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Post-obstructive diuresis after urinary retention — SCE Acute Medicine MCQ

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HardRenal medicinePost-obstructive diuresis after urinary retentionSCE Acute Medicine

A 76-year-old man presents with anuria, suprapubic discomfort and confusion. Creatinine is 612 micromol/L, potassium is 5.9 mmol/L and ultrasound shows bilateral hydronephrosis with a distended bladder. A urethral catheter drains 1.8 L immediately. What is the most important next monitoring priority?

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Correct answer: E — Monitor for post-obstructive diuresis and electrolyte disturbance

Relief of chronic urinary obstruction can cause post-obstructive diuresis with dehydration, sodium disturbance and haemodynamic instability, so close urine output and electrolyte monitoring are needed. Immediate catheter removal would risk recurrent obstruction. Creatinine may lag behind clinical improvement and does not remove the need for monitoring.

Reference: NICE NG148 acute kidney injury; NICE CKS urinary retention