• headache;
  • Chiari 1 malformation;
  • cerebellar tonsils herniation;
  • children;


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.


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.


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.


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.


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.