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The following is a summary of “Calcitonin gene-related peptide in newly diagnosed idiopathic intracranial hypertension: a prospective, cross-sectional, case-control study of cerebrospinal fluid and plasma,” published in the April 2025 issue of Journal of Headache and Pain by Hansen et al. 

Calcitonin Gene-Related Peptide (CGRP) was known to be involved in migraine pain signaling, and its blockage was effective in treatment, but while headache in idiopathic intracranial hypertension (IIH) was often migraine-like, the underlying mechanisms were not understood.  

Researchers conducted a retrospective study to measure the levels of CGRP in plasma and cerebrospinal fluid (CSF) of patients diagnosed with IIH to investigate its involvement in the pathogenesis of headache in IIH.  

They enrolled patients suspected of having IIH at 2 Danish tertiary headache centers. Patients were either confirmed to have IIH or disproven (non-IIH). The non-IIH patients with primary headache disorders were included as headache controls for the IIH group, and sex-, age-, and Body Mass Index (BMI)-matched healthy controls (HC) were recruited. All participants had CSF and blood samples collected, with CGRP levels analyzed using a validated radioimmunoassay, the CSF plasma ratios were calculated, and between-group comparisons were made using Analysis of Variance (ANOVA) or Kruskal-Wallis tests. Sub-analyses included comparisons of HC with non-IIH/IIH with chronic migraine (CM), as well as comparisons between IIH with and without headache. The CGRP levels were correlated with lumbar opening pressure (OP) and BMI, and the correlation between CGRP in plasma and CSF was assessed. Generalized or linear regression models adjusted for confounders such as BMI, age, and active smoking.  

The results showed no significant differences in CGRP levels between the groups of 97 patients with IIH, 52 non-IIH individuals, and 37 HCs in plasma (P= 0.78), CSF (P= 0.79), or CSF: plasma ratio (P= 0.13). After adjusting for BMI, age, and smoking, similar results were obtained and CGRP levels were not associated with migraine phenotype or chronic headache, nor with having any headache vs no headache in IIH. A significant correlation was found between CGRP in plasma and CSF (P< 0.0001). No correlation was observed between CGRP and lumbar OP or BMI.  

Investigators concluded that CGRP levels in plasma and CSF were similar in IIH, non-IIH patients with headache, and HCs, with a correlation between CGRP in plasma and CSF. 

Source: thejournalofheadacheandpain.biomedcentral.com/articles/10.1186/s10194-025-02042-y