Polycystic kidney disease

Question 1

PKD?

Answer 1

Autosomal dominant inherited disorder characterised by the development of multiple renal cysts that gradually expand and replace normal kidney substance, variably associated with extrarenal (liver and cardiovascular abnormalities).

Question 2

PKD Aetiology?

Answer 2

85% caused by mutations in PKD1 on chromosome 16, 15% caused by PKD2 on chromosome 4

Question 3

PKD pathophysiology?

Answer 3

proliferative/hyperplastic abnormality of the tubular epithelium.

Early on, the cysts are connected to the tubules from which they arise and the fluid content is glomerular filtrate.

When cyst diameter >2 mm, they detach from the tubule and the fluid content is derived from secretion of the lining epithelium.

With time, the cysts enlarge and cause progressive damage to adjacent functioning nephrons

Question 4

PKD epidemiology?

Answer 4

most common inherited kidney disorder, 10% of end-stage renal failure.

Question 5

PKD symptoms?

Answer 5

presents at 30-40,

20% have no family hist,

flank pain (from cyst enlargement/bleeding, stone, blood clot migration, infection)

haematuria,

hypertension, associated with berry aneurysms that may present as subarachnoid haemorrhage.

Question 6

PKD signs?

Answer 6

abdo distension,

enlarged cystic kidneys,

palpable liver, hypertension,

signs of chronic renal failure,

signs of associated AAA or aortic valve disease.

Question 7

PKD investigations?

Answer 7

USS or CT will show multiple cysts bilaterally in enlarged kidneys.