Bacterial meningitis in a patient with multiple sclerosis receiving Tysabri

The most important adverse effect of natalizumab is progressive multifocal leukoencephalopathy (PML).1 Apart from PML, there are reports of other cerebral infections including herpes simplex encephalitis (HSE)2,3 and cryptococcal meningitis4 in the literature. The patient was a 29-year-old woman, a known case of multiple sclerosis (MS) for at least 5 years. She was treated using natalizumab since 6 month before. She was under treatment with prednisolone 1 g daily for 5 days for optic neuritis, which was 2 weeks before the onset of symptoms of meningitis. Approximately three days before visiting the neurologist, a continuous headache in the left temporal lobe was developed. The patient was febrile at that time as well. Besides, two days before this, she had started ciprofloxacin for treatment of a urinary tract infection. An investigation for the John Cunningham (JC) virus was negative. The brain magnetic resonance imaging (MRI) showed periventricular lesions (Figure 1-A) with no evidence of PML or HSE encephalitis. Meningeal enhancement was seen after the injection of the contrast medium (Figure 1-B).