Polycystic Kidney Disease

Question 1

What is polycystic kidney disease?

Answer 1

Genetic condition where multiple fluid-filled cysts develop in the kidney leading to significant renal impairment

Question 2

What are the 2 types of PKD?

Answer 2

Autosomal dominant (more common)

• PKD-1: chromosome 16 -> majority
• PKD-2: chromosome 4

Autosomal recessive (ARPKD)
-gene on chromosome 6

Question 3

What are the extra-renal manifestationals of AD PKD?

Answer 3

Cerebral aneurysms

Hepatic/splenic/pancreatic/ovarian/prostatic cysts

Cardiac valve disease -> mitral regurg

Colonic diverticula

Aortic root dilatation

Question 4

What are the complications associated with AD PKD?

Answer 4

Chronic loin pain

Hypertension

CVD

Gross haematuria with cyst rupture (self-limiting)

Renal stones

End-stage renal failure

Question 5

What is the common presentation of ARPKD?

What are the consequences of this?

Answer 5

(I.e. in-utero presentation)
Oligohydramnios
-too little fluid amniotic fluid due to fetus being unable to produce enough urine

Consequences:

• underdevelopment of lungs -> resp failure after birth
• dialysis for first few days of life
• dysmorphic features
• ESRF in adulthood

Question 6

How is PKD (both AR + AD) managed?

Answer 6

Tolvaptan

• vasopressin receptor antagonist
• acts to slow the development of cysts and progression to ESRF

Supportive management of complications:

• antihypertensives
• analgesia (renal colic due to stones )
• Abx if cyst become infected
• Dialysis for ESFR
• Renal transplant
• regular USS to monitor
• advice to avoid NSAIDs + anticoagulents and contact sports (decrease risk of rupturing cyst)

Question 7

Why are NSAIDs and anticoagulents adviced to be avoided in PKD?

Answer 7

When PKD induces CKD because these drugs need to be avoided in CKD

Anticoagulents
-many require renal elimination meaning if renal function is reduced, drugs can accumulate and lead to increased risk of bleeding

NSAIDs
-inhibit renal prostanglandins due to inhibition of COX-1 and COX2
CONSEQUENCES:
-can lead to reduced blood flow and GFR due to decreased production of prostaglandins usually associated with vasodilation
-Sodium retention
-decreased renin stimulation= hyperkalaemia + Type 4 renal acidosis