Chiari type I malformation in children and adolescents with cystic fibrosis.

Chiari type I malformation is characterized by herniation of the cerebellar tonsils through the foramen magnum. An association between Chiari type I malformation and cystic fibrosis (CF) has not previously been established. We report on five children and adolescents with CF in whom Chiari type I malformations were diagnosed. Three patients were 17-18 years old at time of diagnosis, one was 3 years old, and one was 10 months of age. All patients were followed at the Cystic Fibrosis Center at St. Christopher's Hospital for Children and were diagnosed with the malformations between June 1988 and June 1997. Over this same period, 400 CF patients 18 years or younger were followed routinely. All patients had the diagnosis of Chiari type I confirmed by brain-stem MRI. Neurologic findings included swallowing dysfunction, syncopal episodes, numbness of extremities, recurrent vomiting, and headaches. No two patients had the same presenting neurologic findings. Our data suggest that Chiari type I malformation is more common in CF than in the general population. The possibility of Chiari type I malformation should be included in the differential diagnosis of unexplained neurologic complaints in patients with CF.