Abstract text (incl. figure legends and references)

Objective

The use of telemetric intracranial pressure (ICP) monitors has been increasing. The mechanisms of idiopathic intracranial hypertension (IIH) headache have not been fully elucidated. We describe a case series of seven patients with active IIH that a spontaneous headache occurred during real-time telemetric monitoring of ICP.

Methods

Patients with active IIH (>25 cmCSF lumbar puncture opening pressure and papilloedema) were enrolled in a prospective, randomized, placebo controlled, double blind, parallel group exploratory trial (IIH Pressure Trial: ISRCTN12678718). Following insertion of an intraparenchymal ICP monitor (Raumedic™ Neurovent p-Tel, Hembrechts, Germany) participants were randomized to receive Exenatide (10 mcg BD subcutaneous) or placebo for 12 weeks. They underwent assessments including ICP monitoring, and headache phenotyping using a paper diary and a semi-structured interview.

Results

Participants (n=15) had a mean (SD) age of 28(9) years, BMI 38.1(6.2) kg/m2, supine ICP 23.5 (3.9) mmHg and a converted lumbar puncture-position ICP of 32.2(5.6) cmCSF. Seven patients suffered from an acute spontaneous headache attack during the research visits. During the headache we recorded a significant increase in mean (SD) ICP of 12(6)mmHg, p=0.001 in these patients. A maximum ICP of 104 mmHg was recorded at the peak of a headache attack (severity numeric rating scale 10 out of 10) in a participant which then returned baseline (26 mmHg) as pain settled. We also noted an increased ICP waveform fluctuation as the pain severity score escalated and during the duration of the headache attack.

Conclusions

This is the first report to demonstrate real-time evidence of rising ICP and increased fluctuations during an IIH headache. It provides unique insights into the mechanisms of headache in IIH. It further provides future direction to drive research to investigate acute ICP lowering agents for IIH headache.