Mumps : Symptoms, Causes , Diagnosis & Management.

Mumps : Symptoms, Causes , Diagnosis & Management.

Mumps is a viral infection and most often a mild disease of childhood. It affects children between five and nine years of age. However, the mumps can affect both adolescents and adults. Mumps virus is present throughout the world. It spreads by airborne droplets released when an infected person sneezes or coughs and by direct contact with an infected person. In temperate climates the disease incidence is peak in winter and spring while in hot climates the disease may occur at any time of year. Many countries experience epidemics at intervals of 2–5 years. Humans are the only known host for mumps virus. It primarily affects the salivary glands and it is sometimes called infectious parotitis.

In countries where large-scale immunization against mumps has been implemented, disease incidence has dropped dramatically. Before introduction of mumps vaccine, annual incidences were ranging from 100–1000 cases/100000 population.

Mumps is a vaccine-preventable disease. 121 countries or 62% countries of the world have included mumps vaccine in their routine schedule in the form of MMR vaccine.

Symptoms :

After an incubation period (the period between infection and the appearance of signs of a disease) of some two to four weeks mumps begins with non-specific symptoms such as myalgia, headache, malaise and low-grade fever.

Within a day of appearance of non specific symptoms, unilateral or bilateral (one side or both side) swelling of the parotid glands (in cheek and jaw area) develops with pain and tenderness.

Swelling is first visible in front of the lower part of the ear then it extends downward and forward. As swelling increases, the angle of the jawbone below the ear is not visible.

Patients typically complain of worsening pain when eating or drinking acidic foods.

In approximately 10% of cases other salivary glands (submandibular and sublingual glands) may be affected.

After about a week, fever and glandular swelling disappear, and the illness resolves completely if there are no complications.

In approximately 30% of cases, only non-specific symptoms occur or the infection is asymptomatic.

People with mumps are usually considered most infectious for few days before and after onset of parotitis (infection of parotid gland).

Causes:

Mumps is a viral disease caused by a virus (mumps virus) belongs to the genus Rubulavirus of the family Paramyxoviridae. It primarily affects the salivary glands. The incubation time (the period between infection and the appearance of signs of a disease) averages 16–18 days with a range of two to four weeks.

It mostly affects the children in the age group five to nine years but the virus may also affect adults in whom complications such as meningitis and orchitis are relatively more common. Males and females are affected equally with parotitis.

Transmission of infection: Mumps is a contagious disease. Infection spreads through saliva or mucus from the mouth, nose, or throat by an infected person through direct contact, airborne droplet infection or fomites during:

coughing, sneezing, or talking,
sharing items, such as cups or eating utensils, with others, and
touching objects or surfaces with unwashed hands that are then touched by others.

Mumps virus spreads before the salivary glands begin to swell and up to five days after the appearance of swelling. Natural infection with this virus is thought to confer lifelong protection.

Diagnosis :

Complete blood cell count (CBC) – A complete blood cell count reveals a normal, decreased, or elevated white blood cell (WBC) count, with predominating lymphocytes in differential count.

Inflammatory markers-Sera inflammatory markers, such as C-reactive protein or erythrocyte sedimentation rate (ESR), can be elevated to show a nonspecific systemic inflammatory response.

Serum amylase is elevated in mumps parotitis (amylase-S) and in pancreatitis (amylase-P). Serum lipase is elevated in pancreatitis.

Specific immunoglobulin-Mumps infection can be confirmed by a positive mumps-specific immunoglobulin M (IgM) titer or by demonstration of a significant rise in mumps-specific immunoglobulin G (IgG) antibody titers between acute and convalescent sera specimens.  IgG titers can be detected by complement fixation, hemagglutination inhibition, or enzyme immunoassay. (Interpretation of titer rise may have limitations due to potential mumps cross-reaction with other parainfluenza viruses).

For diagnosis, an assay for the detection of mumps-specific immunoglobulin M antibodies in serum and oral fluid specimens is commercially available.

Mumps virus can be isolated from nasopharyngeal swabs, blood, and fluid from the buccal cavity typically within the period of seven days before and nine days after, the onset of parotitis.

Lumbar puncture- If meningitis or encephalitis is suspected, a lumbar puncture to obtain CSF (cerebrospinal fluid) for examination may be considered to clarify cause.

Auditory testing is indicated to assess for development of a hearing impairment.

Scrotal ultrasonography must be performed when orchitis is clinically suspected to rule out testicular torsion.

Management:

Conservative, supportive medical care is indicated for patients with mumps. No antiviral agent is indicated for treatment of this viral illness, as mumps is a self-limited disease. No specific therapy for mumps exists.

Analgesics (acetaminophen, ibuprofen) may be used for headaches or discomfort due to parotitis.

Topical application of warm or cold packs to the swollen parotid area may be used to soothe the painful area.

A light diet with plenty fluid intake is encouraged.

Acidic foods (such as tomato, vinegar-containing food additives) and liquids (such as orange juice) should be avoided to lessen oral pain and discomfort.

Stronger analgesics may be required for patients with orchitis with bed rest, scrotal support, and ice packs. Mumps without associated major complications can be managed on an outpatient basis.

It is advised to follow good hand washing practices.

Patients diagnosed with mumps should be isolated for 5 days from the onset of symptoms to minimize the risk of infecting others by staying home from work or school and staying in a separate room if possible.

Complications:

Mumps can occasionally cause complications, especially in adults. Complications include:

Meningitis: Aseptic meningitis occurs in 10% of patients with mumps.

Encephalitis: Encephalitis occurs rarely (0.02–0.3% of cases) as a complication of mumps. Although the case–fatality rate of mumps encephalitis is low, permanent sequelae, including paralysis, seizures, cranial nerve palsies, aqueductal stenosis and hydrocephalus, may occur.

Orchitis: Inflammation of one or both testicles occurs in 20% of postpubertal males who develops mumps.

Oophoritis: Females who have reached puberty may have inflammation in the ovaries (oophoritis) or breasts (mastitis).

Hearing loss: Cranial nerve involvement (especially eighth cranial nerve damage) is one of the leading causes of deafness in childhood, affecting approximately 5/100000 mumps patients.

Pancreatitis is reported as a complication in approximately 4% of cases.

Occurrence of mumps during the first 12 weeks of pregnancy is associated with 25% incidence of spontaneous abortions.

Death following mumps is rare and is mostly due to encephalitis.

Prevention :

Vaccination is the best way to prevent mumps. Mumps vaccines (live attenuated vaccine) are available as a monovalent vaccine, a bivalent measles-mumps vaccine, or as a trivalent measles-mumps-rubella vaccine (MMR) and measles-mumps-rubella-varicella (MMRV) vaccines.

Two doses of mumps vaccine are 88% (range 66% to 95%) effective at preventing the disease; one dose is 78% range (49% to 91%) effective.

According to WHO, two doses of the vaccine are required for long-term protection against mumps. The first dose of the mumps vaccine (monovalent or MMR) should be given at the age of 12–18 months and the second dose may be administered at range from the second year of life to age at school entry (about 6 years of age). Centre for disease control and prevention, Atlanta (CDC) recommends two doses of MMR vaccine for children, starting with the first dose at 12 -15 months of age, and the second dose at four to six years of age.

IAP recommends MMR at 9 months of age (measles containing vaccine ideally should not be administered before completing 270 days or 9 months of age), second dose at 15-18 months and third dose at 4-6 years of age.

Routine mumps vaccination is recommended by WHO in countries with a well established, effective childhood vaccination programme and the capacity to maintain high levels of vaccination coverage with routine measles and rubella vaccination (coverage >80%) and where the reduction of mumps incidence is a public health priority.

(Insufficient childhood vaccination coverage can result in an epidemiological shift in the incidence of mumps to older age groups, potentially leading to more serious disease burden than occurred before immunization was introduced).

Contraindications to mumps vaccine-

Mumps vaccine (live attenuated vaccine) should not be administered to individuals with advanced immune deficiency.
Mumps vaccination is contraindicated during pregnancy.
Allergy to vaccine components, such as neomycin and gelatin, is a contraindication to administration of the vaccine.

Prevention of transmission –

Patients diagnosed with mumps should stay away with others for at least 5 days from the onset of symptoms.
Encourage the patient for good hand washing practices.
Encourage the patient to cover mouth and nose during coughing and sneezing with tissue, (put used tissue in the trash can) and if tissue is not available cover with upper sleeve or elbow, not the hands.
Drinks and eating utensils of patient should not be shared by others.
Frequently touched surfaces, such as toys, doorknobs, tables, counters should be kept clean.

References-

www.who.int/biologicals/vaccines/mumps/en/
www.who.int/immunization/monitoring_surveillance/burden/vpd/surveillance_type/
www.who.int/immunization/wer8207mumps_Feb07_position_paper.pdf
www.who.int/immunization/diseases/mumps/en/

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