The complexities of chronic post-traumatic headache (CPTH) date back to its initial recognition. By the mid-1800s the persistence of headache after head injury was acknowledged as a manifestation of brain injury or 'molecular derangement.' However, with the advent of financial compensation for these injuries, the psychologic aspects were thought to be predominant, hence such terms as 'compensation neurosis.' The latter concept persisted into the early decades of the 20th century with more sophisticated terms as 'somatization' and 'conversion disorder'.However, by the late 1800s 'post-concussion syndrome' was considered to be a legitimate ailment comprising the triad of headache, dizziness, and alcohol intolerance. In recent decades, post-traumatic headache has been recognized as having an organic or pathophysiologic basis as well as associated psychologic factors.
Terminology and CriteriaThe term CPTH implies an underlying cerebral trauma that is part of the post-concussion syndrome. The International Classification of Headache Disorders, 2nd edition (IHCD) divides criteria for CPTH into pain attributed to moderate or severe head injury and pain attributed to mild head injury.1 The term 'concussion' in Table 1 is not defined, but would include symptoms such as dazed, confused, memory impairment, and dizziness, in addition to headache or brief loss of consciousness, or both. However, mild head injury without concussion or any other of the IHCD criteria can trigger headache. Examples are migraine with aura evoked by heading a ball during soccer or hemiplegic migraine provoked by trivial head trauma. In addition head trauma need not be direct, such as during blast or whiplash injuries. Trauma may be psychologic, as in chronic post-traumatic stress disorder (PTSD). The time limits indicated in the IHCD criteria have been disputed. Many agree that CPTH may develop more than seven days after trauma, but there is evidence that headache beginning more than three months after concussion is a primary headache (migraine or tension-type) rather than due to brain trauma.
2Until there are biologic markers for the condition, seven days is a logical limit. Similarly, the classification of 'chronic' if the headache lasts for more than three months has been disputed as being too short. Criteria of other illnesses define chronic as having a duration of more than six months. The numbers in the classification criteria are arbitrary but necessary operational criteria for research purposes.
EpidemiologyThe prevalence of CPTH is uncertain because 80-90% of head injuries are mild and unreported. Studies of prevalence in people who had reported to an emergency department or doctor's office found CPTH prevalence to range from 15 to 42%. 3,4 Women are somewhat more prone to develop CPTH than men.
KeywordsPost-concussion syndrome, diffusion tensor imaging, tension-type headache, post-traumatic stress disorder, behavioral medicine Disclosure: The author has no conflicts of interest to declare.