Intermittent impulse noise damage
Introduction
Introduction to intermittent impulse noise damage Intermittent impulse noise damage, also known as detonation deafness, is intermittent pulse noise damage caused by guns or bomb explosions. The noise is very strong and the peak of the spectrum changes greatly. It is a jump lift, the automatic rifle noise is 174dB, and the cannon reaches 188dB. When the cannon is launched, a strong positive pressure wave is generated instantaneously, and the pressure can reach 3000kg/cm2 for 5ms, followed by a negative pressure wave, which lasts for 30ms, and is collectively called pressure wave. Such strong noise and shock waves are most likely to cause hearing impairment. basic knowledge The proportion of illness: 0.005% Susceptible people: no specific population Mode of infection: non-infectious Complications: headache, vertigo, Meniere's disease, positional vertigo, tinnitus
Cause
Intermittent impulse noise damage cause
1. The strong positive pressure wave that occurs instantaneously in mechanical damage causes the tympanic membrane to rupture. According to the experiment, the critical perforation pressure of the tympanic membrane is 0.18kg/cm2, and the positive wave of up to 3000kg/cm2 can break through the tympanic membrane, so that the ossicular bone is displaced, and the tympanic chamber is bleeding. The ossicular chain and snail window act on the inner and outer lymph fluids, which can cause severe fluctuations in the endolymph, causing necrosis of the spiral and hair cells.
2. Metabolic disorder knocking causes SDH (succinate dehydrogenase) in hair cells, decreased activity of MDH (malate dehydrogenase), swelling of vascular endothelial cells, obstruction of blood flow and cell degeneration, and detonation waves can make other parts of the body The same rupture and crush injury, the larger the peak value of the detonation wave, or the longer the exposure time or the repeated damage, the more serious the damage, the tympanic membrane can be expressed as blood stasis, turbidity or perforation according to the degree of damage. The inner ear damage is not the same, the middle ear damage is serious and the inner ear damage can be very light.
Prevention
Intermittent impulse noise damage prevention
More blast injuries occur in wars. Therefore, we should improve weapons, reduce the intensity of knocking, strengthen the fortifications, educate the soldiers to pay attention to the protective position during combat, and when shooting guns and gunpowder, pay attention to mouth breathing and swallowing movements. Conducive to the opening of the Eustachian tube, the use of protective earplugs and helmets, there are many types of protective earmuffs and helmets in the country, such as wound V-51R earplugs and JW-2 earplugs.
Complication
Intermittent impulse noise damage complications Complications, headache, dizziness, Meniere's disease, location, vertigo, tinnitus
In acute injuries, there are many complaints of ear pain and tinnitus. Half of them have headaches and dizziness. Due to vestibular membrane peeling and degeneration, vertigo sometimes resembles Meniere's disease, sometimes like positional vertigo, which can last for several months to several years.
Symptom
Intermittent impulse noise damage symptoms Common symptoms Hearing loss Tympanic membrane Congestion Hearing loss Dizziness Ear stun Faint eyeball Tremor Head fainting Tinnitus earache
The response to the instantaneous detonation wave is immediate hearing fatigue and hearing threshold rise, a good temporary threshold shift, which is a reversible lesion. It can return to normal after 1 to 2 hours of rest, sometimes it takes several days or weeks to fully recover, due to the location of the contact source. Different, the hearing loss of the two ears can be different by 20dB. The damaged area first appears in the valley at 6kHz, which is twice as much as that at 4kHz. If it repeatedly receives the knock, it becomes an irreversible permanent threshold shift, which becomes permanent deafness. According to Wang Bozhen (1982) in the investigation of the Vietnam self-defense counterattack, 59.9% of patients with sensorineural deafness, mixed sputum 8.9%, and mental sputum 0.5%, acute complaints of ear pain and tinnitus, half of them have headache And dizziness, due to vestibular membrane peeling and degeneration, vertigo sometimes resembles Meniere's disease, sometimes like positional vertigo, which can last for months to years.
Examine
Intermittent impulse noise damage check
Perform an ear examination to detect hearing.
Diagnosis
Diagnosis and diagnosis of intermittent impulse noise damage
diagnosis
Diagnosis can be based on medical history, clinical symptoms, and laboratory tests.
Differential diagnosis
The disease Meniere's disease, dizziness, deafness and other phase identification.
