Introduction: Longitudinally extensive transverse myelitis (LETM) is defined as involving 3 or more consecutive vertebral levels. In clinical practice, the first-line treatment of noninfectious immune-mediated transverse myelitis is intravenous pulse methylprednisolone. We report a seventeen–month girl patient, who had recurrent hypotonia attacks and panmyelitis in her spinal magnetic resonance images (MRI) treated with intravenous immunoglobulin and she had clinical improvement without any change in MRI findings.Case: A Seventeen-month-old girl presented at the pediatric neurology clinic with generalized hypotonia and weakness. Her spinal magnetic resonance imaging showed diffuse demyelination in whole spinal cord and additionally T2 hyperintensity was present in the medulla oblongata. Serum Aquaporin 4 antibody was negative. Although the radiological lesions did not recovered, clinical improvement became obvious one week after admission with increased control of head and body. After 2 weeks the patient was able to sit, stand and to take a few steps. Fifteen days later from discharge she presented again with weakness. She had three flaccid weakness attacks on follow-up and treated with monthly IVIg.Discussion: Although the accepted first line treatment for transverse myelitis is steroids, other treatment modalities include IVIg and plasmapheresis should be kept on mind especially in the infectious etiologies. We observed clinical improvement after first IVIg administration within a week in our case. And as well, recurrent weakness attacks were relieved with IVIg. As far as we know this is the youngest patient, who had whole spinal cord and medulla oblongata involvement and recurrent hypotonia attacks.