Polycystic Kidney Disease (PKD)

An inherited disorder, polycystic kidney disease is characterized by multiple, bilateral, grape like clusters of fluid-filled cysts that grossly enlarge the kidneys, compressing and eventually replacing functioning renal tissue. This disease appears in two distinct forms.

The infantile form causes stillbirth or early neonatal death. A few infants with this disease survive for 2 years and then develop fatal renal, heart, or respiratory failure.

The adult form begins insidiously but usually becomes obvious between the ages of 30 and 50; rarely, it causes no symptoms until the patient is in his seventies. In the adult form, renal deterioration is more gradual but, as in the infantile form, progresses relentlessly to fatal uremia.

Causes

Signs and symptoms

The most common symptoms of PKD are frequent infections, blood in the urine, anemia, kidney stones, heart murmur, brain aneurysm, and hernia.  The abdominal pain may be felt in any part of the abdomen, or it may be limited to the right upper or left upper quadrant of the abdomen. Other less common symptoms include nail abnormalities, painful menstruation, joint pain, drowsiness, and high blood pressure.

Diagnosis

A family history and a physical examination revealing large bilateral, irregular masses in the flanks strongly suggest polycystic kidney disease. In advanced stages, grossly enlarged and palpable kidneys make the diagnosis obvious. In patients with these findings, the following laboratory results are typical:

• Excretory urography or retrograde utero pyelography reveals enlarged kidneys, with elongation of pelvis, flattening of the calyces, and indentations caused by cysts. Excretory urography of the newborn shows poor excretion of contrast medium.
• Ultrasonography, tomography, and radioisotope scans show kidney enlargement and presence of cysts.
• Computed tomography and magnetic resonance imaging demonstrate multiple areas of cystic damage.
• Urinalysis and creatinine clearance tests-nonspecific tests that evaluate renal function - indicate abnormalities.

Treatment

Polycystic kidney disease can't be cured. The primary goal of treatment is preserving renal parenchyma and preventing infectious complications. Management of secondary hypertension will also help prevent rapid deterioration in function. Progressive renal failure requires treatment similar to that for other types of renal disease, including dialysis or, rarely, a kidney transplant.

Asymptomatic stage

When adult polycystic kidney disease is discovered in the asymptomatic stage, careful monitoring is required, including urine cultures and creatinine clearance tests every 6 months. When a urine culture detects infection, prompt and vigorous antibiotic treatment is needed (even when the patient is asymptomatic).

Progressive renal impairment

As renal impairment progresses, selected patients may undergo dialysis, transplantation, or both. Cystic abscess or retroperitoneal bleeding may require surgical drainage; intractable pain (a rare symptom) may also require surgery. However, because this disease affects both kidneys, nephrectomy usually isn't recommended because it increases the risk of infection in the remaining kidney.

Prevention

Because PKD is an inherited disease, there is currently no known way to prevent it.