When people think of hearing loss or deafness, they usually think of someone who happened to be around a deafening situation, listened to very loud music or suffered trauma on the ear. Very rarely do people consider infections as a cause of infection. Globally 5% of the world’s population have disabling hearing loss and 60% of hearing loss in children due to preventable causes like infections.
Hearing loss occurs when one is unable to hear sounds at 20 decibels and above. There are different levels of hearing loss:
- Mild: They are able to understand speech but cannot hear low sounds, e.g: whispers and speech in the presence of background noise.,
- Moderate: Can hear sounds from 35 to 50. They cannot hear speech unless the speaker uses a raised voice. Hearing aids are recommended at this point.
- Severe: Can hear sounds and speech between 65 to 79 dB. One may find it difficult to communicate effectively without a hearing aid.
- Profound: Can only hear sounds at 80 to 94.9 dB. They are unable to hear speech and require Hearing aids, Lip syncing or sign language to communicate.
Diseases that can lead to Hearing loss
Hearing loss can be caused by bacteria or viral infections that are either congenital or acquired. Some of them include:
- Rubella: This is a disease with an acute rash caused by an RNA virus of the genus Rubivírus and the Togaviridae family, which is highly contagious and mainly affects children. The clinical state is characterized by a maculopapular and diffuse pinpoint rash, starting on the face, scalp, and neck, later spreading to the trunk and limbs. The infection acquired after birth usually causes a mild or even subclinical disease. The main symptoms of this form are retroauricular, cervical and suboccipital lymphadenopathy, rash, and fever. Maternal infection during early pregnancy can lead to infection of the fetus, resulting in congenital rubella. This affects most organsystems, causing cataracts, microphthalmia, heart defects, skin rash, retardation of growth, and hearing loss. In general, hearing loss affects about 50% of individuals with the disease and is normally severe to profound. Auditory manifestations may occur months to years after the initial infection
- Cytomegalovirustomegalovirus (CMV): which belongs to the herpesvirus family, is an enveloped virus that has the largest genome among the viruses that infect animal species. In immunocompetent individuals, it is generally responsible for asymptomatic infections. The highest incidence of the primary infection occurs in two peak periods: the first is in childhood, with early acquisition as a result of perinatal infection, and the second is in adolescence, through sexual transmission or by kissing. It infects up to 70% of children, and about 1–2% of infants are infected with CMV. In the congenital form, clinical manifestations range from the unapparent to the severe and widespread. Cytomegalic inclusion disease develops in about 5% of the infected fetuses. The most common manifestations at presentation are petechiae, hepatosplenomegaly, and jaundice. Deafness occurs in 20–65% of infants with this disease, which is typically bilateral. In patients with hearing loss, a consistent pattern follows, and this can develop over a period of years. Among asymptomatic patients, the rate of hearing loss of such children ranges from 7% to 13% and should therefore be considered in patients with nonsyndromic and nongenetic hearing loss.
- Syphilis: Syphilis is an infectious disease caused by a bacterium, Treponema pallidum, which is predominantly transmitted sexually. If left untreated, the disease can progress to stages that adversely affect the skin and internal organs such as the heart, liver, and nervous system central. Hearing loss can occur because of syphilis, but currently this is rare, and this being most often in the tertiary phase, hearing loss can occur in;
- Otosyphilis may be present in the form of a sudden and fluctuating sensorineural loss, episodic vertigo, with progressive unilateral or bilateral loss. Acquired syphilis may also affect the inner ear, simulating Ménière’s disease. Hearing loss can progress rapidly progressive, initially with good discrimination; tinnitus and vestibular symptoms disappear to the extent that the destruction of the labyrinth is completed.
- Congenital syphilis is due to the hematogenous spread of Treponema pallidum of pregnant women who have not been treated or inadequately treated for their unborn child, via the placenta. Transmission can occur at any stage of pregnancy and in any stage of the disease. Congenital syphilis can cause severe deafness and separately affect both ears. Manifestation occurs when a child is around two years old or between 8 and 20 years old.
- Toxoplasmosis: Toxoplasmosis is caused by infection with the obligate intracellular parasite Toxoplasma gondii. Both in its acute and in its chronic form, it is related to the appearance of a clinically evident disease, including lymphadenopathy, encephalitis, myocarditis, and pneumonitis. In immunocompetent individuals, acute toxoplasmosis is habitually asymptomatic and goes unnoticed in 80–90% of adults and children with acquired infection. In the congenital form, the infection of the placenta determines the hematogenous infection of the fetus. The proportion of fetuses that are infected increases as pregnancy progresses, but the severity of the infection declines.
- Mumps: Also known as Epidemic parotiditis is an acute systemic and contagious viral infection. A Paramyxovirus, with an RNA genome, is involved. The most typical clinical manifestations are sialadenitis, epididymo-orchitis, pancreatitis, meningitis, and hearing loss. Sensorineural hearing loss occurs in up to 5/10,000 cases and may appear some days or weeks after the parotiditis. Deafness is usually sudden, profound, associated with or without nausea, vomiting, dizziness, and tinnitus. Hearing loss, which is unilateral in 80% of cases, is more common for high frequencies of sound and may present reduced caloric responses to the vestibular test. There may be atrophy of the organ of Corti and of the stria vascularis, with minimal effect on the vestibular system.
- Otitis media: Also known as middle ear infection, otitis media is an infection that causes inflammation and build up of fluid behind the ear drum. In some cases, the eardrum is perforated, allowing the pus to escape. It is the most common infection that causes deafness in children. This is because their Eustachian tube is smaller than that of adult, making it more susceptible to blockage by mucus if the child has a cols.
Conclusion
Deafness is caused by a multitude of factors including infections although they are more common in children. Through awareness and early detection, it is possible that many cases of hearing loss could have been prevented.
References
- Ear Health Deafness and Hearing Loss Fact Sheet | Africa Health Organisation. (2019, March 22). Africa Health Organisation. https://aho.org/fact-sheets/ear-health-deafness-and-hearing-loss-fact-sheet/
- World Health Organization: WHO. (2025, February 26). Deafness and hearing loss. https://www.who.int/news-room/fact-sheets/detail/deafness-and-hearing-loss
- Mota, L. a. A., Leitão, P. C. A., De Barros, P. M. F., & Leão, A. M. D. a. C. (2015). Hearing loss in infectious and contagious diseases. In InTech eBooks. https://doi.org/10.5772/61818
- NHS inform. (2024, May 2). Middle ear infection (otitis media) | NHS inform. NHS Inform. https://www.nhsinform.scot/illnesses-and-conditions/ears-nose-and-throat/middle-ear-infection-otitis-media/
