PCKD

Question 1

What is it?

Answer 1

Polycystic kidney disease is a genetic condition where the kidneys develop multiple fluid-filled cysts. Kidney function is also significantly impaired. There are a number of associated findings outside the kidneys such as hepatic cysts and cerebral aneurysms. Palpable, enlarged kidneys may be felt on examination.
There is an autosomal dominant and an autosomal recessive type. The autosomal dominant type of PKD is more common than the autosomal recessive type.

Diagnosis is by kidney ultrasound scan and genetic testing.

Question 2

Autosomal Dominant Genes

Answer 2

PKD-1: chromosome 16 (85% of cases)
PKD-2: chromosome 4 (15% of cases)

Question 3

Extra-renal Manifestations

Answer 3

Cerebral aneurysms
Hepatic, splenic, pancreatic, ovarian and prostatic cysts
Cardiac valve disease (mitral regurgitation)
Colonic diverticula
Aortic root dilatation

Question 4

Complications

Answer 4

Chronic loin pain
Hypertension
Cardiovascular disease
Gross haematuria can occur with cyst rupture (this usually resolves within a few days
Renal stones are more common in patients with PKD
End-stage renal failure occurs at a mean age of 50 years

Question 5

What does oligohydramnios lead to?

Answer 5

The oligohydramnios leads to underdevelopment of the lungs resulting in respiratory failure shortly after birth. Patients may require dialysis within the first few days of life. They can have dysmorphic features such as underdeveloped ear cartilage, low set ears and a flat nasal bridge. They usually have end-stage renal failure before reaching adulthood.

Question 6

Management

Answer 6

Tolvaptan (a vasopressin receptor antagonist) can slow the development of cysts and the progression of renal failure in autosomal dominant polycystic kidney disease. It is recommended by NICE in certain situations although it should be initiated and monitored by a specialist.

Management of polycystic kidney disease is mainly supportive of the complications:

Antihypertensives for hypertension.
Analgesia for renal colic related to stones or cysts.
Antibiotics for infection. Drainage of infected cysts may be required.
Dialysis for end-stage renal failure.
Renal transplant for end-stage renal failure.

Other management steps:

Genetic counselling
Avoid contact sports due to the risk of cyst rupture
Avoid anti-inflammatory medications and anticoagulants
Regular ultrasound to monitor the cysts
Regular bloods to monitor renal function
Regular blood pressure to monitor for hypertension
MR angiogram can be used to diagnose intracranial aneurysms in symptomatic patients or those with a family history