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The Draining Ear

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Tools to Diagnosis & Management


Otorrhea, or ear drainage, poses a diagnostic challenge, since it is the chief complaint in a multitude of disorders. Fluid from the ear usually signals a disorder that requires expeditious and effective management.

 
HISTORY TAKING

The first step in treatment of otorrhea associated with any condition is to establish an accurate diagnosis, wherein history plays an important role. Colour of the draining fluid, accompanying otologic symptoms and other factors provide clues to the source of the problem.

Colour is a very important clue in differentiating an infectious from a non-infectious cause. A yellowish colour almost always indicates an infection within the external auditory canal or the middle ear. White fluid typically indicates a fungal or dermatologic condition in the external auditory canal. Bloody otorrhea is usually associated with trauma but may signal chronic infection with granulation tissue. Fluid that is clear, thin and watery should be considered as an alert to a potential CSF leak.

The duration of otorrhea also provides clues to the acuteness of the cause. New-onset purulent otorrhea often indicates acute otitis externa or otitis media. Intermittent purulent otorrhea without pain is common in patients with chronic otitis media.

A common misconception is that otorrhea with an odour indicates anaerobic infection. However, odour usually indicates destruction of bone in the middle ear or mastoid. This condition commonly occurs with suppurative chronic otitis media with a long-standing tympanic membrane perforation and purulent otorrhea. It signals an impending complication unless treated.

Otalgia associated with otorrhea is characteristic of an acute process, such as otitis externa or acute otitis media with tympanic membrane perforation. Hearing loss can result from complete occlusion of the external auditory canal caused by the otorrhea. Vertigo occurring with otorrhea may signal inner-ear complications of chronic otitis media such as acute labyrinitis.

 

PHYSICAL EXAMINATION

The patient's temperature should be taken and a routine head and neck examination performed, with special attention directed to the ear. The auricle (pinna) is inspected first. The external auditory canal may need to be meticulously cleaned and debrided to allow examination of the canal and tympanic membrane. Use of water and irrigation is contraindicated in patients with otorrhea because it may exacerbate an infectious process or force water through the unseen tympanic membrane if a perforation is present.

 

INVESTIGATIONS

Generally, the cause of otorrhea is evident after thorough history taking and physical examination.

Occasionally, clear, watery otorrhea is collected and tested for glucose or b2-transferrin to rule out CSF leak. Otorrhea cultures are usually reserved for refractory cases in which initial antibiotic therapy has failed. Bacterial and fungal cultures and sensitivities, Gram's stain, and potassium hydroxide preparation are routinely ordered and may help direct subsequent therapy.

Radiological testing can determine temporal bone fracture after a traumatic injury or bone destruction by a severe infectious process or neoplasm. CT scans of the temporal bones, are useful in examining details of the bony architecture. MRI is rarely used in the evaluation of otorrhea.

 
DIFFERENTIAL DIAGNOSIS

1. Otitis externa
Typical otitis externa, or swimmer's ear, is characterised by severe otalgia and is often associated with otorrhea and a history of recent water exposure or trauma to the ear. Initial therapy consists of an ototopical agent - a compound acting locally, analgesics to relieve discomfort, and precautionary measures to keep water from entering the external auditory canal. Dermatologic conditions within the external auditory canal can predispose the ear to bacterial infections and often present as acute or chronic otitis externa. Steroid-containing otologic preparations are the most common treatment for these conditions.

2. Otitis media with tympanic membrane perforation
A patient with acute, suppurative otitis media usually presents with new-onset, progressively worsening otalgia. Many such patients experience a sudden "pop" in the ear (indicating tympanic membrane perforation), followed by purulent otorrhea and immediate relief of otalgia. On physical examination, the external auditory canal is normal and the tympanic membrane is erythematous with a tiny perforation that may or may not release otorrhea. At this stage, infection is likely to resolve eventually, but systemic and ototopical agents, as well as dry ear precautions, may prevent further complications or progression to chronic otitis media.

3. Other causes of otorrhea
Although infections are the most common cause of otorrhea, other important sources exist. CSF leaks occur predominantly after surgery or trauma, and early diagnosis and treatment are important to prevent meningitis.
The presence of granulation tissue in a draining ear refractory to antibiotic therapy should arouse suspicion of neoplasm. Diagnosis is made by performing a biopsy.

 
TREATMENT

Ototopical agents are formulated to treat most of the conditions that cause otorrhea. A variety of single and combination drugs are available to treat fungal and bacterial pathogens. Steroid and antibiotic combinations have become popular for their anti-inflammatory and anti-infective properties. Steroids in these preparations decrease mucosal cutaneous oedema secondary to bacterial infections. Several antibiotic preparations contain an acid as the active ingredient. An acidic environment within the external auditory canal deters bacterial and, particularly, fungal growth but can be quite irritating especially if the tympanic membrane is perforated.

For first-line therapy of acute otitis externa, an otologic preparation in suspension form containing two antibiotics and a steroid is an excellent choice, as is a topical quinolone antibiotic. It is reasonable to exercise caution when using topical aminoglycosides, which are ototoxic when given intravenously. The fluoroquinolones like ciprofloxacin and norfloxacin have recently been added to the arsenal of ototopical agents. They are known to have no ototoxic effects unlike the aminoglycosides. Although, use of systemic fluoroquinolones in children has generally been contraindicated, the topical preparation is safe and effective and is especially helpful in refractory post-tympanostomy otorrhea. Currently no otologic preparation is available for the treatment of fungal infections. Over-the-counter preparations for the prophylaxis of swimmer's ear contain an acid and alcohol.

While these preparations are effective for prophylaxis, generally more potent preparations are required for active infections. Moreover, these preparations cause severe burning and discomfort in patients with a tympanic membrane perforation.


SUMMARY
Otorrhea varies in appearance and can be accompanied by a multitude of symptoms. Recognition of what various combinations indicate - whether otitis externa, chronic otitis media or carcinoma is essential. Once proper diagnosis is made, effective treatment can follow.

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