Polycystic kidney disease is a genetic disease of the kidney in which multiple fluid-filled cysts are seen in the kidneys. In addition to kidneys, other organs may be affected. There are two types depending on the inheritance pattern. Autosomal recessive or autosomal dominant polycystic kidney disease .
What is Autosomal Recessive Polycystic Kidney Disease (ARPKD)?
The ARPKD is seen more often in children. In this disease, the liver is also affected. The affected gene is PKHD1 on chromosome 6. These children have a defect in the protein produced by the gene. The said protein is required for the structural development of the kidney and the liver. This causes cyst formation thus affecting the structure as well as the function of the kidney.
Can it be suspected during pregnancy?
The sonography done during pregnancy may show very severe oligohydramnios or decreased fluid. This indicates that the kidney has not been functioning adequately and such babies could have immature lungs.
What happens after delivery?
In the immediate period after delivery, affected babies have breathing problems due to immature lungs and large kidneys. The lung problem could be life-threatening and overshadows the kidney failure. Some kids may not have a lung problem but have kidney failure only.
At times children get diagnosed in later life when they undergo investigations for large kidneys or blood in urine or hypertension and polycystic kidneys are detected. Sometimes they seek medical advice for liver problems and kidney involvement is detected. Even though the kidney may appear to be temporarily functioning, it eventually fails. In 50% of the children, the kidneys fail completely by 10 years and the rest of the children by 20 years of age.
What investigations are carried out?
- Ultrasonography of the kidney ureter, bladder and liver
- MRI or CT scan of the abdomen
- Genetic testing
- Urine tests to detect protein
- Blood tests to monitor kidney function
How are these children treated?
The treatment is mainly supportive. Medicines are given to decrease protein loss in urine and hypertension so as to delay deterioration in kidney function.
What is Autosomal Dominant Polycystic Kidney Disease (ADPKD)?
ADPKD is usually the cause of kidney failure in adults. The affected genes are either the PKD1 gene on chromosome 16 or the PKD2 gene on chromosome 4. In these, the proteins produced by the said genes are defective causing cysts in the kidney.
What is the age for diagnosis?
These patients usually present in the third or fourth decade of life with high blood pressure, increased thirst and urine output or blood in the urine. A few patients may present earlier in the newborn period making it difficult to diagnose. Renal failure occurs by the third to fifth decade of life.
Which other organs involved?
Cysts may be seen in some patients in the liver and the pancreas . In other blood vessel malformations are seen in the brain, heart valves may be abnormal or hernias may be seen.
What tests are done?
- Ultrasonography of the kidney ureter and bladder
- CT scan or MRI of the brain
- 2D ECHO for the heart
- Genetic test
What treatment is given?
The treatment is mainly supportive. Medicines are given to decrease protein loss in urine and hypertension so as to delay deterioration in kidney function.
Dr. Vaishali More, Sr. Consultant – Pediatric Nephrology, SRCC Mumbai