Patients with a Chiari Type I malformation (herniation of cerebellar tonsils through the foramen magnum) may present with headache.
Pathogenesis: structural lesion in the posterior fossa
Features of the headache:
(1) headache may be precipitated by cough, exercise, laughing and/or sex
(2) variable headache with the Valsalva maneuver
(3) occipital and neck pain
Additional clinical features may include:
(1) dizziness
(2) pain or paresthesias in the arm
(3) restriction in neck movement
(4) ataxia
Imaging of the posterior fossa is important for diagnosis
Differential diagnosis:
(1) subarachnoid hemorrhage
(2) other forms of headache (primary cough, etc)
