S100B and Headache: S100B is a Ca2+ binding protein highly expressed by astrocytes and is being extensively studied as a potential biomarker in mTBI.56,57 A Dutch study demonstrated that patients with headache had a significantly lower median S100B concentration in their serum (within 6 h of mTBI) than those without headache at first examination post-trauma.58 However, in the same cohort study, they demonstrated that elevated levels of acute serum S100B and neurone-specific enolase (NSE) were associated with headaches 6 months after presentation.