Rubella

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 Americas region became the first WHO region to be declared free of rubella and congenital rubella syndrome

• As of 2018, 39 of 53 countries in Europe are 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

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

• 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 rash onset

• Reverse transcriptase polymerase chain reaction (RT-PCR)

  • Sample can be collected throat swabs, oral fluids, or nasopharyngeal secretions

  • Timing of sample collection is important and is best if collected within the first 3 days of an acute illness and within 3 months in case of congenital rubella syndrome

• Rubella infection, including complications, is treated symptomatically

• Patients should be isolated for 7 days after rash onset

Complications

• Rare, except for the congenital rubella syndrome

• Polyarticular arthritis and arthralgia

• Hemorrhagic manifestations due to thrombocytopenia and vascular damage

• Hepatitis

• Encephalitis

Prevention

• See Table 30–7

• Live attenuated rubella virus vaccine is included in the MMR or MMRV vaccine

Prognosis

• Mild illness rarely lasts more than 3–4 days

• Congenital rubella has a high fetal mortality rate, and the associated congenital defects are largely permanent

When to Refer

• Pregnancy

• Meningitis/encephalitis

• Significant vaccination reactions

• Any suspect cases should be reported to public health authorities