Polycystic Kidney Disease

Question 1

Define Polycystic Kidney Disease

Answer 1

Group of disorders characterised by renal cysts and numerous systemic and extrarenal manifestations

Question 2

What are the types of Polycystic Kidney Disease

Answer 2

Autosomal-dominant PKD (ADPKD)

Autosomal-recessive PKD (ARPKD)

Question 3

Aetiology of Polycystic Kidney Disease

Answer 3

Genes PKD1 and PKD2 that code for polycystin 1 and 2

Cysts develop from cells in the tubular portion of the nephron and collecting ducts
Renal cysts develop and grow over time, leading to compression of the normal renal architecture and intrarenal vasculature, increased renal size, interstitial fibrosis and tubular atrophy, and progressive renal impairment.

Question 4

Risk factors for Polycystic Kidney Disease

Answer 4

FMHx of ADPKD or end-stage renal disease

FMHx of intracranial aneurysm/SAH

Question 5

Symptoms of Polycystic Kidney Disease

Answer 5

ARPKD: often present in the neonatal period with enlarged echogenic kidneys - high mortality rate in the first year of life, with many requiring ventilation

• Abdominal/flank pain ( Nephrolithiasis, infection, haemorrhage, hepatic enlargement | UTIs involving the renal parenchyma or cysts - flank pain)
• Haematuria (Gross haematuria associated with worse renal function)
• Headaches (Due to cerebrovascular event)
• UTI: Dysuria, urgency, suprapubic pain, fever

Question 6

Signs of Polycystic Kidney Disease on examination

Answer 6

Hypertension 
Palpable kidneys/abdominal mass ± hepatomegaly (+ FMHx = Highly suggestive of autosomal-dominant PKD (ADPKD))
Cardiac murmur (Mitral valve prolapse | mitral/aortic regurgitation and dilate aortic root are common)
Abdominal hernia/rectus abdominis diastasis (Inguinal, incisional, and paraumbilical hernias, and rectus abdominis diastasis, are common | Usually present with a visible swelling and are detected before the renal disease is detected)

Question 7

Investigations for Polycystic Kidney

Answer 7

Renal USS: Cysts in the kidney
CT/MRI abdomen/pelvis: ADPKD: cysts in the kidneys

Urinalysis: microscopic haematuria, proteinuria, albuminuria, bacteria in UTI
ECG: for those with cardiac murmurs

U+Es: normal or elevated U/Cr
Fasting lipid: increases risk
CRP: raised in cyst infection

CT brain: ?intracranial bleed
Echo: cardiac murmurs
X-ray KUB: ?stones

Question 8

What is the definition of polycystic kidney disease on ultrasound

Answer 8

<30 years of age: at least 2 unilateral or bilateral cysts

30 to 59 years of age: 2 cysts in each kidney

> 60 years of age: 4 cysts in each kidney