Snapshot A 26-year-old teacher presents to his primary care physician for a low-grade fever, swollen jaw, and painful testes. He teaches at an elementary school in Oregon, where many parents decline vaccination for their children. The patient immigrated from China when he was 5 and does not recall if he had been vaccinated prior to immigrating. On physical exam, he has right-sided swollen and tender parotid glands. His bilateral testes are also swollen and tender. He is prescribed antipyretics and analgesics and instructed to be isolated for at least 5 days. Introduction Classification mumps virus a paramyxovirus a helical capsid, linear, single-stranded, negative-sense RNA virus transmission via respiratory secretions most commonly causes parotitis and orchitis can cause aseptic meningitis and pancreatitis Prevention measles, mumps, and rubella (MMR) vaccine given over 2 doses in childhood Epidemiology Incidence decreased worldwide due to effective vaccination highest in winter and spring Demographics higher in children Risk factors exposure to others with mumps or unvaccinated people crowded living environment college dorm lack of vaccination ETIOLOGY Pathogenesis all paramyxoviruses contain the F (fusion) protein can induce cell-to-cell fusion, creating multi-nucleated giant cells helps mediate virus and cell membrane fusion, ultimately resulting in infection of the host cell the virus replicates in the nasopharynx and regional lymph nodes in the glandular epithelium Presentation Symptoms parotitis earache pain in the jaw prodrome low-grade fever malaise headache orchitis pain in testes Physical exam parotitis bilateral or unilateral parotid gland swelling tenderness to palpation earlobe lifted up and outward orchitis bilateral or unilateral testes swelling Studies Labs detection of antibodies immunoglobulin M or G buccal or oral swab with viral isolation or detection on reverse transcriptase-polymerase chain reaction Differential Epstein-Barr virus distinguishing factor may also cause parotitis, but also often causes mononucleosis Acute bacterial parotitis DIAGNOSIS Making the diagnosis based on clinical presentation and confirmed with laboratory studies Treatment Management approach mainstay of treatment is supportive care and prevention with vaccines Conservative supportive care indication all patients modalities antipyretics analgesics hydration Complications Sterility in males who have orchitis after puberty Sensorineural deafness Prognosis Patients infected with mumps virus are often asymptomatic