Metabolic acidosis with extreme elevation of anion gap: case report and literature review.

A patient with severe metabolic acidosis and an extremely elevated (57 mEq/L) serum anion gap (AG) is described, and the multiple factors that produced the patient's complex abnormalities are discussed in detail. These include renal failure, rhabdomyolysis, marked hyperphosphatemia, hemoconcentration, and an unidentified organic metabolic acidosis. A review of the literature indicates that the common thread observed in almost each instance of profoundly elevated AG values is a multifactorial pathogenesis that usually includes renal insufficiency, associated with a proven or likely cause of organic metabolic acidosis, or with exogenous phosphate intoxication.