A short cut review was carried out to determine whether measuring C Reactive Protein might help in the diagnosis of intracranial infection in a patient presenting to the Emergency department with an acute headache. 62 papers were found, but none answered the question. The clinical bottom line is that there doesn't appear to be any evidence for, or against, the use of C Reactive Protein in the diagnosis of intracranial infection in patients presenting to the Emergency department with an acute headache.