Hearing loss can massively affect speaking, language learning, school achievement, and intellectual development and decrease adult job opportunities. It also causes mental retardation and psychological impairment in children. It decreases the cognitive ability of old people. 

Hearing loss can have various reasons like genetics, drugs, and viruses and that's what we are going to discuss in this article.

Overview

Definition of mumps

Mumps is an illness caused by the paramyxovirus, it usually affects children but it can also affect adults. It affects the parotid glands ( which is the main gland responsible for secretion of the saliva in the mouth, it is located between the ear and the jaw ) and causes parotitis (swelling of the parotid glands) 

Mode of transmission

The virus can be found in the saliva. It is transmitted either by direct contact through the secretions of the respiratory system like someone sneezes or coughs, through saliva like kissing or sharing utensils or if an infected person coughed into hands and then touched a door knob.

Humans are the only hosts for the mumps-causing virus. The incidence of mumps increases in winter and also in spring. The breakouts are usually at college dorms, schools and sports teams, places where people are in close contact with each other.

Importance of discussing mumps and hearing loss

But what makes mumps an important topic to discuss Although mumps usually cause flu-like symptoms and bilateral swelling of the parotid glands, it doesn't stop there. Mumps can be accompanied by pancreatitis (which is inflammation of the pancreas), orchitis ( inflammation of the testicle), oophoritis (inflammation of the ovaries), encephalitis (inflammation in the brain), and hearing loss either unilateral ( which is the most common type of bilateral which is a bit rare), also mumps infection in the first trimester can lead to fetal loss (loss of the baby).

How does mumps infection occur?

Mechanism of infection

Entry and spread of the virus in the body

Paramyxovirus starts its replication in the respiratory tract and then can spread to the blood and cause viremia (a state of increase in the number of viruses in the bloodstream) and then spread to other locations like the nervous system and it can cause encephalitis and meningitis, affecting the hearing as well and to the glandular system (a system that consists of glands) causing parotitis either bilateral or unilateral. 

Symptoms and diagnosis

Common symptoms 

Mumps symptoms are flu-like, which are low-grade fever, headache, myalgia ( pain in muscles), anorexia (losing appetite), malaise ( a general feeling of fatigue and discomfort all over your body) and parotid gland swelling which it is usually bilateral.

These flu-like nonspecific symptoms usually precede the swelling of parotid glands by several days.

Diagnostic methods (clinical, serological)

Diagnosis of mumps is made both clinically and serologically ( lab test to know the number of antibodies against a certain virus)

So clinical diagnosis is usually based on the acute attacks and swelling of either one or both of the salivary glands, mostly parotid glands which can last for two or more days.

As for the serological diagnosis when the patient undergoes the serological test, finding mumps antibodies only is not diagnostic but the increase fourfold in the number of mumps antibodies is evidence of the presence of infection.

People who are vaccinated usually give false negative results which means the test shows negative results while they are infected. 

Mumps and hearing loss

Hearing loss is a common and well-known complication of mumps. Studies have shown that 1 in every 1000 patients is susceptible to hearing loss. It's usually unilateral so it may not be noticed immediately by the patients or their guardians. 

How does mumps-induced hearing loss occur?

Most patients who have lost their hearing due to mumps, suffer unilateral hearing loss. It is usually on the same side where the parotid gland is swollen and if the parotid gland is swollen on both sides it is usually on the side where it has severe swelling.

Viral invasion of the inner ear

As mentioned before, after the virus enters the body through the respiratory tract, replicates and then gets into the bloodstream causing viremia. This viremic state allows the virus to reach the inner ear through the bloodstream and causes inflammation in the cochlea (it's a part of the inner ear that plays an important role in the hearing sensation) which leads to hearing loss.

Clinical presentation

Patients who suffer mumps-induced hearing loss suffer from vestibular symptoms like vertigo and tinnitus (having noises in your ears) and a feeling of fullness in their ear on the same side of hearing loss. Patients can also suffer from nausea, vomiting and disequilibrium which gradually fades after several days.

Hearing loss reaches its maximum level when it comes to high frequencies 

After all these symptoms resolve, the patient would suffer dysfunction in the involved ear.

Deafness is very rare among patients suffering Mumps-Induced Hearing Loss since it's very rare for the hearing loss to be bilateral 

Diagnosis and evaluation of hearing loss in mumps patients

Clinical evaluation

The patient undergoes several tests to evaluate their hearing loss 

1. Physical exam:

The doctor starts to examine your ear for causes of your hearing loss like ear wax or infection. 

Whisper test: You get one of your ears covered and start listening to sounds and words at different volumes to evaluate your hearing ability. 

Tuning fork test: A tuning fork is a metal instrument that has two tongs and makes a sound with a certain frequency when hit, it can be used to diagnose hearing loss and to know where the damage has happened.

Audiometer tests: An audiologist (someone specializes in hearing loss) makes a test on a patient by directing sounds and words through the earphones the patients wear, the tones are repeated  at low levels till reach the quietest sound the patient can hear 

Audiological rehabilitation

Hearing aids and assistive listening devices

When hearing loss is caused by damage to the inner ear, hearing ability can be restored by the use of a hearing aid. There are many shapes and kinds of hearing aids, an audiologist can help with the proper and correct choice of hearing aid.

When does the patient need cochlear implants?

When the hearing aid doesn't give the desired result we shift to a cochlear implant.

In severe cases where bilateral hearing loss is caused by mumps, patients will need to be treated by cochlear implants as well.

In some patients where damage has occurred to the central nervous system, cochlear implants don't give a favourable result regarding speech perception, which eventually affects the quality of life.

Prevention

Vaccination

MMR vaccine or Measles-Mumps-Rubella vaccine is recommended for babies between the ages of 12-15 months for the first dose and between 4-6 years of age for the second dose unless it is medically contraindicated or unless the person already is immune against mumps like being diagnosed with mumps, there is serological evidence of the presence of immunity against mumps. Children and adolescents who got the two-dose vaccination showed a dramatic decrease in mumps attacks.

FAQs

Is hearing loss from mumps permanent?

Hearing loss due to mumps can be transient in some cases and can be permanent in others according to the amount of damage that happens to the inner ear.

Which is the most serious complication of mumps?

Mumps has several complications but the most serious one has to be encephalitis or meningitis as they affect the brain.

Can mumps cause permanent damage?

Encephalitis and meningitis caused as a complication of mumps can be permanent and are very serious conditions that need hospitalization, as permanent hearing loss due to mumps is a bit rare

Is it OK to get mumps twice?

Since patients who have already been infected by mumps gain immunity against it. It is very rare to encounter mumps and get infected for the second time.

When to worry about mumps?

When you start to suffer from one or more of the complications caused by mumps like orchitis, oophoritis, pancreatitis, or either unilateral or bilateral hearing loss the most serious complications being encephalitis and meningitis.

How long does it take to fully recover from mumps?

If it is not a severe case with any complications, it usually takes two weeks for full recovery.

Is mumps contagious after 5 days?

The period where a person with mumps can be infectious is before the start of clinical symptoms by 1 or 2 days till after they get parotitis and show clinical symptoms by 7 days.⁹

Which antibiotic is best for mumps?

Mumps is a viral infection, that cannot be treated by antibiotics since antibiotics only treat bacterial infections

What not to do with mumps?

Mumps is very contagious, especially at the beginning so it is advisable to take full precautions not to get anyone else infected as well, mumps cause flu-like symptoms so rest is also advisable

Summary

Mumps is a viral infection caused by the paramyxovirus that primarily affects the parotid glands, leading to swelling. While it typically causes flu-like symptoms, it can result in serious complications, including hearing loss. The virus can spread through respiratory droplets or saliva and is most common in close-contact environments like schools and dorms.

One of the key complications of mumps is hearing loss, which typically affects one ear (unilateral) and occurs due to viral inflammation in the cochlea. Though hearing loss can sometimes be temporary, it can be permanent depending on the extent of the damage. Vaccination with the MMR vaccine significantly reduces the incidence of mumps and its complications, including hearing loss.

Diagnosis is made through clinical symptoms and serological tests. Treatment for hearing loss may include hearing aids or cochlear implants, depending on the severity. Prevention through vaccination is the best method to avoid mumps and its complications.