Viva · IR system
Genitourinary Viva Questions
Oral-exam style questions and answers on genitourinary for MD, DNB and super-specialty practical examinations. Each answer links back to the playbook or Library entry it was written from.
- What are the principal indications for percutaneous nephrostomy?
- The major categories are urinary drainage for obstruction or pyonephrosis, urinary diversion for leaks or fistulae, access for interventions such as PCNL or antegrade stenting, and access for upper-tract medication instillation.
- Why should the renal pelvis not be punctured directly?
- A direct calyceal puncture traverses renal parenchyma, which provides catheter stability and tract tamponade. Direct pelvic or infundibular puncture is associated with greater vascular injury, bleeding, and urine leakage.
- What is the preferred calyx for a drainage nephrostomy and for future antegrade stenting?
- A posterior lower-pole or interpolar calyx is suitable for routine drainage. An interpolar calyx is preferred when antegrade ureteric stenting is anticipated because it provides a more favourable angle toward the ureter.
- Why should contrast injection be minimised in pyonephrosis?
- Contrast injection raises collecting-system pressure and can force infected urine or bacteria into the circulation, precipitating bacteraemia and septic shock. Aspirate first and perform only the manipulation required to establish safe drainage.
- What coagulation parameters are generally acceptable before elective nephrostomy?
- A practical target is platelet count at least 50,000 per microlitre, INR 1.5 or less, prothrombin time approximately 15 seconds or less, and haemoglobin above 8 g/dL. Clinical bleeding history and anticoagulant pharmacology remain important because laboratory tests alone do not measure all bleeding risks.
- How do you manage persistent haematuria after nephrostomy?
- Assess haemodynamics, haemoglobin, coagulation, and catheter position while keeping the catheter in place. Persistent severe haematuria beyond 3 days, or earlier instability, requires CT angiography and usually renal angiography with selective embolisation if arterial injury is found.
- What is the routine nephrostomy exchange interval?
- Exchange every 6–8 weeks initially and extend to 8–12 weeks when repeated exchanges show minimal encrustation. Pregnancy generally requires exchange every 4–6 weeks.
- How should a dislodged nephrostomy catheter be managed?
- Do not blindly reinsert or advance it. Arrange urgent fluoroscopic tract salvage using a hydrophilic wire or perform a new puncture, with greater urgency in infection, a solitary kidney, or complete obstruction.