Odontogenic Pain

2005 Volume 2, Issue 1

www.painmanagementrounds.org

F ROM GR AN D ROU N DS AN D OTH ER CLI N IC AL CON F ER ENCES OF T H E M G H PA I N C E N T E R , M A S S A C H U S E T T S G E N E R A L H O S P I TA L

MGH

Orofacial Pain By ALEXANDRE F.M. DASILVA, DDS DMSC.,

1811

AND

MASSACHUSETTS GENERAL HOSPITAL

MARTIN A. ACQUADRO, MD, DMD, FACP, FACPM

The assessment of head and neck pain requires a careful physical examination of multiple structures and systems, a thorough history, and the employment of auxiliary diagnostic studies. Due to its complexity, patients suffering with this type of pain are frequently followed by multiple healthcare professionals. The goal of this issue of Pain Management Rounds is to present some of the clinical features, diagnostic tests, and treatments available for different chronic pain disorders in the orofacial area.

TEMPOROMANDIBULAR AND MYOFASCIAL DISORDERS Temporomandibular joint (TMJ) articular disorders TMJ damage can be the result of direct trauma, wear and tear from pathologic occlusal forces, or overextension of jaw movements (Figure 1). Other conditions may also affect the TMJs, such as congenital and developmental disorders, inflammatory disorders, osteoarthritis, and ankylosis. Similar to finding abnormalities of the lumbar spine with magnetic resonance imaging (MRI) in asymptomatic patients, evidence of TMJ pathology may be apparent in asymptomatic individuals.1 However, if the patient complains of chronic TMJ dysfunction with pain, a thorough evaluation by a pain specialist is warranted.

Temporomandibular muscle disorders (TMMDs) TMMDs are characterized by dull aching pain that is exacerbated by mandibular function, muscle tenderness in one or more masticatory muscles and, frequently, a decreased mandibular range of motion. A variety of terms exist to describe muscle disorders, with a number of classifications and sub-classifications. These include myofascial dysfunction, myositis, myalgia, myospasm, and myofibrotic contracture.2 The absence of clinical features referable to the TMJ and the presence of muscle tenderness distinguish TMMD from primary TMJ articular disorders.

Myofascial pain dysfunction Dysfunction of the muscles of the shoulders, neck, head, and face is relatively common in the general population and can aggravate headaches and orofacial pain. Fibromyalgia is a type of myofascial dysfunction and is described as a chronic disease with muscle pain and tenderness in multiple body quadrants. It can be exacerbated by stress and anxiety and may be accompanied by a variety of generalized symptoms such as fatigue, morning stiffness, and headache. The patient with fibromyalgia may initially present with facial pain and tenderness in the muscles of mastication. 3 Other systemic myofascial disorders are polymyalgia, lupus erythematosus, polymyositis, and dermatomyositis.

Diagnosis Diagnostic evaluation includes a careful and thorough history and physical examination of the integrity and function of the head and neck structures, with special attention to the TMJ complex and the cranial and cervical muscles and nerves. Evaluation should include a review for a history of primary headaches, surgeries, traumas, and stressors. A review of daily activities, along with posture, repetitive movements, habits, and sleep patterns should be included. A history of parafunctional habits (clenching and grinding of teeth), awakening in the morning with sore jaw muscles, and joint noises when opening the mouth should be elicited. Examination of the oral cavity should look for abnormal occlusion (bite). Teeth sensitivity, painful muscles, and trigger points (TP) should be examined.2 MRI and computed tomography (CT) scan of the TMJs may be necessary to evaluate possible advanced degenerative pathologies or tumors. However, radiographs frequently reveal abnormalities of the TMJ disk position in asymptomatic joints that do not require treatment. Therefore, other than an initial panoramic radiography, imaging exams of the TMJ should only be requested in treatment-resistant chronic pain, unusual pain

MGH PAIN CENTER Jane C. Ballantyne, M.D. Chief, Division of Pain Medicine Editor, Pain Management Rounds Salahadin Abdi, M.D., Ph.D. Director, MGH Pain Center Martin Acquadro, M.D., D.M.D. Director of Cancer Pain Service Steve Barna, M.D. Medical Director, MGH Pain Clinic Gary Brenner, M.D., Ph.D. Director, Pain Medicine Fellowship Lucy Chen, M.D. Katharine Fleischmann, M.D. Director, Acute Pain Service Jatinder Gill, M.D. Karla Hayes, M.D. Eugenia-Daniela Hord, M.D. Ronald Kulich, Ph.D. Jianren Mao, M.D., Ph.D. Director, Pain Research Group Seyed Ali Mostoufi, M.D. Anne Louise Oaklander, M.D., Ph.D. Director, Nerve Injury Unit Director, Center for Shingles and Postherpetic Neuralgia Gary Polykoff, M.D. Milan Stojanovic, M.D. Director, Interventional Pain Management

MGH PAIN CENTER 15 Parkman Street, Suite 324 Boston, MA 02114 Fax : 617-724-2719 The editorial content of Pain Management Rounds is determined solely by the MGH Pain Center, Massachusetts General Hospital.

Pain Management Rounds is approved by the Harvard Medical School Department of Continuing Education to offer continuing education credit

FIGURE 1: Temporomandibular disorders Diagnosis

TM joint articular disorders

TM muscle disorders

Myofascial disorders

Region

Diagnostic features

Pain localized in the pre-auricular area during jaw function. Usually presence of painful click or crepitus during mouth opening. Limited opening (<35 mm), deviated or painful jaw movements.

Tenderness of the masticatory muscles. Dull, aching pain exacerbated by jaw function or palpation.

Diffused dull or aching pain affecting multiple groups of muscles of the head and neck region, as well as other parts of the body.

Diagnostic evaluation

Internal derangement of the TMJ with abnormal function of the disc-condyle complex, and/or degeneration of the joint surface. Palpation is painful. Possible joint swelling in acute phases. MRI, CT, etc. of the joint may rule-out tumors and advanced degenerative stages.

Tenderness during palpation of the masticatory muscles and tendons. Possible limited range of jaw movement and during passive stretching exam. Can be associated with a para-functional habit (bruxism-early morning pain).

Presence of trigger or tender points in one or more groups of muscles. Pain can radiate to distant areas with stimulation or not of the trigger points. Rule out presence of lupus erythematosus.

Patient education and self-care. Medication: NSAIDs, non-opiate analgesics. Physical Therapy: exercise program. Occlusal splints. Oral maxillofacial surgery: arthrocentesis, arthroscopic surgery, open surgery.

Patient education and self-care. Medication: topical and systemic NSAIDs, non-opiate analgesics, muscle-relaxants, antidepressants (usually TCAs), anxiolytics, anticonvulsants, BTX, trigger point injections and vapocoolant spray. Physical Therapy: TENS, massage, exercise program. Occlusal splints. Cognitive-behavior: biofeedback, relaxation, coping skills.

Patient education and self-care. Medication: topical and systemic NSAIDs, non -opiate analgesics, muscle-relaxants, antidepressants (usually TCAs), anxiolytics, anticonvulsants, BTX, trigger point injections and vapocoolant spray. Physical Therapy: TENS, massage, exercise program. Occlusal splints. Cognitive-behavior: biofeedback, relaxation, coping skills.

Treatment

patterns, and sudden changes in occlusion.4 Consideration of other diagnoses by history and physical exam will dictate additional studies and referral to the appropriate specialist.

Treatment Physical therapy: The patient diagnosed with TM disorders may benefit from a complete evaluation and treatment by a physical therapist. The treatment program may include stretching, strengthening, endurance exercises, transcutaneous electrical nerve stimulation (TENS), ultrasound, and hot/cold applications. Outpatients should follow an active exercise program with guidance from a physical therapist.5 Pharmacologic therapy: Pharmacologic therapy includes judicious use of non-steroidal anti-inflammatory drugs (NSAIDs) and other analgesics, and selective use of tricyclic antidepressants (TCAs), anticonvulsants, muscle relaxants, anxiolytics and, rarely, opioids. There is marked inter-patient variability in the response to different pharmacological agents, necessitating trials of agents until the optimal response is obtained. NSAIDs may be used for both their analgesic and anti-inflammatory properties. Although large doses of NSAIDs may provide short-term relief, they have no proven value in the long-term management of TMJ pain.6 Short-term use of centrally acting muscle relaxants include cyclobenzapine (Flexeril) and carisoprodol (Soma). Benzodiazepines, such as diazepam and clonazepan, also decrease muscle spasms, improve sleep, and are anxiolytic; however, their use should be carefully controlled.7 TCAs may also improve sleep and act as indirect analgesics. Trigger point injections, botulinum toxin injections, and physical therapy: Trigger points can be localized by clinical exam and then temporally inactivated by anesthetic injection. This provides prolonged analgesia, allowing the patient a pain-free period to commence physical therapy, with subsequent use of vapo-coolants and

stretching exercises at home.8 However, pain relief may last much longer than the anesthetic effect. Corticosteroids can also be added to the mixture. Botulinum toxin (BTX) injection has proven to be an excellent therapeutic tool for the treatment of myofascial pain. The clinical effects include reduction of muscular tone and contractility and graded chemical denervation in the injected muscular area. Botulinum toxin may also reduce pain and clinical reports support its utility in some chronic pain diseases, including primary headaches, inflammatory pain, and selected cases of neuropathic pain.9,10 However, good level 1 randomized control clinical studies are lacking.11 The beneficial effect of a BTX injection can last an average 4 months and may be repeated if indicated. Behavioral therapy: Biofeedback, relaxation techniques, and cognitive behavioral therapy addressing aversive behaviors are useful and should be considered in chronic cases of orofacial pain.12 Dental treatment: Advocates of occlusal appliances suggest that it temporarily equilibrates occlusion, mechanically unloading the TMJ and limiting masticatory muscle activity, therefore decreasing symptoms of TM disorders. Occlusal appliance therapy seems to be beneficial in cases of myofascial pain, even when there are no signs of parafunctional habits (eg, bruxism).13 Malocclusions have an inconsistent relationship to TMJ disorders, and correcting them may improve masticatory function without guaranteeing pain relief. Temporomandibular joint surgery: Open surgery of the TMJ is associated with considerable morbidity and a lack of efficacy, unless proper and careful patient selection is utilized by an experienced oral and maxillofacial surgeon. 4 More conservative procedures, such as arthrocentesis and arthroscopic surgeries, should be considered first.

ODONTOGENIC PAIN Due to the rich innervation of the mouth, odontogenic pain can present with numerous features, including local pain, headache,

FIGURE 2: Odontogenic pain Diagnosis

Pulpitis

Periodontal

Cracked tooth

Dentinal

Region

Spontaneous or evoked brief

Brief, sharp pain evoked by

Spontaneous and/or evoked

Localized deep continuous pain

throbbing, or dull.

exacerbated by biting or chewing. (eg, crown, root canal )

Look for deep caries and recent or extensive dental work. Pain provoked/exacerbated by percussion, thermal or electric stimulation of affected tooth. Dental x-rays helpful (periapical).

Tooth percussion over compromised periodontium provokes pain. Look for inflammation or abscess (eg, periodontitis, apical) Dental x-rays helpful (bitewings, periapical).

Presence of tooth fracture may be detectable by x-ray. Percussion should elicit pain. Dental x-rays are helpful (periapical taken from different angles).

Exposed dentin or cementum due to recession of periodontium. Possible erosion of dentinal structure. Cold stimulation reproduces pain.

Medication: NSAIDs, nonopiate analgesics. Dentistry: Remove carious lesion, tooth restoration, endodontic treatment or tooth extraction.

Medication: NSAIDs, non-opiate analgesics, antibiotics, mouthwashes. Dentistry: drainage and debridement of periodontal pocket, scaling and root planing, periodontal surgery, endodontic treatment or tooth extraction

Medication: NSAIDs, non-opiate analgesics. Dentistry: depends on level of the tooth fracture-restoration; treatment, or extraction of the tooth.

Medication: Mouthwash (fluoride), desensitizing toothpaste. Dentistry: Fluoride or potassium salts, tooth restoration, endodontic treatment. Patient education, diet, tooth brushing force and frequency, proper toothpaste.

Diagnostic deep /diffuse pain in compromised in compromised periodontium sharp pain in a tooth with history different kinds of stimulus to the dentin (eg, hot or cold drinks). (eg, gingiva, periodontal ligament) of trauma or restorative work dental pulp. Pain may be sharp, features

Diagnostic evaluation

Treatment

or eye symptoms. Differential diagnosis includes trigeminal neuropathic pain, sinus disease, and primary headaches (eg, cluster headache and migraine). Diagnosis: During the history and clinical examination, odontogenic pain must be adequately assessed. Aggravating and relieving factors, duration, and quality of the pain provide key information to differentiate dental pathologies (Figure 2). The clinical exam should include probing of the dental surfaces for cavities or fractures, percussion of the teeth in multiple planes for mobility and fractures, and electrical and thermal stimulation for pulpitis. Radiographic exams contribute greatly to the diagnosis. However, if pathologies of the hard or soft intra-oral structures are ruled-out, consideration of less common disorders that mimic odontogenic pain is warranted. Treatment: If dental disease is the obvious source of pain, referral to a dentist should be made for proper evaluation and treatment. A summary of treatments is provided in Figure 2.

TRIGEMINAL NEUROPATHIC PAIN DISORDERS Trigeminal neuralgia Trigeminal neuralgia is characterized by sudden, stabbing, and severe unilateral facial pain in ≥1 of the 3 divisions of the trigeminal nerve, most frequently the second. Onset is frequently triggered by mechanical stimulation such as talking, chewing, or touch. Attacks can last from seconds to a few minutes. Periods of attacks can last weeks or months, followed by periods of remission for months or years. Incidence increases with age, with the average onset at age 50 years; it more commonly presents in women.2 Limited information is available about the etiology of trigeminal neuralgia other than the possible compression of the trigeminal root by a vessel or tumor.15 Diagnosis: MRI is an important tool for excluding intracranial masses and multiple sclerosis (MS), particularly in younger patients with trigeminal neuralgia symptoms. Novel MRI studies can reveal demyelinating lesions of the white matter associated with MS.16 Treatment: Carbamazepine is the drug of first choice for treatment, with an initial beneficial response in >75% of patients. Baclofen potentiates the action of carbamazepine and can be a useful adjunct. Gabapentin is a safe and well-tolerated adjunct to carbamazepine or may be used as sole treatment. Other less frequently used agents include topiramate, zonisamide, oxcar-

bazepine, lamotrigine, clonazepam, and sodium valproate.17 Some of the surgical approaches to the treatment of trigeminal neuralgia include microvascular decompression, radiofrequency rhizothomy, and gamma knife surgery. Microvascular decompression of the trigeminal nerve provides immediate and long-term pain relief in >70% of patients.18

Deafferentation pain Teeth and dental nerves are commonly removed and, occasionally, these procedures induce a phenomenon known as “phantom tooth pain,” producing pain in previously extracted or endodontically-treated teeth.19 Other facial areas previously harmed by trauma or surgeries may induce deafferentation pain. This pain may be constant with sharp exacerbations, and is associated with local allodynia (Figure 3). Diagnosis: History and physical exam are important to elicit the extent of dental work and other trauma or surgeries in the area. History of prior severe dental pain of the extracted tooth or teeth, as well as prior sinusitis pain, migraine history, and traumatic pain may suggest possible peripheral or central sensitization. Neuroimaging studies may help rule out tumors affecting the trigeminal sensory system. Treatment: Pain therapies are targeted at both the central and peripheral components of deafferentation pain. Clinical studies have demonstrated good results with gabapentin, and clonazepam and baclofen are useful as adjunctive agents. Peripherally acting agents, including topically applied drugs, and nerve blocks have been applied topically with mixed results. A fixed daily dose of an opioid has been used in severe cases, but is considered a last resort. Surgical procedures are mostly ineffective in the treatment of phantom tooth pain and may increase pain severity.20

Acute and post-herpetic neuralgia Acute herpetic neuralgia (AHN) – shingles – usually affects the ophthalmic division of the trigeminal nerve.21 Shingles is almost always unilateral and may be recurrent. Pain is described as burning, itching, well-localized to the dermatome, with lancinating episodes, and is associated with hyperesthesia and hyperalgesia22 (Figure 3). Pain persisting for >1 month after complete healing of

FIGURE 3: Trigeminal neuropathic pain disorders Diagnosis

Trigeminal neuralgia

Deafferentation pain

Acute and postherpetic neuralgia

Burning mouth syndrome

Spontaneous or evoked pain with prolonged after-sensation after tactile stimulation. Trigger zone due to surgery (tooth extraction) or trauma. Positive and negative descriptors (eg, burning, nagging, boring).

Pain associated with herpetic lesions, usually in the V1 dermatome. Spontaneous pain (burning and tingling), but may present as dull and aching. Occasional lancinating evoked pain.

Constant burning pain of the mucous membranes of the tongue, mouth, hard or soft palate, or lips. Usually affects women age >50 years.

Etiologic factors such as trauma or surgery in the painful area. Order MRI if the area is intact to rule-out peripheral or central lesions.

Small cutaneous vesicles (AHN) or scarring (PHN), usually affecting V1. Loss of normal skin color. Corneal ulceration can occur. Sensory changes in affected area (eg, hyperesthesia, dysesthesia).

Rule-out salivary gland dysfunction (xerostomia) or tumor, Sjögren’s, candidiasis, geographic or fissured tongue, and chemical or mechanical irritation. Nutritional deficiencies and menopause can be factors.

Medication: anticonvulsants (eg, carbamazepine, gabapentin); antidepressants; non-opiate analgesics; topical agents (eg, lidocaine 5% patches). Combination of baclofen and anticonvulsants can produce good results. Surgery: ablative surgeries (eg, rhizotomy, gamma knife).

Medication: acyclovir (acute phase) anticonvulsants (eg, carbamazepine,gabapentin); antidepressants; non-opiate analgesics; topical agents (eg, lidocaine 5% patches). Surgery: ablative surgeries (eg, rhizotomy, gamma knife).

Medication: anticonvulsants (eg, gabapentin); benzodiazepines (eg, clonazepan); antidepressants; non-opiate analgesics; topical agents (eg, lidocaine mouthwashes). Cognitive-behavior: biofeedback, relaxation, coping skills.

Region

Brief severe lancinating pain evoked by mechanical stimulaDiagnostic tion of trigger zone (pain-free features between attacks). Usually unilateral, affects the V2/V3 areas (rarely V1). Possible pain remission periods (for months/years). MRI for evidence of tumor or of the trigeDiagnostic vasocompression minal tract or root (cerebroevaluation pontine angle). Rule-out MS, especially in young adults.

Treatment

Medication: anticonvulsants (eg, carbamazepine, gabapentin); antidepressants (eg, amitriptyline, nortriptyline, desipramine); non-opiate analgesics, BTX. Combination of baclofen and anticonvulsants can produce good results. Surgery: microvascular decompression of trigeminal root, ablative surgeries (eg, rhizotomy, gamma knife).

acute herpes zoster lesions is considered post-herpetic neuralgia (PHN). The pain of PHN is diffuse, dull, and aching, with a superficial allodynic sensation evoked by clothes or light touch. Diagnosis: Diagnosis is clinical and based on the presence or past presence of vesicles. Complications should be completely evaluated with CT or MRI imaging. Treatment: Early effective treatment of acute herpes zoster shortens the episode and decreases acute pain and the incidence of PHN. Antiviral therapy with acyclovir starting within 72 hours of the shingles eruption is particularly effective. TCAs, anticonvulsants, and NSAIDs are useful for pain control in AHN; however, if pain remains uncontrolled, opioids are judiciously added. TCAs are the mainstay of treatment in PHN.23 The efficacy of amitriptyline and desipramine has been confirmed in controlled clinical trials; however, a secondary amine (desipramine) which, theoretically, has less anticholinergic effects when compared to a tertiary amine (amitriptyline), is preferred in the elderly. Anxiolytics and anticonvulsants have been used with less success. Topical agents (eg, the lidocaine 5% patch) can produce substantial pain relief with minimal systemic absorption.24 Capsaicin is often poorly tolerated due to cutaneous sensitivity.

Burning mouth syndrome Burning mouth is characterized by burning pain of the mucous membranes of the tongue, mouth, hard palate, or lips. Its prevalence rates are 1.5%-2.5% in the general population. Patients are more likely to be female (3:1) and >50 years old. The onset of pain is gradual, with no precipitating event, and it is usually bilateral. Associated symptoms are altered taste and dry mouth. Although nutritional and menopausal factors and chronic chemical or mechanical irritation have been

suggested as causes, there is inadequate evidence to pinpoint these factors as the isolate etiology of burning mouth syndrome25 (Figure 3). Diagnosis: There are no useful radiographic or laboratory examinations. As always, a careful history and physical examination is required to rule-out other treatable causes. Treatment: In a study of 30 patients, clonazepam given daily lessened pain in 70% of patients.26 Also, tricyclic antidepressants may be effective. Since pharmacological therapy is unsuccessful in many patients, psychological support is important.

PARANASAL, PERIOCULAR, PERIAURICULAR, AND HEAD AND NECK CANCER PAIN Paranasal sinus area pain and headache Acute sinusitis presents with bilateral or unilateral throbbing or sharp facial pain. Frequently, pain is exacerbated by leaning the head forward (Figure 4). Medial orbital pain with radiation to the temple is a feature of ethmoid sinusitis. Frontal sinusitis features forehead pain and headache; maxillary sinusitis is suggested by pain over the upper teeth or orbit. Chronic sinus area pain presents more of a diagnostic dilemma. Pain that is perceived as emanating from the sinuses can have other causes, including referred pain from dental, musculoskeletal areas, and primary headaches.27 Other diagnostic features of sinusitis include purulent discharge from the nasal passages or nasopharynx, intermittent fever, smell or taste disorder, tenderness on tapping the maxillary teeth, and tenderness over the maxillary, frontal, or ethmoidal sinuses. A history of recurrent injury in the form of upper respiratory tract infections and allergies may be elicited. Diagnosis: A combination of history, endoscopic examination, and imaging studies is required to accurately diagnose sinusitis, particularly prior to embarking on surgical treat-

FIGURE 4: Paranasal, periocular, periauricular and head and neck cancer pain Diagnosis

Paranasal sinus pain

Periocular pain

Periauricular pain

Head and neck cancer

Region

Bilateral or unilateral throbbing Pain or tenderness with or Diffuse aching or sudden pain Variety of symptoms. Pain may without eye movement, deep with or without aural discharge be due to tumor, nerve comorbital pain, and referred pain. (eg, otitis media). pression, secondary infection, 2nd myofascial pain, deafferentation, radiotherapy, sinus. chemotherapy.

Diagnostic or pressure frontal area pain, exacerbated by leaning features forward or palpation over the

History of chronic allergies, frequent URIs, sinusitis, Diagnostic headaches of various types, evaluation sinus surgery. Refer to ENT for endoscopic and/or CT study (eg, sinus opacification)

Treatment

ENT evaluation/ treatment Medication: Sinusitis-topical decongestants; systemic antibiotics Chronic sinus pain-NSAIDs; non-opiate analgesics.; topical agents (lidocaine spray); anticonvulsants (eg, gabapentin); antidepressants (eg, amitriptyline), BTX Surgery

Examine eyelids, lacrimal function, conjunctiva, sclera (hemorrhage/ inflammation.). Ophthalmoscopy and ophthalmology referral. Rule-out primary headache (eg, cluster, migraine), temporal arteritis, orbital pseudotumor.

The area is innervated by multiple cranial and cervical nerves so complete functional and structural exam necessary (eg, inspect tympanic membrane, TMJ and myofascia). CT and MRI invaluable for mastoiditis and cholesteatoma.

Complete evaluation by multidisciplinary team. CT, MRI, endoscopy, biopsy and surveillance. Treatment coordination by oncologist

Proper ophthalmologic evaluation and treatment.

Proper ENT evaluation and treatment

Oncologist evaluation and treatment.

Medication: NSAIDs; nonopiate analgesics; corticosteroids; topical or systemic antibiotics, BTX across forehead and glabellar areas in selected cases.

Medication: NSAIDs; nonopiate analgesics; systemic antibiotics, topical corticosteroids, BTX in selected cases

Medication: anticonvulsants (eg, gabapentin); antidepressants (eg, amitriptyline); opiate or non-opiate analgesics; topical agents (eg, lidocaine 5% patches), muscle relaxants.

Surgery

Surgery

ments28 (Figure 4). Of note, even the common cold can cause mucosal thickening of the sinuses sufficient to be seen on MRI. Treatment : Otolaryngologic consultation should be obtained. Endoscopic surgery should be considered if a 6month trial of medical therapy has failed. With careful patient selection, endoscopic sinus surgery can achieve pain relief in most patients. Difficulties arise in those with chronic sinus area pain that mimics sinusitis. When imaging repeatedly demonstrates normal sinuses and there is a lack of any objective evidence of sinusitis, a multidisciplinary approach is required. These patients are unlikely to benefit from surgical intervention.

Periocular pain Ophthalmic pain results from stimulation of pain fibers relating either directly or indirectly to the orbit and can be classified as ocular, orbital, or referred29 (Figure 4). Ocular pain: Corneal irritation or damage is associated with local pain, photophobia, and lacrimation. Anterior scleritis presents with severe ocular pain, while posterior scleritis is characterized by less well-defined orbital pain. Either may be associated with a systemic collagen vascular disease. A triad of red eye, increased intra-ocular pressure, and mid-dilated pupil is pathognomonic of acute angle glaucoma. Orbital pain: Orbital cellulitis presents acutely with pain exacerbated by palpation and movement. Orbital pseudotumor is an inflammatory process of unknown etiology that presents with pain, chemosis, diplopia, and red eye. Trochleitis is characterized by orbital pain with movement, together with exquisite superonasal point tenderness. Referred pain: The proximity and convergence of afferent trigeminal pain fibers produce referred pain. Occasionally, pain from the area of the greater occipital nerve may radiate to

Surgery: ablative surgeries

the eye and face, due to convergence and communication between the cervical nerves, and the trigeminal sensory complex. Migraine, cluster headache, sinusitis, otitis, mastoiditis, temporal giant cell arteritis, and dental pain can be referred to the eye. Diagnosis: MRI is indicated in order to detect multiple sclerosis as a cause of optic neuritis. Raeder’s syndrome requires imaging to rule-out a parasellar mass or carotid dissection. Doppler flow studies are useful in detecting carotid stenosis as a cause of orbital ischemia. A raised erythrocyte sedimentation rate and increased C-reactive protein and fibrinogen levels are strongly associated with temporal giant cell arteritis. Treatment: If temporal arteritis, optic neuritis, or orbital pseudotumor are suspected, high dose corticosteroids should be started immediately, and the patient should be referred to an ophthalmologist or rheumatologist, depending on the suspected diagnosis. All patients with suspected eye pathology should be seen by an ophthalmologist.

Periauricular pain Otitis media presents with dull aching or sudden exquisite pain, with or without aural discharge, inflamed tympanic membrane, and systemic evidence of infection. Otitis externa can be exquisitely painful and is generally an acute process. Mastoiditis and otitis pain may be referred to the eye, pharynx, and neck due to involvement of multiple cranial and cervical nerves, and convergence into the trigeminal sensory complex. A common cause of otalgia that is frequently overlooked is referred myofascial pain from muscles of the neck, pharynx, and face (Figure 4). Diagnosis: Elevated white cell count is supportive, but nonspecific evidence for otitis media. CT and MRI are invaluable for mastoiditis and cholesteatoma. History and physical examination should direct the appropriate otolaryngologic referral.30

Treatment: In general, urgent consultation with an otolaryngologist is required. Pain problems referred to a pain specialist are often from an otolaryngologist who has successfully treated the primary otologic problem, but the patient still suffers from chronic pain. Treatment should be multidimensional and comprehensive, covering possible underlying myofascial and neuropathic pain.

Head and neck cancer Head and neck cancers present with a wide variety of symptoms. Frequently, a multidimensional approach is required during diagnosis, treatment, and recovery.31 Characteristic effects of the various manifestations of malignant disease and its treatment are as follows. Local tumor growth and invasion result in local tissue destruction, secondary infection, nerve compression and secondary myofascial pain. Surgical resection and reconstruction may result in acute postoperative pain, nerve damage, and inadequate vascularization of myocutaneous flaps. Chemotherapy may also result in nerve damage and neuritis. Radiotherapy can induce osteoradionecrosis, cheilosis, damage to salivary glands, secondary infection, and loss of range of motion of the neck and facial muscles. Psychosocial factors inducing fear and anxiety contribute to the overall pain response. There are also cosmetic concerns and fears of tumor recurrence, that cause patients to interpret symptoms as tumor recurrence, rather than the expected secondary complications of therapies (Figure 4). Diagnosis: CT and MRI, endoscopy, biopsy, and surveillance are invaluable in the management of head and neck cancer. Treatment: With particular reference to head and neck cancer, pharmacological and physical therapy can improve the pain and the range of motion of the neck, mouth, and TMJs. Myofascial pain of the shoulders, neck, and head, and headache, are frequent secondary occurrences, and may respond to physical therapy. Nutritional consultation may be helpful, as may dental consultation, to aid with oral function and cosmetics.

CONCLUSION Orofacial pain derives from a vast number of complex etiologies and its successful treatment requires contributions from many different specialties. This pain is one of the most distressing of all painful syndromes and warrants aggressive and appropriate treatment in a multidisciplinary setting. Dr. Alex DaSilva is a dentist and researcher in orofacial pain and headache. He received his DMSc in oral biology with clinical training in orofacial pain from Harvard University. His research interests include the application of multiple neuroimaging techniques, including MRI, to map functional and structural neuronal changes in the brain in migraine and trigeminal neuralgia patients. He is a researcher at the MIT/MGH/HMS Martinos Center for Biomedical Imaging, Harvard Medical School, and is a Harvard School of Dental Medicine Dean’s Scholars awardee. Dr. Martin Acquadro is an Assistant Clinical Professor of Anesthesiology at Harvard Medical School, and Associate Anesthesiologist, Director of the Cancer Pain Service, and Director of the Head and Neck Pain Service of the Massachusetts General Hospital.

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