Primary cough headache is associated with posterior fossa crowdedness: a morphometric MRI study.

The aetiology of primary cough headache (PCH) is obscure. The aim of this study was to investigate the magnetic resonance (MR) morphometric characteristics of the posterior cranial fossa (PCF) in patients with PCH. Eighteen consecutive patients with PCH (14M/4F, mean age 75.1 +/- 6.0 years) and 18 sex- and age-matched control subjects were recruited for study. Based on the midline sagittal MR images, parameters indicating posterior fossa crowdedness were measured. Compared with controls, patients with PCH had a similar size of hindbrain tissue area but a significantly smaller PCF area, resulting in a higher mean hindbrain/PCF ratio (0.78 +/- 0.04 vs. 0.73 +/- 0.06, P = 0.005). In addition, these patients also had a lower position of the cerebellar tonsillar tip, a shorter clivus length and shorter distances from the clivus to the mid-pons and from the basion to the medulla than the control group. Patients with PCH were associated with a more crowded PCF, which might be a contributing factor for the pathogenesis of this headache syndrome.