Facial nerve palsy associated with a low serum vitamin A level in an infant with cystic fibrosis

A previously healthy 10-week-old infant presented with isolated unilateral facial nerve paralysis which progressed to bilateral paralysis over a 2-week period. Evaluation including MRI and CT of the brain and facial nerve, CSF evaluation and EMG yielded no diagnosis. A single F508 gene mutation on the newborn screen prompted sweat chloride testing which confirmed a diagnosis of cystic fibrosis. On measurement of fat-soluble vitamins, levels of vitamin A were approximately 10% of the lower normal range, in the absence of objective evidence of pseudotumor cerebri. This case emphasizes an important association between hypovitaminosis A, cystic fibrosis and facial nerve palsy.