Dextromethorphan for neuropathic pain with Churg-Strauss syndrome

Abstract

successfully controlled with an N-methyl-d-aspartate receptor antagonist, dextromethorphan. Case reportA 48-year-old man who had been treated for asthma visited our hospital because of painful swelling and purpura of the legs. On admission, he was treated with prednisolone at a dose of 20 mg/day, aminophylline at a dose of 400 mg/day, and pranlukast, a leukotriene-receptor antagonist, at a dose of 450 mg/day, which gave good control of his respiratory symptoms. Physical examination showed that the patient's height was 164 cm and his weight was 60 kg. His pulse rate was 90/min, blood pressure 104/76 mmHg, and body temperature was 36.7°C. Neither anemia nor jaundice was observed. No abnormal cardiopulmonary findings were noted. He experienced pain and swelling in his legs, and purpura was observed on his feet. Asymmetrical muscle weakness and sensory loss of limbs were observed in a distaldominant fashion. Muscular atrophy was not recognized. Although decreased deep-tendon reflexes were observed in his left arm, deep-tendon reflexes could not be examined in his legs because of extremely severe pain.Laboratory examinations (Table 1) revealed a white blood cell count of 25 100/mm 3 , eosinophilia of 45%, an erythrocyte sedimentation rate (ESR) of 79 mm/h, a Creactive protein (CRP) concentration of 8.10 mg/dl, a serum alanine aminotransferase concentration of 279 U/l, a serum aspartate aminotransferase concentration of 229 U/l, a blood urea nitrogen concentration of 18.2 mg/dl, a serum creatinine concentration of 1.4 mg/dl, and a serum creatine phosphokinase concentration of 538 U/l. Urinalysis revealed no abnormality. Occult blood was absent from the stool. Hepatitis B virus surface antigen, antihepatitis B core antibody, antihepatitis C antibody, and antinuclear antibody were all negative. Rheumatoid factor was positive. Serum immune complex determination was within normal limits. Antineutrophil cytoplasmic antibodies and anticardiolipin antibodies were absent. The plasma IgE Abstract A 48-year old man who had been treated with prednisolone, aminophylline, and pranlukast, a leukotriene-receptor antagonist, was diagnosed with Churg-Strauss syndrome based on the findings of asthma, eosinophilia, mononeuropathy, and extravascular eosinophils. Intractable neuropathic pain of the legs was successfully controlled with an N-methyl-d-aspartate receptor antagonist, dextromethorphan. We suggest that dextromethorphan receptor antagonists may be a useful treatment for the pain of neuropathy caused by vasculitis syndrome.