Mumps

Virus

Enveloped, negative-sense ssRNA paramyxovirus (same family as measles). Respiratory droplet + saliva contact.

Pathogenesis

Respiratory replication → viremia → SALIVARY GLANDS (parotid, classic) + other glandular/neuro tissue (testes, ovaries, pancreas, meninges) — shared epithelial/glandular tropism.

Clinical Manifestations

PAROTITIS: painful tender parotid swelling (uni/bilateral), ± brief prodrome (fever, headache, malaise) = classic presentation. NOTABLE: substantial proportion (1/3+) ASYMPTOMATIC or nonspecific respiratory symptoms only, no recognizable swelling — clinical picture under-represents true infection scope.

ORCHITIS: most significant extra-salivary complication. POST-PUBERTAL MALES specifically (rare prepubertal) — age-dependence important. Usually unilateral, acute pain+swelling ~1wk after parotitis. KEY TESTABLE POINT: INFERTILITY is COMPARATIVELY RARE even after bilateral orchitis — popular assumption overstates risk. Testicular atrophy more common than frank infertility.

Oophoritis: female counterpart, less common/milder.

Aseptic (viral) meningitis: COMMON CNS complication. Pre-vaccine: LEADING identifiable pediatric aseptic meningitis cause. Self-limited (contrast bacterial meningitis, see CNS topic).

Pancreatitis: less common glandular complication. Sensorineural hearing loss (usually unilateral): RARE but PERMANENT — remember despite low frequency.

Laboratory Diagnosis

Often CLINICAL (classic parotid swelling + compatible epi context, esp. unvaccinated population). Confirmation needed (atypical, outbreak, breakthrough-suspected vaccinated): RT-PCR (buccal/salivary swab, direct detection). Serology (IgM or paired IgG rise) — COMPLICATED in previously vaccinated (prior immune response blunts/alters breakthrough kinetics).

Treatment

NO specific antiviral. ENTIRELY SUPPORTIVE (analgesia, hydration; orchitis: scrotal support+rest). Same pattern as most acute paramyxoviruses.

Prevention — Vaccination

Live attenuated mumps component of MMR (see Measles topic for combo/NIS timing). NOTABLE: LOWER/LESS DURABLE effectiveness than measles/rubella components of SAME vaccine — periodic outbreaks even in well-vaccinated populations (college campuses classic setting). CONTRASTS measles’ more robust long-lasting protection.

The Virus

Mumps virus is an enveloped, negative-sense ssRNA paramyxovirus (the same family as measles, sharing the general replication and structural pattern covered under General Properties of Viruses), transmitted by respiratory droplets and direct contact with infected saliva.

Pathogenesis

After initial respiratory tract replication, the virus spreads via viremia to its characteristic target sites — the salivary glands (parotid glands specifically, dominating the classic clinical picture) and, in a genuinely important minority of cases, several other glandular and neurological tissues (testes, ovaries, pancreas, meninges) that share a comparable epithelial/glandular tissue tropism the virus exploits.

Clinical Manifestations

Parotitis — painful, tender swelling of one or both parotid glands, often preceded by a brief nonspecific prodrome (fever, headache, malaise) — is the classic, defining presentation, though genuinely notable in that a substantial proportion of infections (perhaps a third or more) are asymptomatic or present with only nonspecific respiratory symptoms without any recognizable parotid swelling at all, meaning clinical presentation alone under-represents the true scope of infection in a population.

Orchitis is the most clinically significant extra-salivary complication — occurring in a meaningful proportion of post-pubertal males specifically (a genuinely important age-dependence, since orchitis is rare in prepubertal boys), typically unilateral, presenting with acute testicular pain and swelling roughly a week after parotitis onset. While orchitis causes genuine acute morbidity, infertility is a comparatively rare outcome even after bilateral orchitis — a real, specifically testable point worth remembering precisely, since the popular assumption that mumps orchitis commonly causes sterility considerably overstates the actual risk; some degree of testicular atrophy is more common than frank infertility. Oophoritis is the less common, generally milder female counterpart. Aseptic (viral) meningitis is a genuinely common CNS complication — mumps was, before widespread vaccination, one of the leading identifiable causes of aseptic meningitis in children, generally following a self-limited course distinct from the far more severe bacterial meningitis picture (see Central Nervous System Infections for the broader aseptic-versus-bacterial-meningitis distinction). Pancreatitis is a further, less common glandular complication, and sensorineural hearing loss (typically unilateral) is a rare but genuinely permanent complication worth remembering given its lasting impact despite low frequency.

Laboratory Diagnosis

Diagnosis is often made clinically in a patient with the classic parotid swelling and a compatible exposure/epidemiological context, particularly in an unvaccinated population where mumps remains genuinely common enough to top the differential for parotid swelling directly. Where confirmation is needed (atypical presentation, outbreak investigation, or a vaccinated individual with breakthrough-suspected disease), RT-PCR on a buccal/salivary swab offers direct viral detection, and serology (IgM, or a significant IgG rise on paired sera) supports diagnosis, though genuinely complicated in previously vaccinated individuals, where a prior immune response can blunt or alter the expected antibody kinetics of a breakthrough infection.

Treatment

There is no specific antiviral treatment — management is entirely supportive (analgesia, adequate hydration, and, for orchitis specifically, scrotal support and rest), mirroring the general pattern for most acute paramyxovirus infections covered in this section.

Prevention: Vaccination

The live attenuated mumps component of the MMR vaccine (see Measles for the shared combination formulation and National Immunization Schedule timing) is effective, though genuinely notable for having somewhat lower, less durable effectiveness than the measles or rubella components of the same combined vaccine — a real, specific point reflected in periodic mumps outbreaks reported even in well-vaccinated populations (college campuses and other close-contact settings being classically described settings for such outbreaks), distinguishing mumps from measles’ generally more robust, long-lasting single-course vaccine protection described under that topic.