Mumps
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
promptly to public health authorities. Treatment is supportive. Vaccination is
effective for prevention.
Most viruses that infect humans can affect
both adults and children and are discussed elsewhere in. Viruses
with specific effects on neonates are discussed in Infections in Neonates. This
topic covers a viral infection that is typically acquired during childhood
(although it 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
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 of Mumps
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
·
Orchitis or oophoritis
·
Meningitis or encephalitis
·
Pancreatitis
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 of Mumps
Clinical evaluation
Viral detection via reverse
transcription–polymerase chain reaction (RT-PCR)
Serologic testing
Mumps is suspected in patients with
evidence of 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: Non-Mumps 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.
Non-Mumps Causes of Parotid and Other
Salivary Gland Enlargement
Non-Mumps Causes of Parotid and Other
Salivary Gland Enlargement
Suppurative bacterial parotitis
HIV parotitis
Other viral parotitis
Metabolic disorders (eg, uremia, diabetes
mellitus)
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)
Malignant and benign salivary gland tumors
Drug-related parotid enlargement (eg, due
to iodides, phenylbutazone, or propylthiouracil)
Laboratory diagnosis of mumps is necessary
if disease is
Unilateral
Recurrent
Occurs in previously immunized patients
Causes prominent involvement of tissues
other than the salivary glands
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 for Mumps
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 of Mumps
Supportive care
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 of Mumps
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:
The first dose at age 12 to 15 months
The second dose at age 4 to 6 years
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
health care practitioners should be excused from work from 12 days after the
initial exposure through 25 days after the last exposure.
Key Points
Mumps causes painful enlargement of the
salivary glands, most commonly the parotids.
Cases may occur in vaccinated people
because of primary vaccination failure or waning immunity.
About 20% of infected postpubertal males
develop orchitis, usually unilateral; some testicular atrophy may occur, but
testosterone production and fertility are usually preserved.
Other complications include
meningoencephalitis and pancreatitis.
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.
Universal vaccination is imperative unless
contraindicated (eg, by pregnancy or severe immunosuppression).