Orofacial Pain: How to Evaluate and Treat, Part 1
Orofacial Pain: How to Evaluate and Treat, Part 1
Most pain in or around the oral cavity is attributable to tooth or mucosal pathology. However, tooth or muco-sal pain may also be caused by a variety of other conditions, including brain pathology; vascular inflammatory and cardiac disease; jaw infection or neoplasm; neuropathic abnormality not associated with central pathology; pathology in the neck and thoracic region; myofascial and temporomandibular joint pathology; and disease of the ear, eye, or nose, or of the paranasal sinuses, lymph nodes, and salivary glands. Accurate diagnosis is facilitated when the features of pain presentation in this region are understood.
Classification of and criteria for nondental conditions that can cause tooth pain appear in a number of sources.1-4 Clinical factors, including the patient's description of pain; its intensity, quality, and location; what relieves or exacerbates it; and the presence (or absence) of additional symptoms (eg, dysesthesia) may help establish the diagnosis when oral examination findings are negative.Additional imaging studies may be necessary to rule out problems such as salivary or central disease.
In my 2-part series, I review some of the more significant nondental conditions that cause tooth and mucosal pain; I also address treatment options. Here the focus is on temporal arteritis (TA), trigeminal neuralgia, burning mouth syndrome, postherpetic neuralgia (PHN), vascular conditions, masticatory myofascial conditions, and salivary gland pathology. In an upcoming issue, I will discuss oral cancer, maxillary sinus disease, and nonmalignant disorders of the oral mucosa.
The approximate annual incidence of TA varies by region but was reported in one study to be 4.1 cases per 100,000 persons.5 The typical patient is older than 50 years and looks and feels quite ill at presentation.
Dental pain associated with TA is usually localized to the maxillary posterior teeth (the first or second molar) or the maxilla, including the palate. Pain may also be perceived in or radiate to the frontal-temple region. The intensity of pain is described as moderate to severe and the quality as throbbing or aching/throbbing. It may be bilateral or unilateral. Pain may develop slowly or suddenly but, once established, it is unremitting.6
Chewing may worsen tooth pain as well as general pain--hence the presumption of a dental cause. However, in contrast to pain of pulpal (ie, dental) origin, the pain of TA is often associated with exquisite tenderness (hypersensitivity) of the scalp and face. Patients often report that hair combing or very light touching of the frontal-temple area is painful. Patients may also present with a number of more generalized symptoms, such as malaise or low-grade fever, that are not typically associated with dental pain (unless there is frank infection and cellulitis). There may also be ocular symptoms.
Additional factors that help establish the diagnosis include a significantly elevated erythrocyte sedimentation rate and hardness of the temporal artery on palpation. Temporal artery biopsy confirms the diagnosis. Early diagnosis is crucial because vision loss may result from delayed treatment.7 Treatment consists of high-dose corticosteroids (40 to 60 mg/d) with rapid taper over 7 to 10 days. In some cases, long-term therapy is required.
TRIGEMINAL NEURALGIA (TIC DOULOUREUX)
The pain of trigeminal neuralgia is typically felt in the anterior maxillary or mandibular anterior teeth (within the second and third division of the fifth cranial nerve) or, if the patient is edentulous, in the attached mucosa overlying the alveolar bone or a healed extraction site.8 Less frequently, it is perceived in the posterior teeth.
This pain, which is described as electrical, shocklike, or stabbing, is triggered by light touch and typically radiates along the mandible toward or into the ear on the ipsilateral side of the trigger or, if perceived in the maxillary region, superiorly into the eye or the maxillary sinus. The pain may be severe or excruciating. Unlike the pain of TA, however, the pain of trigeminal neuralgia is episodic, with paroxysms that last for seconds to minutes. A more generalized low-grade pain sometimes follows the severe attack. The severe paroxysmal pain is followed by a variable pain-free interval. Although pain may sometimes remit for months or years, recurring pain may be incapacitating.
Often, patients think that trigeminal neuralgia represents a dental problem because touching a tooth or adjacent mucosa in the trigger zone will initiate the paroxysm. Paroxysms can also be triggered by chewing or drinking, presumably because of the manipulation of the trigger point during these activities. However, in contrast to a patient with tooth pathology, a patient with trigeminal neuralgia often (but not always) reports an additional trigger on the external face (nose, lip, or cheek), so that touch or manipulation of an extraoral area during showering, smiling, shaving, or applying makeup also triggers pain.
Unlike patients with TA, those with trigeminal neuralgia do not have malaise or fever. Laboratory results are normal. A trial of an anticonvulsant medication such as carbamazepine or gabapentin may be useful in establishing the diagnosis.9In a patient whose pain does not respond to medication, or who reports additional sensory abnormality, such as facial numbness or tingling, additional evaluation should include gadolinium- enhanced MRI to rule out central tumor. In a person with neuralgia who is younger than 45 years, consider multiple sclerosis and brain tumor in the differential diagnosis.10
BURNING MOUTH SYNDROME
This condition preferentially affects postmenopausal women older than 50 years.11 Pain may involve the palate, tongue, lips, attached mucosa, oropharynx, or a combination of these. Pain is not typically perceived in the teeth, but severity is comparable to that of mild to moderate toothache. Involvement is usually bilateral, and there may be associated dysgeusia (alteration in taste).
The differential includes such conditions as tongue muscle hyperactivity; oral candidiasis; salivary hypofunction; Sjögren syndrome; denture-related causes; hematinic deficiency states (iron, vitamin B, and folate deficiencies); allergic reactions or reactions to chemical irritants; medication side effects; peripheral neuropathy; and a variety of intraoral diseases, such as migratory glossitis or lichen planus.12 Less likely, but still possible, is undiagnosed or poorly controlled diabetes, a psychological disorder, malignancy, or central pathology. If the burning is unilateral and is associated with dysesthesia (eg, numbness or tingling) in the absence of trauma, consider a neoplasm such as adenocystic carcinoma of the posterior tongue or the vestibule, PHN (see below), or ventral pontine infarction.13
Once these conditions have been ruled out, moderate relief of symptoms can be obtained with clonazepam, 0.25 to 2 mg/d. The combination of gabapentin and clonazepam is also effective.14 Some patients respond to topical anesthetics, such as lidocaine (2%) or dyclonine hydrochloride (1%). I have found that having patients rinse with doxepin elixir every 4 to 6 hours and swallow the last dose at bedtime sometimes relieves pain. About one half to two thirds of patients will experience spontaneous pain remission within 6 to 7 years, with or without treatment. Psychological intervention may also be helpful.15