Sunday, May 7, 2017

Introduction to Mumps



Also known as infectious or epidemic parotitis, mumps is an acute viral disease caused by a paramyxovirus. It’s most prevalent in unvaccinated children between ages 2 and 12, but it can occur in other age-groups. Infants younger than age 1 seldom get this disease because of passive immunity from maternal antibodies. Peak incidence occurs during late winter and early spring.

The prognosis for complete recovery is good, although mumps sometimes causes complications.

Etiology
The mumps paramyxovirus is found in the saliva of an infected person and is transmitted by droplets or by direct contact. The virus is present in the saliva 6 days before to 9 days after onset of parotid gland swelling; the 48-hour period immediately preceding onset of swelling is probably the time of highest communicability.

The incubation period ranges from 14 to 25 days (the average is 18 days). One attack of mumps (even if unilateral) almost always confers lifelong immunity.

Signs and symptoms
Signs and symptoms of mumps vary widely. An estimated 30% of susceptible people have subclinical illness. Mumps usually begins with prodromal signs and symptoms that last for 24 hours; these include myalgia, anorexia, malaise, headache, and low-grade fever, followed by an earache that’s aggravated by chewing, parotid gland tenderness and swelling, a temperature of 101° to 104° F (38.3° to 40° C), and pain when chewing or when drinking sour or acidic liquids. Simultaneously with the swelling of the parotid gland or several days later, one or more of the other salivary glands may become swollen.

Complications
Epididymo-orchitis and mumps meningitis are complications of mumps. 

Epididymo-orchitis, which occurs in about 25% of postpubertal males who contract mumps, produces abrupt onset of testicular swelling and tenderness, scrotal erythema, lower abdominal pain, nausea, vomiting, fever, and chills. Swelling and tenderness related to mumps may last for several weeks.
Mumps meningitis complicates mumps in 10% of patients and affects three to five times more males than females. Signs and symptoms include fever, meningeal irritation (nuchal rigidity, headache, and irritability), vomiting, drowsiness, and a lymphocyte count in cerebrospinal fluid ranging from 500 to 2,000/µl.
Recovery is usually complete. Less-common effects are pancreatitis, deafness, arthritis, myocarditis, encephalitis, pericarditis, oophoritis, and nephritis.

Diagnosis
In mumps, a diagnosis is usually made after the characteristic signs and symptoms develop, especially parotid gland enlargement with a history of exposure to mumps. Serologic antibody testing can verify the diagnosis when parotid or other salivary gland enlargement is absent. If comparison between a blood sample obtained during the acute phase of illness and another sample obtained 3 weeks later shows a fourfold rise in antibody titer, the patient most likely had mumps.

Treatment

Effective treatment includes an analgesic for pain, an antipyretic for fever, and adequate fluid intake to prevent dehydration from fever and anorexia. If the patient can’t swallow, I.V. fluid replacement may be necessary.

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