Child with Facial Weakness

Abstract

Childhood facial weakness is a nuanced neurologic symptom that has a wide etiologic differential diagnosis. The underlying cause often remains unclear despite extensive investigation. The presentation is complicated by the facial nerve’s complex anatomy. The facial nerve originates in the cranial nerve VII (CN VII) nucleus which receives input from bilateral cerebral cortices in the frontal and temporal lobes and anterior cingulate. Each unilateral CN VII nucleus projects an ipsilateral peripheral cranial nerve to ipsilateral facial muscles. Childhood facial weakness can result from various neurologic disorders affecting the brain and/or the CN VII nucleus (central etiologies) or the postnuclear CN VII (peripheral etiologies) course. Disorders are often divided into peripheral versus central and congenital versus acquired. Etiologies can be further divided into the following categories: idiopathic, infectious, congenital, traumatic, and neoplastic. Overall, infectious etiologies are the most common cause of childhood facial weakness and peripheral CN VII weakness is more commonly encountered as opposed to central.