anurie

Anurie is defined by very low or absent urine production. In adults, it is commonly defined as urine output less than 100 mL per day; complete cessation is possible. Oliguria is a lesser degree of reduced urine output (about 100–400 mL/day).

Causes are categorized as prerenal, intrinsic renal, or postrenal. Prerenal causes include severe dehydration, hypovolemia, heart failure, and shock. Intrinsic renal causes include acute tubular necrosis, acute interstitial nephritis, and glomerulonephritis. Postrenal causes include obstruction of bilateral urinary tract, such as ureteral or bladder outlet obstruction.

Pathophysiology involves marked reduction in glomerular filtration rate from decreased renal perfusion, tubular injury, or obstruction. Clinically, patients may have dry skin and mucous membranes, hypotension, edema, and electrolyte disturbances such as hyperkalemia and metabolic acidosis, reflecting acute kidney injury.

Diagnosis relies on urine output measurement, urinalysis, serum creatinine and electrolytes, and imaging to assess for obstruction. Renal ultrasound or other imaging helps identify postrenal causes. Urinary catheterization may be diagnostic and therapeutic if obstruction is suspected.

Management targets the underlying cause and renal perfusion, avoidance of nephrotoxins, and timely relief of obstruction when present. Dialysis may be required in persistent anuria with life-threatening imbalances or uremic symptoms. The prognosis depends on cause and response to treatment; persistent anuria signals severe kidney injury and higher mortality risk.