Acoustic trauma (akutravma) – the damage of an inner ear caused by one-stage or continuous influence of excessively strong sound or noise. The main symptoms of sharp sound defeat – sharply arisen and gradually abating pain and a ring in ears. The chronic akutravma is shown by gradual decrease in auditory acuity, discomfort and feeling of noise in ears, a sleep disorder and increased fatigue. The diagnostic program includes collecting anamnestichesky data and complaints of the patient, an otoskopiya, a speech research and a voice-frequency audiometriya. Treatment includes reception of vitamins . In, nootrop, a darsonvalization and oxygenotherapy, hearing aid.
In modern otolaryngology it is accepted to allocate sharp and chronic (more widespread) akutravma forms. About a quarter of all cases of the acquired neurotouch relative deafness is connected with acoustic damage of an inner ear. The bulk of patients – people whose profession is connected with constant noise. More often the persons working in the closed rooms and the having diseases of the top airways, acoustical pipes and a middle ear are ill. Akutravma makes about 60% of all pathologies caused by influence of physical factors in conditions of production and 23% of all occupational diseases. In this regard, most of patients – efficient persons aged from 30 up to 60 years. The disease with an identical frequency occurs among men and women. Geographical features of distribution are not noted.
The leading etiologichesky factor – excessively loud noise or a sound. The mechanism and speed of development of defeat, its main manifestations depend on character and duration of sound influence. On the basis of it it is expedient to allocate two main reasons for an acoustic trauma.
- Short-term superstrong sound. Includes any sounds which loudness exceeds 120 dB – whistle near an ear, a siren, a vehicle signal, explosion, a firearms shot etc. At the person the sharp akutravma which is often combined with a barotrauma results.
- Constant intensive noise. Regular and long impact of noise, with a volume of 90 dB and above (at hypersensibility – from 60 dB), causes development of a chronic acoustic trauma. In most cases pathology develops at the people facing professional vrednost – workers have spheres heavy machine and shipbuilding, aircraft, metallurgy, the textile industry, etc.
Sharp and chronic (professional) acoustic injuries have various mechanisms of development. Short-term, excessively strong sound causes hemorrhage in a perilimfa of forward department of a webby labyrinth of a snail – one of components of an inner ear. In parallel there is a shift and swelling of external and internal voloskovy cages of kortiyevy body. The last is the final receptor device in which vibrations of a perilimfa will be transformed to a nervous impulse, transferred in TsNS. In some cases there is a lead of body of Korti from the main membrane. The pathogenesis of a chronic akutravma is completely not studied therefore select several probable theories. According to them, continuous impact of loud noise on the hearing aid can cause degenerate changes of kortiyevy body, violation of metabolism and the phenomenon of fatigue, formation of the pathological centers excitement in the subcrustal centers.
Symptoms of an acoustic trauma
The sharp form of a disease is characterized by sharp ear pain at the time of perception of a sound and sudden one - or bilateral loss of hearing. The person loses an opportunity to perceive external sounds and hears only gradually abating ring or peep which can be combined with dizziness, the aching or pulsing pain in an ear. At a combination with a barotrauma the clinical picture is supplemented with bleeding from external acoustical pass and a nose, violation of spatial orientation. The further current depends on weight of defeat. The acoustic trauma of easy degree is characterized by gradual restoration of sound perception to initial level already 5-30 minutes later. At medium-weight and heavy degree within the first 2-3 hours of the patient hears only loud sounds or shout. Further there is a stage-by-stage renewal of sound perception to the level of relative deafness of various degree of expressiveness.
Development of a clinical picture of a chronic acoustic trauma takes place 4 stages.
- The stage of initial manifestations arises already 1-2 days of stay in noise conditions later. It is characterized by discomfort and a ring in an ear. After the termination of influence of external factors these manifestations disappear after several rest-hours. In 10-15 days there is an adaptation, symptoms gradually abate. The general duration of a stage – from 1-2 months to 4-6 years. Further the period of "a clinical pause" in which unpleasant feelings are absent, but gradually follows, it is imperceptible for the patient, auditory acuity decreases. Its duration fluctuates within 2-7 years.
- The stage of increase of symptoms is shown by constant noise in ears and bystry development of relative deafness. At the same time loss of hearing happens consistently: at first the sound on high, then at average and low frequencies ceases to be perceived. The present clinical manifestations are supplemented with nonspecific symptoms: increased fatigue and irritability, deterioration in attention, loss of appetite and sleeplessness. The created relative deafness remains at one level even at further work in the same conditions from 5 to 15 years.
- The terminal stage develops at persons with hypersensibility to noise, 15-20 years of work later under noise influence. Its signs – deterioration in auditory acuity up to inability to perceive informal conversation from distance over 2 meters, intolerable noise in ears, an incoordination of movements and balance, a constant headache and dizziness.
The most widespread complication of an akutravma – deafness. The main reasons for full loss of hearing – untimely diagnostics and treatment. Its development is promoted by failure to follow recommendations of the otolaryngologist and refusal of change of a profession at initial stages of chronic acoustic defeat. Continuous impact of noise leads to system violations: arterial hypertension, neurocirculator dystonia, asteno-neurotic and angiospastichesky syndromes. Any acoustic damage of the voloskovy office of kortiyevy body reduces its resistance to infectious agents, system intoxication and effect of ototoksichny pharmaceuticals.
Diagnosis of an acoustic trauma for the skilled otolaryngologist does not represent difficulties. For this purpose enough anamnestichesky data, complaints of the patient and research of hearing. Other inspections (MRT of mostomozzhechkovy corners, an acoustic impedansometriya) are used for differentiation with other pathologies.
- Anamnestichesky data. At an akutravma there are always situations in which the patient is under the influence of a sharp and loud sound or is long stayed in the conditions of constant noise.
- Otoskopiya. At a part of patients the pathological vtyanutost of an eardrum is visualized that is characteristic of continuous titanic reductions of her muscles. At a combination of sharp acoustic damage to a barotrauma a large number of blood clots and a rupture of an eardrum is defined.
- Speech audiometriya. Allows to establish distance at which shout (80-90 dB), colloquial (50-60 dB) and the shepotny speech (30-35 dB) is perceived sick. Normal the conversation is heard at distance to 20 meters, and whisper – to 5 m. At relative deafness these distances decrease or the speech to become non-demountable. At heavy damages only shout directly over an ear is perceived.
- Voice-frequency threshold audiometriya. Reflects defeat of the sound perceiving device that is shown by the progressing deterioration in air and bone conductivity with increase in frequency of the generated sounds.
Differential diagnosis of a sharp acoustic trauma is carried out with sudden (sharp) neurotouch relative deafness. The second pathology can be result of allergic reaction or sharp violation of brain blood circulation. The chronic akutravma demands differentiation with Menyer's disease, presbiakuzisy and tumors of a mostomozzhechkovy corner. At a padalekmiksiya there is a unilateral relative deafness, spontaneous deterioration or regress of symptoms can be observed. Presbiakuzis arises aged 70 years are more senior, and decrease in auditory acuity is not followed by emergence of third-party noise. Tumors of a mostomozzhechkovy corner, besides relative deafness, are also shown by damage of a facial and trigeminal nerve.
Treatment of an acoustic trauma
Therapeutic actions depending on a form of pathology can be aimed at the maximum restoration of sound perception or prevention of further development of relative deafness. At a sharp akutravma absolute rest, vitamins is shown. In, medicines of calcium and bromine. At a part of patients auditory acuity is independently restored several hours later. If after influence of a short-term sharp sound relative deafness develops, treatment is carried out by analogy with a chronic acoustic trauma.
At a chronic akutrama treatment is most effective at stages of initial manifestations and "a clinical pause". At it is modern the begun treatment at some patients it is possible to reach regress of symptoms. Later therapy is aimed at prevention of further deterioration in hearing. The therapeutic program includes the following medicines and actions:
- Change of a profession. The exception of impact of strong noise on the sound perceiving device prevents further development of relative deafness.
- Nootropa. Medicines of this row improve sound perception and other cognitive functions of the person, speed up work of a brain in general.
- Group B vitamins. Improve metabolism of TsNS, increase its resilience of an excessive impulsation of a middle ear, tone up work of an acoustical nerve.
- Antigipoksanta. Normalize function of the injured hairs of kortiyevy body for the account improvement of metabolism in the conditions of insufficient intake of oxygen and nutrients.
- Darsonvalization. Impact of pulse currents on area of a mastoidal shoot stimulates work of an inner ear. The technique allows to fight against third-party noise in ears.
- Hyperbaric oxygenation (GBO). In the conditions of the increased oxygen pressure brain blood circulation and reparative processes in an inner ear improves.
- Hearing aid. Use of hearing aids gives the chance to improve quality of hearing at the expressed relative deafness.
Forecast and prevention
The forecast for recovery at an acoustic trauma depends on its form. At sharp defeat of easy severity there is a complete recovery of initial auditory acuity. At a heavy sharp or chronic akutravma irreversible relative deafness of various degree develops. Observance of safety regulations on production and in life, work in rooms with full-fledged sound insulation and a sound absorption, use of individual antinoise or special earphones belongs to preventive measures. The important role is won back by regular professional surveys of the persons working as a result of constant noise.