Chiari Malformation Presenting as Headaches Associated with Laughter.

Presentation We describe the case of a 5 year old boy, referred to our outpatient department with a one year history of headaches associated with laughter. Diagnosis Investigation with MRI Brain revealed Chiari Type 1 Malformation (CM-1), with cerebellar tonsillar descent of 19mm below the foramen magnum. Treatment He is being managed conservatively with serial neuroimaging and symptom monitoring. Discussion CM-1 is a hindbrain malformation characterised by ≥5mm herniation of the cerebellar tonsils.1,2 It is diagnosed radiographically, and is increasingly being detected incidentally.3,4 The natural history of asymptomatic patients is usually to remain asymptomatic, and symptomatic patients often show symptom improvement, particularly in paediatric populations.3,5 Neurosurgical interventions may be offered based on symptoms and radiographic findings, but carries a complication rate of 8.2%.6.