Azotemia

Abstract

• Azotemia is an increased concentration of nonprotein nitrogenous compounds (eg urea and creatinine) in the blood. "Uremia" is the clinical syndrome that occurs as a result of severe azotemia due to abnormal renal function.

• Causes:

◦ Reduced glomerular filtration rate:

- Reduced renal perfusion (pre-renal azotemia Pre-renal azotemia).

- Intrinsic renal disease (renal azotemia Uremia).

- Obstruction to urinary outflow (post-renal azotemia).

◦ Uroabdomen leading to reabsorption of urinary nitrogenous compounds (post-renal azotemia).

◦ Increased absorption of nonprotein nitrogenous compounds from the gastro-intestinal tract, eg GI bleeding, high protein meal.

◦ Increased protein catabolism, eg fever, trauma, burns, hyperthyroidism.

• A degree of pre-renal azotemia may be super-imposed on pre-existing renal or post-renal azotemia.