Mumps

ALSO KNOWN AS: Epidemic parotitis

ANATOMY OR SYSTEM AFFECTED: Genitals, glands, nervous system, pancreas

DEFINITION: An acute, contagious childhood disease caused by a virus and characterized by swollen salivary glands.

CAUSES: Viral infection

SYMPTOMS: Swollen salivary glands, fever, headache, stomach upset, loss of appetite, mildly congested nose, red rash; occasionally organ infection or joint inflammation

DURATION: Sixteen to eighteen days

TREATMENTS: Alleviation of symptoms with mild pain medications, adequate fluid and nutritional intake

Causes and Symptoms

Mumps infection is acquired after contact with infected respiratory secretions. An infected person can spread the disease between twelve and twenty-two days after infection. One case in a family generally means that every family member has been infected. Mumps is most commonly transmitted in the winter and early spring. During the sixteen- to eighteen-day incubation period, the virus grows first in the nose and throat; moves to the regional lymph nodes, and then from there into the bloodstream; and finally spreads to multiple organs and the central nervous system.

One-third of patients with mumps infection have no symptoms or only have very mild symptoms. Mumps is more severe after puberty. The first symptoms include fever, headache, stomach upset, loss of appetite, and a mildly congested nose. The most common finding is swelling of the salivary glands. This swelling usually starts on one side and then, in three-quarters of cases, moves to both sides. Salivary gland pain is most pronounced during the first few days and is associated with discomfort when eating or drinking acidic foods, such as orange juice. Rarely, a thin red rash can occur. The fever usually resolves in three to five days, and the salivary gland swelling subsides within seven to ten days.

Between 1 and 10 percent of patients show clinical evidence of central nervous system infection, most commonly meningitis but very rarely encephalitis. Infection of the central nervous system is more common in males than in females. Central nervous system disease typically occurs one to three weeks after the onset of salivary gland swelling, but it can also precede or follow this period. Symptoms include headache, fever, lethargy, stiff neck, and vomiting. Seizures occur in 20 percent of hospitalized patients. Central nervous system infection is almost always limited, without any lasting effect or complications. Hearing loss occurs during mumps illness in 4 percent of patients but is not higher in those with central nervous system involvement. Higher-tone deficits are noted most frequently. Recovery from hearing loss usually occurs within a few weeks following onset. Persistent hearing loss is usually only one-sided.

Orchitis, an infection of the testicles or ovaries, can also occur with mumps. The highest risk for this disease is after puberty, usually in males between fifteen and twenty-nine years of age. Between 14 and 35 percent of males with mumps infection develop orchitis. Fever, malaise, vomiting, and stomach pain are common symptoms. Testicular pain, swelling, and tenderness generally last for three to seven days. Involvement is one-sided in most cases. Symptoms usually began four to eight days following the onset of salivary gland swelling, but they can occur in the absence of gland swelling.

Mumps infection can cause other, less common complications. Infection of the kidney is almost always limited, but rare reports of kidney failure with mumps do exist. Multiple joint migratory arthritis with joint fluid has been described and is usually of short duration. Joint complaints are more common in males in their twenties. The usual signs of joint disease occur one to three weeks after the onset of salivary gland swelling. The large joints are more commonly affected.

Inflammation of the heart occurs in 4 to 15 percent of patients with mumps. It is most common in adults and generally resolves itself within two to four weeks. Infection and inflammation of the pancreas can occasionally occur. Pancreatitis can lead to fatty diarrhea and, very rarely, diabetes. Women who have mumps infection during pregnancy do not have an increased risk of delivering an infant with congenital malformation.

Very rarely, mumps will cause death. It is unclear why, prior to the advent of vaccination, mumps infection killed people each year. More than 50 percent of deaths are of adults.

Not all patients with salivary gland swelling have mumps. Swelling in this area of the face may be attributable to another disease of the salivary gland or another disease affecting other tissues in the face such as lymph nodes or bones. Persistent or recurrent swelling of the parotid gland should be evaluated by a physician.

Treatment and Therapy

Conservative therapy is indicated for mumps infection. No antiviral therapy is available. Adequate fluids and nutrition are important. A patient’s diet should avoid acidic foods and should be light and generous in fluids. Occasionally, mild pain medications may be necessary for severe headaches or salivary gland discomfort. Stronger pain medications may be needed with testicular involvement. In unusual cases where vomiting is severe, intravenous fluids may be required. A spinal tap (lumbar puncture) is rarely indicated, but patients who have this procedure frequently find that it relieves their headaches.

Exposure to mumps infection may cause anxiety in adult family members or day-care employees. A child with mumps should be isolated for nine days after the start of salivary gland swelling. Vaccine administration will probably not prevent infection after exposure, and a history of family exposure to mumps probably indicates past infection. The physician will reassure any adult exposed family members and indicate that it is unlikely that the vaccine will prevent this disease. Nevertheless, exposure may dictate the need to administer the vaccine, as determining immune status is generally not practicable.

Mumps is a self-limited illness and does not require the administration of antiviral medications, antibody preparations, or antibiotics. Mumps vaccine should be given to children to prevent this disease. The MMR vaccine, which combines the vaccines for measles, mumps, and rubella, should be given to children first when they are twelve months to fifteen months of age; a second dose should be given before the child first starts school (four through six years of age). About 98 percent of children will respond to this vaccine and not acquire mumps infection.

Perspective and Prospects

The term “mumps” is derived from an English dialect meaning “grimace,” attributed to the painful parotid gland swelling. The virus was first described in 1934, and a live vaccine was first licensed in 1967. Prior to 1980, the age group most affected by mumps was five- to nine-year-olds. In the 1980s, this group shifted to children and adolescents aged ten to nineteen. In the 1990s, most cases occurred in adults over twenty. This change was caused by the increased use of the mumps vaccine in children but not in adults.

Vaccination has been very successful, especially when combined with the measles and rubella vaccines, given in the second year of life, and repeated prior to school. Side effects from mumps vaccine are extremely rare and can include anything that is seen in mumps infection. Recent research in the area has been directed toward determining whether the vaccine in its present form or in another form should be considered for administration both to decrease adverse reactions and to decrease its cost and improve its applicability to a broader population.

An exceptionally high number of mumps cases reported in 2016 prompted further discussion about the effectiveness of the vaccine, especially over time, and the potential for adding a third dose. According to the Centers for Disease Control (CDC), there were 5,311 reported cases of mumps in 2016, the highest since 2006. By 2020, the number of reported cases of mumps had dropped to 142 cases. The majority of the cases in 2016 occurred on college campuses, which, because of the amount of crowding and socializing, are prime locations for outbreaks of an infection spread through saliva.

However, by 2023, the number of cases had risen to 436. Some experts hypothesized that explanations for the increased outbreaks could include the fact that two doses of the vaccine only ensure 88 percent protection, that more parents have chosen not to vaccinate their children, and that the vaccine could become less potent over time. Others contended that the immunity provided by the childhood vaccine was waning because, in general, people are protected for about thirty years. These experts believe that booster vaccinations should be required for adults.

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