Polycystic kidney disease

Question 1

Define polycystic kidney disease

Answer 1

Autosomal dominant inherited disorder characterised by development of multiple renal cysts that gradually expand & replace normal kidney substance

Variably associated w/ extra renal (liver & cardiovascular) abnormalities

Question 2

Causes of polycystic kidney disease & proportions

2

Answer 2

85% caused by mutation in PKD1 on chromosome 16

15% caused by mutation of PKD2 on chromosome 4

Question 3

Aetiology of polycystic kidney disease

4

Answer 3

Proliferative/hyperplastic abnormality of tubular epithelium
Early on, cysts are connected to tubules from which they arise & fluid content is glomerular filtrate
When cyst diameter >2mm, they detach from tubule & fluid content is derived from secretion of lining epithelium
With time, cysts enlarge & cause progressive damage to adjacent functioning nephrons

Question 4

Epidemiology of polycystic kidney disease

prevalence inherited & effect

Answer 4

MOST COMMON inherited kidney disorder

Responsible for 10% of end stage renal failure

Question 5

Presenting symptoms of polycystic kidney disease

7

Answer 5

Present at 30-40 yrs
20% have no FH
May be asymptomatic
Flank pain - may result from cyst enlargement/bleeding, stone, blood clot migration, infection
Haematuria
Hypertension
Associated w/ berry aneurysms & may present w/ subarachnoid haemorrhage

Question 6

Signs of polycystic kidney disease on physical examination

6

Answer 6

Abdominal distention
Enlarged cystic kidneys
Palpable liver
Hypertension
Signs of chronic renal failure (at late stage)
Signs of associated AAA or aortic valve disease

Question 7

Investigations for polycystic kidney disease

1 -2

Answer 7

US or CT
Will show multiple cysts bilaterally in enlarged kidney
Liver cysts may also be seen