Abstract
For decades doctors dealing with patients with headache have noted that there seems to be a marked increase in headache after accidents with whiplash mechanism, particularly in the acute phase (1, 2). The descriptions of these headaches have often been vague and indistinct. A crucial question has been whether the headache after a neck trauma is an increase in intensity, frequency or other manifestations of a pre-existing headache or whether it is a de novo headache. Whiplash-associated disorders (WAD) are very costly to society and headache is rated as the WAD with the heaviest burden by the patients (3).
The term ‘cervicogenic headache’ (CEH) was coined by Sjaastad et al. in 1983 and the CHISG criteria (Cervicogenic Headache International Study Group) for CEH were issued in 1990 (4). Accidents with whiplash mechanism were among the possible triggers of CEH (4). In the 2nd edition of the IHS classification (2004) CEH (5) has been included, but a mandatory criterion for the diagnosis is to demonstrate neck pathology. In milder traffic accidents with neck trauma such as whiplash, there are most often no detectable abnormal imaging findings. The importance of clinical guidance and the technical pitfalls of imaging were discussed by a radiologist.
In the Oslo study on whiplash (3)—a cohort study designed to search for symptoms and clinical findings during the first year after the accident—de novo CEH was found in a diminishing number of the patients with time from the accident. Three per cent had CEH at 1 year and about half of the patients with CEH at 1 year still suffered from this headache at 6 years. The Lithuanian study presented in this supplement did not confirm the finding of chronic post-whiplash CEH and puts forward alternative theories for the chronic post-whiplash headache (both studies used the CHISG criteria).
Diagnosis leads to treatment. The doctor must be able to give an exact diagnosis of the headache and of the coexistence of different headaches. If the headache is secondary to neck pathology, treatment of the neck will be a natural choice. Having different sets of criteria for CEH is problematic. Headache after whiplash can fulfil the clinical CHISG criteria for CEH, but not the IHS criteria for CEH. This is complicated further by the problem that new studies, particularly of treatment, need to compare the results with earlier studies that have used the first set of criteria, if any. Still, the results from a headache clinic in Brazil show elegantly that it is possible to distinguish the headaches in most patients both before and after the two sets of criteria for CEH.
Conflicts of interest
The author has declared no conflicts of interest.