Polycystic kidney disease

  ADPKD ARPKD
Genetics

Autosomal dominant

  • Chromosome 16 (PKD1 (85%)/PKD2 (15%))
  • PKD2 less severe phenotype
  • Mutations promote cyst formation and fluid secretion

Autosomal recessive

  • Chromosome 6 (PKHD1)
Natural history
  • ESRD mean age 75 yrs (PKD1)/54 yrs (PKD2)
  • 30% present < 1 yo, 30% 1-20 yo, 30% > 20 yo
Presentation
  • Hypertension, renal failure
  • Hematuria (30-50%), nephrolithiasis (25%)
  • Pain (cyst infection/hemorrhage, stretching of capsule)
  • Renal microcysts in collecting ducts
  • Hepatic fibrosis, intrahepatic biliary dilatation -> hepatomegaly, portal hypertension
  • Respiratory distress (compression by large kidneys)
  • HTN
Extrarenal 
  • Cerebral aneurysms (5-20% prevalence, increases with age)
  • Hepatic cysts (10-50% prevalence, increases with age) (massive cysts almost exclusively in women - estrogen driven?)
    • Autosomal dominant polycystic liver disease not a/w renal cysts or cerebral aneurysms
  • Pancreatic cysts
  • Cardiac valve disease
  • Colonic diverticula
  • Abdominal wall and inguinal hernia
  • Seminal vesicle cysts
  

Diagnosis

  • Asymptomatic with positive family history or symptomatic - ultrasound of kidneys
    • Children < 18 yo - recommend not screening (no benefit/tx to early diagnosis)
    • 15-39 yo - at least 3 unilateral/bilateral kidney cysts (100% spec/PPV, ~ 90% sens)
    • 40-59 yo - at least 2 cysts in each kidney (90% sens, 100% spec, 100% PPV)
    • > 60 yo - at least 4 cysts in each kidney (100% sens/spec)
  • Known familial genotype - genetic testing vs. ultrasound

Differential diagnosis

  • ADPKD is bilateral and progressive
  • Benign simple cysts - people unlikely to have more in # than the US criteria for ADPKD
  • Medullary sponge kidney - does not involve renal cortex
  • Acquired cystic disease (e.g. dialysis/CKD) - kidneys are usually normal in size, no extrarenal manifestations
  • ***
  • HTN - treat with ACEi/ARB
  • Cerebral aneurysm - screening if high risk (prior rupture, family hx of rupture, anticoagulated, HTN)
  • Hepatic cysts - can cause pain if infection or hemorrhage
    • If symptomatic - cyst decompression, partial resection (if refractory), liver/kidney transplantation
author: last edited: Sept. 10, 2018, 8:34 a.m. | pk: 135 | unpublished