Mumps
(Epidemic Parotitis)
Most viruses that infect humans can affect both adults and children and are discussed elsewhere in THE MANUAL. Viruses with specific effects on neonates are discussed in Infections in Neonates. This chapter covers viral infections that are typically acquired during childhood (although many may also affect adults).
The causative agent of mumps, a paramyxovirus, is spread by droplets or saliva. The virus probably enters through the nose or mouth. It is in saliva up to 7 days before salivary gland swelling appears with maximal transmissibility just before the development of parotitis. It is also in blood and urine and, if the central nervous system (CNS) is involved, in cerebrospinal fluid (CSF). One attack usually confers permanent immunity.
Mumps is less communicable than measles. It occurs mainly in unimmunized populations, but outbreaks among largely immunized populations have occurred. A combination of primary vaccine failure (failure to develop immunity after vaccination) and waning immunity may have played a part in these outbreaks. In 2006, there was a resurgence of mumps in the US with 6584 cases, which occurred primarily in young adults with prior vaccination. Since that time, sporadic outbreaks, mainly at college campuses and in other close-knit communities, have contributed to cases fluctuating from a low of 229 in 2012 to high of 6366 in 2016 and 6109 in 2017 (see Centers for Disease Control and Prevention [CDC] Mumps Cases and Outbreaks).
As with measles, mumps cases may be imported, leading to indigenous transmission, especially in congregate settings (eg, college campuses) or closed communities (eg, tradition-observant Jewish communities). Peak incidence of mumps is during late winter and early spring. Disease occurs at any age but is unusual in children < 2 years, particularly those < 1 year. About 25 to 30% of cases are clinically inapparent.
Symptoms and Signs
After a 12- to 24-day incubation period, most people develop headache, anorexia, malaise, and a low- to moderate-grade fever. The salivary glands become involved 12 to 24 hours later, with fever up to 39.5 to 40° C. Fever persists for 24 to 72 hours. Glandular swelling peaks on about the 2nd day and lasts 5 to 7 days. Involved glands are extremely tender during the febrile period.
Parotitis is usually bilateral but may be unilateral, especially at the onset. Pain while chewing or swallowing, especially while swallowing acidic liquids such as vinegar or citrus juice, is its earliest symptom. It later causes swelling beyond the parotid in front of and below the ear. Occasionally, the submandibular and sublingual glands also swell and, more rarely, are the only glands affected. Submandibular gland involvement causes neck swelling beneath the jaw, and suprasternal edema may develop, perhaps because of lymphatic obstruction by enlarged salivary glands. When sublingual glands are involved, the tongue may swell. The oral duct openings of the affected glands are edematous and slightly inflamed. The skin over the glands may become tense and shiny.
Complications
Mumps may involve organs other than the salivary glands, particularly in postpubertal patients. Such complications include
About 20% of infected postpubertal males develop orchitis (testicular inflammation), usually unilateral, with pain, tenderness, edema, erythema, and warmth of the scrotum. Some testicular atrophy may ensue, but testosterone production and fertility are usually preserved. In females, oophoritis (gonadal involvement) is less commonly recognized, is less painful, and does not impair fertility.
Meningitis, typically with headache, vomiting, stiff neck, and CSF pleocytosis, occurs in 1 to 10% of patients with parotitis. Encephalitis, with drowsiness, seizures, or coma, occurs in about 1/5000 to 1/1000 cases. About 50% of CNS mumps infections occur without parotitis.
Pancreatitis, typically with sudden severe nausea, vomiting, and epigastric pain, may occur toward the end of the first week. These symptoms disappear in about 1 week, leading to complete recovery.
Prostatitis, nephritis, myocarditis, hepatitis, mastitis, polyarthritis, deafness, and lacrimal gland involvement occur extremely rarely. Inflammation of the thyroid and thymus glands may cause edema and swelling over the sternum, but sternal swelling more often results from submandibular gland involvement with obstruction of lymphatic drainage.
Diagnosis
Mumps is suspected in patients with salivary gland inflammation and typical systemic symptoms, particularly if there is parotitis or a known mumps outbreak. Laboratory testing is not needed to make a diagnosis but is strongly recommended for public health purposes. Other conditions can cause similar glandular involvement (see Table: Other Causes of Parotid and Other Salivary Gland Enlargement). Mumps is also suspected in patients with unexplained aseptic meningitis or encephalitis during mumps outbreaks. Lumbar puncture is necessary for patients with meningeal signs.
Other Causes of Parotid and Other Salivary Gland Enlargement
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Suppurative bacterial parotitis |
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HIV parotitis |
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Other viral parotitis |
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Metabolic disorders (eg, uremia, diabetes mellitus) |
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Mikulicz syndrome (a chronic, usually painless parotid and lacrimal gland swelling of unknown etiology that occurs with tuberculosis, sarcoidosis, systemic lupus erythematosus, leukemia, and lymphosarcoma) |
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Malignant and benign salivary gland tumors |
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Drug-related parotid enlargement (eg, due to iodides, phenylbutazone, or propylthiouracil) |
Laboratory diagnosis of mumps is necessary if disease is
Mumps testing is also recommended for all patients with parotitis lasting ≥ 2 days without an identified cause. RT-PCR is the preferred method of diagnosis; however, serologic testing of acute and convalescent sera by complement fixation or enzyme-linked immunosorbent assays (ELISA) and viral culture of the throat, CSF, and occasionally the urine can be done. In previously immunized populations, IgM testing may be falsely negative; therefore, RT-PCR assays should be done on samples of saliva or throat washings as early in the course of the disease as possible.
Other laboratory tests are generally unnecessary. In undifferentiated aseptic meningitis, an elevated serum amylase level can be a helpful clue in the diagnosis of mumps despite the absence of parotitis. White blood cell count is nonspecific; it may be normal but usually shows slight leukopenia and neutropenia. In meningitis, CSF glucose is usually normal but is occasionally between 20 and 40 mg/dL (1.1 and 2.2 mmol/L), as in bacterial meningitis. CSF protein is only mildly elevated.
Prognosis
Uncomplicated mumps usually resolves, although a relapse occurs rarely after about 2 weeks. Prognosis for patients with meningitis is usually good, although permanent sequelae, such as unilateral (or rarely bilateral) nerve deafness or facial paralysis, may result. Postinfectious encephalitis, acute cerebellar ataxia, transverse myelitis, and polyneuritis occur rarely.
Treatment
Treatment of mumps and its complications is supportive. The patient is isolated until glandular swelling subsides. A soft diet reduces pain caused by chewing. Acidic substances (eg, citrus fruit juices) that cause discomfort should be avoided.
Repeated vomiting due to pancreatitis may necessitate IV hydration. For orchitis, bed rest and support of the scrotum in cotton on an adhesive-tape bridge between the thighs to minimize tension or use of ice packs often relieves pain. Corticosteroids have not been shown to hasten resolution of orchitis.
Prevention
Vaccination with live mumps virus vaccine (also see Table: Recommended Immunization Schedule for Ages 0–6 Years and see Table: Recommended Immunization Schedule for Ages 7–18 Years) provides effective prevention and causes no significant local or systemic reactions. Two doses, given as a combined measles, mumps, and rubella vaccine, are recommended for children:
Adults born during or after 1957 should have 1 dose, unless they have had mumps diagnosed by a health care practitioner. Pregnant women and people with an impaired immune system should not be given such live-attenuated vaccines.
Postexposure vaccination does not protect against mumps from that exposure. Mumps immune globulin is no longer available, and serum immune globulin is not helpful. The Centers for Disease Control and Prevention recommend isolation of infected patients with standard and respiratory droplet precautions for 5 days after the onset of parotitis. Susceptible contacts should be vaccinated, and a 3rd dose is recommended for previously immunized people at increased risk of mumps during an outbreak, as determined by public health officials. Robust data are lacking, but a 3rd dose and additional measures may help control an outbreak (1). Nonimmune asymptomatic healthcare providers should be excused from work from 11 days after the initial exposure until 25 days after the last exposure.
Prevention reference
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1. Marin M, Marlow M, Moore KL, Patel M: Recommendation of the Advisory Committee on Immunization Practices for use of a third dose of mumps virus–containing vaccine in persons at increased risk for mumps during an outbreak. MMWR Morb Mortal Wkly Rep 67:33–38, 2018. doi: http://dx.doi.org/10.15585/mmwr.mm6701a7.
Key Points
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Mumps causes painful enlargement of the salivary glands, most commonly the parotids.
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Cases may occur in vaccinated people because of primary vaccination failure or waning immunity.
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About 20% of infected postpubertal males develop orchitis, usually unilateral; some testicular atrophy may occur, but testosterone production and fertility are usually preserved.
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Other complications include meningoencephalitis and pancreatitis.
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Laboratory diagnosis is done mainly for public health purposes and when disease manifestations are atypical, such as absence of parotitis, unilateral or recurrent parotitis, parotitis in previously immunized patients, or prominent involvement of tissues other than the salivary glands.
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Universal vaccination is imperative unless contraindicated (eg, by pregnancy or severe immunosuppression).
More Information
Drugs Mentioned In This Article
| Drug Name | Select Trade |
|---|---|
propylthiouracil |
No US brand name |
immune globulin |
Gammagard S/D |
