​What is the cause of deafness? This is the culprit!

Deafness is not unfamiliar to many people. There are many types of deafness. The most common type of deafness is the gradual decline in hearing as people age. Some other causes are congenital developmental deficiencies or pathological deafness caused by illness. Deafness must be treated promptly.

Causes of Deafness

Main causes: congenital malformation, obstruction of external auditory canal, middle ear inflammation, ear trauma, middle ear tumor, otosclerosis, acute infectious disease, bacterial or viral infection, drug poisoning, vascular sclerosis, bone hyperplasia, insufficient blood supply, degenerative lesions, blast, auditory neuropathy, autoimmune disorder, Meniere's disease, central deafness

Depending on the type of deafness, the causes vary:

1. Conductive hearing loss

1. Congenital: Common congenital malformations include malformations of the external ear and middle ear, such as congenital atresia of the external auditory canal or incomplete development of the tympanic membrane, ossicles, cochlear window, and vestibular window.

2. Acquired: obstruction of the external auditory canal, such as cerumen embolism, bone warts, foreign bodies, tumors, inflammation, etc. Purulence or non-purulent inflammation of the middle ear may cause obstruction of the middle ear sound transmission mechanism, or ear trauma may damage the ossicular chain, or benign or malignant tumors of the middle ear or otosclerosis, etc.

2. Sensorineural hearing loss

1. Congenital: often caused by incomplete development of the inner ear structures or auditory nerve, or caused by viral infection or taking ototoxic drugs during pregnancy, or injury during childbirth, etc.

2. Acquired: There are several reasons:

(1) Infectious disease-induced deafness: Various acute infectious diseases, bacterial or viral infections, such as epidemic encephalitis B, mumps, purulent meningitis, measles, scarlet fever, influenza, herpes zoster oticus, typhoid fever, etc. can damage the inner ear and cause sensorineural deafness of varying degrees.

(2) Drug-induced deafness: It is more common in aminoglycoside antibiotics, such as gentamicin, kanamycin, polymyxin, dihydrostreptomycin, neomycin, etc. Other drugs such as quinine, salicylic acid, cisplatin, etc. can also cause sensorineural deafness. Ear drug poisoning is closely related to the body's susceptibility. Drug-induced deafness is bilateral, often accompanied by tinnitus, and vestibular function may also be impaired. Long-term use of such drugs in the middle ear may also penetrate into the inner ear through the cochlear window membrane, so this should be noted.

(3) Presbycusis: It is mostly caused by vascular sclerosis and bone hyperplasia in the elderly, which leads to insufficient blood supply to the spiral organ hair cells and spiral ganglion, degenerative lesions, or decline of the central nervous system, resulting in hearing loss.

(4) Traumatic deafness: Craniocerebral trauma and temporal bone fractures can damage the inner ear structure, leading to inner ear bleeding, or inner ear damage caused by strong concussions, all of which can lead to sensorineural deafness, sometimes accompanied by tinnitus and vertigo. Those with mild symptoms can recover. Accidental damage to the inner ear structure during ear surgery can also lead to deafness.

(5) Sudden deafness: It is a type of sensorineural deafness that occurs suddenly and has unknown causes. It is currently believed that acute vascular obstruction and viral infection are common causes of this disease. The lesions may involve the spiral organ and even rupture the vestibular membrane and cochlear window membrane. Deafness can appear in an instant or reach a peak quickly within hours or days. It is mostly unilateral but may also affect both ears, accompanied by tinnitus and sometimes vertigo. Early treatment can achieve better results.

(6) Blast-induced hearing loss: It is an acute damage to the hearing organ caused by sudden strong pressure waves and strong pulse noise. The eardrum and cochlea are the parts of the hearing organ that are most vulnerable to damage. When people are exposed to noise above 90dB(A), cochlear damage may occur. If the intensity exceeds 120dB, permanent deafness may occur. Tympanic membrane damage is related to the intensity of the pressure wave and manifests as tympanic membrane congestion or tympanic membrane perforation. The degree of deafness is related to noise intensity, number of exposures, peak value, pulse width, spectrum, individual differences and other factors of the pressure wave. The nature of deafness is mostly sensorineural or mixed.