Q: I am a 50-year-old woman who is experiencing some "pressure" noises in my left ear. I believe it is due to some hearing loss while I was down with a bad flu in January.

I have recovered from my flu but my left ear still has the disturbing sounds. They get worse when the surroundings are noisy or when a microphone is being used. They can also last the whole day. I consulted an ear, nose and throat doctor, who said the sounds are due to my bad flu.

I wish someone could tell me what is happening to my left ear.

A: From your description, the recent bad flu you had may have led to sensorineural hearing loss, arising from an inner-ear infection.

This type of hearing loss occurs when there is damage to the inner ear (cochlea) or the nerve pathways from the inner ear to the brain.

Flu infections can cause an inner- or middle-ear infection, or both.

Middle-ear infections can cause conductive hearing loss, which happens when sound is not conducted efficiently through the outer-ear canal to the eardrum and the tiny bones of the middle ear.

Conductive hearing loss usually involves a reduction in sound level or in one's ability to hear faint sounds.

On some occasions, this may worsen to inner-ear sensorineural hearing loss despite appropriate antibiotic treatment. The sensation of autophonia - hearing one's own voice or chewing and swallowing noises louder in the head - suggests the problem stems from the middle ear.

But if one experiences distorted hearing, hearing echoes or the reverberation of sounds, this may imply sensorineural hearing loss.

INJURY TO HAIR CELLS

You said that the sound in your ear gets worse in noisy places.

This phenomenon is known as hyperacusis, and it occurs when there is a partial injury to the outer hair cells in the ear. This causes an abnormal tuning effect of the outer hair cells, causing loud sounds to be amplified suddenly and inappropriately. Hyperacusis is associated with inner-ear injury and, at times, certain thyroid conditions.

You may wish to check your thyroid hormone status. Abnormal thyroid hormone levels may indirectly weaken your immune system and could cause recurrent upper respiratory tract infections.

Certain viruses can cause both upper respiratory tract infection and sensorineural hearing loss.

Some of these viruses, such as measles and mumps, do not have an antidote, so the hearing loss may not be treatable.

Other viruses, like herpes zoster, are known to cause irreversible sensorineural hearing loss, facial nerve weakness and dizziness.

Unlike bacteria, which can be treated with antibiotics, it remains debatable whether anti-viral therapy is useful even when prescribed in the acute stages.

To confirm if you have sudden sensorineural hearing loss, a hearing test and a magnetic resonance imaging scan with contrast of the auditory system will be required to rule out small inner-ear tumours.

A magnetic resonance imaging scan enables doctors to look for lesions along the hearing pathway.

Blood tests are also needed to rule out other causes, like an infection or autoimmune disease.

The main treatment for idiopathic hearing loss is high-dose oral prednisolone for a week. If the hearing loss persists, the doctor may prescribe steroid injections into the middle-ear region. Repeated injections can be done in the outpatient setting, and are painless.

Some risks are infection resulting in pain, persistent perforation of the ear drum and further hearing loss. Others have also tried antioxidant treatment with success.

All ear, nose and throat surgeons are capable of diagnosing and treating this inner-ear condition. However, about 20 to 30 per cent of patients with sudden sensorineural hearing loss will not improve and some deteriorate into profound deafness, even with treatment. In these cases, special hearing aids or implant surgery may help.