The Ear

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Chapter 5 The Ear

“People need to have things trumpeted into their ears several times and from all directions—the first sound pricks up the ear, the second shakes it, and with the third it goes in.”

René Théophile Hyacinthe Laennec, 1821; letter to his cousin Menadec

“The ears should be kept perfectly clean; but it must never be done in company. It should never be done with a pin, and still less with the fingers but always with an ear-picker.”

St. John Baptiste de la Salle (1651–1719), The Rules of Christian Manners and Civility, I

Generalities

The ear is an important site for physical examination; abnormalities may reflect either local or systemic disease. It also is an important sensory organ, whose function can be assessed (albeit in a rudimentary manner) with basic bedside tools.

1 What are the components of the ear?

External ear (comprising the auricle and the external auditory canal)

Middle ear

Inner ear

Nervous supply

A. External Ear

2 What is the external auditory canal?

It is a 1-cm–long conduit, opening outside through the auricle and delimited inside by the eardrum. It is made by bone in its inner two thirds and cartilage in its outer third. The latter is also rich in sebaceous glands, ceruminous glands (responsible for the production of wax, or “cerumen”), and hair follicles.

3 What is “wax” made of?

Of a combination of desquamated keratin, debris, and secretions by ceruminous glands (which, in turn, are responsible for the wax color). Usually soft and brownish, wax can also become abundant and inspissated.

4 What is the best way to remove cerumen?

There are various schools of thought. The first relies on a number of proprietary substances, all purportedly able to soften the wax when instilled as a solution into the external canal. Another method relies instead on removing the cerumen mechanically, bit by bit through a metal loop. Its effectiveness depends in great part on the examiner. Our favorite method is to flush the canal with warm tap water using a syringe with a 14- to 16-gauge plastic IV catheter. Remember that wax removal is not easy, and serious complications (even hematomas) may result from inexperienced insertion of various wax-removing probes, especially the infamous cotton-tipped swabs—particularly if carried out by patients or their associates.

5 What is the nervous supply of the external canal?

Mostly trigeminal—hence, exquisitely sensitive. Still, the innermost part of the canal is supplied by the vagus (and its stimulation may indeed cause a vagal response, often just a dry cough).

6 What is the auricle (or pinna)?

It is the part of the external ear that is outside the canal (Fig. 5-1). Made of cartilage and skin, it is highly flexible.

Figure 5-1 Anatomy of the external auditory meatus.

(From Granger N: Crash Course Anatomy. St. Louis, Mosby, 2007.)

7 What are auricular bumps? What causes them?

Auricular papules or nodules are common. Most are benign, but some represent early neoplasms or clues to underlying systemic disorders. Specific etiologies include:

Darwin’s tubercle (Fig. 5-2): Benign and congenital nodule near the auricular apex (on the helix, at the junction of upper and middle thirds). Nontender and rarely bilateral, it was first described by the British sculptor Thomas Woolner, a founding member of the Pre-Raphaelite Brotherhood and a spare-time anatomist. Woolner depicted it in his statue of “Puck,” and Charles Darwin was so impressed that he named it the Woolnerian tip. It is an atavistic feature (i.e., a trait typical of our mammalian ancestors—more specifically, monkeys).

Keloids (Fig. 5-3): Smooth and flesh-colored papule(s) on one or both sides of the earlobe. They indicate an exuberant and fibrotic response to injury.

Tophi: One or more nontender nodules on the auricular edges. They are named after the Latin tufa (a calcareous and volcanic deposit) and may indeed be mildly hard. They can occur on both helix and antihelix, and usually indicate hyperuricemia and gout.

Chondrodermatitis nodularis chronica helicis (CNH): This is a common, benign, and painful condition of the most prominent projection of the ear, usually the apex of the helix, but it also may affect the antihelix. It is typical of the right ear of middle-aged to older men, usually fair-skinned individuals with cutaneous sun-damage. In 10–35% of cases, it may also affect women. It is rather common (in a series, the most frequent external ear condition seen in an ear-nose-throat clinic) and is probably due to prolonged and excessive pressure, leading to inflammation, edema, and ischemic necrosis. This eventually degenerates into secondary perichondritis due to the vascular characteristics of the ear. Onset may be precipitated by pressure, trauma, or cold. Sleeping on the affected side is also common. The nodule appears spontaneously and painfully, rapidly enlarging to a maximum size of 4–8 mm, after which it remains stable. It is firm, tender, skin-colored, sharply demarcated, and round to oval in shape. The edge is usually raised, with a central ulcer or crust. It is not associated with systemic disorders.

Figure 5-2 Darwin’s tubercle (left) and tophi (right).

(From Seidel HM, Ball JW, Daims JE, Benedict GW: Mosby’s Guide to Physical Examination, 3rd ed. St. Louis, Mosby, 1995.)

Figure 5-3 Keloids of the earlobe.

(From Fitzpatrick JE, Aeling H: Dermatology Secrets. Philadelphia, Hanley & Belfus, 1996.)

8 Can I really diagnose gout by looking at the ear?

Yes. Presence of tophi should prompt questions about podagra, chiragra, or gonagra—medieval monikers for monoarticular arthritis of the great toe, hand, or knee, a frequent nuisance of the well-fed (and drunk) aristocracy of old. Similar nodules over extensor surfaces of elbows, hands, or feet are also consistent with tophaceous gout. Since urate crystals precipitate more easily in colder areas of the skin, auricles and nasal cartilages are often the first tophi sites.

9 What are the causes of itching of the ear?

Usually local disorders, often infectious (hence, use otoscopy). Still, systemic disorders may present this way too—for example, diabetes, hepatitis, or lymphoma.

10 What is otorrhea?

It is diarrhea of the ear. In other words, the ear “runs” (which is indeed the meaning of reo in Greek). A discharge from the ear always argues for infection, either in the middle (see later) or external ear. These infections are often associated with pruritus and pain (otalgia).

11 How can the color of the discharge provide clues to its origin?

A bloody discharge suggests trauma or cancer.

A clear and serous discharge suggests leakage of cerebrospinal fluid—often posttraumatic.

A purulent discharge suggests either infection of the middle ear with perforation of the drum (otitis interna) or infection of the external ear (otitis externa).

12 Why is otitis externa “maligna” so malignant?

Because it occurs only in patients with impaired neutrophil function from either quantitative or qualitative disorders (such as leukemia, poorly controlled diabetes, or treatment with corticosteroids and chemotherapy). This leads to a Pseudomonas aeruginosa infection that usually spreads directly into adjacent structures (causing a diffusely swollen and exquisitely tender auricle) and eventually spills into the bloodstream. If missed, it can cause gram-negative sepsis, shock, and even death. Hence, prognosis is guarded, and diagnosis/treatment imperative.

13 What is instead garden variety “otitis externa”?

Simple otitis externa per se is a rather common inflammation of the external canal, seen in subjects who suffer from eczema, psoriasis, or dermatitis, but also individuals with narrow ear canals. The skin can become so swollen as to close the ear canal and thus cause temporary deafness. It also can be so painful as to impede sleep. Discharge from the ear is usually scanty. Once again, the main symptom is otalgia—typically exacerbated by manipulation of the tragus.

No. Ear pain can be referred from other sites too—for example, the teeth, pharynx, and spine. In fact, any process affecting the territory of distribution of trigeminal, facial, glossopharyngeal, vagus, and even C2 and C3 cervical nerves can cause ipsilateral otalgia.

18 Distinguish among vesicles, bullae, and pustules

Vesicles are blisters that contain clear fluid; bullae are blisters larger than 0.5 cm in diameter, and pustules are blisters that contain purulent fluid.

19 What may induce vesicles in the auricle?

Not too many causes: (1) severe contact dermatitis (such as poison ivy); (2) varicella/zoster; and (3) Ramsay Hunt syndrome (painful and vesicular rash of the inferior portion of the auricle, due to herpetic infection of the geniculate ganglion and treated with acyclovir. See questions 48 and 49).

20 What are the causes of auricular red spots?

Trauma: This also may result in auricular ecchymoses and even hematomas (see question 22).

Port wine stain: Usually congenital and of only cosmetic importance. One of the most famous port wine stains in history was on the forehead of Soviet President Michail Gorbachev.

Sturge-Weber disease: Port wine nevus on the upper part of the scalp, associated with intracranial vascular abnormalities that may cause cerebellar calcifications and seizures.

21 Who were Sturge and Weber?

William A. Sturge (1850–1919) was a native of Bristol, England. A devout Quaker, a passionate liberal, and a strong supporter of women’s rights (including free access to medical education), he married a physician named Emily Bovell, with whom he shared a practice in London. An excellent speaker, teacher, and compassionate physician, Dr. Sturge contracted rheumatic fever at age 44, eventually abandoning medicine and moving to the French Riviera. Still, he found the energy to look after Queen Victoria during her four visits to France. After his second marriage to a young archeologist, he studied early Greek art and became the founder and first president of the East Anglia Society of Prehistoric Archaeology, collecting more than 100,000 archeologic pieces, which upon his death were donated to various museums. Throughout his life, he wrote only four medical papers.

Frederick Parkes Weber (1863–1962) is the English physician associated with Rendu-Osler-Weber disease. In addition to these two conditions, he also described Weber-Klippel syndrome and Weber-Christian disease. An enthusiast of physical exercise and an avid climber (like his father), he lived well into his 90s, spending the last part of his life collecting ancient coins and vases, which he eventually donated to the British Museum.

22 What is a tender and swollen auricle?

It is an uncommon but dramatic event. A diffusely swollen auricle is usually due to:

Trauma: Easily identifiably by a history of recent altercation, especially if supported by other evidence of trauma, like a broken nose or a black eye. In fact, a “cauliflower” ear auricle is a time-honored occupational hazard of boxers, first portrayed in a beautiful Hellenistic statue of a resting fighter (Fig. 5-4). Unless evacuated, auricular hematomas heal with fibrosis and deformity and may even result in hearing loss. For instance, it has been suggested that Edison’s deafness was the result of having been picked up by the ears as a child. Still, there is no evidence that he had a cauliflower ear. President Johnson, on the other hand, contributed to our advance in veterinary medicine by demonstrating that cauliflower ears do not occur in dogs, especially beagles. In fact, he used to pick up his pooch by the ears and then toss him around in front of the press corps. LBJ, however, had no ear problems we know of, with the possible exception of selective deafness to war protesters in nearby Lafayette Park.

Relapsing polychondritis: May affect all facial cartilages, including the alar of the nose and the auricular of the ear(s).

Otitis externa maligna (see question 12).

Figure 5-4 The Resting Boxer (Museo Nazionale Romano, Rome; photo by the author). Bronze seated statue of a battered fighter, with cauliflower ear and copper inlays to portray blood running from cuts. First century copy of an original second century work by Apollonius the Athenian. Found in Rome during the 1885 excavations of the once opulent Baths of Diocletian (300 AD). The Baths had fallen into ruin after the Goths destroyed the supplying aqueducts during their 537 AD siege. To escape being melted down for metal as all other bronze statues, the Boxer had been hidden beneath the foundations of Aurelianus’ Temple of the Sun. Covered in finely sifted earth to avoid damage, he hybernated for 1350 years, until being finally brought to light, seated upright, and so dignified that Italian archeologist Rodolfo Lanciani wrote: “I have witnessed in my long career many discoveries. I have experienced surprise after surprise. I have sometimes, and most unexpectedly, met with real masterpieces, but I have never felt such an extraordinary impression as the one created by the sight of this magnificent specimen of a semi-barbaric athlete, coming slowly out of the ground, as if awakening from a thousand year–long sleep after long and terrible struggles.”

23 Why should one palpate the pulse anterior to the tragus?

Because this pulse, so often overlooked, corresponds to the temporalis artery, a branch of the external carotid. This supplies the lateral area of the scalp and can be compromised in polymyalgia rheumatica or temporal arteritis (a vasculitis of all branches of the external carotid). Hence, it must be palpated in all patients with proximal muscle weakness and jaw claudication, since tenderness of the vessel and/or nodularity may be an important diagnostic clue.

24 Why should one inspect (and palpate) the postauricular space?

To rule out mastoiditis in patients complaining of earache. In this case, there will be exquisite tenderness in the 1 -cm crescent-shaped depression immediately behind the external auditory canal (and also on the mastoid tip, see question 16). In addition, there may be (1) a palpable posterior auricular node (presenting as a nodule in the area of the mastoid process); and (2) a positive Battle’s sign (ecchymosis over the mastoid, most often due to trauma and indicative of basilar skull fracture).

25 When does Battle’s sign occur?

It usually occurs approximately 48 hours after the traumatic event.

26 Where are preauricular and postauricular lymph nodes? What may cause their swelling?

The preauricular lymph node is immediately anterior to the tragus; its tender swelling usually reflects conjunctivitis or periorbital inflammation. The postauricular node is instead over the mastoid process; its tender swelling indicates otitis externa or mastoiditis.

27 Can I diagnose coronary artery disease by looking at the auricle?

Maybe. Earlobe creases in adults are an acquired phenomenon and thus different from the folds occasionally present in normal children or the congenital creases of newborns with Beckwith syndrome (gigantism, macroglossia, and umbilical abnormalities in a setting of hepatosplenomegaly, renal hyperplasia, and microcephaly). Still, the possible association between diagonal earlobe fissures and coronary artery disease was indeed described by the American Sanders T. Frank and then reported in the 1990s by William J. Elliott. In an 8-year study of 108 patients, Dr. Elliott found greater cardiac mortality rates in patients with a crease in at least one earlobe and suggested that loss of elastin could explain both crease(s) and arteriosclerosis. In a follow-up study of 1000 patients admitted to a medical service, he found that 74% of those with a crease had coronary artery disease as compared to 16% of the creaseless ones. Since then, more than 30 studies have found, with a few exceptions, similar results. Overall, except for Asians and Native Americans, creases appear to be a significant independent variable for coronary artery disease. They are associated with higher rates of cardiac events in patients hospitalized for suspected ischemia and are also significantly correlated with male gender, cigarette smoking, cardiac familiarity, hypertension, and age. In fact, some authors have suggested that skin creases and heart disease might simply share an equally higher prevalence in older subjects without being pathogenetically associated. Hence, the jury is still out on the subject. A related but even more interesting sign is hair in the canal, which also seems to be associated with coronary artery disease in retrospect, without any relationship to its pathogenesis.

28 Why should a clinician auscultate over an auricle?

Because it may reveal a bruit consistent with arteriovenous malformation of the carotid artery. In patients presenting with unilateral tinnitus (often paroxysmal and without associated vertigo, nausea, nystagmus, abnormal audiogram, or magnetic resonance imaging of the posterior fossa), auscultation of the ear during episodes of tinnitus may reveal the bruit. Whenever the symptom disappears, so does the bruit. This is a clue that may require a magnetic resonance arteriogram or angiogram.

29 How is auscultation of the auricle performed?

By placing the diaphragm of the stethoscope over the auricle. Listen for bruits (clues to arteriovenous fistulas) and crepitus (clues to temporomandibular disease).

B. Middle Ear (Tympanic Cavity)

To equalize pressure on both sides of the eardrum. Although usually closed, the “tube” serves this function by reopening upon yawning or swallowing (and, forcefully, through the Valsalva maneuver, which incidentally was developed by Antonio Valsalva exactly for this reason, since the stethoscope had not been invented yet).

33 Does the middle ear house anything else?

Two muscles, both of which are supposed to contract whenever loud noise requires some dampening of sound transmission: (1) the stapedius (which attaches to the neck of the stapes and is supplied by the facial nerve); and (2) the tensor tympani (which attaches instead to the malleus and is supplied by the trigeminal nerve).

34 How can the tympanic membrane be examined?

Through otoscopy.

C. Otoscopic Examination

35 What is the best way to otoscopically visualize the tympanic membrane?

Ask the patient to turn the head slightly to the side. Then grasp the superior aspect of the auricle (the helix), and gently pull it up and out (i.e., posteriorly). This reduces the curvature of the external canal and eases the speculum insertion (if examining a child, straighten the canal by pulling instead the auricle down and back). These maneuvers may also elicit pain, thus alerting the clinician to inflammatory processes in the canal. Once this part has been completed, gently insert the speculum. To examine the right ear, hold the otoscope up in your right hand; to examine the left ear, hold it instead in your left hand. If cerumen obstructs the view, remove it (previously discussed). To minimize discomfort, always choose the appropriate speculum size.

36 Other than cerumen, what else may prevent visualization of the tympanic membrane?

Otitis externa (also called swimmer’s ear): Swelling and erythema of the ear canal (see questions 13 and 14).

Exostosis: Bony protuberance(s) covered by normal skin and projecting into the canal’s lumen making visualization difficult. Often bilateral.

Furuncle(s): Exquisitely tender, erythematous, and inflammatory nodule(s) on the canal’s wall.

37 How should the external canal appear otoscopically?

It should be neither red, nor swollen, nor tender. And, of course, there should be no foreign bodies. This is especially important in children.

38 What does the normal tympanic membrane look like?

As pale, gray, translucent, and surrounded by a ring (anulus in Latin). Always inspect it carefully, since this may be the site of tiny perforations. The normal tympanic membrane also includes visible projections of the malleus (hammer in Latin), the largest of the three auditory ossicles, and actually more of a “club” than a hammer. It comprises a head (caput), a neck (collum), and a handle (manubrium) (Fig. 5-5). From the base of the manubrium arises the short lateral process. The manubrium and lateral process are attached firmly to the tympanic membrane, with the lateral process projecting anteriorly and superiorly. The head articulates instead with a saddle-shaped surface on the body of the incus. Otoscopically the only visualized structures are (1) the short lateral process and the manubrium; (2) the umbo of the malleus (from the Latin umbo, boss of a shield, knob), which coincides with the head of the hammer and presents as an inferior and posterior projection through the tympanic membrane; (3) a reflective triangular cone of light, located inferiorly and anteriorly to the umbo; (4) the flaccid portion of the tympanic membrane (pars flaccida), located anteriorly and superiorly to the manubrium; and (5) the pars tensa, which is located just posteriorly to the manubrium. “Flaccida” and “tensa” reflect, respectively, areas of greater or lesser mobility of the tympanic membrane.