Acoustic trauma is a lesion of the inner ear caused by simultaneous or continuous exposure to excessively strong sound or noise. The main symptoms of acute sound damage are pain and ringing in the ears that have arisen sharply and gradually subsiding. Chronic acutrauma is manifested by a gradual decrease in hearing acuity, discomfort and a feeling of tinnitus, sleep disturbance and increased fatigue. The diagnostic program includes the collection of anamnestic data and patient complaints, otoscopy, speech examination and tonal audiometry. Treatment includes taking vitamins gr. In, nootropics, darsonvalization and oxygen therapy, hearing prosthetics.
H83.3 Noise effects of the inner ear. Acoustic trauma
In modern otolaryngology, it is customary to distinguish acute and chronic (more common) forms of acutrauma. Approximately a quarter of all cases of acquired sensorineural hearing loss are associated with acoustic damage to the inner ear. The majority of patients are people whose profession is associated with constant noise. People who work in confined spaces and have diseases of the upper respiratory tract, auditory tubes and middle ear are more likely to get sick. Acutrauma accounts for about 60% of all pathologies caused by exposure to physical factors in production conditions and 23% of all occupational diseases. In this regard, the majority of patients are able-bodied persons aged 30 to 60 years. The disease occurs with the same frequency among men and women. Geographical features of distribution are not noted.
Causes of acoustic trauma
The leading etiological factor of acutrauma is excessively loud noise or sound. The mechanism and rate of development of the lesion, its main manifestations depend on the nature and duration of the sound effect. Based on this, it is advisable to distinguish two main causes of acoustic trauma.
Short-term super-strong sound. Includes any sounds whose volume exceeds 120 dB – a whistle near the ear, a siren, a vehicle signal, an explosion, a firearm shot, etc. As a result, a person has acute acutrauma, which is often combined with barotrauma.
Constant intense noise. Regular and prolonged exposure to noise with a volume of 90 dB or higher (with increased sensitivity – from 60 dB), causes the development of chronic acoustic trauma. In the vast majority of cases, pathology develops in people facing occupational hazards – in workers in the field of heavy machinery and shipbuilding, aviation, metallurgy, textile industry, etc.
Acute and chronic (occupational) acoustic injuries have different mechanisms of development. A short-term, excessively strong sound causes hemorrhage in the perilymph of the anterior part of the membranous labyrinth of the cochlea – one of the components of the inner ear. In parallel, there is a displacement and swelling of the external and internal hair cells of the cortical organ. The latter is a finite receptor apparatus in which perilymph vibrations are converted into a nerve impulse transmitted to the central nervous system. In some cases, there is a separation of the Corti organ from the main membrane.
The pathogenesis of chronic acutrauma has not been fully studied, so there are several possible theories. According to them, constant exposure to loud noises on the hearing aid can cause degenerative changes in the cortical organ, metabolic disorders and fatigue phenomenon, the formation of pathological foci of arousal in subcortical centers.
Symptoms of acoustic trauma
The acute form of the disease is characterized by sharp pain in the ears at the moment of sound perception and sudden one- or two-sided hearing loss. A person is deprived of the ability to perceive external sounds and hears only a gradually subsiding ringing or squeaking, which can be combined with dizziness, aching or throbbing pain inside the ear. When combined with barotrauma, the clinical picture is complemented by bleeding from the external auditory canal and nose, violation of spatial orientation. The further course depends on the severity of the lesion.
Acoustic trauma of a mild degree is characterized by a gradual restoration of sound perception to the original level after 5-30 minutes. In moderate to severe cases, during the first 2-3 hours, the patient hears only loud sounds or a scream. Then there is a gradual resumption of sound perception to the level of hearing loss of varying degrees of severity.
The development of the clinical picture of chronic acoustic trauma goes through 4 stages.
- The stage of initial manifestations occurs after 1-2 days of being in noise conditions. It is characterized by discomfort and ringing inside the ear. After the cessation of external factors, these manifestations disappear after a few hours of rest. After 10-15 days, adaptation occurs, the symptoms gradually subside. The total duration of the stage is from 1-2 months to 4-6 years. This is followed by a period of “clinical pause” in which there are no unpleasant sensations, but gradually, imperceptibly for the patient, the hearing acuity decreases. Its duration ranges from 2-7 years.
- The stage of increasing symptoms is manifested by constant tinnitus and the rapid development of hearing loss. At the same time, hearing loss occurs sequentially: first, the sound at high, then at medium and low frequencies ceases to be perceived. The present clinical manifestations are complemented by nonspecific symptoms: increased fatigue and irritability, impaired attention, loss of appetite and insomnia. The formed hearing loss remains at the same level even when continuing to work in the same conditions from 5 to 15 years.
- The terminal stage develops in people with hypersensitivity to noise, after 15-20 years of working under noise exposure. Its signs are deterioration of hearing acuity up to the inability to perceive spoken language from a distance of more than 2 meters, unbearable tinnitus, impaired coordination of movements and balance, constant headache and dizziness.
The most common complication of acutrauma is deafness. The main causes of complete hearing loss are untimely diagnosis and treatment. Its development is facilitated by non-compliance with the recommendations of an otolaryngologist and refusal to change professions at the initial stages of chronic acoustic damage. Constant exposure to noise leads to systemic disorders: arterial hypertension, neurocirculatory dystonia, astheno-neurotic and angiospastic syndromes. Any acoustic damage to the hair apparatus of the cortical organ reduces its resistance to infectious agents, systemic intoxication and the action of ototoxic pharmaceuticals.
The diagnosis of acoustic trauma for an experienced otolaryngologist is not difficult. Anamnestic information, patient complaints and hearing research are enough for this. Other examinations (MRI of cerebellar angles, acoustic impedance measurement) are used to differentiate with other pathologies.
- Anamnestic data. With acutrauma, there are always situations in which the patient is under the influence of a sharp and loud sound or has been in constant noise for a long time.
- Otoscopy. In some patients, pathological retraction of the eardrum is visualized, which is characteristic of constant tetanic contractions of its musculature. When acute acoustic damage is combined with barotrauma, a large number of blood clots and a rupture of the eardrum are determined.
- Speech audiometry. Allows you to set the distance at which the patient perceives the cry (80-90 dB), spoken (50-60 dB) and whispered speech (30-35 dB). Normally, a conversation can be heard at a distance of up to 20 meters, and a whisper – up to 5 m. With hearing loss, these distances decrease or speech becomes indistinct. In case of severe injuries, only a scream is perceived directly above the ear.
- Tonal threshold audiometry. Reflects the defeat of the sound-receiving apparatus, which is manifested by a progressive deterioration of air and bone conduction with an increase in the frequency of generated sounds.
Differential diagnosis of acute acoustic trauma is performed with sudden (acute) sensorineural hearing loss. The second pathology may be the result of an allergic reaction or an acute violation of cerebral circulation. Chronic acutrauma requires differentiation with Meniere’s disease, presbyacoussis and tumors of the cerebellar angle. With padalecmixia, unilateral hearing loss occurs, spontaneous deterioration or regression of symptoms may occur. Presbyacoussis occurs at the age of over 70 years, and a decrease in hearing acuity is not accompanied by the appearance of third-party noises. Tumors of the cerebellar angle, in addition to hearing loss, are also manifested by lesions of the facial and trigeminal nerves.
Treatment of acoustic trauma
Therapeutic measures, depending on the form of pathology, can be aimed at maximizing the restoration of sound perception or preventing further development of hearing loss. In acute acutrauma, complete rest, vitamins g. B, calcium and bromine preparations are indicated. In some patients, hearing acuity recovers independently after a few hours. If hearing loss develops after exposure to short-term acute sound, treatment is carried out by analogy with chronic acoustic trauma.
In chronic acutrama, treatment is most effective at the stages of initial manifestations and “clinical pause”. With modern treatment initiated in some patients, it is possible to achieve regression of symptoms. Later therapy is aimed at preventing further hearing impairment. The therapeutic program includes the following drugs and activities:
- Change of profession. The exclusion of the impact of strong noise on the sound-receiving apparatus prevents the further development of hearing loss.
- Nootropics. Drugs of this series improve sound perception and other cognitive functions of a person, activate the work of the brain as a whole.
- Vitamins of group B. Improve the metabolism of the central nervous system, increase its resistance to excessive impulses of the middle ear, tone the work of the auditory nerve.
- Antihypoxants. Normalize the function of damaged cortical organ hairs by improving metabolism in conditions of insufficient supply of oxygen and nutrients.
- Darsonvalization. The impact of pulsed currents on the mastoid process area stimulates the inner ear. The technique allows you to deal with third-party noise in the ears.
- Hyperbaric oxygenation (HBO). In conditions of increased oxygen pressure, cerebral blood circulation and reparative processes in the inner ear improve.
- Auditory prosthetics. The use of hearing aids makes it possible to improve the quality of hearing with severe hearing loss.
Prognosis and prevention
The prognosis for recovery from acoustic trauma depends on its form. With an acute lesion of mild severity, a complete restoration of the original hearing acuity occurs. With severe acute or chronic acutrauma, irreversible hearing loss of varying degrees develops. Preventive measures include compliance with safety regulations at work and in life, work in rooms with full sound insulation and sound absorption, the use of individual anti-noise or special headphones. Regular occupational examinations of persons working under the influence of constant noise play an important role.