Otalgia

1. OTALGIA Otalgia is defined as ear pain. Two separate and distinct types of otalgia exist. Pain that originates within the ear is primary otalgia ; pain that originates outside the ear is referred otalgia .

2. Typical sources of primary otalgia are  external otitis ,  otitis media ,  mastoiditis , and auricular infections . Most physicians are well trained in the diagnosis of these conditions. When an ear is draining and accompanied by  tympanic membrane perforation , simply looking in the ear and noting the pathology can make the diagnosis. When the tympanic membrane appears normal, however, the diagnosis becomes more difficult.

3. Reports document that not all otalgia originates from the ear. Many remote anatomic sites share dual innervation with the ear, and noxious stimuli to these areas may be perceived as otogenic pain. By definition, referred otalgia is the sensation of ear pain originating from a source outside the ear. To better understand referred otalgia , the physician first must understand the anatomic distribution of nerves associated with the ear. Irritation of these nerves, as well as irritation of distant branches of these nerves, can cause the perception of pain within the ear.

4. PATHOPHYSIOLOGY The sensory innervation of the ear is served by the auriculotemporal branch of the fifth cranial nerve (CN V), the first and second cervical nerves, the Jacobson branch of the glossopharyngeal nerve, the Arnold branch of the vagus nerve, and the Ramsey Hunt branch of the facial nerve. Neuroanatomically , the sensation of otalgia is thought to center in the spinal tract nucleus of CN V. Not surprisingly, fibers from CNs V, VII, VIV, and X and cervical nerves 1, 2, and 3 have been found to enter this spinal tract nucleus caudally near the medulla. Hence, noxious stimulation of any branch of the aforementioned nerves may be interpreted as otalgia .

5. PHYSICAL EXAMINATION The physical examination should include an exhaustive otologic , neuro-otologic , head, and neck examination. Careful rhinoscopy , nasopharyngoscopy , and indirect laryngoscopy are mandatory. Palpation of the neck is important to look for thyroid disease, adenopathy , and musculoskeletal disorders.

6. CAUSES Dental disorders are the most common cause of referred pain to the ear. Of this group of disorders, temporomandibular dysfunctions account for most patients. [1] Bruxism, degenerative joint disease, or stress can lead to internal derangements within the joint. The third division of the trigeminal nerve and the auriculotemporal nerve mediate pain, which is often perceived deep within the ear. Other odontogenic causes range from abscessed teeth to poorly fitting dentures. Within the oral cavity, the sensory innervation becomes quite complex. The tongue receives fibers from the glossopharyngeal nerve, the facial nerve receives fibers from the chorda tympani, and the trigeminal nerve receives fibers from the lingual branch and vagus nerve posteriorly. All these nerves have distributions in the ear  as well.

7. Sinusitis  is another very common source of ear pain. The neural pathway is along the second branch of the trigeminal nerve and the auriculotemporal nerve. Because the trigeminal nerve supplies the nasal cavity, patients with inflammatory mucosal contact points and nasal obstruction may develop symptoms in their ears. The proximity of the eustachian tube orifice also contributes to the problem.

8. Neck problems can also refer pain to the ears. These disorders include cervical osteoarthritis, cervical myofascial pain syndrome, and traumatic injuries. [2, 3]  The cervical spine is sensitive and well supplied by the cervical nerve roots. Muscular pain from the trapezius or sternocleidomastoid may project postauricularly to the mastoid and occipital area.

9. Sensory branches of the vagus and glossopharyngeal nerves supply upper aerodigestive tract mucosal areas such as the nasopharynx , oropharynx, hypopharynx , and larynx. The vagus continues caudally and supplies sensory enervation to the bronchus, esophagus, and heart as well. Irritative lesions at any of these sites may mimic stimulation of Arnold and Jacobson nerves.

10. Tonsillitis  and  pharyngitis  are very common causes of earaches in children. Less commonly, laryngitis,  laryngeal tumors ,  esophagitis , and even  angina pectoris may manifest as otalgia . Eagle syndrome, in which the elongated styloid process irritates branches of CN VIV and CN IX, is even rarer. This crossing of signals works both ways; thus, stimulation of the ear canal may be felt as a tickle in the throat or may produce the cough reflex.

11. Sometimes, pain may be from irritation of the nerves themselves without an inciting source. These disorders are termed  neuralgias . Neuralgias are typified by lancinating pain in the distribution of the involved nerve. Otologic symptoms of trigeminal neuralgia are referred along its auriculotemporal branch. Geniculate neuralgia is rare but can be observed in Ramsey Hunt syndrome. This neuralgia involves the irritation of facial nerve sensory fibers, which corresponds to the pain sensation felt within the auricle. Sphenopalatine and vidian neuralgias cause similar aural pain via crossing fibers of the greater superficial petrosal nerves and the facial nerves. Glossopharyngeal neuralgia, which causes a phantom tonsillar pain, may also cause otalgia by simulating excitation of the Jacobson nerve.

12. A number of otologic conditions can produce ear discomfort without altering the external appearance of the auditory canal and tympanic membrane.  Ménière disease  is associated with a sensation of aural fullness, in addition to  vertigo , tinnitus , and fluctuating hearing loss. Tumors of the  temporal bone , such as meningiomas ,  glomus jugulare , and cerebellopontine angle lesions, have been associated with otalgia , possibly by nerve root compression.  Bell palsy  is often associated (as many as 60% of cases) with otogenic pain thought to emanate from the sensory fibers of the facial nerve.

13. Eustachian tube dysfunction  causing an intermittent inability to equalize middle ear pressures may manifest with such minimal tympanic membrane bulging or retraction that even otomicroscopy does not detect an abnormality. The problem may be as simple as a sensitive ear canal that requires protection from cold winds along with reassurance that nothing is actually wrong.

14. D/D Acute Laryngitis Adenoidectomy Allergic Fungal Sinusitis Allergic Rhinitis Barosinusitis Bell Palsy Chronic Laryngitis, Infectious or Allergic Complications of Otitis Media Contact Granulomas Deep Neck Infections Eustachian Tube Function External Ear, Benign Tumors External Ear, Infections External Ear, Inflammatory Diseases External Ear, Malignant External Otitis

15. Fractures, Mandibular, Alveolar Fractures, Maxillary, Zygomatic Malignant Nasopharyngeal Tumors Malignant Tumors of the Base of Tongue Malignant Tumors of the Floor of the Mouth Malignant Tumors of the Nasal Cavity Malignant Tumors of the Sinuses Malignant Tumors of the Temporal Bone Malignant Tumors of the Tonsil Middle Ear, Acute Otitis Media, Medical Treatment Middle Ear, Acute Otitis Media, Surgical Treatment Middle Ear, Eustachian Tube, Inflammation/Infection Middle Ear, Mastoiditis Middle Ear, Otitis Media with Effusion Neck Cancer, Unknown Primary Site Neck, Cervical Metastases, Detection Neck, Cervical Metastases, Surgery

16. Parapharyngeal Space Tumors Parotitis Sinusitis, Acute, Medical Treatment Sinusitis, Chronic, Medical Treatment Sinusitis, Maxillary, Acute, Surgical Treatment Sinusitis, Maxillary, Chronic, Surgical Treatment Sinusitis, Sphenoid, Acute, Surgical Treatment Skull Base, Petrous Apex, Infection Skull Base, Petrous Apex, Tumors Temporal Bone Fractures Thyroid Cancer Tonsillectomy Tonsillitis and Peritonsillar Abscess

17. WORKUP Frequently, the workup suggests that otalgia may be a problem of dental origin. A complete blood cell count may indicate an occult infection. Thyroid function and erythrocyte sedimentation rate (ESR) studies may reveal thyroiditis and temporal arteritis. Chest radiography to seek bronchogenic pathology may be necessary. The perception of aural fullness may be described as ear pain and is observed in conditions associated with endolymphatic hydrops and eustachian tube dysfunction. Ménière disease can be diagnosed by history, audiometrics , and a battery of laboratory tests.

18. In the absence of obvious fluid within the middle ear, aural fullness secondary to eustachian tube dysfunction may manifest with a practically imperceptible bulging or retraction of the tympanic membrane. If autoinsufflation is not effective in relieving this pressure, consider a diagnostic myringotomy. Despite the full battery of testing, a group of patients always remains for whom an etiology is not evident. If not contraindicated, a brief course of nonsteroidal anti-inflammatory agents (NSAIDs) may be helpful.

19. IMAGING STUDIES Dental radiography CT scanning: Obtain CT scans of the head or temporal bone, sinuses, and/or neck when no obvious source of the pain can be found. The scan usually includes a brief survey of the sinuses and intracranial contents. CT scanning can reveal significant information about the temporomandibular joint or can be used to diagnose intratemporal lesions. MRI: If indicated by clinical or audiometric suspicion, an MRI may be necessary to define a cerebellopontine angle or other intracranial tumor.

20. Panorex imagery: Panorex imagery is quite useful in diagnosing temporomandibular joint dysfunction, odontogenic pathology, and styloid abnormalities. The high prevalence of dental-related otalgia in the authors' study group underscores the need for an alliance with a person well trained in temporomandibular joint–related disorders. Referral to a competent dentist or oral surgeon may be indicated. PET scanning: As this emerging modality for identifying malignant tumors becomes more readily available, it may be possible to diagnose cancer earlier. PET images fused with CT or MRI adds tremendously detailed information about the location of head and neck neoplasms.

21. OTHER TESTS Audiography Vestibulocochlear testing Nasal endoscopy Upper aerodigestive tract endoscopy, laryngoscopy Blood tests - CBC count, WBC count (to look for infection), sickle cell anemia, thyroid function studies and antibodies for thyroiditis

22. T/t & Management Identification of a causative etiology is often necessary to successfully treat referred otalgia . Once determined, most causes of referred otalgia can be readily treated. Use antibiotics in treating various types of infections ( eg , tonsillitis, pharyngitis, sinusitis). Use antivirals if the causative agent is suspected to be viral such as in cases associated with herpes zoster or shingles. Antifungals are indicated if the source is caused by a fungus ( eg , oral thrush/candidiasis). Antiulcer/antacid medications can be used for esophagitis and gastroesophageal reflux disease. Use NSAIDs when myalgias and neuralgias are suspected. Re-examine the patient after a 2-week trial of NSAIDs. Strong narcotic analgesics are not indicated and should not be used to treat referred otalgia . Narcotics may mask symptoms, making the correct diagnosis difficult to reach.

23. Perform a detailed search for the underlying diagnosis before initiating treatment. Starting analgesics before reaching a diagnosis increases the difficulty of determining the cause and may possibly obscure a life-threatening condition such as an occult cancer. Any of the previously mentioned treatments can be implemented when the exact cause of referred otalgia is suspected. If the problem persists after a 2- to 3-week trial, a more advanced algorithm is indicated.

24. History should include the following: Otologic history - Tinnitus, hearing, vertigo Sinuses Pulmonary history Cardiac history Dental history - Mastication GI history - Dysphagia, esophagitis, reflux Neurologic history - Neuralgias Musculoskeletal history - Arthritis Cervicofacial history Myalgias Trauma - Cervical spine (C-spine) Infections - Tonsillitis, pharyngitis

25. Physical examination should include the following : Nasopharyngoscopy Laryngoscopy

26. Preliminary testing (appropriate to symptoms) should include the following : Audio Barium swallow ECG C-spine radiography Chest radiography Panorex imaging

27. Treat the underlying problem appropriately with trial medications ( eg , antibiotics, NSAIDs) and 2-week follow-up or with appropriate consultation ( eg , dentist, gastroenterologist, neurologist, rheumatologist, neurosurgeon). If the findings on history, physical examination, and testing are inconclusive, consider local anesthesia to block the source of pain as follows:

28. Nasal cavity pathology: Spray may localize the problem to the sinus or sphenopalatine oral cavity; consider specific nerve blocks. Larynx: Use gargle or transtracheal 4% lidocaine . Ear canal: Use topical agent for sensitive ear canal; consider injection for chorda tympani. Muscular trigger points: Lidocaine injection can be useful in diagnosis.

29. If history and physical examination findings are inconclusive, perform other diagnostic procedures if suspicion still exists for the following conditions : Upper respiratory tract tumor - Panendoscopy, chest radiography, CT scanning, or MRI as needed Sinus disease - Sinus CT scanning Intracranial/ intratemporal disease - Audiometric battery and CT scanning or MRI as needed Autoimmune disease - ESR, thyroid function studies (thyroiditis, temporal arteritis) Endolymphatic hydrops - ESR, thyroid function test (TFT), fluorescent treponemal antibody absorption (FTA-Abs) test, fasting glucose, lipid profile Eustachian tube dysfunction - Autoinsufflation (consider myringotomy) Psychiatric disorder - Consider psychiatric consultation.

30. MEDICATION Use antibiotics in treating various types of infections ( eg , tonsillitis, pharyngitis, sinusitis). Use antivirals if the causative agent is suspected to be viral such as in cases associated with herpes zoster or shingles. Antifungals are indicated if the source is caused by a fungus ( eg , oral thrush/candidiasis). Antiulcer/antacid medications can be used for esophagitis or gastroesophageal reflux disease. Use NSAIDs when myalgias and neuralgias are suspected. Reexamine the patient after a 2-week trial of NSAIDs.

31. Perform a detailed search for the underlying diagnosis before initiating treatment. Starting analgesics before reaching a diagnosis increases the difficulty of determining the cause and may possibly obscure a life-threatening condition such as an occult cancer. Any of the previously mentioned treatments can be implemented when the exact cause of referred otalgia is suspected. If the problem persists after a 2- to 3-week trial, a more advanced algorithm is indicated.

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