Polycystic Kidney Disease

Question 1

What are the risk factors for progressive disease in ADPKD? (4)

Answer 1

Causative gene mutation within family

Early age of onset

Kidney size

Hypertension

Proteinuria

High urinary Na excretion

Question 2

Symptoms (P) to ask in ADPKD history? (5)

Answer 2

Flank pain

Haematuria

Proteinuria

HTN

Renal impairment on a routine blood test

Incidental finding on imagings

Question 3

How is the diagnosis of ADPKD established?

Answer 3

Primarily by imaging: ≥10 cysts (≥5mm) in each kidney

1. USS if +ve FH but asymptomatic with normal renal function
2. CT/MRI (if eGFT <60) if renal impairment/palpable kidneys

Genetic testing is indicated in equivocal cases (generally required only in atypical cases to rule out ADPKD in a potential kidney donor)

• Remember that diagnostic counseling needs to be held prior - to discuss the benefits & adverse consequences of diagnostic testing

Also genetic counselling (for family planning)

Question 4

What are the indications for nephrectomy in ADPKD? (3)

Answer 4

Disabling symptoms due to massively enlarged kidneys

Development of abdominal wall hernias

Prior to kidney transplant (recurrent infection, suspected Ca, extension of native kidney to the potential pelvic surgical site)

Question 5

What are the renal complications of the ADPKD? (3)

Answer 5

Haematuria (35-50%; due to cyst rupture) - occasionally need embolisation or nephrectomy

Renal stones (20%) - larger the kidney, higher the risks

Flank/Abdominal pain

RCC (infrequent)

Question 6

What are the extra-renal complications of ADPKD? (5)

Answer 6

1. Cerebral aneurysm - SAH or ICH** (5-20%)
2. Hepatic cysts
3. Pancreatic cysts
4. Cardiac valve disease
5. Seminal vesicle cysts

Question 7

What are the cardiac manifestations of ADPKD? (4)

Answer 7

Valvular heart disease*

Coronary aneurysms

Pericardial effusions

Cardiomyopathies

Question 8

Management of ADPKD?

Answer 8

Non-pharm

• Salt restriction <2g/d + dietician involvement (higher salt excretion is ass/w kidney growth)
• Increase fluid intake (>3L/d), unless eGFR <30 or at risk of hyponatraemia (suppresses ADH - a possible mechanism that inhibit cyst growth)

Pharm

• Control BP: ACEi or ARB, target BP <110/75
• Consider Tolvaptan (with renal) - slows the progression of disease (TEMPO and REPRISE trials)
  
  • Main contraindication is any liver pathologies
  • Must monitor LFTs
  • Must educate patient - to stop taking it at time of illness/dehydration

RRT

• HD usually - PD less preferred due to limited intra-abdominal space (massive kidneys)
• Transplantation