Ch35 Regional and Referred Orofacial Pain

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Ch35 Regional and Referred Orofacial Pain Powered By Docstoc
					     Regional and Referred
     Orofacial Pain
             Edmond L. Truelove, DDS, MSD

              Referred cardiac pain, 359                            Referred pain from cervical myofascial
              Pain referred from neoplastic disease of              trigger points and degenerative disease,
              the pharynx, nasopharynx, base of tongue,             363
              and hypopharynx, 360                                  Pain referral from carotidynia, 364
              Pain referred from lung lesions, 361                  Pain referral from giant cell arteritis, 364
              Pain referred from intracranial lesions, 361          Pain referred from thyroid disease, 364
              Pain referred from disorders of the ears,             Pain referred from salivary obstruction,
              nose, throat, and sinuses, 361                        infection, or neoplastic disease, 365
              Referred pain from ear and eustachian                 Pain referred from dental structures to
              tube symptoms, 362                                    other sites, 365
              Referred pain from the esophagus, 363                 Suggested reading, 366

The diagnosis of facial pain is often complicated by              The greatest concern is pain referral by serious and
referral of pain to the face, jaws, and teeth from patho-     progressive pathology, including infections, vascular
logic conditions in nearby structures. The process lead-      disorders, and neoplastic disease. Well-known sources
ing to referral of sensations is not completely understood    of pain referred to the jaws include the pain of ischemic
but appears to involve a number of mechanisms, includ-        cardiac disease, esophageal pathology, and central
ing peripheral and central neural synaptic connections as     lesions that cause increased intracranial pressure or pro-
well as multiple converging ascending sensory and noci-       duce compression of one or more of the cranial nerves.
ceptive paths within major nerves serving regional areas      Major sources of referred pain are discussed, but the
and the convergence of nerves supplying distant sites. In     reader is reminded that thorough epidemiologic
some cases the sensation may be attributable to the com-      research documenting all important categories and
mon peripheral innervation of the tissues. This is seen in    sources of pain referral to the head and neck has not
referral of pain from sinus pathology to the maxillary        been completed, and the full extent of possible sources
dentition or alveolar process. A second mechanism             of pain referral is yet to be documented.
resulting in referral is interneuronal communication in
the brain stem. Regardless of the process, it is abun-
dantly clear that pain felt in a region does not necessar-     Referred cardiac pain
ily mean that the source pathology is in that tissue. The
astute clinician is persistently vigilant in assessing each   One of the most important sources of pain referral to
patient to rule out the possibility of referred orofacial     the jaws comes from symptoms generated during
pain from near or distant sources. Failure of local find-     attacks of angina in ischemic heart disease. Typically,
ings to clearly and decisively identify the source of pain    pain or other unpleasant symptoms develop in the jaws
should result in a systematic search for other sources        during actual ischemic episodes with remission of pain
rather than an assumption that the painful symptom is         when the crisis is over. Symptoms are usually felt in the
caused by an atypical presentation of local pathology.        left body of the mandible or left ramus, but pain may
Endodontic treatment of sound teeth and extraction of         also occur within the mandibular teeth on the left side.
otherwise healthy dentition frequently occurs when pain       It has generally been suggested that the pain is located
is referred to the mouth.                                     at the angle of the mandible, but pain can occur over the

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entire left side of the mandible or in the maxillary teeth     may provide additional information, but ultimately, the
on the left. It is relatively common for the patient to also   patient should be returned to his or her primary care
report pain in one or more of the following areas on the       physician for definitive assessment of cardiac function.
left side: lateral neck, shoulder, elbow, biceps, chest, or
back. Symptoms most frequently onset during periods
of exertion, exposure to cold, stressful events, and            Pain referred from neoplastic disease of
shortly after meals. The duration can be brief, lasting         the pharynx, nasopharynx, base of
only a few seconds, or persist for 15 minutes or longer.        tongue, and hypopharynx
Symptoms are usually resolved with nitroglycerin sub-
lingually or as a dermal patch and can be replicated           Neoplastic disease has known and documented poten-
with cardiac stress testing.                                   tial for referring pain to the face and mouth. The site of
    Whereas most clinicians are familiar with the con-         referral can vary, depending on the tissue involved and
cept of referred cardiac pain, they may not recognize          individual characteristics of the patient. Nevertheless,
that other, nonpainful, sensory symptoms can be                several patterns of referral are more common than oth-
referred during ischemic episodes. Patients may com-           ers. Base of tongue and hypopharyngeal lesions can
plain of cold sensitivity in the teeth on the left; a left-    refer symptoms of pain, burning, and fullness to the
sided sensation of tightness in the muscles of mastica-        posterior region of the mandible, the ramus, and body
tion; feelings of pressure within the mandible or              of the mandible. Symptoms can also be referred to the
maxilla, neck, or the dentition of the left side; and even     ear, preauricular region, and in the general distribution
sensations of paresthesia and tingling that create the         of pain from disorders of the temporomandibular joint
urge to rub or massage the site of referred sensation.         (TMJ). These lesions can also cause pain, burning, and
Pain or tightness in the chest may accompany other             paresthesia unilaterally in the tongue and floor of the
referred sensations, but some patients have no direct          mouth. Typically, symptoms are ill-defined and may
cardiac or chest complaints. Fatigue upon exertion,            increase during swallowing, jaw function, and eating or
however, is frequent and should be taken seriously.            speaking. If the lesion is superficial or eroded, spicy
    When cardiac sensations are referred to the jaws it is     foods and acids can increase symptoms and, if deep
not uncommon for the patient to report temporary reso-         within tissues, palpation and swallowing can be
lution of symptoms after dental therapy with a return of       provocative, resulting in generation of pain much in the
symptoms later that are slightly different. Since dental       same way that tender muscles in myofascial pain pro-
caries and periodontal disease are both common oral            voke symptoms when subjected to palpation. Invasion
diseases it is understandable that patients with referred      of neoplastic disease into peripheral neural tissues can
cardiac pain would receive treatment for active dental         also initiate sensations of local or referred paresthesia
caries or periodontal disease before the clinician would       and numbness. As the size of the neoplasm increases,
begin to search for alternative explanations. Concurrent       symptoms progress and usually become more localized.
cardiac pain and dental symptoms arising from decay,               Nasopharyngeal lesions even more frequently refer
apical pathology, or active periodontal infection are eas-     pain to the ear and TMJ region and can refer pain into
ily confused, and at times, the dentist must first attend to   the posterior of the maxilla and maxillary teeth. Hearing
the active dental disease before exploring other sources       changes are sometimes reported in cases of nasopharyn-
of pain. However, if the dental status is stable and it is     geal malignancy. As nasopharyngeal tumors advance, a
not possible to provoke the painful symptoms reported          number of cranial nerves can be compromised, depend-
by the patient using normally accepted means for chal-         ing on the site of the tumor, but frequently several nerves
lenging dental innervation (cold testing, percussion, elec-    are affected, since they emerge from the cranial base in
tric pulp testing, diagnostic anesthesia), it is prudent to    close approximation. Occasionally, the multiple involve-
begin early to rule out cardiac disease in those within the    ment of cranial nerves causes confusion in establishment
risk group for ischemic cardiac disease.                       of a diagnosis and symptoms are mistaken as signs of
    Many patients with referred ischemic pain already          hypochondriasis or somatization disorder. When symp-
have a history of heart disease. For those with undiag-        toms include referred sensory dysfunction or pain into
nosed ischemia, it is advisable to assess their risk factors   the face or jaws, patients may be mistaken as having TMJ
for cardiovascular disease to determine whether further        pain secondary to psychologic or behavioral problems.
cardiac assessment is appropriate. Important history           Jaw function can be compromised because of involve-
findings include family history, obesity, high-fat diet,       ment of motor innervation provided by several of the cra-
tobacco use, hypertension, alcoholism, age, and a              nial nerves. The neoplastically generated neurologic dys-
sedentary life style. If assessment of risk factors suggests   function can take the form of muscle weakness,
that the potential for cardiac disease with pain referral      contractions, or paralysis, depending on the nature of the
is present, use of nitroglycerin during symptom attacks        invasion and stage of disease. Taste can also be altered via
                                              REGIONAL AND REFERRED OROFACIAL PAIN                                   361

invasion of the tongue or tumor impact on the seventh           first symptom of lung cancer and other inflammatory or
and ninth cranial nerves, which provide taste to the pos-       destructive forms of lung disease. Treatment of the lung
terior one-third of the tongue. Facial weakness or paral-       lesion results in elimination of the referred facial pain.
ysis can also occur, causing a mistaken diagnosis of sim-       Patients presenting with a complaint of facial pain with-
ple Bell’s palsy. Sensory, motor, special sensory (taste,       out local pathology and a positive history of lung dis-
etc.), and autonomic functions can be disturbed or extin-       ease or tumor should be evaluated for recurrence.
guished along with localized pain or referral of pain into
the face and jaws. The consequences of errors in diagno-
sis of referred pain arising from nasopharyngeal tumors          Pain referred from intracranial lesions
can be devastating. Neoplastic disease symptoms as
described here can be confused with a number of chronic         Lesions of the central nervous system (CNS) located
oral pains, including temporomandibular disorders               within the cranial vault can produce generalized
(TMD), myofascial pain, burning mouth syndrome, glos-           headache and trigger more localized referred pain. The
sodynia, reflux, dysgeusia, sinusitis, and pulpal pathol-       types of problems generating these pains include tumors
ogy. Symptoms can also mimic cranial neuralgias, with           that are either benign or malignant; vascular lesions,
paroxysmal pain triggered by movement or swallowing.            such as aneurysms; demyelinating diseases, including
When arising from referred neoplastic peripheral lesions,       multiple sclerosis (MS); post-traumatic brain injury; and
symptoms are unilateral except in midbase-of-tongue             disorders of cranial fluid pressure (intracranial hyper-
lesions or other midline lesions, in which case symptoms        tension, hypotension, etc.). Generalized problems cause
can be bilateral but not necessarily identical. As with         diffuse bilateral pain that is most often characterized as
referred cardiac pain, it is always advisable to remember       “headache.” Isolated unilateral lesions can produce gen-
that many common findings in uninvolved patients (TMJ           eralized head pain if they increase pressure within the
clicking or crepitus, deviation in jaw opening, occlusal        cranium; pain may be unilateral or bilateral with pain
discrepancies, etc.) can cause the clinician to associate the   dominant on one side. The pain can be felt in the tem-
referred pain with findings that represent normal varia-        poral region, leading to an erroneous diagnosis of
tion. The ability to trigger pain with provocative chal-        myofascial pain. Localized lesions can also refer pain
lenging of suspected sites of pathology, such as the joint      along the distribution of the neural path affected. For
or muscles, and prevention or elimination of pain after         example, tumor or vascular pressure on the trigeminal
diagnostic anesthesia or topical application of ethyl chlo-     nerve may cause neuralgia-like (paroxysmal) or persis-
ride to the suspected muscle help to differentiate local jaw    tent pain far peripherally in the nerve and into the jaws
pathology from referred pain. Any time that pain is             and teeth. If neuralgia-like, the pain can be triggered by
accompanied with paresthesia, numbness, or other signs          light touch and stimulation that is not usually nocicep-
of neuropathy, it is important to consider malignant dis-       tive. Change of position (sitting, bending over, reclining)
ease as the referral mechanism. History findings that           can increase or decrease some intracranial sources of
increase concern for neoplastic symptom referral to the         referred facial pain. Diagnosis is often confused with
jaws include long-standing tobacco use, chronic alcohol         tension-type headache (TTHA), migraine, TMD,
consumption, prior head and neck radiation or                   myofascial pain, sinusitis, and trigeminal neuralgia.
chemotherapy for non-head and neck malignancy or for            Diagnosis is usually made through neurologic referral,
leukemia or lymphoma, and bone marrow transplant or             MRI of the brain, computed tomography (CT), and lum-
organ transplant. Studies have shown that use of chronic        bar puncture. Symptoms that cannot be fully explained
immunosuppressive therapy increases the risk for head           by local findings or that escalate in the face of rational
and neck malignancy at a later date. The only way to            treatment require assessment to rule out CNS pathology.
confirm or rule out the presence of tumor in these periph-
eral regions is to seek evaluation by an otolaryngologist
and to consider magnetic resonance imaging (MRI). Neu-           Pain referred from disorders of the
rologic consultation may also be appropriate.                    ears, nose, throat, and sinuses
                                                                The close proximity of the ears, nose, and throat struc-
 Pain referred from lung lesions                                tures to the face and jaws, along with shared innerva-
                                                                tion, sets the stage for possible confusion in diagnosis,
Lesions of the upper lobes of the lung have been                caused by referral of painful symptoms to the face. The
reported to refer pain to the face and jaws. The pain is        most common source of referred pain is disease of the
usually unilateral and diffuse in distribution. The refer-      sinuses. It is particularly easy to mistake sinus pain for
ral mechanism is most likely through input of the vagus,        odontogenic pathology when sinus involvement is uni-
which refers the pain to the face. Facial pain can be the       lateral, because inflammation in the region can cause
 362     CHAPTER 35

percussion and biting sensitivity in one or more teeth in      differential diagnosis of sinus versus dental infection is
the quadrant of the maxilla adjacent to the inflamed           the common occurrence of odontogenic infection
sinus and because neuronal sensitization of the second         spreading into the lining of the sinus causing reactive
division of the trigeminal nerve can trigger hypersensi-       swelling, owing to fluid retention, and overt infection of
tivity of dental innervation, leading to responses that        the sinus. The end result is infection in both areas with
mimic odontogenic pathology. In either of these situa-         little success if only one source of infection is treated.
tions the teeth and periodontium can be mildly to                   Allergic rhinitis can provoke headaches and migraine
exquisitely hypersensitive to touch, palpation, percus-        along with sinus stuffiness and congestion. When the
sion, and thermal stimulation. Symptoms can be                 pain is localized in the face rather than more cephalic, it
restricted to as few as two teeth, but usually more than       is easy for the treating doctor to assume that odonto-
one tooth is reactive. The molars and bicuspids are the        genic infection or sinus congestion is triggering the pain.
most frequently symptomatic in sinusitis. The two most
common errors in diagnosis are to label the problems as
arising from pulpitis or occlusal trauma. When sinus            Referred pain from ear and
disease is bilateral (allergic, infectious) symptoms can be     eustachian tube symptoms
referred bilaterally, and since bilateral odontogenic
pathology that is simultaneously painful is not a fre-         Disease of the external, middle, and inner ear can gen-
quent occurrence, a diagnosis of pulpitis is less often        erate symptoms in the face and jaws. Inflammation in
entertained, and more commonly, a diagnosis of                 the external ear canal caused by allergy or local factors
occlusal traumatism, bruxism, or myofascial pain is            (trauma, foreign objects, etc.), or infection can provoke
suggested. Findings that help to reduce the risk that          symptoms around the TMJ that are poorly localized
sinus disease will be incorrectly diagnosed as odonto-         and trigger modifications in jaw posturing (protrusive
genic include a history of episodic or recent sympto-          jaw thrusting) to reduce the symptoms during jaw
matic sinus disease, respiratory allergies, nasal dis-         movement and function, which in turn often initiates
charge, nasal obstruction, pain with extraoral palpation       the onset of secondary myalgia and muscle fatigue. The
of the maxillary and or frontal sinus, and palpation ten-      pseudo bite that results from the protrusive posturing
derness with intraoral and extraoral palpation over the        sometimes confuses the examiner, and an incorrect diag-
maxillary sinuses. Other findings that reduce the prob-        nosis of joint changes or myofascial pain secondary to
ability that odontogenic problems are generating the           occlusal factors is established. External canal inflamma-
pain include lack of obvious periapical infection or deep      tion can cause palpation tenderness over the joint, lead-
caries, prolonged pain with thermal stimulation of the         ing to an erroneous diagnosis of arthritic joint inflam-
teeth, and a significant elevation in facial pain when         mation. The most common infectious agents in adults
bending over. The diagnosis becomes more confusing             are bacteria and fungi, and their presence is usually eas-
however if nonsymptomatic dental disease is present            ily identified by visualization of inflammatory changes
(early caries, cracked restorations, signs of tooth wear,      in the external canal, and in more severe cases by exu-
etc.). Final diagnosis may require CT of the sinuses; ear,     dation from the ear. Fungal infections result in the
nose, and throat consultation; or therapeutic trial using      growth of fungal colonies along the wall of the external
an appropriate antibiotic, decongestant, and nasal             canal, producing a film that covers the wall. Usually
spray. Panoramic radiographs of the jaws and sinuses,          patients who present with these conditions have a prior
and dental radiographs of the teeth and alveolar struc-        history of external otitis. As the external canal becomes
tures can sometimes identify clouding of the sinus cav-        more inflamed, pain develops as the condyle generates
ity, but if both sinuses are involved it may be difficult to   tissue distortion along one surface of the canal.
distinguish the presence of sinus changes on dental                Middle ear disease can also refer pain anteriorly to
films, since both sides have the same appearance. When         the TMJ, masseter region, and posterior maxillary
sinus disease is suspected, CT of the region effectively       teeth. Pressure caused by fluid accumulation and
identifies thickening of the sinus mucosa and fluid lev-       inflammation behind the tympanic membrane causes
els in the sinus caused by sinusitis.                          pain to be localized to the ear (classic earache) and
     Sinus tumors can produce referred pain to the teeth       sometimes produces a generalized ache over the side of
and alveolar tissues. As the tumor invades, it may affect      the head and forward to the preauricular region. Diag-
regional innervation, and referred pain can be replaced        nosis is established through otoscopic examination of
by paresthesia or numbness. Also, the perception of pre-       the tympanic membrane. Middle ear infection can be
mature occlusal contact and a high occlusion can               unilateral or bilateral. In some cases a reduction in hear-
develop. If the lesion is expanding, it can destroy            ing acuity or balance can occur as the condition
osseous support or produce occlusal changes by causing         becomes chronic. The onset of facial pain accompanied
expansion of the alveolar structures. Complicating the         by a hearing deficit, vertigo, or a sensation of fullness
                                             REGIONAL AND REFERRED OROFACIAL PAIN                                  363

within the ear should automatically trigger an assess-        topical anesthetic rinses or gels swallowed. Usually
ment of the ears. Tumors of the middle ear provoke uni-       referred esophageal pain is low grade and persistent,
lateral symptoms that are progressive and eventually          with a rise in pain during swallowing. Another source
include hearing loss, vertigo, localized pain, referral of    of pain arising in the esophagus is glossopharyngeal
pain to the jaws and face, and facial nerve dysfunction       neuralgia with a local trigger in the upper aerodigestive
(loss of facial expression, drooping). When pain associ-      tract. Movement in the esophageal tissues or cutaneous
ated with tumors of the middle ear begins, it is often dif-   stimulation during swallowing triggers the neuralgia
fuse and often referred to the TMJ and midfacial region.      pain, which can be felt in the throat but more often is
Secondary myofascial pain often develops.                     referred higher into the back of the oropharyngeal
    Tinnitus is another symptom of ear disease that           region and to the base of the tongue or mandible. Top-
many clinicians confuse as arising from TMD. Although         ical anesthetic gel swallowed differentiates referred pain
studies report higher rates of tinnitus in patients with      arising from the esophagus. Pain from glossopharyngeal
TMD, most tinnitus occurs in patients without TMD,            neuralgia is usually significantly sharper and more
and both tinnitus and TMD have been associated with           severe than pain caused by local pathology in the esoph-
depression and high rates of somatic complaints. Since        agus. It is also of shorter durations and paroxysmal in
tinnitus can be caused by a number of serious condi-          nature. Referred esophageal pain is easily confused with
tions, all patients with tinnitus should be referred for      burning mouth syndrome, atypical facial pain, or
assessment of ear pathology and CNS and cardiovascu-          myofascial pain. Diagnosis is confirmed by blocking
lar function. Hypertension and vascular disease can           symptoms with topical or regional anesthesia and by
cause tinnitus and headache, so the combination of tin-       conducting a thorough medical workup that includes
nitus and headache certainly requires a thorough med-         endoscopy, soft-tissue MRI, and other forms of soft-
ical evaluation to rule out both local pathology and sys-     tissue imaging designed to detect lesions of the esopha-
temic dysfunction, such as hypertension.                      gus. The greatest risk from referred esophageal pain is
    Eustachian tube dysfunction, as occurs in allergy         malignant disease in the wall of the esophagus, which
and middle ear infections, can generate a sensation of        often is not detected until significantly advanced
fullness and plugging of the ears and discomfort in the       because symptoms are subtle and usually thought to be
ear, TMJ, and preauricular region. The reason for the         caused by reflux or chronic indigestion.
dysfunction must be determined, since it can arise from
reactions to allergins, tumors, or infections. Nasopha-
ryngeal carcinomas and other tumors can cause                  Referred pain from cervical myofascial
eustachian tube dysfunction and often cause altered            trigger points and degenerative disease
neurologic function in cranial nerves VIII, IX, and XI.
                                                              Perhaps one of the most common of all sites for referred
                                                              pain to the oral and facial complex is cervical disease
 Referred pain from the esophagus                             and dysfunction. Among chronic pain disorders, cervi-
                                                              cal problems are prevalent and persistent. Since several
Less is known about symptom referral to the face from         local disorders of the jaws (TMD, odontogenic infec-
pathology in the esophagus than that in the nasal and         tion, periodontal disease) are also prevalent, it is under-
ear region, but symptom referral does occur irregularly.      standable that clinicians sometimes confuse referred
In general, symptoms are provoked by neoplastic dis-          cervical symptoms with local dental pathology. Most
ease, esophagitis caused by reflux, and by esophageal         cervical pain that is referred to the face and jaws arises
muscle pain and myalgia generated by dysfunction in           from cervical myalgia and myofascial pain of the ante-
swallowing and by esophageal strictures. Lesions on the       rior and posterior strap muscles of the neck. Compres-
lateral wall of the esophagus can produce unilateral          sion of cervical nerves can cause cervical, shoulder, and
referral to the jaws and mouth, and lesions near the          arm pain. It is often accompanied by paresthesia of the
midline can produce bilateral symptoms. The usual             fingers. Under normal circumstances referred cervical
region of referral is the posterior aspect of the tongue      pain is located in the lateral aspect of the face, the max-
and ramus of the mandible. Symptoms can also be               illa and maxillary teeth, and the region of the TMJ. The
referred to the lateral aspect of the mandible up to the      eye and retro-orbital region are also common sites for
preauricular and auricular regions. Symptoms often            referred cervical pain and particularly from cervical
increase after sleeping in a reclining position. Symptoms     myofascial pain trigger points. Pain can arise from any
also increase with acidic and spicy foods or excessive        of the major cervical muscles, including the paraverte-
swallowing during eating or habitual activities. Symp-        bral muscles along the posterior aspect of the neck and
toms at the referred site are improved with trials of         the sternocleidomastoid, located along the lateral aspect
antacids, coating agents, antireflux medications, and         of the neck. Palpation of the affected muscle or muscle
 364     CHAPTER 35

trigger provokes local pain within the muscle and refers      females and is most common in young adult females and
pain to the distant site. Repeated stimulation of the         elderly women. It is characterized by significant pain aris-
muscle can provoke prolonged pain at the distant site,        ing from the carotid during palpation of the vessel. Refer-
and desensitization of the trigger by chilling with ice or    ral of pain to the mandible, lateral face, and preauricular
vapocoolant sprays (ethyl chloride or fluormethane) or        region occurs. The pathophysiology that triggers the pain
by anesthetic infiltration (2% lidocaine, without a vaso-     is also not well understood, but patients often respond to
constrictor, or other accepted injectable local anesthetic)   either indomethacin or amitriptyline. The mechanism of
into the muscle trigger extinguishes the referred pain.       action is not clear, and whether the condition undergoes
Headaches are also frequently caused by cervical muscle       spontaneous remission without treatment is not known.
dysfunction. Referral of pain to the teeth from cervical
muscles is common and can result in diagnostic confu-
sion. In many cases, neck movement does not specifi-           Pain referral from giant cell arteritis
cally trigger the referred pain but specific localized pal-
pation does, as does muscle fatigue. Triggers from            Giant cell arteritis (GCA), or temporal arteritis, affects
cervical muscles to the muscles of mastication or the         elderly patients and often refers pain into the jaws, face,
TMJ also occur. Referred neurologic symptoms are usu-         and eyes. It can mimic TMD and also creates headaches
ally of a sharper quality than referred muscle symptoms       that are characterized by muscle tension except that they
and are more likely to be triggered by turning the head       are often unilateral or predominantly one-sided. The
or flexing the neck. Turning the head can also provoke        facial pain of GCA is usually diffuse and mild at onset,
myofascial pain in the neck and trigger referral of pain      but over a number of months, symptoms progress and
to the face and structures of the jaws. The most com-         become more severe. Use of the jaw becomes more diffi-
monly accepted method for diagnosis of referred pain          cult, and jaw fatigue is common when the condition is
from the cervical region is to palpate the muscles of the     chronic. Visual acuity can be progressively affected as
neck and upper shoulder region (splenius capitis, sca-        giant cell lesions involve the optic vessels. Since the only
lene, sternocleidomastoid, trapezius) while observing         symptoms may be headaches, jaw fatigue, and jaw pain
for the development of pain at the site of complaint          it is easy to understand why treating physicians and den-
(maxillary teeth, face, TMJ, muscles of mastication).         tists can fail to detect giant cell arteritis early, but dis-
Flexing and extending the neck and lateral rotations can      covery is important, since the vascular lesions of GCA
be used to help detect referred nerve compression pain        can be progressive and lead to blindness. Additionally,
as seen in degenerative cervical pathology and pain aris-     involvement of the carotid can increase the risk of
ing from tense cervical muscles. Since muscle tension         stroke. Diagnosis is easily confirmed by detection of pain
and pain in the pericranial, masticatory, and cervical        during palpation of the carotid or temporal artery, refer-
muscles can occur in response to stress (anxiety, tension,    ral of pain to a distant facial or head site during palpa-
depression, etc.), it is common for patients with such        tion of the vessel, and by detection of an elevated ery-
disorders to have symptoms arising in several regions         throcyte sedimentation rate. Temporal artery biopsy is
(headaches, facial pain, neck pain) with cervical con-        often used to confirm the diagnosis, and treatment with
stituents triggering local and referred pain and              long-term systemic prednisone is the treatment of choice.
headache. Occasionally, progressive pathology of the
cervical spine causes progressively more severe pain at
the distant site. Since the lateral aspect of the neck and     Pain referred from thyroid disease
the area from the lower lateral border of the mandible
downward to the clavicle are innervated by cervical           Normally, hyperthyroid or hypothyroid disease does
nerves, it is possible for serious pathology associated       not cause localized pain in the neck or referred pain to
with the cervical nerves to trigger pain in the lower part    the face or dental structures. One exception that occa-
of the face and anterior of the neck immediately below        sionally occurs is pain that arises from Hashimoto thy-
the mandible, causing confusion and errors, including         roiditis, which is an autoimmune inflammatory disease
errors in attributing submandibular pain to salivary          of the thyroid gland. It can cause painful or tender
gland and lymph node disease.                                 enlargement of the thyroid, and in a small percentage of
                                                              cases, pain can be referred into the mandible or other
                                                              submandibular sites. Palpation of the thyroid can pro-
 Pain referral from carotidynia                               voke the same referred symptom. Thyroid function
                                                              studies should be ordered and thyroid scans completed
Carotidynia is an uncommon condition that is poorly           to determine the exact nature of the thyroid dysfunc-
understood. The epidemiology of the disorder is not well      tion. Subacute thyroiditis has also been reported to
documented, but it appears to occur predominantly in          cause referred pain to the face.
                                             REGIONAL AND REFERRED OROFACIAL PAIN                                    365

 Pain referred from salivary obstruction,                     behavior sometimes occurs, causing significant restric-
                                                              tions in mandibular movement, further increasing the
 infection, or neoplastic disease
                                                              likelihood of the pulpal condition being incorrectly diag-
Normally, pain arising in the major salivary glands is        nosed as muscular dysfunction and TMD.
localized to the region of the gland but not necessarily           Another common cause of referred odontogenic
localized enough to distinguish that the gland is painful,    pain is pericoronitis arising around erupting third
rather than adjacent structures. When salivary obstruc-       molars. The pattern of tissue pain and inflammation
tion, infection, or neoplasia is located in the parotid, it   frequently results in musculoskeletal tightness and mus-
can create symptoms around the gland that are diffuse         cular tension and trismus. Some of the symptoms are
enough to be confused with myofascial pain of the mas-        provoked by inflammatory changes that spread to
seters or even refer pain preauricularly to the area          include regional fascial and muscular tissues, but neu-
around the TMJ. Stimulation of the gland to function          rogenic sensitization also contributes to the pattern of
during the first phase of eating causes increased gland       pain and dysfunction that spreads through the affected
discomfort and a sensation that chewing is producing          site. Occasionally, pulpal or periapical infection or
pain in the muscles or joint. The presentation of pain        inflammation in the anterior of the maxilla results in
onset in the area of the muscle or joint with first jaw use   referred pain to the orbital region on the affected side.
usually results in an erroneous diagnosis of TMD. Per-             Odontogenic inflammatory pain, as occurs in pulpi-
sistent aching can occur if the lesion is caused by an        tis, can also trigger paroxysmal pain with light to mod-
infiltrating tumor, and palpation of the soft tissue over     erate cutaneous or thermal stimulation of the dentition.
the gland leads to a diagnosis of myofascial pain rather      The pain is usually felt in the tooth with pulpitis, but the
than parotitis or parotid pain. Any suspicion that pain       extent of pain or hypersensitivity felt in the tooth may
may be arising from parotid pathology requires that the       not be as great as in the site of referral. Generally,
gland be examined carefully, including assessment for         referred odontogenic pain is felt in sites in the maxilla
purulent discharge or lack of flow, as seen in obstruc-       or mandible on the same side as the pulpal pathology.
tion, and palpation of the gland for enlargement or a         With exquisite hypersensitivity in pulpitis, even very
mass. Malignant salivary gland tumors, in some cases,         light touch, mechanical stimulation, or thermal chal-
have a predisposition for following perineural channels       lenge can provoke pain that spreads and radiates
with resultant neurologic stimulation, pain, and pares-       throughout the entire side of the head. Pain of pulpitis
thesias. Lesions of the submandibular gland can also          or pulpal necrosis is sometimes referred to the muscles
trigger pain within the gland and pain referred into the      of mastication and particularly the masseter and tem-
tongue, laryngeal region, and the posterior of the            poralis muscles. It is provoked by the same factors that
mandible. The same types of lesions should be consid-         would be expected to worsen muscle pain, including
ered and appropriate diagnostic steps taken to rule out       chewing, cold air, tension, clenching and parafunction,
submandibular salivary gland pathology.                       and any thermal challenge to the face or dentition.
                                                                   Pain arising in the periodontium can also be referred
                                                              to adjacent structures, but in most circumstances, the
 Pain referred from dental structures                         pain is referred from the area of periodontal hypersen-
                                                              sitivity or inflammation to dentition in the same neuro-
 to other sites
                                                              logic distribution as the periodontal origin of the stimu-
It is not often thought that dental structures and the den-   lus. The referral pattern frequently results in a
tition commonly refer pain to adjacent or distant sites,      misdiagnosis of pulpitis or cracked tooth. The pattern
however, such patterns of pain referral do occur with         of referral is usually to a tooth more anterior in the
regularity and, when present, lead to delayed or incor-       arch. Diagnosis is best established by triggering symp-
rect diagnosis and treatment. Among the most common           toms after periodontal probing and stimulation of the
sources of referred odontogenic pain is pulpitis in the       peridontium followed by extinguishing the odontogenic
posterior dentition. Pulpitis can refer pain to the adja-     pain by application of topical anesthetic onto the perio-
cent muscles of mastication and particularly the masseter     dontal trigger or by careful infiltration of local anesthetic
and temporalis, creating the illusion of pain arising from    into the same area. These areas of periodontal hypersen-
myofascial pain. Odontogenic pain is also sometimes           sitivity are usually not in regions of advanced periodon-
referred into the maxilla and sinus region and into the       tal disease and are more likely to occur in tissues in which
preauricular zone near the TMJ. Diagnosis can become          pocket depth is less than 5 mm. The trigger is usually
difficult when the referred pain also stimulates muscle       along the lateral soft-tissue wall of the pocket. If the tis-
tension, which reduces mandibular range of movement,          sue is inflamed, the problem can sometimes be resolved
further mimicking TMD. As pulpitis pain progresses and        with aggressive local periodontal therapy. The triggers
becomes both more chronic and severe, adaptive motor          can also be extinguished, in some cases, with regular
 366     CHAPTER 35

application of local anesthetic several times a day, com-        Blume HG. Cervicogenic headaches: radiofrequency neurot-
bined use of a topical steroid cream and topical antibiotic           omy and the cervical disc and fusion. Clin Exp Rheumatol
therapy and systemic use of an antidepressant (amitripty-             2000;18(Suppl 19):S53–8.
line 30–60 mg/d). Occasionally, persistent periodontal           Chukwuemeka AO, John LC. An unusual cause of unilateral
triggers respond to sclerosing injections, when other ther-           face pain. Int J Clin Pract 1999;53:312.
apies have failed. Surgical excision of the triggers is not as   Clerico DM, Fieldman R. Referred headache of rhinogenic ori-
effective, and they often return.                                     gin in the absence of sinusitis. Headache 1994;34:226–9.
    Another oral soft-tissue problem that results in             Ellis BD, Kosmorsky GS. Referred ocular pain relieved by
referred pain is the development of hyperpathic scar tis-             suboccipital injection. Headache 1995;35:101–3.
sue in sites of surgery or traumatic mucosal injury. These       Ellrich J, Anderson OK, Messlinger K, Arendt-Nielsen L. Con-
triggers are different from the periodontal triggers just             vergence of meningeal and facial afferents onto trigeminal
discussed in that the periodontal triggers associated with            brainstem neurons: an electrophysiological study in rat
periodontalgia, once stimulated, provoke continuous                   and man. Pain 1999;82:229–37.
pain and aching. The triggers in surgical sites and scars        Falace DA, Reid K, Rayens MK. The influence of deep (odon-
generate sharper pain that is brief and only occurs dur-              togenic) pain intensity, quality, and duration on the inci-
ing direct stimulation of the trigger site. These triggers            dence and characteristics of referred orofacial pain. J Oro-
sometimes respond to excision and may represent small                 fac Pain 1996;10:232–9.
traumatic neuromas. They also may respond to topical             Goldberg HL. Chest cancer refers pain to the face and jaw: a
anesthetic protocols and topical steroids, but may not                case review. Cranio 1997;15:167–9.
remain quiet without systemic medications, such as car-          Kreiner M, Oekson JP. Toothache of cardiac origin. J Orofac
bamazepine or other antiseizure agents. Ruling out a                  Pain 1999;13:201–7.
peripheral neuropathy versus a soft-tissue trigger of a          McCarron MO, Gone I. Glossopharyngeal neuralgia referred
true neuralgia is important in such cases.                            from a pontine lesion. Cephalalgia 1999;19:115–7.
                                                                 Smith MJ, Myall RW. Subacute thyroiditis as a cause of facial
                                                                      pain. Oral Surg Oral Med Oral Pathol 1977;43:59–62.
 Suggested reading                                               Taub E, Argoff CE, Winterkorn JM, Milhorat TH. Resolution
                                                                      of chronic cluster headache after resection of a tentorial
Bansevicius D, Sjaastad O. Cervicogenic headache: the influ-          meningioma: case report. Neurosurgery 1995;37:319–21.
   ence of mental load on pain level and EM of shoulder-         Webb CJ, Makura ZG, McCormick MS. Glossopharyngeal
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Bindoff LA, Heseltine D. Unilateral facial pain in patients           Laryngol Otol 2000;114:70–2.
   with lung cancer: A referred pain via the vagus? Lancet       Yanagisawa K, Kveton JF. Referred otalgia. Am J Otolaryngol
   1998;1:812–5.                                                      1992;13:322–7.

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