DOWN BUT NOT OUT. S. Agresta 1 , J. Canterbury 1 , J. Wiese 1 ; 1 Tulane University, New Orleans, LA (Tracking ID #77016) LEARNING OBJECTIVES: 1. Recognize an under-diagnosed cause of rhabdomyolysis. CASE INFORMATION: A 55 year-old obese man presented with severe shortness of breath after being found at his nursing home. His morbid obesity (550 pounds) confined him to a wheelchair. On the evening prior to admission, he fell from his wheelchair without a loss of consciousness or traumatic injury. A nursing aid found him twelve hours later. At presentation, he complained of diffuse pain; he noted associated shortness of breath but no chest pain or palpitations. His heart and breath sounds were normal; pitting edema extended to the knees. His vital signs were normal. His urine was scant (less than 10 cc/hr) and dark brown in color. His CPK was 35,000 U/L, BUN 75 mg/dL and creatinine 2.1 mg/dL. IMPLICATIONS/DISCUSSION: Although rhabdomyolysis is usually seen with crush injuries or toxic myopathies, prolonged stasis and extended isometric contraction as occurs with seizures should also prompt immediate evaluation for the syndrome. A timely diagnosis is essential, as the degree of renal tubular necrosis is proportional to the time and duration of tubular exposure to the myoglobin pigment. Aggressive diuresis decreases this exposure time; this is the main focus of treatment. The color of the urine (brown as opposed to yellow or clear) predicts the pigment concentration in the tubules, and is a better measure of severity and treatment efficacy than the CPK level. Early diuresis, with or without alkalinization, should be maintained until the urine is consistently clear. Acute renal failure is often attributed to the primary disease (sepsis, MI) in patients found down. Rhabdomyolysis should be excluded as an independent cause of renal failure in all patients found down for an undetermined or prolonged period of time.