Isolated Unilateral Oculomotor Neuropathy Following A Presumed Infection Treated With Corticosteroids in a Child

BACKGROUND Oculomotor neuropathy represents a very small proportion of cranial nerve palsies in children. It may result from both congenital and acquired causes. Acquired causes include vasculopathies, inflammation, infections, and neoplasms. However, only a limited number of studies in adults and children have identified post-infectious isolated oculomotor neuropathy, and even fewer have investigated the therapeutic role of corticosteroids in its treatment. CASE REPORT A previously healthy 4-year-old Saudi boy presented to the emergency department with acute onset of substantial drooping of the left upper eyelid, diplopia, and subjective low-grade fever. There were no symptoms of increased intracranial pressure and no history of head trauma. Physical examination revealed complete left-sided oculomotor neuropathy and anisocoria, without involvement of other cranial nerves or additional focal findings. Neuroimaging (computed tomography, contrast-enhanced magnetic resonance imaging, magnetic resonance angiography, and magnetic resonance venography), cerebrospinal fluid analysis, and opening pressure assessment showed normal results. Other serological findings were unremarkable. No underlying etiology was identified, and a post-infectious immune-mediated process was suspected. Oral prednisolone was initiated at a dose of 2 mg/kg/day for 5 days, followed by a 5-day taper. Follow-up at 3 months demonstrated complete resolution. CONCLUSIONS This case of isolated unilateral oculomotor neuropathy after presumed infection demonstrated complete clinical recovery after a short course of oral corticosteroids. Although a causal relationship cannot be established, such treatment may be cautiously considered in children who present with acute oculomotor neuropathy and a possible post-infectious process after an extensive, inconclusive workup. Further studies are needed to confirm this observation.