Autosomal dominant polycystic kidney disease is characterised by renal cysts, hepatic cysts, intracranial aneurysmsand aortic root dilatation.
It is the most common inherited disorder of the kidneys. It peaks between the ages of 30 and 40, and affects men and women equally.
Classification of Autosomal Dominant Polycystic Kidney Disease
| Classification | Description |
|---|---|
| Type 1 ADPKD | A mutation in PKD1 on chromosome 16. This is the more severe type. |
| Type 2 ADPKD | A mutation in PKD2 on chromosome 4. This is the less severe form |
- Cause
- Mutation in PKD1 and PKD2
- Pathophysiology
- PKD1 and PKD2 encode polycystin-1 and polycystin-2 which are part of primary cilia
- Primary cilia act as mechanosensors in renal tubular epithelial cells
- Mutations in PKD1 and PKD2
- Increased intracellular Ca2+ → activation of signalling pathways → cell proliferation and fluid secretion
- Disrupted planar cell polarity → misoriented cell division → tubular dilation → cyst formation
- The cysts expand, compress the parenchyma, and lead to ischaemia → fibrosis
- Similar ciliary dysfunction in other organs leads to extrarenal manifestations
- Signs and symptoms
- Haematuria
- Loin pain
- Hypertension
- Recurrent UTI
- Urolithiasis
- Headache
- This may be due to a ruptured berry aneurysm
- Renal failure
- This occurs in the 5th decade of life
- Physical examination
- Palpable kidneys or abdominal mass
- Hepatomegaly due to hepatic cysts
- Abdominal wall hernias
- Cardiac murmur
- Differentials
- Autosomal recessive polycystic kidney disease (ARPKD)
- In ARPKD, symptoms present soon after birth
- Medullary cystic renal disease
- In medullary cystic renal disease, the kidneys are smaller and recurrent gout is common
- Acquired cystic kidney disease
- Simple renal cysts
- Tuberous sclerosis
- Von-Hippel-Lindau syndrome
- Autosomal recessive polycystic kidney disease (ARPKD)
- Investigations
- Renal ultrasound is the first-line imaging modality
- The diagnosis can be made based on the Ravine criteria which counts the number of renal cysts according to the age group
- MRI is more sensitive than ultrasound for smaller cysts
- MRI can also be used to screen for intracranial aneurysms
- Urea and creatinine to assess renal function
- Urinalysis for haematuria or proteinuria
- Genetic testing when imaging is inconclusive
- Renal ultrasound is the first-line imaging modality
- Treatment
- Referral to a nephrologist
- Treat hypertension
- Treat renal pain
- Treat UTIs
- Treat urolithiasis
- Renal replacement therapy if indicated
- V2 receptor antagonist (Tolvaptan)
- This may slow the progression of cysts and renal insufficiency
- Complications
- Hepatic cysts
- Hypertension → coronary artery disease, stroke, and myocardial infarction
- Intracranial aneurysms → subarachnoid haemorrhage
- Gestational hypertension and preeclampsia
- Chronic kidney disease and end-stage renal disease