidney to live. It is crucial to perform a careful study of the unaffected side in order to determine its functional capacity. In the past, multi-cystic kidneys were routinely surgically removed; however, close surveillance of the patient over the course of time may preclude the need for this surgery. If in the long run, the patient develops high blood pressure, infection, pain, or any changes suggestive of malignancy, then a nephrectomy (surgical removal of the kidney) will be advised.

Hydronephrosis, or swollen kidney, may also appear similar to a multi-cystic kidney in a prenatal ultrasound. This condition could be due to 1) an obstruction in the urinary tract or 2) reflux (urine backing up into the kidney from the bladder) or 3) may be a self-limiting process which would resolve spontaneously either before birth or after. The cause for hydronephrosis can be determined after birth by performing tests that your urologist would order. The causes (if it does not resolve on its own) are able to be corrected by surgery.

In the event that the affected kidney would ultimately fail and/or need to be removed, as long as the remaining kidney has normal function, your baby will be able to enjoy a normal, healthy life. Of course, for a person with only one kidney, it is important to maintain optimum overall health to protect that kidney from any other preventable damage. It will remain an important part of that person's medical care that routine surveillance of kidney function continues through life. I hope this helps alleviate your fears and helps you prepare for your baby's birth.

This information is provided for general medical educational purposes only. Please consult your physician for diagnostic and treatment options pertaining to your specific medical condition. More individualized care is available at the Henry Ford Hospital and its satellites (1 800 653-6568).

Sincerely,
HFHS M.D.-BE
*keyword: prenatal unilateral cystic kidney