Deafness (hearing loss) - causes of sudden and gradual deafness

Conductive deafness is the result of changes to the external ear canal, the eardrum, or the middle ear. These changes hinder the proper transmission of sounds to the inner ear.

Sensorineural deafness occurs as a result of damage to the inner ear (sensory deafness) or to the eighth nervecranial, i.e. auditory (neuro-derivative deafness). Sensory hearing loss can be reversible and is rarely life-threatening. Neurogenic hearing loss, on the other hand, is rarely reversed and can be caused by the presence of life-threatening conditions.

Conductive deafness (hearing loss) - causes

The cause of conductive deafness may be obstruction of the external ear canal, e.g. by earwax (the so-called wax plug), a foreign body, inflammation of the outer ear (so-called swimmer's ear), less often by a tumor.

Conductive hearing loss in the middle ear can be caused by:

• acute otitis media is the most common cause of temporary hearing loss in children. If left untreated, it can lead to permanent deafness, especially if cholesteatoma (lumpy inflammation) develops;
• exudative otitis media - there is pain or a feeling of fullness in the ear, sometimes tinnitus, altered appearance of the eardrum. Risk factors are acute otitis media or other inflammatory conditions that contribute to this disease;
• chronic otitis media - long-lasting leakage from the ear is characteristic, usually visible perforation (perforation) of the eardrum, the presence of changes in the external auditory canal, sometimes the presence of cholesteatoma;
• ear trauma - often visible perforation of the eardrum and / or the presence of blood outside it;
• otosclerosis - auditory ossicles dysfunction (often related to pregnancy);
• tumors (benign or malignant) - characteristic issingle-sided deafness;

Sensorineural deafness (hearing loss) - causes

Sensorineural hearing loss, i.e. the hearing loss of the inner ear, can be caused by:

• genetic diseases (e.g. connexin mutation 28, Waardenburg syndrome) - in Waardenburg syndrome sometimes white streaks of hair on the forehead or eyes of different colors appear;
• exposure to strong sounds - some patients also develop tinnitus. In this case, the hearing loss is temporary, unless the eardrum and ossicles are damaged and lasts for several hours or days;
• senile hearing impairment (presbyacusis) - progressivebilateral hearing loss ;
• infection, e.g. meningitis, purulent labyrinthitis;
• autoimmune diseases, e.g. rheumatoid arthritis, amyotrophic lateral sclerosis;
• Meniere's disease - after each attack of the disease, hearing loss (usually unilateral)tinnitus and dizziness are also characteristic;
• barotrauma (barotrauma) - going through sudden changes in the surrounding pressure. Occasionally there is severe pain and dizziness. In this case, the risk factors for deaf development are a previous episode of hearing loss and / or hearing loss in close relatives;
• head trauma (with fracture of the skull base or concussion of the cochlea - the most important part of the inner ear) - labyrinthine disorders (increased dizziness with the sensation of spinning or linear movement), sometimes defects in the facial or trigeminal nerve;

Reception deafness can also be caused by the so-called ototoxic drugs (causing damage to the inner ear), e.g. acetylsalicylic acid, aminoglycosides, vancomycin, cisplatin, furosemide, ethacrynic acid, quinine.

Neurogenic deafness (hearing loss) - causes

• tumors of the post-cerebellar angle (e.g. neuroma of the auditory nerve, meningioma) - there is one-sided deafness, often with tinnitus, vestibular disorders (difficult orientation in the dark, dizziness), sometimes defects in the facial nerve or nerve tripartite;
• demyelinating diseases, e.g. multiple sclerosis - single-sided deafness is characteristic, and multifocal symptoms also appear. These ailments are periodically increasing and disappearing;

Sudden deafness - causes of sudden deafness

Sudden deafness may have an idiopathic background, which means that it is not entirely clear what causes it. In such cases it is usually suspected:

• viral infection (especially herpes simplex virus);
• paroxysmal autoimmune disorders;
• sharp obstruction of the small vessels of the inner ear;

The obvious reasons include:

• acute infections, e.g. bacterial meningitis, Lyme disease, epidemic parotitis, i.e. mumps, shingles. Sudden hearing loss may occur during the acute phase of the disease or immediately after its completion;
• serious head injury - with a fracture of the temporal bone or combined with a cochlear injury after a strong concussion;
• ear trauma, including barotrauma when diving to great depths, or violent exertion (such as lifting weights) causing a paraphilacic fistula between the middle and inner ear, resulting in sudden deafness. A paraphytic fistula can also be congenital, causing a sudden loss of hearing either spontaneously or underneaththe influence of injuries or large changes in the surrounding pressure;
• ww. ototoxic drugs can lead to deafness even one day after taking them, especially if they are overdosed;

The causes of deafness may be latent, i.e. deafness may be a separate first symptom of certain conditions that usually manifest themselves in a different way:

• acoustic neuroma;
• autoimmune disorders, e.g. Cogan's syndrome, various forms of vasculitis;
• cerebellar stroke;
• Meniere's disease;
• multiple sclerosis;
• reactivation of syphilitic infection in HIV-infected;
• rare hematological disorders - Waldenström's macroglobulinemia, sickle cell disease and some forms of leukemia;

Based on: The Merck manual. Clinical Symptoms: A Practical Guide to Diagnostics and Therapy, pp. ed. Porter R., Kaplan J., Homeier B., Wrocław 2010

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