CURRENT Essentials of Critical Care.pdf

Chapter 14 Renal Disorders 207■■■Acute Tubular Necrosis (ATN)Essentials of Diagnosis• Acute renal failure without prerenal, postrenal, glomerular, orinterstitial features• History of hypotension, exposure to nephrotoxic antibiotics orradiocontrast agents• Reduced urine output, malaise, nausea, altered sensorium• Acute onset oliguria with ischemic ATN; Fe Na 1% but maybe nonoliguric• Urinalysis: muddy brown granular casts, epithelial cells, redcells, white cells; unremarkable sediment in toxin-induced ATN• Inability of kidney to regulate sodium, electrolytes, water• Usually in conjunction with multiorgan failure, ARDS, medications• Leading cause of acute renal failure in ICU; mortality rate50–80% among those requiring dialysisDifferential Diagnosis• Sepsis• Hypoperfusion or ischemia• Radiocontrast media administration• Medications: aminoglycosides, amphotericin B, cisplatin• Myoglobinuria and hemoglobinuriaTreatment• Prevention: N-acetylcysteine and saline prior to radiocontrast;no benefit of mannitol and diuretics over saline alone• Avoid potential nephrotoxic insults such as hypotension, hypovolemia,nephrotoxic agents• Maintain adequate renal perfusion• Nutritional support recommended but benefit not proven• Hemodialysis with intensive protocols including earlier initiation,increased frequency appears to result in improved outcome• During recovery phase, monitor electrolytes and volume statusclosely with post–ATN diuresis■ PearlRecovery of renal function occurs more often with nonoliguric acutetubular necrosis than when oliguric. The use of diuretics to convertoliguric ATN into the nonoliguric variety, however, does not improveoverall prognosis.ReferenceEsson ML et al: Diagnosis and treatment of acute tubular necrosis. Ann InternMed 2002;137:744. [PMID: 12416948]