Nonsensory hearing loss

Nonsensory hearing loss

Sensorineural hearing loss (NT) is hearing loss with preserved speech perception due to damage to the sound-perceiving apparatus or the central part of the auditory tester. Cochlear neuritis is a disease of the auditory tester, clinically manifested by HT and subjective tinnitus. Involvement of the pre-door root of the VIII cranial nerve in the process causes the occurrence of both auditory and vestibular disorders (systemic dizziness and imbalance).

• • NT can be the result of damage to any part of the auditory tester, from neurosensory epithelial cells of the spiral organ to subcortical and cortical auditory centers. However, most often NT is caused by pathology of the receptor and root of the vestibulocochlear nerve.
  • Unilateral hearing loss and deafness almost always have a peripheral origin.

Frequency

• • 1-6% of the world’s population suffers from a hearing loss that makes communication difficult
  • NT is observed more often than conductive hearing loss, in 74 and 24% of cases, respectively.
  • They note a trend towards an increase in the number of patients with NT
  • Acute NT occurs more often in men and predominantly at a young age (the average age of patients is 21-38 years)
  • 70-90.4% of patients suffering from NT report tinnitus.

Classification

• • Acute (sudden deafness) NT and chronic NT
  • Downstream – reversible, stable, progressive NT
  • According to the severity of hearing loss
  • 1 degree (mild) – the average hearing loss for tones 500, 1000, 2000, 4000 Hz does not exceed 50 dB, conversational speech is perceived from a distance of 6 to 4 m
  • II degree (medium) – average hearing loss from 50 to 70 dB, conversational speech is perceived from a distance of 4 to 1 m
  • III degree (severe) – the average hearing loss exceeds 70 dB, conversational speech is perceived from a distance of 1 to 0.25 m
  • With an average hearing loss of more than 80 dB and colloquial speech perceived at a distance of less than 0.25 m, one speaks of deafness
  • By etiology
  • Acquired (70-80%) as a result of birth trauma (accompanied by cerebrovascular accident and asphyxia), hemolytic disease of newborns
  • Congenital (20-30%)
  • Genetically determined (hereditary) HT, transmitted both in an autosomal recessive and autosomal dominant manner (see also Appendix 2. Inherited diseases: sorted phenotypes)
  • Caused by an infectious disease of the mother during pregnancy (rubella, measles, influenza, toxoplasmosis). Etiology
  • Infectious diseases (30%): viral – influenza, mumps, measles, rubella, herpes; bacterial – meningococcal meningitis, syphilis, typhoid
  • Intoxication (more than 2%)
  • Ototoxic drugs – aminoglycoside antibiotics (streptomycin, monomycin, kanamycin, neomycin, gentamicin, tobramycin, amikacin), cytostatics (endoxan, cisplatin, etc.), NSAIDs, antiarrhythmic products (quinidine, etc.), loop diuretics (furosemide)
  • Household (alcohol, nicotine) and industrial (gasoline, hydrogen sulfide, aniline, fluorine, mercury, arsenic, etc.) toxic substances
  • Traumatic factor
  • Mechanical trauma can lead to a fracture of the base of the skull with a fissure of the pyramid of the temporal bone, infrequently accompanied by damage to the auditory root of the VIII cranial nerve
  • Barotrauma (pressure in the middle ear above 400 mm of water column) causes rupture of the secondary tympanic membrane, fracture of the base of the stirrup, rupture of the vestibular membrane
  • Acoustic and vibration injuries at the level of maximum permissible parameters lead to damage to receptors in the cochlea. The combination of both factors together gives an adverse effect 2.5 times more often than exposure to noise and vibration separately. High-frequency impulse noise above 160 dB causes, as a rule, irreversible LT
  • Vascular-rheological disorders. Changes in vascular tone due to direct or reflex stimulation of the sympathetic nerve endings of large arteries (internal carotid, vertebral), as well as circulatory disorders in the vertebrobasilar basin due to changes in the vertebral arteries, lead to circulatory disorders in the spiral arteries and arteries of the vascular stria, the formation of blood clots, hemorrhages in endo- and perilymphatic spaces
  • Age-related changes in the hearing tester (presbycusia)
  • Neurinoma of the VIII cranial nerve
  • Paget’s disease
  • sickle cell anemia
  • Hypoparathyroidism
  • Allergy
  • Local and general exposure to radioactive substances
  • Meteorological factor: there is a significant relationship between sudden NT and the state of the weather, between fluctuations in the spectrum of atmospheric electromagnetic waves, the passage of cyclones in the form of a warm front of low pressure and the frequency of development of pathology. It has been established that acute sudden NT occurs more often in the second month of each season (January, April, July, October).

Risk factors

• • Toddlers
  • NT of unknown etiology in family members
  • consanguineous marriages
  • Frequent abortions in the mother
  • Rubella, influenza in the first trimester of pregnancy in the mother
  • Drinking alcohol and smoking during pregnancy
  • Pathology of the placenta
  • The birth weight of the child is less than 2,500 g
  • Severe neonatal jaundice
  • In adults
  • Obesity
  • Hypercholesterolemia
  • Anemia
  • Arterial

hypertension

• • Reduced adaptive capacity in stressful situations due to the psychological characteristics of the individual. Pathogenesis – ischemia and malnutrition of sensitive cells and other nerve elements up to degeneration as a result of impaired microcirculation and capillary stasis.

Clinical picture

• • Hearing loss
  • Subjective noise in the ear(s)
  • Signs of vestibular neuritis (not always)
  • Unexplained dizziness
  • Unsteadiness when standing and walking.

Diagnostics

• • Functional studies of auditory and vestibular testers
  • Acumetry (the study of hearing in a whisper and spoken language) – a significant difference between the perception of whispered and spoken speech
  • Tuning fork research methods – shortening of the perception of the sounding tuning fork C | 28 in the experience of Schwabach, positive experiments of Rinne and Federici, in the experience of Weber, the sound of the tuning fork CP8 is lateralized into a better hearing or healthy ear
  • Audiological methods
  • Tonal threshold audiometry – downward configuration of the curves due to the deterioration in the perception of predominantly large tones, the absence of an air-bone interval, a break in the curves at the frequencies of their maximum decrease; high frequency tinnitus
  • Suprathreshold audiometry – a positive phenomenon of accelerated volume rise
  • ultrasound
  • The thresholds of audibility of ultrasounds are increased by 2-3 times or more compared to the norm.
  • Lateralization of ultrasound into a healthy or better hearing ear
  • Objective audiometry (in adults – an additional research method)
  • Measuring the acoustic impedance of the middle ear
  • Electrocochleography
  • Registration of cortical and stem potentials
  • In babies, the recording of auditory evoked potentials is the main (often the only) method for diagnosing a hearing defect.

Otoscopy – pathological changes are traditionally not detected. Differential Diagnosis

• • Meniere’s disease
  • Otosclerosis (cochlear form)
  • Neurinoma of the VIII cranial nerve.

Treatment:

Tactics of conducting

• • Therapy for acute NT is considered as an emergency (preferably in a specialized hospital)
  • Elimination of the etiological factor
  • Starting treatment as early as possible
  • It is mandatory to use complex etiotropic and pathogenetic therapy, which allows to normalize microcirculation in the inner ear
  • In the period of stabilization of NT – courses of maintenance treatment 1-2 times / year
  • B vitamins
  • Biostimulants
  • Anticholinesterase agents
  • Classes with an audiologist
  • Physiotherapy: endoural or mastoid electrophoresis 1-5% prozerin solution, 1-5% potassium iodide solution, 1% nicotinic acid solution, mud applications on the area of ​​the mastoid processes; balneotherapy (especially radon therapy)
  • Acupuncture, electroacupuncture, magnetopuncture, pharmacopuncture
  • Bilateral hearing loss, deafness in one ear and hearing loss in the other – indications for hearing aids
  • A new trend in hearing rehabilitation is the method of cochlear stimulation using an electric current supplied directly to the cochlea – electrode hearing aids or cochlear implantation.

Conservative therapy

• • Etiotropic drugs for toxic NT – antidote products; unithiol (5 ml 5% IM solution for 20 days) and

sodium thiosulfate (5-10 ml of 30% solution IV, 10 injections per course), as well as an activator of tissue respiration – calcium pantothenate (1-2 ml of 20% solution 1-2 r / day p / to, in / m or in / in).

• • Normalization of oxygenation of the tissues of the inner ear
  • Hyperbaric oxygenation (10 sessions of 45-60 minutes each)
  • Normobaric inhalations of CO2 and carbogen.
  • Normalization of microcirculation in the ear labyrinth
  • Anti-coagulation therapy: heparin 15,000-20,000 IU/day in 4 doses i.v. or i.m.
  • Trental (pentoxifylline) 0.1-0.3 g/day IV drip in combination with low molecular weight dextrans, glucose
  • Piracetam nbsp; – 20% solution for

2-6 g/day in 0.9% solution of NaCl IV drip every day (total 3-5 injections)

• • ATP, cocarboxylase, vitamins B1, B6, B12.
  • Anticholinesterase Products
  • Galantamine 1 ml 0.5% solution with 1-2% solution of novocaine meatotympanally every day, for a course of 15 injections
  • Prozerin 1 ml of 0.05% solution with 1-2% solution of novocaine meatotympanally every day, for a course of 15 injections.
  • Vasodilators
  • Nicotinic acid nbsp; 0.1% solution, starting with 1 ml, increasing the dose to 5 ml, then reducing it to 1 ml IM or IV
  • Stugeron (cinnarizine) 0.05 g 2-3 r / day orally with meals.
  • Glucocorticoids – dexamethasone (4 mg/day), prednisolone hemisuccinate (30-60 mg/day) IM or IV.
  • Fibrinolytic products – streptokinase 200 GOO-250,000 IU IV in 50 ml of 0.9% NaCl solution for 30 minutes, then 100,000 IU / h for 16-18 hours.
  • Drugs are also administered by endural phonophoresis: first, a broad-spectrum antibiotic in combination with glucocorticoid products, and from 5-6 days – novocaine and dibazol.

Surgical treatment is indicated for excruciating tinnitus and the ineffectiveness of conservative treatment. The intervention is carried out on the autonomic nervous system (resection of the tympanic plexus, removal of the stellate node, upper cervical sympathetic node). Destructive operations on the cochlea and the vestibulocochlear nerve are performed infrequently and only in cases of grade III HT or complete deafness. The prognosis depends on the periods of treatment initiation, the level of damage to the auditory tester, and the etiological factor. Prevention

• • Elimination of the negative impact of environmental factors on hearing function (noise, vibration, chemical, household and professional hazards)
  • Exclusion of alcohol and smoking in persons with NT
  • Exclusion from medical practice (especially in babies) of ototoxic drugs or their use for health reasons with the appointment of detoxification agents (hemodez), antihistamine products, vitamins
  • Appointment of trental (pentoxifylline) to infectious patients with a high probability of developing NT and deafness (especially with meningococcal infection). Synonyms
  • Perceptual hearing loss
  • Acoustic neuritis
  • cochlear neuritis

Reduction. NT – sensorineural hearing loss See also Meniere’s disease, Otitis media chronic purulent, Otitis media secretory. Otosclerosis

ICD

• H90.3 Sensorineural hearing loss, bilateral
• H90.4 Sensorineural hearing loss, unilateral with normal hearing in contralateral ear
• H90.5 Sensorineural hearing loss, unspecified