The Spectrum of Rhabdomyolysis

Abstract

Episodes of rhabdomyolysis (87) in 77 patients were studied. Alcoholism was the most common etiologic factor (67%). This may reflect in part the liberal definition of alcoholic rhabdomyolysis. Multiple factors existed in 59% of the episodes. Myoglobinuria was detected by orthotolidine dipstick in the absence of hematuria in only 50% of patients. Urine testing is not a sensitive clue to the presence of rhabodomyolysis. Twenty-two patients were azotemic (creatinine > 3.0 mg/dl) on admission. These patients had higher average values for serum K, anion gap, P and uric acid and a lower average serum Ca concentration that did nonazotemic patients. Discriminant analysis of the 65 patients without admission azotemia separated them into 2 groups: a group at high risk for renal failure, 11/27 (41%), a group at low risk, 0/30 (0%). The low-risk group had an R value < 0.1 where R = 0.7 [serum K] + 1.1 [serum creatinine] + 0.6 [serum albumin]-6.6. Twenty-nine patients (33%) had ARF [acute renal failure]. Six of these patients died. Hypocalcemia developed in 63% of the patients. It was similar in frequency and degree in 16 patients with ARF not due to rhabdomyolysis. Two patients had hypercalcemia during the course of ARF. These 2 and 56 patients with hypercalcemia described in the literature are reviewed. Hyperkalemia and hyperphosphatemia were similar in degree and frequency in patients with rhabdomyolysis-related ARF and other types of ARF. The anion gap on admision was markedly increased in rhabdomyolysis-related ARF (28 meq/l) in contrast to the other types of ARF (17 meq/l). The frequency of oliguria, need for dialysis and mortality were not different in rhabdomyolysis-and non-rhabdomyolysis-related ARF. Alcohol and compression with or without drug abuse are common pathogenic factors for rhabdomyolysis. A dark brown, orthotolidine-positive urine without red cells remains an important clue to rhabdomyolysis, but this finding is absent in > 1/2 of patients and is an insensitive marker. Elevations of CK [creatine kinase] ad myoglobin levels are diagnostic of muscle injury. Other routine blood chemistry tests are not sensitive indicators of rhabdomyolysis. A formula may be used to predict high and low risk for developing acute renal failure after rhabdomyolysis. This formula utilizes admission serum K, creatinine and albumin concentrations. Patients with rhabdomyolysis-related ARF do not differ from patients with nonrhabdomyolysis ARF with regard to serum K, P, and Ca concentrations, rate of rise of serum creatinine, BUN [blood urea nitrogen] to creatinine ratio, oliguria, dialysis and mortality. Patients with rhabdomyolysis with ARF do have higher serum uric acid and anion gap levels.