Tinnitus

Noise-induced hearing loss is the most common cause of tinnitus, says Dr Gwen Lewis.

Examine the ear and take a history to exclude any physical cause (Photograph: SPL)
Examine the ear and take a history to exclude any physical cause (Photograph: SPL)

Tinnitus is the perception of sound in the absence of any corresponding external sound. Tinnitus is not a disease but a symptom generated within the auditory pathway. The cause is not fully understood.

Tinnitus rarely indicates serious disease and this is the most important message to convey to patients who are concerned and distressed by the noise.

1. How does it manifest?

Tinnitus may be heard in one or both ears. The noise may be low, medium or high-pitched and may be constant, variable or intermittent. It may be described as humming, hissing, buzzing, tinging, whistling, ticking, clicking or roaring; it is sometimes described as being like the sound of cicadas or waves. Some patients even describe the noise as being a complete musical tune.

2. Who is affected?

Tinnitus is common in all age groups and especially after exposure to loud noises. It is estimated that 10% of the population have tinnitus all of the time, while in around 1% of adults it may be so distressing as to affect quality of life.

3. Precipitating factors

Noise-induced hearing loss is the most common cause of tinnitus. The condition is often worse when a person is stressed or anxious. Emotional upsets may be associated with onset.

Tinnitus becomes more noticeable in quiet environments, so is often appreciated more at night and can lead to insomnia and hence anxiety. Many patients complain that they never have a good night's sleep.

In some cases, tinnitus may be precipitated by physical factors, which include head injury or an acute illness, such as a respiratory infection or ear infection. Rarely, wax occluding the external auditory meatus of the ear may cause tinnitus. Drugs such as aspirin may also cause the symptom, as may withdrawal of benzodiazepines.

One recent study found that tinnitus is not just the result of damage or obstruction in the ear but is brought on by the brain overcompensating for lost hearing.1 In this study, 22 patients with tinnitus underwent brain scans and it was found that tinnitus occurs when one part of the brain tries to produce sounds to replace missing frequencies and another part of the brain fails to stop the unwanted sounds from reaching the auditory cortex.

4. Initial investigation

A patient presenting with tinnitus should have a full history taken to exclude any possible physical cause, and examination of the ears should be undertaken.

Sometimes an actual bruit from the patient's ears may be perceived, which is thought to arise from muscle spasm that causes clicks or crackling around the middle ear.

The sound may be in time with the pulse which results from altered blood flow or increased turbulence near the ear and is known as pulsatile tinnitus.

KEY POINTS
  • Tinnitus may be heard in one or both ears and may be constant or variable.
  • Noise-induced hearing loss is the most common cause.
  • A patient presenting with tinnitus should have a full history taken and an examination of the ears.
  • Patients should be reassured that tinnitus rarely indicates serious disease.

5. Management

Patients presenting with tinnitus should be reassured that in the majority of cases the symptom does not indicate any serious disease, having excluded any physical cause for the symptom.

Studies have shown that even without any treatment the noises disappear or at least diminish in the majority of cases as the brain loses interest and stops surveying the signal.

However, many patients find the symptom distressing at first and in some cases their anxiety continues in spite of reassurance. Adjustments should be made to current medication if appropriate.

The noise of tinnitus is often appreciated less when a person is busy, so they should be advised to maintain interests and keep themselves occupied.

Referral to ENT may be needed for further reassurance, or for provision of relaxation therapy or stress management or CBT, or the fitting of a white noise generator which may mask the tinnitus.

With explanation, counselling and reassurance, the majority of patients with tinnitus can be managed in general practice.

  • Dr Lewis is a GP in Windsor, Berkshire

Reflect on this article and add notes to your CPD Organiser on MIMS Learning

Reference

1. Leaver AM, Renier L, Chevillet MA et al. Neuron 2011; 69: 33-43.

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