April 12, 2010

Tough Call — Differentiating a Diagnosis Between Temporomandibular Joint Disorder and Sinusitis
By Janet L. Rogers, PhD, and Julie K. Freeman, MSPT
For The Record
Vol. 22 No. 7 P. 24

Forty million people suffer from temporomandibular joint disorder (TMD). An umbrella term, TMD is often used to refer to acute or chronic inflammatory conditions of the temporomandibular joint (TMJ), which connects the mandible to the skull. The inflammation involved with TMD frequently results in pain in the TMJ. Another disorder commonly associated with facial pain is sinusitis. Though different in etiology and treatment, the symptoms are similar, creating difficulty in differentiating diagnoses. Misdiagnosis not only results in persistent patient discomfort but also exposure to various costly treatments that often yield no significant results.

Anatomy Review
The TMJ is located in the glenoid fossa and articular eminence of the temporal bone above and the mandibular condyle below with an interposed articular disc. A fibrous capsule in the form of an inverted pyramid surrounds the joint. The joint is divided into two sections: a lower superior and inferior joint space. The disc is attached to the joint capsule anteriorly and to the tendon of the lateral pterygoid muscle.

TMJ movement is controlled by a complex balance of many muscles that allow the mouth to open and close when performing activities such as talking, chewing, singing, and yawning. One muscle responsible for opening the mouth is the digastric muscle, which acts to pull the jaw inferiorly and posteriorly. In addition to opening the mouth, the lateral pterygoid muscle functions to allow the mandible to glide forward. The temporalis muscle is divided into anterior and posterior portions. The anterior portion elevates the mandible, and the posterior portion retracts the mandible. The middle portion handles both elevation and retraction. The masseter muscle produces a powerful force to elevate the mandible while the medial pterygoid muscle forms the facial sling with the masseter muscle. These muscles combined are responsible for closing the mouth.1

In close proximity to the TMJ are the various sinuses. These consist of air-filled bony cavities located in the face and skull adjacent to the nose. There are eight paranasal sinuses that occur as paired structures. The frontal sinuses are situated beneath the bone of the forehead and just in front of the bone overlying the brain. The ethmoid sinuses are located between the eyes just behind the bridge of the nose. Each ethmoid is comprised of seven to 10 smaller chambers that collectively make up the sinus. Deep within the skull behind the ethmoid sinuses are the sphenoid sinuses, small cavities approximately the size of a large grape. The right and left sphenoid sit next to each other and are separated by a thin septum. The maxillary sinuses are two air-filled cavities within the maxilla, the bone that forms the cheek and upper jaw. They are located above the teeth, below the eye, and just to the side of the nose.2

TMD Symptoms
Signs and symptoms associated with TMD can be complex and vary in their presentation. The symptoms will involve more than one of the numerous TMJ components: muscles, tendons, ligaments, bones, connective tissue, and teeth. Patients typically report experiencing any of the following symptoms either alone or in some combination: chronic headaches, earaches, teeth clenching or grinding, clicking or popping of the jaw, shoulder pain and stiffness, tooth pain with no apparent cause, jaws that “lock” in an open or closed position, jaw soreness in the morning, difficulty swallowing, dizziness, poor coordination, fatigue, and numbness in the arms.

Two major observations involving muscles are dysfunction and pain. The dysfunction can present a limitation in the TMJ’s ability to move and can be minor or severe. With milder cases, a patient may experience only a clicking or popping in the jaw. Referred pain from muscles is the source of much diagnosing confusion because it mimics maxillary sinus pain, resulting in many patients being treated unsuccessfully with antibiotics and decongestants.

Face and neck pain may also be symptoms. In addition to tenderness with palpation to the facial muscles and the TMJ itself, pain may radiate to the neck or shoulders. Ligaments may be overstretched and muscle spasms are common and then become part of a cycle that can eventually lead to tissue damage, pain, and muscle tenderness. If the cycle is not broken, symptoms will persist or worsen.3

Etiology
Presently accepted etiologies of TMD are trauma, stress, hormonal imbalance, and malocclusion. Frequently, spasms are a result of trauma to the joint such as a motor vehicle accident, a home or occupational injury, or physical assault. Trauma may be subdivided into microtrauma and macrotrauma. Macrotrauma results from a single major injury from an outside source such as a blow to the jaw or other direct impact. Microtrauma results from prolonged exposure to repetitive mild trauma such as grinding or clenching one’s teeth.

Additional causes of TMD include degenerative conditions such as arthritis. Like any other joint in the body, the TMJ is susceptible to arthritic changes. Osteoarthritis, degenerative joint disease, and rheumatoid arthritis can result in destruction to the joint. Pain generally arises from within the joint itself in front of the ear, but it may be referred elsewhere in the skull, face, or jaw, making an accurate diagnosis difficult.

Teeth disorders may also cause TMD. Movement of the teeth can affect how they come in contact when the mouth is closed and the overall relationship among the teeth, muscles, and joints. If a patient has problems with teeth grinding or clenching, pressure can often be relieved by a mouth guard at night. The patient can be taught the lips-together, teeth-apart position for waking hours.

Many nerves (sensory, motor, and mixed) are in the TMJ region. The most common pain of neurogenic origin around the TMJ is from the nerves in the joint capsule. This is frequently seen in the inflammatory stage of osteoarthritis, rheumatoid arthritis, gouty arthritis, psoriatic arthritis, collagen diseases, and traumatic injury to the TMJ.

Another source of TMJ pain may be vascular in origin. This pain is often reported as throbbing and pulsing such as in a migraine headache. A classic migraine can be differentiated from muscle contraction headaches and TMJ by checking a series of symptoms called the prodroma. The prodroma variations seen in vascular pain consists of the photophobia with varying degrees of sensitivity to light, nausea and occasional vomiting, the person not wanting to move his or her head or body, and scotoma with the patient experiencing dark spots or dark areas in the visual field.

A second vascular disorder commonly confused with TMJ is temporal arteritis, which presents as a sharp, diffuse pain in front of the tragus of the ear and can refer pain into the temple. A laboratory test, erythrocyte sedimentation rate, and blood vessel biopsy can confirm the diagnosis.

Ototis externa or fungus of the ear is an infection of the external ear skin. The pain is often generalized in such a way that the TMJ is frequently believed to be the cause. A visual examination will reveal an inflamed ear canal with occasional temporary hearing loss. The patient will also give a painful response when the ear is folded forward or down.3

Upper respiratory infection (URI) is a common disease and its impact on joint complications has been established. TMJ symptoms are found to be strongly associated with the experience of infection or the current infectious state. Septic arthritis is one such complication and the infection route is known as a hematogenous spread. Research has revealed that bacteria can be detected with high incidence in the human TMJ. The displaced disc in TMJ has shown high detection rates of Staphylococcus aureus, one of the pathogens in a URI.4

Sinusitis is a bacterial invasion of the sinus cavities’ mucous membrane lining. In maxillary sinusitis, the mucous membranes in the base of the sinus cavities become inflamed, leading the patient to experience pain in the TMJ and the maxillary teeth (most often the maxillary molars).3 Pharyngitis/sinusitis is a good candidate as a bacterial supply depot for the TMJ because its anatomical proximity makes it easy for the direct spread of bacteria. Additionally, high vascularity in the area makes it a good condition for hematogenous spread. Maxillary sinusitis/rhinitis and tonsillitis/pharyngitis are common infectious diseases in the head and neck area.

Differential Diagnosis
To differentiate TMD from sinusitis, one should understand the basic signs and symptoms common to each disorder. Signs and symptoms of sinusitis may be divided into two categories: very important and less important.

Very important symptoms include facial pain and pressure, facial congestion or fullness, nasal obstruction, thick and discolored discharge, and a change in taste or smell. Less important symptoms include headache, fatigue, bad breath, fever, tooth pain, a cough, and ear pressure.

To diagnose sinusitis, an individual must exhibit two of the very important symptoms or one very important symptom and two of the less important symptoms.5 In contrast, patients with TMD usually present with one or more of the following signs and symptoms (The absence of any of the following symptoms should indicate that some disorder other than TMD could be causing the pain.): pain on palpation of the TMJ, pain in the TMJ with or without movement of the mandible, joint sounds (clicking, popping, crepitating noise) with movement of the mandible, a restricted ability to open the mouth up to 40 mm or lateral deflection of the mandible on opening, or a restricted ability to move the mandible laterally in either direction.3

If the above signs and symptoms are absent, sinusitis should be suspected. Because sinusitis is a bacterial invasion of the mucous membrane lining of the nasal accessory sinuses, a gentle tapping over the involved sinus will produce pain. In maxillary sinusitis, the mucous membranes in the floor of the sinuses become inflamed and the patient experiences a generalized pain in the region of the TMJ and the maxillary teeth, usually the maxillary molars.

Summary
The TMJ is not the sole structure capable of causing facial pain. Facial pain syndromes may be the result of a single disorder or a combination of several factors. All present with similar signs and symptoms when in reality they may be separate, simple, treatable entities that will challenge the diagnostic skills of healthcare professionals. Due to the overlap of symptoms and diagnostic complexity, patients are often misdiagnosed and subjected to multiple, costly treatments. These may include numerous endodontic procedures and splints, nondiagnostic skull and sinus x-rays, and the prescribing of tranquilizers, antidepressants, and narcotics. To make a correct diagnosis, it is imperative to have a thorough understanding of the anatomy and physiology of the structures that surround and support the TMJ. The ability to recognize and understand physiological and anatomical deviations helps clarify the cause and mechanism of pain production and will indicate the correct treatment.

— Janet L. Rogers, PhD, is an associate professor in the School of Allied Health at Southern Illinois University.

— Julie K. Freeman, MSPT, is an assistant professor in the School of Allied Health at Southern Illinois University.

References
1. Levangie PK, Norkin CC. Joint Structure & Function: A Comprehensive Analysis. 4th ed. Philadelphia: F. A. Davis; 2005.

2. Ghorayeb BY. Anatomy of the sinuses. Available at: http://www.ghorayeb.com/anatomysinuses.html. Accessed March 15, 2010.

3. Tanaka TT. Facial pain disorders commonly confused with TMJ dysfunction. CDA. 1985;13(3):56-61.

4. Jeon YD, Lee JI, Cho BO, et al. Statistical correlation between pharyngitis and temporomandibular joint disease. Oral Surg Oral Med Oral Pathol Oral Radiol Endol. 2005;99(6): 677-681.

5. Levine H. Sinusitis diagnosis. Available at: http://www.american-rhinologic.org/patientinfo.diagnosis.phtml. Accessed February 15, 2010.