[Methotrexate-induced interstitial pneumonitis in a child with acute lymphoblastic leukemia].

We report a case of 5-year-old boy with acute lymphoblastic leukemia who developed interstitial pneumonitis induced by methotrexate (MTX). The patient was hospitalized with fever, cough, dyspnea and hypoxemia during maintenance treatment with low dose MTX and 6-mercaptopurine. A diagnosis of MTX pneumonitis was made based on the clinical findings, viral and serologic studies, negative microbiology and the radiological features. The patient recovered after cessation of the MTX treatment. Interstitial pneumonitis caused by MTX is well-recognized and the prevalence has been estimated to be 0.3-7.5% among patients with adult rheumatoid arthritis. However, there are few reports in the literature regarding this adverse effect in patients with leukemia. Furthermore, very few cases of childhood leukemia have been reported regarding MTX induced interstitial pneumonitis. Physicians should be aware of this rare complication during maintenance treatment with weekly low dose MTX for acute lymphoblastic leukemia in children.

Acute transverse myelitis after Japanese B encephalitis vaccination in a 4-year-old girl.

Fourteen days after Japanese B encephalitis (JBE) vaccination, a 4-year-old girl developed the full clinical manifestation of ATM within 24h. She showed acute ascending flaccid paraplegia with sensory disturbance, bladder dysfunction and meningeal sign. Cerebrospinal fluid examination revealed neutrophil pleocytosis and elevated protein level. Magnetic resonance imaging (MRI) showed diffuse swelling of the cervical and lumbar cord with low signal intensity on T1 and high signal intensity on T2-weighted imaging. These findings suggested that she had developed meningo-radiculomyelopathy. Since sequential MRI studies showed prompt reduction of the cord swelling, the high-dose methylprednisolone therapy employed seemed to have been effective for improvement of inflammation. Even with such potent drug treatment, she still has substantial flaccid diplegia and sphincter disorder 1 year later, and so we are convinced that the pathological change of the cord was as severe as in necrotizing myelopathy. Although the pathological process remains unknown, cellular autoimmune mechanism against the JBE vaccination is suspected.