Objective: Previous studies have indicated that many patients with chronic pain (PWCP) referred to pain facilities for the treatment of neck and/or low back pain complain of associated headaches. The purpose of this study was to characterize the nature of these headaches according to International Headache Society (IHS) headache diagnostic criteria.
Design: In preparation for this study, a questionnaire that reflected IHS headache diagnostic criteria was developed. All consecutive patients admitted to our pain facility complaining of headache completed this questionnaire and received a physical and neurologic examination focused on key aspects of headache. A headache interview was also conducted, using the questionnaire as a question guide. All questionnaires were entered in a computerized database, and IHS diagnoses were arrived at for each patient. As many IHS diagnoses as possible were assigned to each PWCP as long as IHS criteria were fulfilled. In addition, a frequency distribution for headache precipitants and neck-associated symptoms was developed and evaluated by discriminant analysis to determine the diagnostic value of these factors in relation to each IHS diagnostic group.
Setting: Pain facility (multidisciplinary pain center).
Patients: Consecutive PWCP.
Results: Of 1,466 PWCP, 154 (10.5%) were identified as suffering from severe headache interfering with function. Of these, 55.8% indicated that their headaches were related to an injury for which they were seeking treatment and 83.7% had neck pain. Migraine headache represented the most common diagnostic group (90.3%), with cervicogenic headache representing the second most common (33.8%). Of the total group, 44.2% had more than one headache diagnosis, that is, there was overlap. Cervicogenic headache patients had the greatest percentage of overlap (94.2%), with migraine patients being second (68.3%). The most frequent headache precipitant was mental stress, followed by neck position and activity/exercise. The migraine and cervicogenic headache groups had a statistically significant greater number of neck-associated symptoms when compared with the remaining patients. Of the total headache group, 74.6% complained that they had a tender point at the back of their neck. Cervicogenic, migraine, and tension PWCP had the greatest frequency of head or neck tender points. The discriminant analysis for neck-associated symptoms yielded the following symptoms as the most common predictors of headache across IHS diagnostic groups: clues to onset were severe headache beginning at the neck or tender point and numbness in arms and legs; headache brought on by neck position and arms overhead; and neck symptoms consisting of a tender point in the neck and feeling severe headache in the neck.
Conclusions: Headache can and should be considered a frequent comorbid condition in PWCP. Because of the overlap data, more precise diagnostic criteria may be required to separate cervicogenic headache from migraine headache. Neck-associated symptoms seem to be important even to those PWCP diagnosed with migraine headache.