Headache in children with Chiari I malformation.

Background: Headache is the most common symptom of Chiari 1 malformation, a condition characterized by the herniation of cerebellar tonsils through the foramen magnum. However, the headache pattern of cases with Chiari 1 malformations is not well defined in the literature, especially in children.
Objective: The aim of this retrospective chart review was to evaluate the frequency and the characteristics of headache in children with Chiari 1 malformation at initial evaluation and during follow up.
Methods: Forty-five cases with tonsillar ectopia were selected among 9947 cases under 18 years of age who underwent neuroimaging between 2002 and 2010. A semistructured clinical interview (mean follow-up: 5.2 years) was conducted. Headache was classified according to the second edition of the International Classification of Headache Disorders.
Results: Possible associations between clinical picture, in particular headache pattern, but also other signs and symptoms attributable to Chiari 1 malformation, and the extent of tonsillar ectopia were found for 3 different groups: those with borderline (<5 mm, N = 12), mild (5-9 mm, N = 27), and severe tonsillar ectopia (≥10 mm, N = 6), respectively. Twenty-four out of 33 (73%) cases with Chiari 1 malformation complained of headache, and 9/33 (27%) of those patients (5 with mild and 4 with severe tonsillar ectopia) reported headache attributed to Chiari 1 malformation.
Conclusions: In our studied pediatric population, the most common symptom for cases diagnosed with Chiari 1 malformation was headache, and headache attributed to Chiari 1 malformation was the most common headache pattern in patients with Chiari 1 malformation. The presence of headache attributed to Chiari 1 malformation along with 3 other signs or symptoms of Chiari 1 malformation were highly predictive of severe tonsillar ectopia.
(© 2014 American Headache Society.)