Ear, nose and throat

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chapter 27 Ear, nose and throat

INTRODUCTION AND OVERVIEW

This chapter is a brief summation of commonly encountered otolaryngology, head and neck issues in general practice. It is not exhaustive but, rather, aims to give the reader an understanding of common problems and assist in management.

THE EAR

The ear is the organ of hearing. In medicine it is divided for descriptive and functional purposes into an outer, middle and inner ear (Fig 27.1). The ear amplifies sound, converting it from mechanical energy into an electrical impulse, which the individual translates. It is unusual for any disease process to affect more than one component at any one time.

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FIGURE 27.1 Anatomy of the ear

OUTER EAR

The outer ear acts as a funnel, collecting sound waves and concentrating them onto the tympanic membrane (eardrum). It includes the pinna (auricle) and external auditory canal (EAC), and it represents the part accessible to examination, and is not uncommonly an area of decoration by piercing. The EAC is cylindrical in shape, and approximately 2.5 cm long. The lateral EAC is composed of cartilage, and the medial part is bony. The cartilaginous aspect contains hair, and cerumen (earwax) is produced here. The canal is lined with very specialised squamous epithelium, which self-cleans in a migratory pattern from inside to out. It is important at this stage to understand the harm caused by cotton buds in inhibiting this process. Cotton buds tend to compress wax and can cause occlusion, deafness and infection.

Ear wax

Excess ear wax may present as loss of hearing acuity, tinnitus, a sense of fullness in the ear or dizziness.

The chemical basis of cerumen, or ear wax, is a fat. Like all body fats, the fluidity is affected by the ratio of omega-3 to omega-6 fatty acids and saturated fats.

Although genetic factors are thought to be involved, hard wax (inviting medical removal) may simply reflect a lack of omega-3s in the person’s diet. Hence, increasing omega-3 intake may help to prevent the problem. In the acute situation, treatment is with drops to soften the ear wax. This may need to be followed by syringing or suction aural toilet.

Trauma

‘Cauliflower ear’

‘Cauliflower ear’ is a commonly seen injury endured by rugby players caused by blunt trauma to the ear. The shearing forces cause a sub-perichondrial haematoma, (Fig 27.2) which compromises the diffusion nutrient supply to the cartilage. The haematoma is susceptible to infection, which can further deplete nutrient supply to the cartilage. The cartilage is replaced with fibrous scar tissue and deformity results. Therefore immediate haematoma evacuation is required in cases of acute trauma.

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FIGURE 27.2 Haematoma in cauliflower ear

Foreign body

Festive seasons and birthdays often herald the season of foreign bodies in the ears of children (Fig 27.3). Anything small enough, from beads to batteries, has been found there. The deeper the foreign body, the more difficult and painful it is to remove. In children a general anaesthetic may be required. In general, appropriate equipment allows easy removal with a compliant child. The hardest to remove is often the foreign body that others have attempted to remove. It may be associated with tympanic membrane perforation, although this is unlikely and depends largely on the mechanism of trauma. If associated with a perforated eardrum, it is reassuring to know that most heal spontaneously. Water precautions should be adhered to until the eardrum heals, and an audiogram is recommended (in a perforated tympanic membrane).

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FIGURE 27.3 Removal of foreign body from the ear

One unpleasant type of foreign body is an insect near or attached to the tympanic membrane. As first aid, instant pain relief and destruction of the creature, olive oil poured straight into the ear is safe and effective.

Otitis externa

Ear infections are particularly common in cultures where swimming is popular. Otitis externa (OE) refers to infection of the EAC (Fig 27.4). It is commonly caused by Pseudomonas, Staphylococcus aureus or fungal species. However, because the EAC is just like skin, other causes of OE include viral infection and allergy (seborrhoeic).

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FIGURE 27.4 Otitis extema

Otitis externa is often preceded by a combination of maceration (cotton buds) and water trapping. Dermatological conditions of the ear canal also predispose to OE. It is not uncommon to have exostoses, which can predispose to OE by water trapping. In OE the canal is typically oedematous and reddened. The diagnosis is made clinically with discharge, deafness and severe otalgia. In fungal infections, spores may be encountered. Compared with otitis media, otitis externa is exquisitely tender, esapecially with traction of the pinna, or there is pain with movement of the jaw, and the patient can therefore be difficult to examine.

A swab for culture and sensitivity of causative organisms can guide therapy decisions. The recalcitrant nature of OE is often due to inadequate use of ototopical medication. Oral antibiotics are rarely warranted for OE and reserved for systemic illness, severe surrounding cellulitis and recalcitrant infections. Topical preparations are far more effective in attaining higher antibiotic concentration at the infected site, and minimise the risk of antimicrobial resistance. It is important to perform a micro-ear toilet to clear the EAC of debris, to allow greater penetration of the antibiotics/antifungals. This is also possible with ‘tissue spears’—the corners of a tissue may be rolled and gently inserted into the ear in a twisting motion, to absorb moisture. This also allows better penetration of antibiotics and antifungals. A cotton bud has rigidity and therefore causes more trauma, whereas the tissue spear acts purely as absorbent. In severe cases of occlusion, an otowick is used. This is a cottonoid pledget that expands with ototopical antibiotic/antifungal preparations to allow delivery of the ototopical preparation to the area of inflammation/infection.

Ototopical medication has recently come under close scrutiny because of the potential toxic effect of the aminoglycosides in some ototopical medications. The Australasian Society of Otolaryngology, Head and Neck Surgeons recently published guidelines on their use.1

• When possible, topical antibiotic preparations that are free of potential ototoxicity are preferable to those that do have the potential for otologic injury in patients with an open middle ear or mastoid.
• When a potentially ototoxic antibiotic is chosen, it should be used only in infected ears and it should be discontinued shortly after the infection has resolved.
• When a potentially ototoxic antibiotic drop is prescribed for a patient with an open middle ear or mastoid, the patient or parent should be warned of the risk of ototoxicity.
• The patient or parent should be specifically instructed to call the physician or return to the office if the patient develops dizziness or vertigo, hearing loss or a worsening of hearing if such an impairment was already present, or tinnitus.
• If the tympanic membrane is known to be intact and the middle ear and mastoid are closed, then the use of potentially ototoxic preparations presents no risk of ototoxic injury.

Prevention: Keep the ear dry, especially with swimming and water sports. This can be achieved with fitted earplugs and a bathing cap. If the canal becomes wet, apply spirit drops to help dry the canal. Dry canal with a hair dryer held about 30 cm from the ear.

Malignant otitis externa

What may seem a simple ear infection in an immunocompromised patient (commonly the diabetic or elderly patient) can rapidly deteriorate into a life-threatening condition. A Pseudomonas infection can colonise and spread into the temporal bone and become very difficult to eradicate. The patient presents with severe otalgia, aural discharge and progressive cranial nerve neuropathies. These patients warrant urgent referral to otolaryngology services.

Tumours

Basal cell carcinoma and squamous cell carcinoma (melanoma is less likely) must not be forgotten in consideration of ongoing discharge and eczema of the pinna in elderly patients, especially as the area is prone to UV sun exposure. Initially superficial, these lesions tend to ulcerate and weep. They require definitive surgical management.

Prevention: Everyday sun protection with sunscreen, including the ears, and a hat with a broad brim.

Exostoses

Exostoses are a benign condition of the EAC seen frequently in avid swimmers, culminating over many years. They are more commonly associated with cold water exposure and are well represented in surfing communities. An osteoma is a single, solitary lump, whereas exostoses are multiple. They are smooth bony protuberances of the ear canal. Although benign in nature, they become problematic when they are large enough to inhibit the ear’s natural self-cleaning. Water trapping occurs on repeated swimming, and the ear canal becomes irritated, and macerated with attempted cleaning, and it is then only a matter of time before repeated infections occur. It is more a problem in this population as it limits the joy of the aetiology: swimming and water sports. Most are observed until they become problematic and then are surgically reduced.

Prevention: Fitted earplugs can be worn for swimming, and the ear canal should be dried with a hairdryer after swimming and hair washing.

TYMPANIC MEMBRANE

The tympanic membrane (eardrum) is the Rolf Harris of the ear. It is a thin membrane separating the external auditory canal from the middle ear, approximately 10 mm in diameter (Fig 27.5). It vibrates (wobbles) in response to mechanical energy from sound waves. It is attached to the ossicles (ear bones), which together amplify sound energy to the inner ear. The tympanic membrane is important not only in sound transmission but also in preventing water entering the middle ear cleft. The respiratory epithelium of the middle ear cleft differs from the squamous epithelium of the external auditory canal. Impaired function consequently has profound effects on the hearing ability of the affected ear. Various conditions can affect the tympanic membrane, and include:

• myringitis—infection of the tympanic membrane; may be viral or bacterial; treated with ototopical antibiotics
• bulla myringitis—an acutely painful condition characterised by bulla formation on the tympanic membrane; often caused by a virus and as such supportive therapy is required, although superimposed bacterial infection is not uncommon
• myringosclerosis—scarring of the tympanic membrane in the form of collagen deposits; appears as ‘clouds’ or ‘chalk marks’ on otoscopy and is often a result of trauma from infection or previous grommet insertion; intervention is rarely necessary unless the condition is causing conductive hearing loss.
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FIGURE 27.5 The tympanic membrane

Tympanic membrane perforation

Tympanic membrane perforation (Fig 27.6) may result from trauma (personal or surgical), infection or pressure changes. It may be marginal, involving part of the tympanic membrane annulus, or central, involving any other part. It needs to be distinguished from a retraction.

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FIGURE 27.6 Tympanic membrane perforation

Examine by removing the blood clot by suction or by gentle mopping. Exclude any foreign body and check the hearing, as perforation can cause hearing loss.

The mainstay of treatment is supportive, maintaining water precautions (to prevent infection) and obtaining an audiogram. Prescribe a broad-spectrum antibiotic and adequate analgesia. Review in two days, then weekly until healed. Perforations tend to heal spontaneously over days to months in a non-infected ear with good eustachian tube function. Hearing should be rechecked two months after the injury.

Non-healing perforations may require surgical repair with a myringoplasty. Referral is warranted earlier if suspicious of complications such as inner ear involvement expressed as tinnitus, vertigo, sensorineural hearing loss, bleeding, otalgia or facial nerve paralysis.

Prevention: Discourage any objects being inserted into the ear canal except by trained professionals.

MIDDLE EAR

The middle ear is a collective term describing the space bounded by the tympanic membrane laterally and the inner ear medially. It houses the ossicles, the bones of sound conduction. It is lined by respiratory mucosa and has a connection to the posteriorly based mastoid air cells, and is drained by the eustachian tube antero-inferiorly. The external ear collects the sound waves, while the middle ear amplifies the sound transmission to the inner ear. The eustachian tube’s primary function is to allow equalisation of pressure, to maximise sound transmission.

Middle ear effusion

Failure of adequate drainage is not uncommon in children, as the eustachian tube is shorter, the diameter is thinner and it lies in a more horizontal plane than the adult eustachian tube (Table 27.1). The narrow lumen is easily obstructed in upper respiratory tract infections, there is less capacity for natural drainage, and its length is thought to allow more exposure to reflux and, hence, inflammation. Adenoidal hypertrophy may predispose to lower eustachian tube obstruction. (In the adult population, one must be wary of neoplastic postnasal obstruction.)

TABLE 27.1 Issue in a child’s eustachian tube, compared with an adult

Anatomy Consequence
More horizontal lie Less capacity to drain
Smaller diameter More easily occluded
Shorter
Easier to reflux
More prone to inflammation

Failure of drainage leads to accumulation of fluid, as water is absorbed through the middle ear mucosa, the tympanic membrane is retracted or the fluid thickens. Consequently, the ossicles fail to vibrate, and lack of aeration of the middle ear cleft leads to dampening of the sound waves and conductive hearing loss.

Surgical treatment (grommets ± adenoidectomy) is usually reserved for non-resolving effusions causing developmental delay such as speech and learning. Most will, spontaneously, resorb or drain within 4–6 weeks. Referral is indicated if there is persistent middle ear effusion three months after an attack of acute otitis media, or if there are signs of hearing loss, frequent recurrences or severe complications (e.g. mastoiditis).

Acute otitis media

Accumulation and contamination of middle ear fluid, which is normally sterile, leads to infection, otitis media. It is a common disease of the paediatric population. The patient typically presents as a febrile, runny-nose mouth breather. Again, this is because of the special relationship of the eustachian tube with the post-nasal space. Because of this relationship it may also be associated with rhinitis, sinusitis, snoring, obstructive sleep apnoea and asthma-like associations. It has an increased incidence in lower socioeconomic groups, and an alarmingly high prevalence in the Australian Indigenous population.

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FIGURE 27.7 Middle ear with Eustachian tube

The common organisms found in infection of the middle ear include Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. A less likely cause of infection is gram-negative bacteria or a viral aetiology.

The controversy surrounding the use of oral antibiotics in acute otitis media has been noted. In a meta-analysis it was found that the NNT (number needed to treat to benefit one patient) was 17. The benefit was small—a reduction in pain by 12 hours. In this study, the likelihood of complications was not increased in the non-treated group.2,3 Against this, the cost of increasing antibiotic resistance, and the disruption to the ecosystem of the gut flora, have to be counted.

Pain relief in otitis media can be as simple as showing the parent how to use a 2 mL syringe to put olive oil into the child’s ear.

Complicated otitis media (see below) requires full medical treatment.

Recurrent otitis media has been considered a response to food allergy. The theory is that cytokines released when problem foods are eaten results in oedema of membranes in the respiratory tract. Easy blockage of small passages, such as the eustachian tube, ensues.

It can be a useful trial of therapy to put all children on a strict one-month dairy-free diet before sending them for tonsillectomy, grommets or other surgical interventions. Many respond to this diet, and a few respond once gluten/wheat, citrus and other food allergens are also withdrawn. It should be noted that such ‘allergic’ responses are not usually mediated through the immunoglobin E (IgE) arm of the immune system and as such should not, strictly speaking, be called allergies.

The immune mechanisms involved may be IgG or IgA mediated, or a direct cytokine response not involving any immune globulin. Inhalant allergens must also be considered; and, of course, a marked and statistically significant association has been found between the incidence of otitis media and tonsillectomy in children and parental smoking in the home environment.

Otitis media, along with chronic sinusitis, recurrent tonsillitis and migraine, all tend to cluster within individuals and families. Understanding the biochemistry helps us see them as systemic problems, and rationalises the approach.

In babies and children, a red tympanic membrane does not necessarily mean otitis media. The tympanic membrane can appear red if the child is crying.

Complications of otitis media

Acute otitis media generally responds well to adequate analgesia with or without oral antibiotics. Most effusions will resolve within 3–6 months with active non-intervention. Surgical intervention is reserved for chronicity, recurrence or impending complication of otitis media. There is much debate surrounding absolute indications for intervening.

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