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Mumps is an acute, contagious, systemic viral disease, usually causing painful enlargement of the salivary glands, most commonly the parotids. Complications may include orchitis, meningoencephalitis, and pancreatitis. Diagnosis is usually clinical; all cases are reported to public health authorities. Treatment is supportive. Vaccination is effective for prevention.
The causative agent, a paramyxovirus, is spread by droplets or saliva. The virus probably enters through the nose or mouth. It is in saliva up to 6 days before salivary gland swelling appears. It is also in blood and urine and, if the CNS is involved, in CSF. One attack usually confers permanent immunity.
Mumps is less communicable than measles. It occurs mainly in unimmunized populations, but outbreaks on college campuses 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. As with measles, mumps cases may be imported, leading to indigenous transmission, especially in congregate settings (eg, college campuses). Peak incidence of mumps is during late winter and early spring. Disease occurs at any age but is unusual in children < 2 yr, particularly those < 1 yr. About 25 to 30% of cases are clinically inapparent.
Symptoms and Signs
After a 14- 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 h later, with fever up to 39.5 to 40° C. Fever persists 24 to 72 h. 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. 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 postpubertal male patients 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 1/1000 to 5000 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 wk, 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.
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 1: Other Viruses: 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.
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Table 1
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| 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's syndrome (a chronic, usually painless parotid and lacrimal gland swelling of unknown etiology that occurs with TB, sarcoidosis, SLE, 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)
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Laboratory diagnosis is necessary if disease is unilateral, is recurrent, occurs in previously immunized patients, or causes prominent involvement of tissues other than the salivary glands. Testing is also recommended for all patients with parotitis lasting ≥ 2 days without an identified cause. Acute and convalescent sera are tested by complement fixation or enzyme-linked immunosorbent assays (ELISA). If the laboratory is capable, the virus can usually be cultured from the throat, CSF, and occasionally the urine, or viral RNA can be detected by reverse transcription–PCR.
Other laboratory tests are generally unnecessary, although serum amylase level can also be measured; elevation suggests mumps. WBC 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 wk. Prognosis of 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 (see Immunization: Measles, Mumps, and Rubella and see Table 12: Approach to the Care of Normal Infants and Children: Recommended Immunization Schedule for Ages 0–6 yr) provides effective prevention and causes no significant local or systemic reactions. Two doses, given as combined measles, mumps and rubella vaccine, are recommended for children; the first is given at age 12 to 15 mo, and the second at age 4 to 6 yr. 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 and serum immune globulin are also not helpful.
Last full review/revision November 2009 by Mary T. Caserta, MD
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