Orofacial Pain

A Guide for the Headache Physician

Martina K. Shephard, BDent(Hons), MBBS(Hons), FRACDS; E. Anne MacGregor, MD, FFSRH; Joanna M. Zakrzewska, MD, FDSRCS, FFPMRCA

Disclosures

Headache. 2014;54(1):22-39. 

In This Article

Facial Pain With/Without Intraoral Pain

TMDs

TMDs are the most common causes of orofacial pain, affecting 10–15% of the population.[39,40] Presenting features include pain localized to the pre- and post-auricular areas, the angle and ramus of the mandible, and the temporal region. There may be associated clicking, sticking, or locking of the temporomandibular joints. The pain may be intermittent or continuous, and is usually described as dull, aching, or throbbing, or in the words of patients: "weight on the side of the face getting heavier and heavier," "pressure feeling," "elastic band that is too tight," or "needles digging in." Some patients experience pain that is sharp or shooting in character, intermixed with dull continuous pain. The pain commonly radiates into the temporal or occipital regions into the neck and across the malar region of the face; it can be unilateral or bilateral, and of varying severity. There may be an associated bruxing or clenching habit. The pain is typically aggravated by opening the mouth wide, yawning, or chewing. There may be limitation of mouth opening.[41]

TMD has historically been classified using the Research Diagnostic Criteria into myofascial pain, disc displacement, and other disorders,[42,43] as the International Classification of Headache Disorders (ICHD)-II of TMD was not useful in clinical settings.[2] Newer classification criteria refer to myalgia, myofascial pain with referral, and myalgia with disc involvement.[41]

A large prospective cohort study is currently underway in the USA investigating the prognostic factors related to the development of TMD.[44–46] Participants with and without TMD participate in a battery of psychometric, biometric, and genetic tests. Baseline data on the psychological characteristics of the TMD cases demonstrate that this population shows higher levels of distress, catastrophizing, and increased somatic awareness compared with non-TMD controls. A number of other studies have reported similar findings.[47–49]

TMD has been linked with other psychological and chronic pain conditions, including fibromyalgia, back pain, headaches, chronic widespread pain, and hypermobility.[50–53] Degenerative temporomandibular joint disease is rare but may occur in rheumatoid arthritis. Interest has been raised recently in the possibility of TMD-related headache, which may involve aspects of peripheral and central sensitization.[54]

Management of TMD is primarily conservative, as in the majority of cases, the disorder is self-limiting. Careful explanations are crucial as it has been shown that patients experience a considerable amount of uncertainty both in terms of diagnosis and then management, as dentists also often find it difficult to manage.[55–57] Approximately 10% of patients develop chronic pain, and this has been linked to fibromyalgia, depression, and chronic widespread pain.[58] Therapies used for TMD include simple analgesia, tricyclic antidepressants, occlusal splints or bite guards, diet modifications, physiotherapy, cognitive behavioral therapy, and surgery.[59–61] Evidence for the majority of these therapeutic options is poor, and there remains considerable confusion about the best form of management.[7] Surgery is only indicated for TMD with significant functional limitation or in cases with associated degenerative joint disease or disc dysfunction.[62] Education, psychological support and self-management strategies are recommended as part of a multidisciplinary approach to the management of TMD, and these should be done early to reduce costs.[63–65] There remains considerable variation in the way TMD is diagnosed and managed partly due to conflicting evidence. It is anticipated that the large US-based Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) study will provide more robust evidence, as it is a prospective study that has enrolled asymptomatic participants.[44–46]

Giant Cell Arteritis

Giant cell arteritis (GCA) is an important differential diagnosis in any patient over the age of 50 years presenting with temporal or pre-auricular pain. This condition is potentially vision-threatening and needs to be identified and treated as a matter of urgency. The pain of GCA is often described as "throbbing" and continuous, and may be associated with jaw claudication, visual symptoms, and systemic illness, including musculoskeletal pain in the upper limbs (polymyalgia rheumatica). Clinical examination may demonstrate a reduced pulse in a tortuous temporal artery. Blood tests for erythrocyte sedimentation rate and C-reactive protein (CRP) should be performed urgently as these will assist in confirmation of the diagnosis, followed by temporal artery biopsy.[66] If the clinical presentation is strongly suggestive of GCA, treatment with high-dose corticosteroids should be commenced prior to the receipt of test results, and urgent referral to ophthalmology should be made to avoid loss of vision.[67]

Post-herpetic Neuralgia

Post-herpetic neuralgia is a neuropathic pain arising after reactivation of herpes virus species (most commonly varicella zoster), which may involve branches of the trigeminal nerve. The first division is most commonly affected; however, involvement of the second or third divisions may result in facial or intraoral neuropathic pain. The pain is unilateral and restricted anatomically to 1 or more branches of the trigeminal nerve, and is described as "burning" and continuous.[18] History often reveals an episode of herpes virus reactivation including the presence of "blisters," "ulcers," or vesicles on the skin or intraorally, associated with extreme pain in the same region, which typically precedes the appearance of the vesicles. Pain may persist for up to 6 weeks following an episode of herpes virus reactivation, and allodynia is often present on examination. Ongoing pain and neurological abnormalities 3–6 months following the acute episode is classified as post-herpetic neuralgia and is common in elderly patients, resulting in considerable impact on quality of life.[68] There is often a complaint of severe itching. Management is as for other types of neuropathic pain.[69] However, it is important to treat the acute episode with high-dose antiviral medications and even tricyclic antidepressants in elderly patients as they are at higher risk of developing post-herpetic neuralgia. Antiviral medication should be commenced within 72 hours of the onset of rash/vesicles but may be started up to 7 days following onset, particularly in immunocompromised or older individuals.[70]

Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a condition characterized by episodic, usually unilateral, severe attacks of facial pain, which are often described as "shooting," "electric shock-like," or "stabbing." Metaphors used by patients include "plugged into the mains and switched on and off" and "rockets and explosions." The pain attacks are of very short duration (seconds) with a refractory period, and periods of complete pain remission may occur, which can last for months or even years.[71] With time, the remission periods tend to shorten. Some patients describe a continuous dull ache or burning after an acute attack, eg, "red hot iron being pushed and turned inside the cheek," and if this sensation persists, it has variously been labeled as atypical TN, type 2 TN,[72] or TN with concomitant pain.[73] The pain is restricted to the anatomical boundaries of divisions of the trigeminal nerve and most commonly affects the second and third divisions. The pain is triggered by a variety of light touch stimuli, including talking, eating or tooth-brushing, face-washing, or cold winds. Patients will usually be able to identify a discrete "trigger zone" within which sensory stimuli will produce a pain attack. It is a severe and disabling pain, and has a significant impact upon quality of life. One of our patients described her TN experience as follows: "My whole life was falling apart. My husband was losing weight, everything was falling apart in our house, my job and there was nothing I could do about the pain."

In some patients, there is an identifiable cause, such as an intracranial lesion or a vascular compression of the trigeminal nerve.[74] TN is reported in up to 3.8% of patients with multiple sclerosis.[75] For this reason, imaging (MRI) forms an essential part of the work-up for TN. Management will depend on whether there is an identifiable cause, but is primarily medical, and aims to achieve symptom relief. Medical management involves the use of anticonvulsants such as carbamazepine or oxcarbazepine.[74,76] Second line agents include lamotrigine and baclofen. Because of the increasing number of anticonvulsants now available, many patients are referred unnecessarily late for surgical interventions that can offer the best quality-of-life outcomes.[77] Surgical procedures such as microvascular decompression may be performed if there is imaging evidence of a lesion affecting the trigeminal nerve root, and the disease is causing a significant impact on quality of life.[78,79] Other less invasive surgical procedures such as radiofrequency thermocoagulation, glycerol rhizotomy, balloon compression, or gamma knife surgery tend to provide shorter periods of pain relief and have a higher risk of sensory loss. They are used in patients who are medically unfit for major surgery such as microvascular decompression. It remains difficult for patients and clinicians to make decisions about treatment due to a lack of high-quality evidence. Some data suggest that many patients prefer a surgical option rather than ongoing medical management.[80]

Glossopharyngeal Neuralgia

Glossopharyngeal neuralgia has a similar presentation to TN, although the location of the pain is different. Patients may experience paroxysmal attacks of pain felt deeply in the throat, ear, or posterior aspect of the tongue. The triggers for pain attacks include chewing, talking, drinking, and swallowing. The condition is usually managed medically with anticonvulsant drugs. Refractory cases may require surgery in the form of microvascular decompression.[81]

Anesthesia Dolorosa

Anesthesia dolorosa is a condition arising from damage to the trigeminal nerve, usually during surgery for TN. The condition develops 3–6 months following the traumatic incident. It is characterized by "painful numbness." Patients will report continuous facial pain in an area of numbness, often described as "burning," "pressure," or "stinging." This is a typical patient description: "The right side of my face, from my chin to above my right eye, is numb and I frequently experience a 'crawling' sensation on the right side of my face and scalp. Also, my face has quite a bit of pressure and feels as though it is being pulled or tugged, as if in a visor."

The pain is persistent, severe, and associated with a high level of psychological distress and comorbidity. It is often resistant to treatment. The area involved may include all 3 divisions of the trigeminal nerve. Examination findings may include objective sensory deficits, allodynia, and hyperalgesia or hypoalgesia.[82] Management options are as for neuropathic pain, with psychological support playing a significant role. In the new ICHD classification, this entity has been named "painful post-traumatic trigeminal neuropathy."[18]

Persistent Idiopathic Facial Pain/Atypical Facial Pain

This term is used to describe a facial pain presentation that does not fit the clinical pattern for any other diagnosis and is relatively rare.[18,83] It is often continuous, "nagging" and "dull" in nature, and is not restricted by neurological anatomical boundaries.[84,85] An example of a patient's description of the pain is: "Concrete poured into my head and then moving around."

There is a high level of associated psychological comorbidity and a high prevalence of chronic pain elsewhere in the body.[5,32] It is often associated with conditions such as irritable bowel syndrome and chronic widespread pain. The etiology of the condition is unclear, although recent research has suggested the possibility of a pathophysiology similar to trigeminal neuropathic pain.[86,87] There is often a history of mental health problems that may predate the pain. Management is often difficult and includes medical and psychological input, using a multidisciplinary team approach.[88–90] Because of the very broad definition that has been proposed in the new ICHD classification, this diagnosis will continue to be applied to a very heterogeneous group of patients and thus limit further research into the condition.[18]

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