# Acute Tubular Necrosis --- **Acute tubular necrosis** or **ATN** is a condition where the epithelial cells of the [[nephron#anatomy|renal tubule]] are damaged so badly that they die and are sloughed off. It is the most common cause of intrarenal [[acute kidney injury]]. ## Cause Acute tubular necrosis can be caused by a variety of reasons: - low perfusion - a lack of blood flow to the kidneys (which can be caused by things such as dehydration, shock, obstruction, etc.) causes [[tissue perfusion|ischemia]] in the parenchyma of the kidney. - nephrotoxic medications - NSAIDS, vancomycin, lithium, contrast (big one) - infections - especially [[sepsis]] - autoimmune disorders - [[systemic lupus erythematosus]] ## Signs & Symptoms The signs and symptoms of acute tubular necrosis are largely those that have to do with the decreased kidney function. - **muddy brown casts** in the urine are *pathognomonic* for (or are only found in) ATN - these are the ischemic, sloughed off cells of the renal tubules - decreased urine output - edema (fluid buildup) - buildup of toxins/wastes - fatigue - confusion - nausea/vomiting - seizures are a rare but severe complication of ATN ## Complications Acute tubular necrosis is the main intrarenal cause of [[acute kidney injury|AKI]]. ## Diagnostic Tests Urinalysis, especially looking for those muddy brown casts. ## Treatment Fortunately acute tubular necrosis is reversible if the underlying cause is treated. It takes about 7-14 days to heal up. ___