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.
•Typical sources of primary otalgia are external otitis, otitis media, mastoiditis, and auricular infections.
•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.
•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.
•Irritation of these nerves, as well as irritation of distant branches of these nerves, can cause the perception of pain within the ear.
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 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.
Physical Examination
•The physical examination should include an exhaustive otologic, neuro-otologic, head, and neck examination.
•Nasal endoscopy, nasopharyngoscopy, and indirect laryngoscopy are mandatory.
•Palpation of the neck is important to look for thyroid disease,lymphadenopathy ,and musculo-skeletal disorders.
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.
•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 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.
•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.
•Neck problems can also refer pain to the ears. These disorders include cervical osteoarthritis, cervical myofascial pain syndrome, and traumatic injuries.
• The cervical spine is sensitive and well supplied by the cervical nerve roots. Muscular pain from the trapezius or sternocleidomastoid may project postauricular to the mastoid and occipital area.
•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 the stimulation of Arnold and Jacobson’s nerves.
•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 9 , 10 ,11 & 12 , mainly due to stretching on CN 12 .
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 other laboratory tests.•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 auto insufflation 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.
•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.
•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.
•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
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.