Mumps, or infectious parotitis, is a paramyxovirus infection caused by a single stranded RNA virus.
Although this infection is less common since the introduction of the MMR vaccine in the UK, its prevalence has been increasing due to a reduced uptake of this vaccine in some areas.1
Children in the age range four to 15 are at the highest risk of developing mumps, but it can occur at any age. It is most unusual, however, for children under one year to develop it.
Pathogenesis and presentation
The mumps virus lives in saliva and urine and is transmitted via respiratory droplets or by direct contact.
Significant contact is considered as being in the same room for 15 minutes or more, or face-to-face contact. The incubation period of the virus is 15 to 24 days. It is more common in the winter months.
About three in 10 patients with mumps have a subclinical infection and have no symptoms. Patients with mumps are most infectious from about two days before the onset of symptoms and until about nine days after the symptoms start.
Most present with a tender parotid swelling which may be unilateral or bilateral. The swelling usually lasts from four to eight days. The patient may suffer from a dry mouth, and chewing and swallowing are often uncomfortable.
A fever, headache, fatigue and anorexia often accompany the illness. Malaise and generalised myalgia can also be common.
For most patients, mumps is a mild illness. On rare occasions a patient may develop the complications of mumps in the absence of the usual preceding clinical symptoms.
Teenagers and adults with mumps are more likely to develop complications (see box below). Multiple complications may occur in any one patient.
Diagnosis
The diagnosis of mumps is usually a clinical one. As mumps is a notifiable disease, the local Health Protection Unit (HPU) should be informed of potential cases and they will arrange a testing kit for confirmation and surveillance purposes.
Laboratory diagnosis is based on isolation of the virus, detection of viral nucleic acid, or by serological confirmation (generally the presence of IgM mumps antibodies).2
This is usually done using an oral fluid swab. There are commercial assays available that detect mumps IgG. They are designed for the diagnosis of acute infection and have not been validated for determining if there is a need for protection against mumps.
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Management
There is no specific treatment for mumps. Symptomatic treatment is generally all that is needed. The patient should rest, and drink adequate fluids. It is best to avoid citrus fruit juice, because this can make the parotid pain worse.
Paracetamol or ibuprofen will offer symptomatic relief, and of course aspirin should not be given to children below the age of 16.
It is recommended that children with mumps stay away from school for nine days after their parotid glands first become swollen. Symptoms usually resolve after about a week.
Specific treatments, such as human normal immunoglobulin, antibiotics or corticosteroids are not recommended for mumps.
Mumps epididymo-orchitis causes much concern in post-pubertal boys and young men. Patients should be reassured that the symptoms will completely resolve within one or two weeks, and that long-term problems with fertility are unlikely.
As there is no specific treatment, symptomatic measures should be recommended, including use of a scrotal support, the application of warm or cold packs, and paracetamol or ibuprofen.
If there are concerns about fertility, semen analysis can be offered three months after the mumps has resolved. This is of particular value if the epididymo-orchitis was bilateral, or particularly severe.
Occasionally mumps will occur in pregnancy. Pregnant women who are suspected of having mumps should be managed in the same way as otherwise healthy people.
If a pregnant woman has been exposed to mumps, they should be advised to seek medical advice if they go on to develop symptoms. The MMR vaccine is contraindicated in pregnancy.
Admission to hospital is rarely required, but may be necessary for patients with signs of mumps encephalitis (such as an altered level or loss of consciousness, focal neurological signs or seizures) and for patients with mumps meningitis (severe headache, vomiting, high fever, lethargy and neck ache).
It is important to discuss the case with the admitting doctor beforehand to ensure that appropriate isolation measures are available.
Immunisation
The MMR vaccine is currently routinely offered to all children aged 12 to 15 months in the UK.
A second dose is offered as part of the routine pre-school booster programme at three years and four months of age.
A previous history of mumps is not a contraindication for MMR vaccine.
The only absolute contraindications to the MMR vaccine are immunosuppression and a proven anaphylaxis to this vaccine in the past.
- Dr Newson is a GP in the West Midlands.
The Complications of Mumps |
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References
1. Pearce A, Law C, Elliman D et al. Factors associated with uptake of measles, mumps, and rubella vaccine (MMR). BMJ 2008; 336: 754-7.
2. Hviid A, Rubin S, Muhlemann K. Mumps. Lancet 2008; 371: 932-44.
Further Reading
- Mumps, Clinical Knowledge Summaries (December 2009). Available at www.cks.nhs.uk/mumps (accessed 16 February 2010)
- Guidelines on Mumps, Health Protection Agency. Available at www.hpa.org.uk/HPA/Topics/InfectiousDiseases/InfectionsAZ/1191942172909/ (accessed 16 February 2010).
