Purpose : Psychological stress is well documented to increase pain responses, so called stress-induced hyperalgesia （SIH）. The neural basis for SIH is not fully understood, ample evidence supported the notions that dysfunction of brain mechanisms plays a role for SIH such as increases in nociception in the deep craniofacial tissues under psychological stress conditions.
Study selection : Descending modulatory effects of the nucleus raphe magnus （NRM） on neural activity in the trigeminal subnucleus caudalis （Vc） and upper cervical spinal Cord （C2） regions, which are well documented to be the substrates to constitute the descending pain control, can regulate pain responses in the deep craniofacial tissues, while dysfunction of descending pain controls could increase pain responses. Here, to understand the modulatory roles of stress conditions on the descending pain controls, we have determined the neural changes in the Vc, C2 and NRM regions in response to deep craniofacial tissue injury using psychophysical stressed model in the rats.
Results : Our studies revealed that repeated stress conditionings had facilitatory effects on nociceptive neural activities evoked by deep craniofacial tissue injury in Vc, C2 and NRM regions. These results appeared to be consistent with those seen in various spinal pain models, indicating that stress-induced hyperalgesia could be induced in a non-site specific manner where noxious stimulation was applied.
Conclusions : Enhanced nociceptive responses in the deep craniofacial tissues under psychophysical stress conditions could be induced by dysfunction of the descending pain controls.
“Pain” is one of body defense mechanisms and crucial for the life support. Orofacial nociceptive information is received trigeminal ganglion neurons and transmitted to trigeminal spinal subnucleus caudalis and upper cervical spinal cord. The nociceptive information ascends to the central nervous system ; consequently, lead to orofacial pain perception.
Recent studies have indicated that plastic changes in the activities of trigeminal ganglion neurons, satellite glial cells in trigeminal ganglion, secondary neurons, microglia and astrocytes in trigeminal spinal subnucleus caudalis and upper cervical spinal cord following orofacial inflammation and trigeminal nerve injury are responsible for orofacial pain mechanisms. This review outlines the current knowledge on the orofacial pain signaling mechanisms and its pathophysiology following trigeminal pathological changes.
Patients: A 50-year old female complained of pain on the left lateral temporal area and left-upper posterior teeth. The dentist diagnosed atypical odontalgia, and she received drug therapy. But the symptom did not change and she was referred to our pain clinic. The clinical examination and panoramic radiograph revealed no obvious problems and pathological tissue alterations. According to the criteria of the International Classification of Headache Disorders, 3rd edition ; beta version, we suspected migraine without aura and neurovascular orofacial pain associated to it. In addition, she had tension-type headache and panic disorder as her past medical history. So we referred her to a physician and a psychiatrist, and managed the patient together with them. Based on the diagnosis of tension-type headache, migraine without aura and anxiety disorder, psychotherapy and kampo medicine relieved her pain and associated symptoms.
Discussion: This patient is classified into the type C of MW classification（both psychic symptoms and somatic diseases are present）. For such a case, we need multimodal management including psychological supports by psychiatrists. We managed this patient by psychotherapy and kampo medicine which could be effective for the management of pain accompanied with a variety of associated symptoms.
Conclusion: For patients with complicated orofacial conditions, both physiological and psychological problems should be taken into account, and also be managed in multidisciplinary approaches in a liaison system.
Primary glossodynia is characterized by abnormal sensations such as tongue pain without pathological changes and is not fully understood. Primary glossodynia is reported to be associated with neurophathic pain. We describe the cases of 3 patients（2 males, 1 female, mean age 54.3 years, range 42-79 years） with primary glossodynia that was treated with the concomitant medication of pregabalin （50-300mg/day）, tramadol hydrochloride/acetaminophen tablets （37.5/325-150/1,300mg/day）, and powdered processed aconite roots （0.5-1.5mg/day）. This medication remarkably relieved the patientsʼ primary glossodynia and promoted health-reated quality of life of them. Significant adverse events did not occur in any of the cases. This concomitant medication may be useful for the treatment of primary glossodynia.
Patient: The patient was a male in his mid-40s. He had been suffering from lingual hypesthesia on the right side with a burning sensation for 2 months. He visited our liaison outpatient clinic which perform team medicine by dentists and psychiatrists. According to the letter of referral, his previous oral and maxillofacial surgeon decided to refer him to our liaison outpatient clinic since the CT imaging did not show any abnormality, and he was under strong psychosocial stress. Our team performed MRI to reconsider the possibility of trigeminal neuropathy due to an organic disease, as the patient has continued to complain of his oral symptom even after his psychosocial stress relieved and the sign of depressive mood ameliorated subsequently. The MRI image pointed out some sort of cerebral abnormal lesion which could cause trigeminal neuropathy. Thus the team referred him to the neurology physicians, which turned out as trigeminal neuropathy presenting right trigeminal hypesthesia and dysesthesia caused by some organic lesion in the brain. Although the oligoclonal band was negative, the possibility of multiple sclerosis was undeniable according to the clinical presentation of spatial and temporal frequency. Therefore, careful follow up by the department of neurology is continued.
Discussion : Pain and hypesthesia are subjective complaints. Therefore, information obtained by medical interviews and appropriate examinations are particularly important for the diagnosis. This case was difficult to diagnose as strong psychosocial stress was apparent. However, performing head MRI by our clinic leaded to the discovery of organic disease in the brain.
Conclusions : This was a case first diagnosed as burning tongue caused by psychosocial stressor, but later diagnosed as some organic disease in the brain by collaboration and discussion by dentists and psychiatrists. We regarded this case as a valuable suggestive case in everyday clinical practice.
Patient: A 37-year-old man experienced severe pain at the maxillary left second molar and orbital area. First, he visited an ophthalmology clinic ; however, his pain did not alleviate. Second, he visited a nearby dental clinic, where he was prescribed clarithromycin and loxoprofen sodium ; however, his symptom did not improve. Dental caries was detected and removed. However, the pulsating severe pain over the tooth and temporal region still occurred more than 5 times per day, and this symptom was accompanied by conjunctival hyperemia and nasal discharge. When the symptoms occurred, the patient exhibited restlessness in the clinic. Since, we first diagnosed his condition as cluster headache, oxygen was administered, following which the pain decreased. Subsequently, we consulted the physician at our hospital and the patient was prescribed sumatriptan succinate 100mg. However, the patient presented to us again after the symptoms recurred. At this time, we suspected paroxysmal hemicrania（PH） and prescribed indomethacin 50mg. The symptoms of toothache and headache alleviated. There has been no recurrence of pain since then.
Discussion: In total, 15％ of patients who develop PH experience toothache, and they often visit a dental clinic with paroxysmal toothache and facial pain. In this case, the patient presented with a chief complaint of toothache ; however, the cause of toothache was thought to be PH.
Conclusion: We believe that dentists should have adequate knowledge of headaches, because patients often visit the dentistry department with neurovascular toothache.
Patient: We report a case of xerostomia and glossodynia that was treated with traditional Japanese kampo medicines.
Case: A 31-year-old female complained of dry mouth and tongue pain for two months after extraction of four wisdom teeth. Three months later, she was treated with Goreisan, but with no improvement in her symptoms.
General condition: She complained of headache, coldness of limbs, general malaise and severe menstrual pain.
Clinical test results: VAS 43, Anti-SS-A and anti SS-B antibody negative, Saxon test for xerostomia : 1.2g/2min, CMI area Ⅱ＋angry type, SDS 47, State-trait anxiety inventory（STAI）scores : state-anxiety 48（Ⅳ）, trait anxiety 47（Ⅳ）.
Clinical diagnosis: Xerostomia and psychogenic glossodynia.
Treatment and subsequent course: Since the Saxon test was 1.2g/2 min, assuming dry mouth as being the cause of the tongue pain, we started administration of 5 g/day of Hochuekkito and 5 g/day of Tokishakuyakusan. After 35 days, her Saxon test result improved to 1.9g/2 min. However, since tongue pain severity on a visual analogue scale（VAS）was 43 and she had a neurotic tendency, therapy was changed to 5 g/day of Kamishoyosan, which was discontined after 56 days when tongue pain scores on the VAS were zero.
Discussion: In this case, the patient had a combination of basal metabolic decline, body fluid loss, peripheral circulatory failure and anxiety symptoms. Therefore, her symptoms improved with a two-stage treatment consisting of supplementing vital energy and blood, controlling fluid balance and treatment of anxiety symptoms using kampo medicines.
Conclusions: In cases where xerostomia and glossodynia coexist, it may be difficult to decide the treatment policy. However, there are cases in which the treatment efficacy of xerostomia and glossodynia can be improved by using psychological tests, oriental medicine examination methods and administration of Hozai and Qi medicine.
Patient: A 38-year-old man suffered from pain of the right lower molar and difficulty with mouth opening. No abnormal findings were observed in the panoramic radiography and periodontal tissue examinations. No conspicuous pain of the right mandibular molar was observed, and there was no abnormal finding of the temporomandibular joint. Although several marked tender points were observed at the right masseter muscle, it was difficult to palpate the obvious muscle induration. Referred pain was recognized in the right first molar due to compression of the right masseter muscle. The pain was diagnosed as myofascial pain of the right masseter muscle. Observations of the right masseter muscle using the ultrasound diagnostic equipment showed findings that appeared to be adhesions of the fascia. We injected 1％ mepivacaine into the site believed to be an adhesion of the fascia under ultrasound guidance, and adhesion release was confirmed. Pain was relieved after this injection, and the extent of mouth opening was also increased.
Discussion: This case describes myofascial pain without obvious muscle induration. Symptom improvement was observed by releasing the adhesion of the fascia under ultrasound guidance.
Conclusion: This report suggests that ultrasound-guided fascia release is an effective treatment for myofascial pain without muscle induration.