Child with mumps.
Mumps is a contagious viral illness caused by the paramyxovirus. It is a human systemic disease that occurs worldwide but is highly preventable via the mumps vaccine. The mumps vaccine was introduced in 1967, and the disease became nationally reportable in 1968. The incidence has decreased substantially with vaccination, but periods of resurgence have occurred in recent years.[1]
See the Centers for Disease Control and Prevention (CDC) recommended immunization schedule for persons aged 0-18 years,[2] the catch-up schedule for persons aged 4 months to 18 years,[3] and the adult immunization schedule for persons older than 18 years.[4] See the full recommendations for the measles, mumps, rubella (MMR) and measles, mumps, rubella, varicella (MMRV) vaccines from the Advisory Committee on Immunization Practices,[5] including benefit versus risk profile and contraindications.
The mumps virus is transmitted by respiratory droplets, direct contact, or contaminated fomites. It has an incubation period of 14-18 days, ranging from 12-25 days after initial transmission.[6] After the incubation period, prodromal symptoms occur and last anywhere from 3-5 days. After the prodrome, the symptoms of the virus depend on which organ is affected. The most common presentation is a parotitis, which occurs in 30-40% of patients. Other reported sites of infection are the testes, pancreas, eyes, ovaries, central nervous system, joints, and kidneys. A patient is considered infectious from about 3 days before the onset and up to 4 days after the start of active parotitis. Infections can be asymptomatic in up to 20% of persons.
Mumps occurs worldwide, with a peak incidence during late winter to early spring. Sporadic mumps outbreaks have occurred among susceptible individuals in various settings, including military posts, schools, colleges and universities, and summer camps. During outbreaks, mumps can affect vaccinated individuals, but prior immunization helps to limit the symptoms, duration, and spread of mumps.[6]
United States
Prior to the vaccine about 50% of children contracted mumps. Approximately 200,000 cases were reported in 1964 before the introduction of the vaccine compared with 291 cases in 2005. A resurgence occurred in 1986 and 1987, with almost 13,000 cases reported, and it was associated with a lack of state requirements for immunizations. These cases were mostly in older school-aged children (10-19 y). In the 1990s, 30-40% of cases reported each year were in persons aged 15 years or older as opposed to 90% being younger than 15 years old in earlier years.[7] . Since the introduction of the two-dose MMR vaccination in 1989, US mumps cases decreased more than 99%, with only a few hundred cases reported each year.[8]
An outbreak of mumps occurred in Iowa, with 219 cases reported in 2006. In addition, another 14 cases of people with symptoms consistent with the virus were reported in nearby states (Illinois, Nebraska, and Minnesota). This is the largest number of cases reported in the United States since 1988. The median age of the 219 persons was 21 years, with 30% being college students. In 1991, Iowa mandated that 2 doses of mumps vaccine be required for all people entering public schools. Vaccination history was studied in 133 people from this outbreak: 65% (87) of the patients had received 2 doses, 14% (19) had received only 1 dose, and 6% (8) received no vaccine at all. The source of the Iowa epidemic is unknown.[9]
CDC data showed that two large mumps outbreaks occurred in 2009-2010. One of the outbreaks was in New York City, which involved over 3,000 people and affected students who were part of a close religious community and attended schools in which they participated in activities that involved very close contact. The source of the infection was a student who returned from the United Kingdom during a large mumps outbreak in that country. The second outbreak occurred in the US Territory of Guam, which involved around 500 school-aged children. From January 1 to March 29, 2019, 34 states and the District of Columbia reported mumps infections in 426 people to the CDC.[8]
Among the infected, the most commonly reported symptoms were parotitis (83%), submaxillary/submandibular gland swelling (40%), fever (36%), and sore throat (32%). The average length of illness was 5.1 days. Complications, including encephalitis and orchitis, were reported in 5% of patients.
International
The variations in the number of persons who receive the mumps vaccination worldwide make it difficult to estimate the numbers affected. The incidence varies markedly from region to region.
The United Kingdom reported an epidemic of mumps in 2005, with 56,390 cases reported in persons aged 15-24 years who were not vaccinated.[7]
Sex
For parotitis, males and females are affected equally.
Symptomatic meningitis has a male-to-female ratio of 3:1.
Age
Before the mumps vaccine was introduced, most cases were in children aged 5-9 years, with 90% being younger than 15 years. The resurgence in the late 1980s affected older children aged 10-19 years. In more recent years, up to 30-40% of cases have been in persons older than 15 years.[1]
The prognosis of mumps infection is usually good. Children with mumps typically fully recover within a few weeks. When mumps occurs among adults, the illness is more likely to be severe.
The most serious complication is encephalitis, with a mortality rate of 1.5%.
Mumps during pregnancy increases the risk of embryonic and fetal death, as well as spontaneous abortion, although malformations following mumps virus infection during pregnancy have not been reported.[10]
Unilateral orchitis rarely causes sterility; however bilateral orchitis carries an increased risk.
Unilateral sensorineural hearing loss is believed to be a rare complication; however, subclinical or unrecognized mumps may contribute toward a higher incidence of unilateral hearing loss in childhood than is currently known. Bilateral involvement has also been documented.
For excellent patient education resources, visit eMedicine's Bacterial and Viral Infections Center. Also, see eMedicine's patient education article Mumps.
Between 1980 and 1999, an average of one death per year has occurred due to mumps. Most deaths occur in persons older than 19 years.
CNS involvement is common, but symptomatic meningitis occurs in only about 1-10% of patients. It usually resolves without complications, but adults are at a higher risk for sequelae. Encephalitis is rare (0.1% of cases). It has a mortality rate of 1.5%.[11, 12, 13, 14, 15]
Orchitis (usually unilateral) occurs in 50% of postpubertal males. It causes testicular atrophy in as many as 50% of persons affected but rarely causes sterility. The risk of sterility is higher in bilateral orchitis.[12, 16] Oophoritis occurs in a small percentage of postpubertal girls.
Pancreatitis occurs in 3% of persons infected with mumps. The hyperglycemia that results is usually transient, but a few cases of diabetes mellitus have been reported. It is not conclusive that the mumps virus has been the definitive cause.[15]
Deafness has been reported in 1 per 20,000 cases of mumps. In 80% of cases, the hearing loss is reported to be unilateral. Permanent unilateral deafness caused by mumps arises at an estimated frequency of one in 20,000 cases.[17, 18, 15]
Some deaths due to myocarditis have been reported. The incidence of this complication is reported to be up to 15%, but it is usually asymptomatic.[19]
The risk of spontaneous abortion is increased in women with mumps during the first trimester of pregnancy. Mumps during pregnancy has not been associated with congenital malformations.[20]
Other reported complications include chronic arthritis, arthralgias, and nephritis.[19]
Mumps is typically caused by a single-stranded RNA virus belonging to the Paramyxovirus genus. Humans serve as the only natural host for the mumps virus.
Other viruses implicated in recurrent parotitis are influenza, echovirus, parainfluenza (types 1 and 3), and coxsackievirus A. More rare causes of parotitis seen in persons with HIV infection are adenovirus or cytomegalovirus.
Risk factors include lack of immunization or incomplete immunization, international travel, and immune deficiencies.
After the incubation period, mumps usually has a prodromal phase, which consists of nonspecific viral symptoms: low-grade fever, malaise, myalgias, and headache.
The prodromal phase is usually followed by unilateral or bilateral parotid gland swelling. This usually occurs within the first 2 days of infection. Parotitis may be unilateral or bilateral. Initial unilateral involvement is followed by contralateral involvement in 90% of cases. Parotid swelling can last up to 10 days.[21]
Infections can be asymptomatic in up to 20% of persons and may be nonspecific or have predominantly respiratory symptoms in up to 50%.
Patients typically complain of worsening pain when eating or drinking acidic foods.
Persons can present with other symptoms without a preceding parotitis. CNS presentations can include headache, neck pain, and fever. Preceding parotitis can be absent in up to 50% of these persons.[17, 11, 13, 14]
Orchitis can occur in up to 50% of postpubertal males, and as many as 30% have bilateral involvement. Sterility is rare.[16, 12] Patients can present with abdominal pain due to oophoritis or pancreatitis. Oophoritis occurs in up to 5% of postpubertal females.
Sudden hearing loss results from a vestibular reaction.[17]
Other rare presenting symptoms can be due to arthralgias, arthritis, mastitis, thyroiditis, thrombocytopenic purpura, or nephritis.
Low-grade fever is common with mumps.
Classic parotid gland swelling typically manifests without warmth or erythema and rapidly progresses over several days. Swelling may be preceded by parotid tenderness and/or earache. Enlargement of the contralateral parotid gland is not uncommon.
The swollen parotid gland may lift the earlobe upward and outward.
The patient may have tenderness over the angle of the mandible, which itself may be obscured by parotid swelling.
Opening of the Stensen duct can be edematous and erythematous.
Trismus may or may not be present.
Submandibular and sublingual glands may also be involved and swollen.
A morbilliform rash may be present.
Potential complications of mumps are as follows:
Mumps has traditionally been considered a clinical diagnosis. However, data from a 2007 outbreak found that only 298 of 2082 cases (14%) of clinically diagnosed mumps were laboratory confirmed.[22] Laboratory evaluation is usually undertaken in the emergency department to look for other causes of a patient's symptoms or to evaluate for complications or comorbidity. Mumps-specific tests can generally be performed on an outpatient basis.
Mumps virus can be isolated from nasopharyngeal swabs, urine, blood, and fluid from buccal cavity typically from 7 days before up until 9 days after the onset of parotitis.
Mumps infection can be confirmed by demonstrating the following:
Leukocytosis or leukopenia may be present with lymphocyte predominance.
Serum amylase levels may be elevated.
CNS infections usually exhibit a lymphocytic pleocytosis. A viral culture of CSF (within first 3 days of clinical symptoms), urine (within first 2 weeks of symptoms), or saliva (starting on day 2 of symptoms and for one week after) can also be used to make the diagnosis.[23]
No specific imaging studies are diagnostic.
Imaging studies may be needed as a further workup with certain complications of mumps.
Testicular ultrasonography may be performed when acute orchitis is suspected, with specific indication to rule out torsion.
Prehospital Care
Supportive care is usually all that is needed for patients with mumps.
Persons exposed to the virus should be counseled on vaccination and risks.
Emergency Department Care
Supportive care with analgesics and antipyretics as needed. Symptomatic treatment with warm and/or cold compresses over the parotid gland may also be comforting. and outpatient follow up is indicated for straightforward infections.
Complications due to mumps should be treated based on presentation, as follows:
Vaccination remains the best protection. The Centers for Disease Control and Prevention posts the latest immunization schedules on their Web site.
All children older than 1 year and all adults should receive the full two-dose mumps vaccine unless contraindicated. The vaccine is live and is prepared within a chicken embryo and usually given as the mumps, measles, and rubella (MMR) vaccine. Groups who are of concern include those with severe egg allergies, pregnant women, and people who have high fevers or other severe illness or in the immunocompromised host.
If the history of being infected with the mumps virus or vaccination status is questioned, blood tests may be performed to check antibody levels, or the vaccine should simply be administered. In January 2018, The Advisory Committee on Immunization Practices (ACIP) recommended that persons previously vaccinated with 2 doses of a mumps virus–containing vaccine who are identified by public health authorities as being part of a group or population at increased risk for acquiring mumps because of an outbreak should receive a third dose of a mumps virus–containing vaccine to improve protection against mumps disease and related complications. Studies show that high-risk individuals during a mumps outbreak who had received a third dose of MMR vaccine had a lower risk of mumps than did those who had received two doses.[24]
The main reported adverse reactions to the vaccine have been pain, redness, and swelling at the injection site; joint or muscle aches; fevers; and, rarely, parotitis. Other more serious reported complications include CNS effects, such as deafness, febrile seizures,[25] and encephalitis, which are extremely rare and should not deter vaccination.
Acute mumps in an individual and/or community may result from a combination of factors, including incomplete vaccination, waning immunity over time (≥10 years since vaccination), and/or antigenic variation of mumps viruses.[26]
Current evidence suggests that patients diagnosed with mumps should be isolated with standard and droplet precautions in a hospital setting for 5 days from the onset of parotitis, including the exclusion of healthcare personnel from work during this period. Transmissibility is greatest immediately after onset of parotitis and decreases rapidly over the subsequent 5 days. Transmission may also occur from patients prior to development of parotitis or with subclinical mumps.[27]
In the past 15 years, the use of MMR has decreased because of a reported connection between vaccinations (especially MMR) and autism. A retrospective cohort study was conducted using an administrative claims database associated with a large US health plan comparing younger siblings with older siblings with autism spectrum disorder (ASD) versus younger siblings with older siblings without ASD.
Of 95,727 children with older siblings, 994 (1.04%) were diagnosed with ASD, and 1,929 (2.02%) had an older sibling with ASD. Of those with older siblings with ASD, 134 (6.9%) had ASD, versus 860 (0.9%) children with unaffected siblings (P < .001). MMR vaccination rates (1 dose) were 84% n = 78,549) at age 2 years and 92% (n = 86,063) at age 5 years for children with unaffected older siblings, versus 73% (n = 1409) at age 2 years and 86% (n = 1,660) at age 5 years for children with affected siblings. MMR vaccine receipt was not associated with an increased risk of ASD at any age. For children with older siblings with ASD, at age 2 years, the adjusted relative risk (RR) of ASD for 1 dose of MMR vaccine versus no vaccine was 0.76 (95% CI, 0.48-1.22; P = 0.25), and, at age 5 years, the RR of ASD for 2 doses compared with no vaccine was 0.56 (95% CI, 0.30-1.04; P = 0.07). For children whose older siblings did not have ASD, at age 2 years, the adjusted RR of ASD for 1 dose was 0.91 (95% CI, 0.68-1.20; P = 0.50) and, at age 5 years, the RR of ASD for 2 doses was 1.09 (95% CI, 0.76-1.54; P = 0.65).[28]
The study showed no association between either 1 or 2 doses of MMR vaccination and an increased ASD risk, even in children with an increased risk for ASD.
The American Academy of Pediatrics (AAP) reports that no available evidence supports the hypothesis that MMR vaccine causes autism or associated disorders. They also report that separate administration of measles, mumps, and rubella vaccines to children provides no benefit over the administration of the combination MMR vaccine. The AAP concluded that autism is a complex disorder of uncertain and multiple etiologies.[29]
Patients with specific complications may require further inpatient care.
Persons with encephalitis, meningitis, nephritis, myocarditis, or severe pancreatitis require inpatient management and monitoring.
Classic mumps with no major complications can be managed on an outpatient basis with supportive care and good follow up.
Current evidence suggests that patients diagnosed with mumps should be isolated for 5 days from the onset of symptoms.[27]
Scrotal support, ice, and analgesia are indicated.
Hearing testing is performed upon resolution of symptoms.
Transfer is rarely needed. Indication to transfer would be if major complications are present and current hospital does not have appropriate services to treat the patient appropriately.
Child with mumps.
