Friday, January 15, 2010

Acute Tubular Necrosis

Acute tubular necrosis (ATN) is a renal desorder which consists of the death of tubular cells. It is caused by lack of oxygen or by toxic drug exposure. Tubular cells form the renal tubules of the nephrons of the kidney, and they continually replace themselves; so, if the cause of acute tubular necrosis is removed then recovery is likely. ATN usually results in acute renal failure (ARF). The presence of brown epithelial casts in the urine during urinalysis is pathognomonic for ATN.

Acute tubular necrosis can be classified as either toxic or ischemic. Ischemic ATN occurs when the tubular cells do not get enough oxygen, a condition that they are highly sensitive and susceptible to, due to their very high metabolism. Toxic ATN occurs when the tubular cells are exposed to a toxic substance (nephrotoxic ATN). Toxic acute tubular necrosis is characterized by proximal tubular epithelium necrosis due to toxic substances, such as poisons, organic solvents, or drugs. Necrotic cells fall into the tubule lumen, obliterating it, and determining acute renal failure.

There are medical and surgical situations which are associated with a high risk for developing ischemic acute tubular necrosis: 1) infection in the blood or tissues; 2)hypotension; 3) obstructive jaundice; 4) open heart surgery, or repair of abdominal aortic aneurysm.