Anuria

Specialty: Nephrology and urology.

• cessation of urine production
• complete absence of urination
• zero urinary output

Why it occurs

• Total or complete urinary obstruction (bilateral stone impaction, advanced bladder or prostatic neoplasia, or a single functioning kidney)
• Severe circulatory or distributive shock (extreme renal hypoperfusion that nullifies filtration pressure)
• Bilateral renal cortical necrosis (diffuse cortical ischemia associated with severe obstetric complications or sepsis)
• Rapidly progressive glomerulonephritis (massive extracapillary deposition of crescents that destroys the glomeruli)
• Bilateral renal artery thrombosis or embolism (acute mainstream vascular occlusion)

Initial workup

Placement of a Foley bladder catheter to confirm the absence of intracesical urine and rule out infravesical obstruction; Emergency renal and urinary tract ultrasound to immediately rule out hydronephrosis or bladder ballooning; urgent blood analysis with renal profile, electrolytes and arterial blood gases; Renal CT angiography if occlusive vascular pathology is suspected.

Standard management

• 8.4% baking soda — administer centrally in severe metabolic acidosis with pH <7.1 secondary to anuric renal failure
• Calcium polystyrene sulfonate — cation exchange resin, 15-30 g orally or rectally to control moderate hyperkalemia awaiting renal replacement therapy
• Preparation for emergency dialysis (hemodialysis) if it does not respond to initial measures and presents criteria for dialysis urgency.