Child Neurology: Alternating hemiplegia of childhood

Abstract

Alternating hemiplegia of childhood (AHC) is a rare disorder characterized by recurrent attacks of hemiplegia affecting either side of the body, abnormalities of ocular movement, movement disorders, and progressive developmental delay. Children with AHC often have a delay in diagnosis or are misdiagnosed. A broad differential diagnosis is necessary when considering this condition. The clinical features of AHC were first described more than 3 decades ago but its cause remains largely unknown and there is little treatment evidence available. Early diagnosis and multicenter collaboration are necessary to better understand the prognosis of AHC and develop more effective treatments. A 12-month-old boy was sent for neurologic consultation after an episode of transient right-sided paralysis. His mother states that during the episode he was fully conscious but half of his body was paralyzed and he appeared to have a stroke. This episode lasted 6 hours and resolved when he slept. He was at his normal baseline upon waking. His mother states that the patient had a similar episode, although occurring on the left side, when he was 4 months old. There was a family history of migraines but no other neurologic disorders. He achieved normal developmental milestones during the first year of life and at 12 months of age was walking independently and had some words. Neurologic examination, done once symptoms had resolved, was normal. ### Differential diagnosis. Acute focal weakness in a child has many serious etiologies that must be investigated (table 1). The evaluation is focused on excluding serious or treatable causes. Evaluation should begin with MRI, magnetic resonance …