otalgia

Referred Otalgia: A Diagnostic Conundrum in an Aging Population

Sheldon P. Hersh, MD, FACS
Joshua N. Hersh, MD
Volume 55 - Issue 7 - July 2015

ABSTRACT: Referred otalgia relates to ear pain that originates from a site other than the ear. An appreciation of the sensory innervation of the ear enables the clinician to focus in on an array of possible sites of involvement that share neural pathways with the ear. Particular attention should be paid to cases of referred otalgia involving elderly individuals as ear pain in this age group may be the sole symptom of an otherwise silent neoplasm located in an area unrelated to or at significant distance from the ear. This article reviews how to identify cases of referred otalgia along with an overview of possible underlying pathologies.  

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Arthur Conan Doyle, noted physician and Sherlock Holmes creator, once remarked, “There is nothing more deceptive than an obvious fact.”1 Such is the case when patients present to their healthcare practitioners with complaints of otalgia, also known as ear pain. Pain arising from the ear is commonly identified as primary otalgia, whereas pain originating from any source other than the ear is classified as nonotogenic, secondary, or referred otalgia. Referred otalgia accounts for approximately 50% of ear pain in adult patients.2 

As the number of older adults steadily increases, healthcare providers should recognize that a wide spectrum of disease states common in the elderly may cause referred otalgia. Some conditions, such as a parotid mass or dental abscess, may be an obvious source of ear pain, while others, including coronary artery disease or gastroesophageal reflux disease (GERD), may be entirely unexpected.3-5 

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Perhaps most unsettling, however, is the distinct possibility of an otherwise asymptomatic malignancy, with no obvious relationship to the ear, presenting as otalgia. In fact, it may represent the only symptom of an occult neoplasm located within the head and neck or the upper aerodigestive tract.3 Adding to the diagnostic uncertainty in some cases of referred otalgia is the possible lack of correlation between the severity of ear pain and the gravity of the underlying pathology.3,4 Pain secondary to acute pharyngitis or associated with otitis externa (ie, swimmer’s ear), for instance, may prove to be significantly more severe than the referred pain caused by a distant malignant neoplasm.6 

Diagnosing Otalgia

Primary otalgia commonly results from an inflammatory, infectious, or neoplastic process involving the external or middle ear. It often presents with overt clinical manifestations that should result in a relatively prompt diagnosis. When no characteristic evidence of ear disease is present in spite of ongoing otalgia, referred otalgia should be foremost in the healthcare practitioner’s mind and the search to identify the source of the patient’s pain should begin in earnest. 

A comprehensive examination of the head and neck—including endoscopic visualization of the nasopharynx, base of tongue, larynx, and hypopharynx—is an essential next step.7 Consideration should also be given to the aerodigestive tract and thoracic structures, all of which share sensory innervation with the ear.7,8 In the event that the physical examination proves negative, a CT or MRI can identify a possible site of involvement.3,9 

At the outset, an appreciation of the sensory innervation of the various parts of the ear (Figure 1) is crucial in gaining a clear understanding of the multiplicity of sites that can give rise to referred otalgia. In 1964, Hora and Brown emphasized that the differential diagnosis of referred otalgia is, in fact, a differential diagnosis of the disease processes affecting structures that share common sensory pathways with the ear (Figure 2).10 Pinpointing the portion of the ear where pain appears to be located may prove helpful in identifying the origin of the underlying disease process.7 

 

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Origin of Pain

The ear represents a confluence of disparate sensory nerves, most of which function in an independent fashion but at times do so in concert with one another. Cranial nerves V, VII, IX, and X, along with upper cervical nerves C2 and C3, supply sensory innervation to disparate parts of the ear. However, sensory innervation may differ from patient to patient as a result of varying degrees of sensory overlap that could possibly influence any one patient’s clinical presentation (Figure 1).11 

The trigeminal nerve (CN V) innervates the anterior auricle, tragus, lateral surface of the tympanic membrane, and anterior portion of the external auditory canal principally via the auriculotemporal branch of the mandibular division. The facial nerve (CN VII) provides sensory innervation to the postauricular area, posterior auricle, and lateral surface of the external auditory canal via the posterior auricular nerve. Jacobson’s nerve, a branch of the glossopharyngeal nerve (CN IX), travels to the eustachian tube, middle ear, and inner surface of the tympanic membrane. Arnold’s nerve, a vagal derivative (CN X), provides innervation to the posterior-inferior region of the external ear canal, adjoining portion of the lateral tympanic membrane, and concha. The greater auricular and lesser occipital nerves, derived from upper cervical nerves C2 and C3, supply innervation to the postauricular region, including the skin overlying the mastoid and parotid gland. 

Locating the source of referred ear pain may prove particularly challenging in an elderly patient. The ear shares sensory pathways with 4 cranial nerves as well as branches from the second and third cervical roots. An awareness of these shared pathways in tandem with an appreciation of the numerous inflammatory, degenerative, and neoplastic disorders common to this age group increases the likelihood of a timely diagnosis. Potential disorders involving sites that result in referred otalgia include:

•Dental pathology. This disorder, via the auriculotemporal branch of the CN V, is the most common source of referred pain—constituting anywhere from approximately 50% to 74% of cases.8,12 Mandibular molars are the teeth most commonly involved.9 Caries, abscesses, and malocclusions secondary to lack of dentition and/or poorly fitting dentures constitute the majority of these cases.7 Furthermore, the presence of oral ulcers principally in the posterior third of the tongue, tonsillar region, and pharynx can also result in otalgia.7 

•Temporomandibular joint dysfunction (TMJ). TMJ dysfunction may be a result of spasms of the muscles of mastication or intrinsic joint disease (eg, arthritis or osteoarthrosis).4 Otalgia occurs in over 70% of patients with TMJ,3 with pain being particularly severe while eating or during passive movements of the mandible.2 Muscle spasms typically include the temporalis, masseter, and internal and external pterygoids. Factors commonly associated with TMJ dysfunction include bruxism, clenching of teeth, stress, dental malocclusion, and history of maxillofacial trauma.4 Ear symptoms other than pain can include dizziness, tinnitus, aural fullness, and perceived loss of hearing.

•Trauma and degenerative diseases of the cervical spine. Trauma and degenerative diseases of the cervical spine are commonly encountered amongst the elderly. Degenerative processes—including osteoarthritis, disc herniation, spondylosis, stenosis, and cervical facet syndrome in addition to whiplash injuries and cervical meningiomas—may all result in referred otalgia.8 Upper cervical spine involvement is more common in this age group and is influenced by the presence of degenerative osseous changes and issues related to bone density.13 

•Head and neck neoplasms. A neoplasm of the head and neck must be seriously entertained in light of the significant incidence of referred pain caused by malignancies of the upper aerodigestive tract. Malignancies of the nasopharynx, hypopharynx, oropharynx, larynx, tongue, parotid gland, infratemporal fossa, and base of the skull have all been implicated. Careful attention should be paid to those patients with known risk factors that include advanced age, smoking, alcohol abuse, history of head and neck or lung malignancy, and previous radiation exposure, such as the case study presented. In a similar vein, any concurrent reports of dysphagia, dysphonia, odynophagia, or weight loss should signal the possibility of an underlying malignancy.4,7,11

•Myofascial pain syndromes. Myofascial pain syndromes have been identified as a potential source of referred pain to the ear. Trigger points, colloquially referred to as knots, are defined as small, firm, hyperreactive nodules that may form within the skeletal muscles of the head and neck. Degenerative disease of the upper cervical spine is often present. Both the onset and intensity of pain are often not constant, as they typically wax and wane in an unpredictable fashion. Digital palpation of the muscle in question has been found to be the most straightforward technique by which to identify a trigger point.4,14 

•Neuralgias. Neuralgias, which typically lack other neurologic deficits, may result in marked ear pain by way of the trigeminal, glossopharyngeal, or facial nerves. Unilateral ear pain, which is often brief, intermittent, and lancing in nature, is set off by triggers that include touch, mastication, swallowing, cold, or pressure applied to the ear. At times, because of overlapping sensory innervation, it may prove difficult to isolate the offending nerve.7,9,15 

•Shingles. Reactivation of varicella-zoster virus resulting in herpes zoster (ie, shingles) presents as a painful vesicular rash that is typically confined to 1 or more dermatomes. The face is the second most common area of involvement, and reactivation may have an impact on any of the regional cranial nerve ganglia.2,16 Involvement of the geniculate ganglion (CN VII) may result in Ramsay Hunt syndrome, a condition that gives rise to a vesicular eruption about the ear, facial paralysis, and a number of other otologic presentations that include hearing loss and vertigo.7 Vesicles commonly appear within the external auditory canal, on the tympanic membrane surface, or about the auricle. Although the painful rash is often pathognomonic of the condition, cases do occur in which no rash is evident. Zoster sine herpete (ie, pain without rash) clearly adds an element of confusion and delay to what should be a relatively straightforward clinical diagnosis.16 

•GERD. Ear pain may result from GERD by way of stimulating the glossopharyngeal and vagus nerves. Reports of sore throat, dysphonia, cough, foreign body sensation in the throat, or dysphagia in conjunction with otalgia should immediately draw the healthcare practitioner’s attention to the possibility of GERD.7 Of note, gastroesophageal refluxate may encroach upon eustachian tube orifices, resulting in tubal dysfunction and eventual serous otitis media, which can result in ear discomfort.2 

In the event of a comprehensive assessment failing to identify any site of involvement, healthcare practitioners would perhaps be better served by initially staying clear of a diagnosis of functional otalgia.10 Neilan and Roland found that practitioners should remain wary even when no definitive pathology is located and recommended that an all-inclusive physical examination as well as imaging studies be repeated at appropriately planned intervals.4 

To understand and appreciate referred otalgia is to understand and appreciate the innervation of all structures that share neural pathways with the ear. The diagnosis of referred otalgia in an aged patient demands that a careful examination of the head and neck and upper aerodigestive tract be performed. Those individuals with a history of smoking, alcohol abuse, or radiation should raise the specter of an underlying malignancy at any of the sites that share innervation with the ear. As in the case study, imaging studies may prove decisive in identifying pathology that remains otherwise silent.  

Sheldon P. Hersh, MD, is in private practice in Queens, NY, and is affiliated with the department of otolaryngology/head and neck surgery at North Shore-LIJ, Lenox Hill Hospital, in New York, NY.

Joshua N. Hersh, MD, works at Princeton & Rutgers Neurology in Somerset, NJ.

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