Mumps in Children
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Direct answer
Mumps is an acute paramyxovirus infection whose signature is painful parotid swelling, complicated in a distinctive pattern: aseptic meningitis (symptomatic in one in ten, though pleocytosis appears in over half), orchitis in 20-30% of postpubertal males — rarely causing infertility — plus pancreatitis and rare deafness. Parotitis is unilateral in most at onset, with the ear pushed up and out and Stensen's duct orifice inflamed without pus. Cerebrospinal fluid in mumps meningitis may show low glucose, separating it from most viral meningitides in exams. Diagnosis in atypical cases rests on polymerase chain reaction and IgM serology; prevention is the live mumps vaccine, delivered in India as MMR at 9 months and 15-18 months under the Indian Academy of Paediatrics schedule.
What you must remember
- Agent and onset: an RNA paramyxovirus with an incubation period of 16-18 days; infectivity spans from about 2 days before to 5 days after parotid swelling.
- Parotitis detail: the swelling crosses the angle of the jaw, lifts the ear lobe, and Stensen's duct opening is erythematous; expressing pus from the duct points to bacterial (suppurative) parotitis instead.
- Meningitis and encephalitis: aseptic meningitis is common and benign; cerebrospinal fluid shows lymphocytes with glucose that may be low — a uniquely examinable quirk; encephalitis and aqueductal stenosis with hydrocephalus are rare.
- Orchitis and oophoritis: orchitis affects 20-30% of postpubertal males, is usually unilateral, and sterility is uncommon; prepubertal testicular involvement is rare.
- Pancreatitis: mid-epigastric pain with raised lipase; self-limiting, with epidemiological links to later type 1 diabetes.
- Deafness: sudden unilateral sensorineural hearing loss, historically quoted near one case per 20,000, is the leading feared complication and is usually permanent.
- Vaccine anchor: India's Universal Immunisation Programme does not include mumps, so the Indian Academy of Paediatrics recommends MMR (mumps-measles-rubella) at 9 months and 15-18 months, with the Jeryl Lynn strain the classic preparation worldwide.
Working through the clinical course
An unvaccinated six-year-old is brought with three days of fever and painful right facial swelling that obscures the jaw angle and displaces the ear. The sequence of reasoning runs: confirm the gland (tender, oedematous parotid lifting the ear, with an inflamed Stensen's duct orifice), exclude the mimics (a fluctuant mass or pus from the duct suggests staphylococcal parotitis; a dental abscess does not lift the ear; reactive lymphadenitis lies below the jaw angle and spares the duct), and then counsel using the natural history: swelling peaks by day 3, the other side follows in a minority, and the child is managed with analgesia, hydration and soft diet. Search actively for complications — headache and neck stiffness warrant lumbar puncture, where lymphocytic pleocytosis with a low glucose in the right setting is mumps meningitis, treated supportively; epigastric pain radiating to the back suggests pancreatitis; and a postpubertal adolescent with a hot, swollen scrotum needs orchitis confirmation and reassurance about fertility.
Serology or polymerase chain reaction is reserved for atypical or complicated presentations, and school exclusion until five days after swelling onset completes the public-health loop in the Indian context, where the absence of mumps from the national programme makes outbreaks recurring.
How the examiner frames it
Mumps questions are built on discriminating features rather than diagnosis: the low cerebrospinal fluid glucose, the Warthin-Finkeldey multinucleated giant cells, the raised serum amylase from parotid origin (amylase does not equal pancreatitis unless lipase rises with abdominal signs), and the orchitis-sterility reassurance that examiners love to invert. A modern favourite is the Indian programme gap — mumps is not in the Universal Immunisation Programme — so an MCQ on prevention expects MMR from the Indian Academy of Paediatrics schedule. In the viva, the classic trap is a "bilateral parotitis of three weeks" in a malnourished child, where recurrent parotitis, HIV and Sjögren-like syndromes displace mumps, and chronicity, not acuity, is the tell.
Frequently asked questions
What is the incubation period and infectious window of mumps?
About 16-18 days from exposure to parotitis, with infectivity from roughly 2 days before swelling until 5 days after, guiding exclusion from school.
Why is mumps meningitis unusual among viral meningitides?
Because cerebrospinal fluid glucose may be low, mimicking tuberculous or partially treated bacterial meningitis, unlike the normal glucose of most viral meningitides.
Does mumps orchitis cause infertility?
Orchitis affects 20-30% of postpubertal males and is usually unilateral; testicular atrophy can follow, but absolute sterility is uncommon.
How is mumps prevented in India?
By the live MMR vaccine at 9 months and 15-18 months per the Indian Academy of Paediatrics immunisation schedule, since mumps is absent from the Universal Immunisation Programme.
Which laboratory tests confirm mumps in an atypical case?
IgM serology on serum or oral fluid, or reverse-transcriptase polymerase chain reaction on saliva, urine or cerebrospinal fluid during the first days of illness.