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Mumps
Frances Yung-tao Wu, MD
image BASICS
An acute, generalized paramyxovirus infection typically presenting with unilateral or bilateral parotitis
DESCRIPTION
  • Up to 1/3 of individuals with mumps are asymptomatic.
  • Painful parotitis occurs in 95% of symptomatic mumps cases. Epidemics in late winter and spring. Transmission by respiratory secretions.
  • Incubation period is 14 to 24 days.
  • System(s) affected: hematologic/lymphatic/immunologic, reproductive, skin, exocrine
  • Synonym(s): epidemic parotitis; infectious parotitis
EPIDEMIOLOGY
  • Predominant age: 85% of mumps case occur before age 15 years:
    • Adult cases are typically more severe.
  • Predominant sex: male = female
  • Geriatric population: Most adults are immune.
  • Acute epidemic mumps
    • Most cases occur in unvaccinated children between ages 5 and 15 years.
    • Recent (2006) U.S. epidemic in vaccinated college students aged 18 to 24 years: 5,700 U.S. cases:
      • Another U.S. epidemic in 2009 to 2010 in New York/New Jersey: >1,500 cases
  • Mumps is unusual in children <2 years of age and most infants <1 year are immune.
    • Period of maximal communicability is 24 hours before to 72 hours after onset of parotitis
Incidence
  • 1,151 cases in the United States in 2014 (1)
  • Occasional epidemic outbreaks in a given region
Prevalence
  • 0.0064/100,000 persons
  • 90% of adults are seropositive even without history.
ETIOLOGY AND PATHOPHYSIOLOGY
Mumps virus replicates in glandular epithelium of parotids, pancreas, and testes, leading to interstitial edema and inflammation.
  • Interstitial glandular hemorrhage may occur.
  • Pressure caused by edema of the testes against the tunica albuginea can lead to necrosis and loss of function.
RISK FACTORS
  • Foreign travel: Many other nations do not vaccinate for mumps, including most of Africa and South Asia.
  • Crowded environments such as dormitories, barracks, or detention facilities increase risk of transmission.
  • Immunity wanes after single-dose vaccination:
    • When receiving two doses, immunity drops from 95% to 86% after 9 years.
    • Genotypic variation from original vaccine strain may have a role in decreased vaccine efficacy (2).
GENERAL PREVENTION
  • Vaccination
    • Two doses of live mumps vaccine or measlesmumps-rubella (MMR) vaccine are recommended, first at 12 to 15 months and second at 4 to 6 years of age.
    • 95% effective in clinical studies, but field trials show 68-95% efficacy, which may be below level for herd immunity to prevent spread.
    • Scandinavian data suggest prevention may require 95% first dose and >80% second dose adherence.
    • Adverse effects: most common proven effect is idiopathic thrombocytopenic purpura (ITP), with incidence of 3.3/100,000 doses
    • No relationship between MMR vaccine and autism
    • Immunoglobulin (Ig) is not effective in preventing mumps.
  • Postexposure vaccination does not protect from recent exposure (3)[B]
  • Isolate hospitalized patients for 5 days after onset.
  • Isolate nonimmune individuals for 26 days after last case onset (social quarantine).
Pregnancy Considerations
  • Live viral vaccines are typically contraindicated in pregnancy; however, vaccination of children should not be delayed due to a pregnant family member.
  • Immunization of contacts protects against future (but not current) exposures.
image DIAGNOSIS
PHYSICAL EXAM
  • Painful parotid swelling (unilateral or bilateral) obscures angle of mandible and elevates earlobe
  • Meningeal signs in 15%, encephalitis in 0.5%
  • Rarely arthritis, orchitis, thyroiditis, mastitis, pancreatitis, oophoritis, myocarditis
  • Rare maculopapular, erythematous rash
  • Up to 50% of cases may be very mild.
  • Redness at opening of Stensen duct but no pus
  • Swelling in sternal area; rare, but pathognomonic of mumps
DIFFERENTIAL DIAGNOSIS
  • If not epidemic, other viruses are more common: parainfluenza parotitis, Epstein-Barr virus, coxsackievirus, adenovirus, parvovirus B19
  • Suppurative parotitis: often associated with Staphylococcus aureus (presence of Wharton duct pus on massaging parotid gland essentialy excludes diagnosis of mumps)
  • Recurrent allergic parotitis
  • Salivary calculus with intermittent swelling
  • Lymphadenitis from any cause, including HIV infection
  • Cytomegalovirus parotitis in immunocompromised patients
  • Mikulicz syndrome: chronic, painless parotid and lacrimal gland swelling of unknown cause that occurs in tuberculosis, sarcoidosis, lupus, leukemia, lymphosarcoma, and salivary gland tumors
  • Sjögren syndrome, diabetes mellitus, uremia, malnutrition
  • Drug-related parotid enlargement (iodides, guanethidine, phenothiazine)
  • Other causes of the complications of mumps (meningoencephalitis, orchitis, oophoritis, pancreatitis, polyarthritis, nephritis, myocarditis, prostatitis)
  • Mumps orchitis must be differentiated from testicular torsion and from chlamydial or bacterial orchitis. (Testicular sonogram can be useful.)
DIAGNOSTIC TESTS & INTERPRETATION
  • Three special tests used to confirm an outbreak—if positive, report to health department (1)[A]
    • IgM titer (positive by day 5 in 100% of nonimmunized patients)
    • Swab of parotid duct or other affected salivary ducts for viral culture
    • Rise in IgG titer samples; test should be ordered if patient previously immunized: 1st sample within 5 days of onset, and 2nd, 2 weeks later.
  • Other potential findings: elevated serum amylase; CSF leukocytosis, or leukopenia.
  • Testicular ultrasound may help differentiate mumps orchitis from testicular torsion.
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Diagnostic Procedures/Other
If meningitis is present, lumbar puncture to exclude bacterial process. CSF pleocytosis, usually lymphocytes, is found in 65% of patients with parotitis.
Test Interpretation
Periductal edema and lymphocytic infiltration in affected glands on biopsy
image TREATMENT
  • No specific antiviral therapy, only supportive care (1)[A],(4)[C]
  • Analgesics to relieve pain
  • Avoid corticosteroids for mumps orchitis because they can reduce testosterone concentrations and increase testicular atrophy.
  • IVIG only successful for certain autoimmune-based sequelae:
    • Postinfectious encephalitis
    • Guillain-Barré syndrome
    • ITP
  • Interferon-&agr;2b improved severe bilateral orchitis but did not decrease testicular atrophy in small studies (5)[B].
GENERAL MEASURES
  • Rarely need to hospitalize patients with high fever, pancreatitis, or CNS symptoms for supportive care, steroids, or interferon using appropriate isolation precautions
  • Orchitis
    • Ice packs to scrotum can help to relieve pain.
    • Scrotal support with adhesive bridge while recumbent and/or athletic supporter while ambulatory
MEDICATION
First Line
  • Analgesics and anti-inflammatory medications (acetaminophen, nonsteroidal anti-inflammatory drugs [NSAIDs]) may diminish pain and swelling in acute orchitis and arthritis mumps.
  • May use acetaminophen for fever and/or pain
  • Precautions: Avoid aspirin for pain in children as previously associated with Reye syndrome.
Second Line
  • Interferon-&agr;2b
  • Chinese medicinal herbs and acupuncture have not shown benefit in randomized controlled trials (6,7).
INPATIENT CONSIDERATIONS
Admission Criteria/Initial Stabilization
  • Hospitalize only if CNS symptoms occur.
  • Outpatient supportive care if no complications
IV Fluids
If severe nausea or vomiting accompanies pancreatitis
image ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
Mumps orchitis:
  • Bed rest and local supportive clothing (e.g., two pairs of briefs) or adhesive-tape bridge
  • Withhold from school until no longer contagious (9 days after onset of pain)
Patient Monitoring
Most cases will be mild. Monitor hydration status.
DIET
Liquid diet if unable to chew
PATIENT EDUCATION
Orchitis is common in older children but rarely results in sterility, even if bilateral.
PROGNOSIS
  • Complete recovery is typical; immunity is lifelong.
  • Transient sensorineural hearing loss in 4% of adults
  • Recurrence after 2 weeks may be nonepidemic parotitis.
REFERENCES
1. Centers for Disease Control and Prevention. Overview of mumps. http://www.cdc.gov/mumps/about/index.html
2. Gouma S, Sane J, Gijselaar D, et al. Two major mumps genotype G variants dominated recent mumps outbreaks in the Netherlands (2009-2012). J Gen Virol. 2014;95(Pt 5):1074-1082.
3. Fiebelkorn AP, Lawler J, Curns AT, et al. Mumps postexposure prophylaxis with a third dose of measles-mumps-rubella vaccine, Orange County, New York, USA. Emerg Infect Dis. 2013;19(9):1411-1417.
4. Davis NF, McGuire BB, Mahon JA, et al. The increasing incidence of mumps orchitis: a comprehensive review. BJU Int. 2010;105(8):1060-1065.
5. Yapanoglu T, Kocaturk H, Aksoy Y, et al. Long-term efficacy and safety of interferon-alpha-2B in patients with mumps orchitis. Int Urol Nephrol. 2010;42(4):867-871.
6. Shu M, Zhang YQ, Li Z, et al. Chinese medicinal herbs for mumps. Cochrane Database Syst Rev. 2012;(9):CD008578.
7. He J, Zheng M, Zhang M, et al. Acupuncture for mumps in children. Cochrane Database Syst Rev. 2012;(9):CD008400.
Additional Reading
&NA;
  • Flaherty DK. The vaccine-autism connection: a public health crisis caused by unethical medical practices and fraudulent science. Ann Pharmacother. 2011;45(10):1302-1304.
  • MacDonald N, Hatchette T, Elkout L, et al. Mumps is back: why is mumps eradication not working? Adv Exp Med Biol. 2011;697:197-220.
  • Shirts BH, Welch RJ, Couturier MR. Seropositivity rates for measles, mumps, and rubella IgG and costs associated with testing and revaccination. Clin Vaccine Immunol. 2013;20(3):443-445.
  • Zamir CS, Schroeder H, Shoob H, et al. Characteristics of a large mumps outbreak: clinical severity, complications and association with vaccination status of mumps outbreak cases. Hum Vaccin Immunother. 2015;11(6):1413-1417.
Codes
&NA;
ICD10
  • B26.9 Mumps without complication
  • B26.1 Mumps meningitis
  • B26.2 Mumps encephalitis
Clinical Pearls
&NA;
  • Mumps is a clinical diagnosis based on swelling of ≥1 parotid glands for ≥2 days without other obvious cause. Confirmatory testing must be done in epidemic settings.
  • Ultrasound is useful to distinguish testicular torsion from testicular pain related to mumps orchitis.
  • A history of vaccination with MMR does not exclude mumps. The MMR vaccine is 68-95% effective after a series of two immunizations. Immunity commonly wanes over time.