Acute tubular necrosis

Acute tubular necrosis or (ATN) is a medical condition involving the death of tubular cells that form the tubulethat transports urineto the ureterswhile reabsorbing 99% of the water (and highly concentrating the salts and metabolic byproducts). Tubular cells continually replace themselves and if the cause of ATN is removed then recovery is likely. ATN presents with acute renal failureto the point that the two concepts are used interchangeably.

It may be classified as either toxic or ischemic. Toxic ATN occurs when the tubular cells are exposed to a toxic substance (nephrotoxicATN). Ischemic ATN occurs when the tubular cells do not get enough oxygen, a condition they are highly senistive to due to their very high metabolism.

Toxic ATN

Toxic ATN can be caused by free hemoglobinor myoglobin, by medication such as antibioticsand cytostaticdrugs, or by intoxication (ethylene glycol, "anti-freeze").

Histopathology: Toxic ATN is characterized by proximal tubular epithelium necrosis (no nuclei, intense eosinophilic homogeneous cytoplasm, but preserved shape) due to a toxic substance (poisons, organic solvents, drugs, heavy metals). Necrotic cells fall into the tubule lumen, obliterating it, and determining acute renal failure. Basement membrane is intact, so the tubular epithelium regeneration is possible. Glomeruliare not affected.

Ischemic ATN

Ischemic ATN can be caused when the kidneysare not sufficiently perfused for a long amount of time (i.e. renal artery stenosis) or during shock. Hypoperfusioncan also be caused by embolismof the renal arteries.

External link

• Photo at: Atlas of Pathology
• Acute Tubular Necrosis

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It uses material from the http://en.wikipedia.org/wiki/Acute+tubular+necrosis Wikipedia article Acute tubular necrosis.