Temporomandibular Dysfunction and Migraine
Headaches typically begin as episodic disorders but certain causative factors influence the progression from episodic to daily or near-daily head-ache disorders. Over the last five years, multiple epidemiological studies have identified common risk factors for transformation of episodic to chronic migraine. The most common risk factors include: obesity, socioeconomic status, medication overuse, and previous head trauma.1 Under-recognized and easily treatable patients are those who have developed myofascial pain syndromes of the head and neck with subsequent dramatic worsening of previously benign headache syndromes. These patients will not typically respond to traditional headache preventatives until the myofascial pain syndrome is addressed. This article discusses such a case and presents an approach to these patients.
A 40 year-old white female with 8 years of menstrual-associated migraine is referred to the author for “worsening migraines” of three months duration which occurred after a “hard fall.” During the fall, she landed on her right arm and shoulder without head injury. She has seen her family physician, dentist, a rheumatologist, and at least one other neurologist for this condition. Her main complaint is one of headaches with a Headache Impact Test-6 (HIT-6) score of 69 (previously 40). The pain was primarily on the right side and was associated with nausea, photophobia, phonophobia, osmophobia, and visual aura on most days. Gabapentin, topiramate, and extended release divalproex prophylaxis were not helpful and she was requiring near-daily short acting narcotics. The initial exam revealed myofascial trigger points in the right masseter and medial pterygoid and an otherwise normal neurological examination. She was given a two-week detailed headache diary and pain location chart. At her two week follow-up visit, the diary and pain charts revealed right jaw and facial pain in addition to her right hemicranial migraines. The jaw and facial pain was dull and aggravated by chewing. The patient’s husband confirmed nocturnal bruxism. The headache met ICDH-II criteria (see Table 1) for medication overuse headache.2
Temporomandibular dysfunction (TMD) encompasses problems involving the temporomandibular joint or associated structures, as well as the masticatory musculature. Primary headache disorders have been shown to occur significantly more often in TMD patients and vice-versa.3,4,5 One small trial has demonstrated a significant decrease in headache frequency compared to placebo with TMD treatment.6 To the author’s knowledge, no larger studies have been published.
Increasingly over the last decade, scientific data have strengthened the author’s belief that noxious stimuli in the head and neck regions can lead to secondary sensitization of the trigeminal system. From a clinical perspective, this sensitization may, in turn, lower the migraine ‘threshold’ in susceptible patients. Pain models relating central sensitization and myofascial trigger points have already been developed for tension-type headaches.7
The author’s history evaluation in these patients includes HIT-6 score, detailed headache questionnaire, and pain location charts and diaries. The HIT-6 was developed to evaluate a patient’s headache-associated disability over the previous four weeks. A score between 60 and 78 indicates severe impairment. The author prefers the HIT-6 over the more popular Migraine Disability Assessment (MIDAS) questionnaire that evaluates headache disability over the previous 12 weeks.
For examination of a patient similar to the case presented, the author includes a thorough evaluation of the head and neck musculoskeletal system in addition to a routine neurological examination. This includes palpation of the extra-oral masticatory musculature of the face and jaw, the temporal tendon, and medial pterygoid intra-orally. While examination of the medial pterygoid can be performed intraorally or extraorally, the author prefers an intraoral technique. Placing a gloved index finger (right hand to examine the left medial pterygoid) posterior and buccal to the last upper molar, use the thumb to oppose the index finger with the muscle and ramus of the mandible between. Try this on yourself to refine the technique.
Examination of jaw function, such as opening measurements and temporomandibular joint articular palpation, are also included in the examination.
Cessation of bruxism with an oral appliance is an appropriate goal but may not be enough to achieve the desired clinical effect. The author prefers trigger point injections in combination with tricyclic antidepressants—such as amitriptyline or nortriptyline—or the muscle relaxer, tizanidine, along with an appropriate oral appliance. Others have used spray and stretch techniques in place of trigger point injections.8 With any headache syndrome, if medication overuse is present it must be addressed. Strategies for medication-overuse treatment are beyond the scope of this article. Most patients do not respond to pharmacological migraine prevention only and so the myofascial pain syndrome and the headache syndrome must be simultaneously addressed.
The patient was counseled about medication overuse and withdrawn from daily narcotics. The patient did not tolerate multiple nighttime oral appliances fabricated by her dentist. She was also concerned about weight gain associated with the tricyclic antidepressants. She was given trigger point injections in the masseter and medial pterygoid and oral bedtime tizanidine. This resulted in complete resolution of her jaw pain and a return to her previous episodic migraine pattern. Interestingly, no specific methods were used to treat her medication-overuse problem other than education about the condition. Periodically, she requires “booster” trigger-point injections, but her need for this is becoming less frequent.
This article describes a patient who had a stable, episodic migraine pattern that was aggravated by temporomandibular dysfunction. Diagnosis and treatment of the TMD led to a return of her previous migraine pattern after traditional migraine preventatives failed. Myofascial pain of the head and neck, including TMD, must be adequately addressed to return refractive headache syndromes to a more stable and manageable episodic level.