Polycystic Kidney Disease

Key Features

• The most common monogenic kidney disease, affecting over 12 million individuals worldwide

• End-stage kidney disease develops in 50% of patients by age 60

• Disease has variable penetrance but accounts for 5–10% of all end-stage kidney disease cases globally

• Family history is present in 75% of cases

• At least two genes identified as causal of disorder

  • PKD1 on the short arm of chromosome 16 (85–90% of patients)

  • PKD2 on chromosome 4 (10–15% of patients)

Clinical Findings

• Abdominal or flank pain

• Microscopic or gross hematuria

• History of urinary tract infections and nephrolithiasis is common

• Large kidneys that may be palpable on abdominal examination

• Nephrolithiasis, primarily calcium oxalate stones, in up to 20%

• Hypertension in 50%

• Abdominal mass

• Arterial aneurysms in the circle of Willis in 10–15%

• Mitral valve prolapse in up to 25%

• Aortic aneurysms

• Aortic valve abnormalities

• Hepatic cysts in 40–50%

• Pancreatic and splenic cysts also occur

Diagnosis

• Renal ultrasonogram: diagnostic depending on age and number of cysts

• Urinalysis: may show hematuria and mild proteinuria

• CT scan: infected cyst has increased wall thickness

• Cerebral arteriography screening: not recommended unless patient

  • Has a family history of aneurysms

  • Is employed in a high risk profession (such as airline pilot)

  • Is undergoing elective surgery prone to cause moderate to severe hypertension

• Kidney size, reported as total kidney volume

  • Best predictor of kidney function decline in patients with autosomal dominant polycystic kidney disease

  • Can be measured via CT or MRI using the Mayo Classification system (www.mayo.edu/research/documents/pkd-center-adkpkd-classification/doc-20094754)

Treatment

• Pain

  • Bed rest and analgesics

  • Cyst decompression can help with chronic pain

• Hypertension

  • Treat with ACE inhibitors or ARBs if tolerated

  • Intensive blood pressure control (≤ 110/75 mm Hg) is recommended in adults younger than 50 years of age with eGFR > 60 mL/min/1.73m²

  • For other affected individuals, goal blood pressure is ≤ 130/85 mm Hg.

• Tolvaptan

  • A vasopressin receptor antagonist

  • Decreases the rate of change in the total kidney volume and the decline in the estimated glomerular filtration rate (eGFR)

  • FDA approved for the treatment of autosomal dominant polycystic kidney disease

• Hydration (at least 2 L/day)

• Treatment with octreotide, sirolimus, and tyrosine kinase inhibitors decrease the rate of cyst growth but not the rate of decline in kidney function; not routinely used

• Caffeine may worsen cyst formation; patients may want to limit total intake