The Difficulty of Diagnosing a Post-Traumatic Headache
Headaches following a traumatic brain injury are often assumed to be—and are frequently diagnosed with little investigation as—“post-traumatic headache.” Post-traumatic headache, or PTH, is a headache classification with specific diagnostic criteria, but it is just one of numerous explanations for headaches following head trauma.
The International Headache Society publishes the International Classification of Headache Disorders (ICHD). The ICHD classifies headaches and gives detailed descriptions of their diagnostic criteria. The most current publication by the International Headache Society is the ICHD-3, which identifies roughly 300 different headache disorders. ICHD-3 describes PTH as a headache that is due to either whiplash or a blow to the head that begins within seven days after the traumatic incident. It is categorized based on the severity of a person’s head trauma (mild, moderate, severe) and the duration of the headaches. When a headache lasts less than three months, it is considered acute. Any PTH lasting longer than three months is termed persistent or chronic.
A headache that follows a traumatic brain injury is not easily diagnosed as PTH. One criterion is consistent throughout all subtypes of headaches in the ICHD-3: the headache must be “not better accounted for by another ICHD-3 diagnosis.” The ICHD-3 requires consideration of medical history, diagnostic criteria, and analysis of other potentially applicable diagnoses to ensure best fit. The prevalence of other headache subtypes, such as tension-type headache (occurring in 30-78% of the general population), makes it imperative to consider other potential headache diagnosis.
An adequate headache history is important for proper diagnosis. The mnemonic C-O-L-D-E-R can be used to obtain relevant information and help with a more accurate diagnosis:
Character: what does the headache feel like?
Onset: how does the headache start?
Location: where does the headache hurt?
Duration: how long does the headache last?
Exacerbation: what makes the headache worse?
Relief: what makes the headache better?