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Optic Neuritis
Optic neuritis is an acute inflammation or demyelination of the optic nerve,
characterized by an impairment of vision, progressing over hours or days (see
Chapter 30 Eye: Visual Disturbances ). The disease is primarily unilateral but an
increased incidence of bilateral involvement is found in children. Optic neuritis in
children is thought to be an autoimmune process following a viral disease. At
times, a contiguous sinusitis may cause the illness. Of patients with unilateral
optic neuritis, 20% will eventually be diagnosed with multiple sclerosis.
On examination, decreased visual acuity and decreased color vision are
associated with a relative afferent pupillary deficit to light and a central scotoma
in the affected eye. The relative afferent pupil defect is demonstrated by the
swinging flashlight maneuver. The pupil of the affected eye constricts briskly
when light is shone into the contralateral eye (the consensual light reflex) and
dilates when light is immediately shone into the affected eye. With bilateral
disease, the change in pupillary reflexes may not be apparent. Funduscopic
examination discloses a hyperemic, swollen optic disc. In rare cases of
retrobulbar optic neuritis, funduscopic examination is normal.
Optic neuritis must be distinguished from papilledema, which is secondary to
increased ICP. Papilledema is almost always bilateral and associated with normal
vision and normal pupil reactivity until late in the disease. In cases of bilateral
optic neuritis, differentiation may be impossible because funduscopic findings are
identical in the two illnesses. If any doubt of increased ICP persists, the patient
should undergo evaluation by CT or MRI of the brain and, if normal, CSF
analysis. In optic neuritis, the opening pressure is normal, but there may be a mild
lymphocytic pleocytosis or elevated CSF protein level.
The course of the illness is variable, with most patients recovering to normal or
near-normal vision in 4 to 5 weeks. Treatment with high-dose systemic
corticosteroids is poorly studied in the pediatric population, and has not been
shown to improve the ultimate prognosis. Treatment may, however, result in a
slightly faster resolution of symptoms. The efficacy of IV immunoglobulin and
plasmapheresis has not been established.

Facial Nerve Palsy
Weakness in the distribution of cranial nerve VII (facial) may be produced by
either central (upper motor neuron) or peripheral (lower motor neuron)
dysfunction. Peripheral disease is most common in children, particularly when the
facial weakness is an isolated finding. Bell palsy refers to peripheral facial nerve
weakness with no identifiable underlying cause. It is believed to be caused by