Pediatric neurologists at Ondokuz Mayis University, Samsun, Turkey report a 4- year-old boy who presented with fever, headache, drowsiness, and seizures. Neurologic exam revealed drowsiness and meningeal signs. Four days following a 3-week course of acyclovir therapy for herpes encephalitis, he developed visual impairment and visual hallucinations lasting 1 week. Loss of vision became total, with normal appearing fundi. Visual hallucinations included unfamiliar children hiding under his bed, and he spoke to someone unknown. The hallucinations occurred 2-3 times daily and were 2-5 minutes in duration, without behavioral changes or cognitive impairment. MRI showed bilateral optic nerve hyperintensity on T2-weighted contrast-enhanced images, consistent with retrobulbar optic neuritis; hyperintensities also involved the dentate nuclei, cerebellum, basal ganglia, and brainstem. EEG showed diffuse slowing and left temporoparietal spike waves. CSF PCR was positive for herpes simplex virus-1 DNA. Following a 3-week course of corticosteroid therapy, the optic neuritis resolved and vision returned to normal after 1 month. During 1 year follow up while taking oxcarbazepine, he had no seizures nor hallucinations. [1]

COMMENT. Charles Bonnet syndrome (CBS) is characterized by complex visual hallucinations in association with visual impairment and normal cognitive and behavioral status. The syndrome is described usually in adults with macular degeneration and sometimes with multiple sclerosis. In a 9-year-old partially sighted boy with paroxysmal visual zoopsias the CB syndrome is described as phantom vision [2]. Only 3 previous pediatric cases in the literature were cited, two with cone-rod dystrophy. In these children, 6 and 8 years old, formed visual hallucinations noted shortly after loss of vision included geometric shapes, people, and buildings, stationary and in motion. [3]

CBS should be differentiated from migraine and epilepsy. One report of a case of CBS disappearing with successive monotherapies of carbamazepine and valproic acid but worsening with levetiracetam is suggestive of an epilepsy origin for CBS. [4]

Epilepsy and complex visual hallucinations. Except for one case, a 12-year-old boy with birth trauma and seizures who described seeing colored triangles followed by seeing a “robber coming after him with a gun,” Penfield reported no elaborate visual hallucinations elicited by stimulation of the occipital lobes, only gross light, shadows and colors. [5]

Lennox WG reports a girl, aged 9 years, who had generalized tonic-clonic seizures, preceded by visual hallucinations in which small objects or persons, “like a comic book,” appeared in one field of vision, and followed by headache or vomiting. The EEG showed triphasic spikes or slow spike-and-wave discharges in the right posterior temporal or occipital area. The father had migraine from childhood and a maternal aunt had complex partial seizures. This case points to both a migraine and seizure origin for the visual hallucinations [6]. EEG is recommended if CBS develops in a patient with worsening of neurological signs. [7]