The clinical utility of serologic markers in the evaluation of the acute scrotum

Objective: To examine the presence of interleukin-1 (IL-1), interleukin-6 ( IL-6), and creatine phosphokinase-MM (CPK-MM) in patients with acute scrota l pain and assess their clinical utility in the diagnosis of testicular tor sion (TT) and epididymitis. Methods: Twenty-five patients with acute scrota l pain were prospectively enrolled over a two-year period. History, physica l examination, complete blood count, urinalysis, and scrotal ultrasound wer e performed. Testicular torsion was confirmed by surgical exploration. Epid idymitis was diagnosed using physical examination, scrotal ultrasound, and positive urinalysis. Venous blood was assayed for IL-1, IL-6, and CPK-MM in triplicate during the routine drawing of blood in the emergency department . The data are reported as medians +/- interquartile ranges (IQRs). Results : Twenty-five patients with acute scrotal pain were evaluated; 11 with TT, three with torsion of the appendix testis (TAT), ten with epididymitis, and one with varicocele. One patient had both TT and epididymitis. Interleukin -1 was not detectable in either group. The CPK-MM values between TT and epi didymitis were virtually identical at; 99.8 and 100 IU/L, respectively. The median value for IL-6 was 1.03 (IQR = 0.19 to 2.86) vs 20.86 (IQR = 2.14 t o 65.50) pg/mL in the torsion and epididymitis groups, respectively. The 97 .5% CI for the difference of medians of 19.9 was 0.4 to 65.1, p = 0.02. Usi ng receiver operating characteristic (ROC) curve analysis for IL-6, the are a under the curve was 0.82 for torsion and 0.67 for epididymitis. Using a c utoff value of IL-6 greater than or equal to 1.41 pg/mL, the positive predi ctive value of IL-6 in diagnosing epididymitis was 78.6%, with a negative p redictive value of 100% for TT. There were no cases of missed TT on follow- up. Conclusions: This preliminary investigation of serologic markers demons trates that IL-6 is significantly elevated in epididymitis as compared with TT. Creatine phosphokinase-MM and IL-1 were not found to be of diagnostic utility. The small sample size of this study precludes a definitive conclus ion as to the utility of these markers in the emergency department. However , IL-6 may be clinically useful as an additional element in differentiating the causes of acute scrotal pain, and further study is warranted.