Carpal tunnel syndrome associated with interleukin-2 therapy

BACKGROUND. Interleukin-2 (IL-2) has been extensively used in our institution in the treatment of cancer and has protean neurologic side effects. Carpal tunnel syndrome developing in patients receiving IL-2 appears to have a good prognosis and may spare the patient unneeded investigation. METHODS. A retrospective evaluation was undertaken for all patients using our institution's Patient Studies database. The patients were examined and their charts reviewed. RESULTS. We found eight patients with renal cell carcinoma who developed carpal tunnel syndrome (CTS) during treatment with IL-2, 5- fluorouracil (5-FU), and alpha-interferon (α-IFN). The symptoms were bilateral in five patients and all patients improved with cessation of therapy. Three patients had recurrent symptoms with subsequent courses of therapy. Symptoms occurred during or shortly after IL-2 infusion and resolved after therapy was completed with conservative management. The number of courses given did not seem to correlate with the development of symptoms. Neurophysiologic studies demonstrated conduction velocity slowing without evidence of acute denervation. CONCLUSIONS. IL-2 can produce focal entrapment of the median nerve at the wrist, which reverses with drug withdrawal. IL-2 mediates the inflammatory response and can cause interstitial edema that likely causes CTS to develop in predisposed patients undergoing treatment.