Snapshot A 2-year-old child presents to the pediatrician’s office for a rash. Her mother is against vaccines, so the child had not received any childhood vaccines. Her father, however, is worried about her lack of vaccination and asks the doctor if this is measles or rubella. On physical exam, she has a high fever as well as a confluent maculopapular rash. She also has blue-white spots on her buccal mucosa. The family is instructed to take isolation precautions and to bring in the child’s siblings who are also unvaccinated. Introduction Classification measles (rubeola) virus a paramyxovirus an enveloped, helical capsid, linear, single-stranded, negative-sense RNA virus highly contagious via respiratory secretions causes measles Prevention measles, mumps, and rubella (MMR) vaccine given over 2 doses Epidemiology Incidence decreased in the US due to vaccination endemic in parts of Europe, Africa, and Asia Demographics more common in children Risk factors lack of vaccination travel to endemic areas 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 hemagglutinin (HA) protein helps the virus attach to the host cell the virus replicates in epithelial cells in the respiratory tract and lymph nodes Presentation Symptoms prodrome high-grade fever Cough Conjunctivitis Coryza rash Physical exam Koplik spots buccal mucosa with bluish white macules with background of bright red pathognomonic for measles confluent maculopapular rash starts in the head and neck and spreads downward to trunk initially blanching with pressure in the first few days excludes palms and soles lymphadenopathy Studies Labs detection of measles-specific immunoglobulin M or G detection of virus on reverse transcriptase-polymerase chain reaction Biopsy of lymph node Warthin-Finkeldey giant cells, or fused lymphocytes, with paracortical hyperplasia Differential Drug reaction distinguishing factors typically presents with a morbiliform rash, characterized by red macules that may be confluent typically is not accompanied by systemic symptoms such as a high fever Parvovirus B19 infection distinguishing factors slapped cheek rash maculopapular rash on trunk and limbs that does not spread from head/neck downward 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 Medical vitamin A indication reduces morbidity and mortality in all patients Complications Subacute sclerosing panencephalitis neurodegenerative disease presents in adolescence/adulthood initial symptoms: memory loss, change in behavior, irritability progresses to motor dysfunction (e.g., myoclonic jerks, ataxis, seizures) MRI shoulds multiple white-matter hyperintensities, scarring, and cerebral atrophy poor prognosis, usually fatal within 1-3 years of diagnosis Encephalitis Giant cell pneumonia in the immunosuppressed Prognosis Prodrome followed by rash