[Optic neuritis attributable to Mycoplasma pneumoniae].

Optic neuritis (ON) is an inflammatory disease whose etiology remains obscure. We report a case of ON attributable to Mycoplasma pneumoniae (MP). A 26-year-old man presented a sudden onset bilateral loss of visual acuity, without any history of pulmonary or ear-nose-throat infection. Diagnosis of optic neuritis was made on the basis of visual field loss, though optic disks and visual evoked potentials were normal. Color vision could not be assessed due to a congenital dyschromatopsia. The neurological examination was normal. On magnetic resonance imaging, there was no enhancement or enlargement of optic nerves, but a demyelinating lesion of the cervical spinal cord. Lumbar puncture revealed lymphocytic meningitis with 60 white blood cells, all of them being lymphocytes. Oligoclonal bands were presents in the CSF. With no evidence of any other infection or auto-immune disease, the diagnosis of Mycoplasma pneumoniae infection was established due to the presence of Mycoplasma pneumoniae specific IgM antibodies. Outcome was quite favorable within three months without treatment. Neurological symptoms--encephalitis, meningitis, polyradiculitis, or more rarely ON or cerebella ataxia--are the main extra pulmonary manifestations of Mycoplasma pneumoniae infection. Search for anti-Mycoplasma pneumoniae IgM antibodies should be performed routinely when On is diagnosed.