Possible trimethoprim/sulfamethoxazole-induced aseptic meningitis.

OBJECTIVE: To report a case of trimethoprim/sulfamethoxazole (TMP/SMX)-induced aseptic meningitis.

CASE SUMMARY: An 18-year-old woman diagnosed with acute myeloid leukemia was admitted for a bone marrow transplant. She had already attained remission with daunorubicin, thioguanine, and high-dose cytarabine. A routine lumbar puncture performed on admission revealed an abnormally elevated leukocyte count, and meningitis was suspected. The patient had been taking TMP/SMX (trimethoprim 120 mg) twice daily on Monday, Tuesday, and Wednesday for the past 3 months; no other medication was being used. Upon examination, the patient mentioned having had headaches for the past few weeks. Since viral, bacterial, and fungal cultures were negative, a diagnosis of aseptic meningitis was made. According to the Naranjo probability scale, TMP/SMX was a possible cause of the aseptic meningitis. Eleven days after discontinuation of TMP/SMX, lumbar puncture results had returned to normal.

DISCUSSION: Many drugs have been associated with aseptic meningitis. Antibiotics are often linked with aseptic meningitis, with TMP/SMX being the most frequently associated antibiotic. Many cases of TMP/SMX-induced aseptic meningitis have been reported, while few cases have been reported with trimethoprim and sulfamethoxazole given separately.

CONCLUSIONS: Despite the widespread use of TMP/SMX and the years of experience we have had with the drug, it is important to remain vigilant regarding possible adverse effects, particularly aseptic meningitis.