We report the case of a 12-year-old male who presented with photopsia and decreased visual acuity for several weeks.
Personal history included bilateral sensorineural hearing loss treated with a cochlear implant, asthma, dermatitis and alopecia.
Examination revealed a visual acuity of 0.1 in both eyes, with normal anterior biomycosis, normal intrinsic ocular motility and eye fundus with bilateral temporal papillary mildness.
The visual field shows a centrocaecal scotoma with increased blind spot in both eyes.
At another center, the patient was diagnosed with retrobulbar neuropathy and treatment with IV corticoids was started, followed by a descending oral regimen, without improvement.
Electroretinogram, brain magnetic resonance imaging and electroencephalogram are normal, and the Farnsworth 100 test and contrast sensitivity test are altered.
Visual Evoked Potentials show a bilateral delay in P100 wave latency, which is not significant, suggesting demyelination.
A decrease in the activity of biotinidase (undetectable biotinidase) is observed in the pathology study of congenital malformations.
Treatment was initiated with oral biotin (5 mg/12 h), a rapid clinical improvement, presenting 15 days later a visual acuity of the unit in both eyes, and a clear improvement of the visual field, which still retains a slight increase after 30 days.
There was also an improvement in her dermatitis, alopecia and asthma after the administration of biotin, without any improvement in hearing loss.
