Rubella

Key Features

Essentials of Diagnosis

• Exposure 14–21 days before onset

• No prodrome in children, mild prodrome in adults; mild symptoms (fever, malaise, coryza) coincide or precede eruption of rash by up to 5 days

• Posterior cervical and postauricular lymphadenopathy 5–10 days before rash

• Fine maculopapular rash of 3 days' duration; face to trunk to extremities

• Leukopenia, thrombocytopenia

General Considerations

• Transmitted by inhalation of infective droplets; it is moderately communicable

• Disease is transmissible from 1 week before the rash appears until 15 days afterward

• Infection usually confers permanent immunity

Demographics

• The last reported cases of endemic rubella and congenital rubella syndrome were in 2009 from the Americas region

• In 2015, the WHO declared the Americas region free of rubella and congenital rubella syndrome

• While 45 countries in Europe have been declared free of rubella, some European countries are facing a challenge with lower immunization coverage among refugees and migrants

• Worldwide, cases are decreasing due to widespread implementation of rubella-containing vaccines

• On the other hand, the number of cases of congenital rubella syndrome is increasing, particularly in Southeast Asia

Clinical Findings

Symptoms and Signs

Postnatal rubella

• Most cases are asymptomatic

• Fever and malaise, usually mild, accompanied by tender suboccipital adenitis, may precede the eruption by 1 week

• Early posterior cervical and postauricular lymphadenopathy is common

• A fine, pink maculopapular rash appears and fades from the face, trunk, and extremities in rapid progression (2–3 days), usually lasting 1 day in each area

Congenital rubella

• Infection has devastating effects on the fetus in utero

  • Fetal death

  • Preterm delivery

  • Teratogenic effects

• Severity of symptoms is directly related to the gestational age

  • Fetal infection during the first trimester leads to congenital rubella in at least 80% of fetuses

  • An infection during the fourth month can lead to 10% risk of a single congenital defect

  • In the second trimester of pregnancy, deafness is the primary complication

• The manifestations of congenital rubella syndrome can be divided into transient, permanent, and developmental

• Transient manifestations: thrombocytopenic purpura, low birth weight, and hepatosplenomegaly

• Other manifestations: early-onset cataracts and glaucoma, microphthalmia, hearing deficits, psychomotor retardation, congenital heart defects (patent ductus arteriosus, branch pulmonary artery stenosis)

Differential Diagnosis

• Infectious mononucleosis

• Measles

• Echovirus infections

• Coxsackievirus infections

Diagnosis

• Antibody testing can be performed on sera or saliva

• Diagnosis of acute infection is based on elevated IgM antibody, fourfold or greater rise in IgG antibody titers, or isolation of the virus

• IgM is detectable in 50% of persons on day 1 of the rash but in most on day 5 after ...