Reversible Encephalopathy Due to Sulfasalazine

Background: Sulfasalazine was devised by Swedish physician in the late 1930s in an attempt to treat rheumatic polyarthritis. It is still a widely used anti-inflammatory agent especially in the treatment of rheumatologic disorders and inflamatory bowel diseases. Most of its side effects are benign, tolerable, and dose dependent, but less common severe systemic reactions have also been revealed. Case Presentation: A 42-year-old woman diagnosed with rheumatoid arthritis was admitted to emergency service because of status epilepticus. Hepatitis and myelotoxicity were also present after laboratory investigations. The patient was on sulfasalazine treatment for 3 weeks with a daily dose of 2g. Cranial magnetic resonance imaging (MRI) revealed bilateral petiventricular and subcortical lesions in the white matter of especially temporal and occipital regions. Cerebrospinal fluid (CSF) examination showed very high protein level (564 mg/L). After discontinuation of treatment, the clinical, CSF, and MRI findings regressed rapidly Conclusions: Side effects of sulfasalazine include neurotoxicity such as status epilepticus, cranial MRI lesions, and CSF abnormalities that were diagnosed in our patient after excluding other etiologic factors causing encephalitis.