Autosomal Dominant Polycystic Kidney Disease

Overview
  • Autosomal Dominant Polycystic Kidney Disease (ADPKD) is an inherited disorder resulting in the development of multiple, characteristic cysts within the renal parenchyma.
Genetics
  • ADPKD is inherited in an autosomal dominant pattern. Mutation of either of two genes, PKD1 or PKD2, can result in disease. These proteins are structurally quite different but are believed to act in concert to mediate cell-matrix adhesion.
Morphology
  • Gross Appearance
    • Kidneys possess numerous cysts 3-4cm in diameter that are filled with a clear or bloody fluid. Consequently, kidneys can grow to enormous sizes and may be readily palpable in the abdomen or pelvis.
  • Histological Appearance
    • Cysts are derived from giant dilations of nephronic segments. While normal renal tissue may exist between the cysts, the unaffected renal parenchyma undergoes atrophy due to progressive expansion and pressure from the cysts.
Clinical Consequences
  • Presenting Symptoms
    • Patients sometimes present with abdominal or flank pain. In some cases, hematuria or signs of a urinary tract infection are present. Frequently, secondary hypertension develops due to declining renal function.
  • Extra-renal Manifestation
    • Although the most important clinical manifestation of ADPKD is in the kidneys, the disease affects multiple organ systems. There is an increased risk of berry aneurysms as well as development of cysts in the liver.
  • Course
    • Clinical symptomology usually becomes apparent in adult life, in the fourth or fifth decade. Although the progression of disease is relatively slow, in many cases it follows an inexorable path to chronic renal failure.
Epidemiology
  • ADPKD is quite common and accounts for nearly 10% of cases of chronic renal failure. As described above, clinical symptoms appear in adult life.