Kidney Cysts

Suspicious Features

• Multiple cysts (especially bilateral)

• Symptomatic cysts causing haematuria, infection, or flank pain

• Complex cysts or cysts with solid components (risk of malignancy)

• History of renal malignancy in the patient or close relatives

When to Suspect Polycystic Kidney Disease (PCKD)

• Typically consider PCKD if the imaging shows 2 or more cysts per kidney, depending on the patient’s age.

• Family history of PCKD raises suspicion.

• Other clues: Hypertension at a young age, enlarged kidneys on palpation, or extrarenal manifestations (e.g. liver cysts, intracranial aneurysms).

Medication to Prevent Progression

• Tolvaptan (a vasopressin V2 receptor antagonist):

  • Shown to slow disease progression in rapidly progressing autosomal dominant PCKD.

  • Listed on the PBS in Australia for selected patients (restricted criteria).

  • Requires monitoring for hepatotoxicity (regular LFT checks).

Notes

1. Simple cysts:

   • Very common, especially in older adults.

   • Generally benign and require follow-up imaging only if they are symptomatic or display complex features (Bosniak classification on CT/MRI).

2. PCKD Screening:

   • Recommended for first-degree relatives (children, siblings) of individuals with PCKD.

   • Typically starts with renal ultrasound, sometimes from late childhood/early adulthood.

3. Blood Pressure Control:

   • Essential in PCKD to slow progression of renal disease.

   • ACE inhibitors or ARBs often first-line for BP management.

4. Annual Renal Ultrasound:

   • May be indicated in at-risk individuals to monitor cyst growth, detect complications (infection, haemorrhage), or screen for malignant transformation in complex cysts.