Anuria - Causes and Symptoms

Definition

By anuria (from the Greek "an", lack, and "ouron", urine) we mean the complete suspension of urine production, with diuresis of less than 100 ml in 24 hours. This symptom is the expression of a sudden interruption of renal function.

Anuria must be differentiated from urinary retention, which consists in the impossibility of emitting the urine contained in the bladder.

Pre-renal anuria

Pre-renal anuria is secondary to reduced perfusion (reduced blood supply) of the kidney.

Causes include severe arterial hypotension (shock) and reduced blood volumes secondary to profuse bleeding, vomiting and diarrhea, reduced hydration, excessive sweating, abuse of diuretics and extensive burns.

Pre-renal anuria can also occur in cases of reduced cardiac output (heart failure, constrictive pericarditis, myocardial infarction, pulmonary embolism), peripheral vasodilation (septic or anaphylactic shock) and increased vascular resistance (surgery, hepato-renal syndrome, etc.).

Renal anuria

Renal anuria is due to damage to the kidneys, generally of ischemic or toxic nature.

It may develop due to necrosis, due to the effect of nephrotoxic substances (heavy metals, contrast media, NSAIDs, aminoglycosides and other antibiotics) and due to prolonged ischemia.

Renal anuria can result from glomerular and interstitial nephropathies (glomerulonephritis and pyelonephritis), infections, transfusions with incongruous blood, crushing syndromes and systemic diseases responsible for glomerular damage (eg multiple myeloma, amyloidosis and granulomatosis of Wegener).

Post-renal anuria

Post-renal anuria is due to an obstruction of the urinary tract, the consequences of which later affect the kidney itself. This can occur in the presence of stones, urethritis, prostatitis, prostatic hypertrophy and carcinoma, abdominal trauma and bladder neoplasms.