Headache in Arnold-Chiari malformation type I – clinical cases and literature review

Abstract

Arnold Chiari type I malformation is characterized by elongation and protrusion of the cerebellar tonsils by more than 5 mm through foramen magnum. Headache is the most common initial clinical manifestation.
We present two cases of patients with headache with herniation of the cerebellar tonsils through foramen magnum. The first patient reports brief episodes of occipital headache typical for Chiari malformation, worsened by cough, as well as episodes of migraine headache with occipital or frontal localization.
In the second patient with headache the fundoscopy revealed papilledema and MRI showed mild protrusion (2.5 mm) of the cerebellar tonsils in foramen magnum. Chiari type I malformation can be asymptomatic or presents with a wide spectrum of neurologic symptoms, of which headache is the most common. Although brief episodes of headache with occipital/suboccipital localization, provoked by cough and other Valsalva-like maneuvers, are the hallmark of Chiari type I malformation, comorbidity with forms of primary headache is possible. The presence of bilateral papilledema without ventricular dilatation in a patient with cerebellar herniation makes the differential diagnosis with idiopathic intracranial hypertension very difficult and requires follow-up with MRI.