Chirag P. Shah

BASICS

DESCRIPTION

• Rubella is a worldwide contagious viral infection best known for its distinctive red rash.

• It is also known as German measles because it was first described by German physicians.

• After an incubation period of 14–21 days, rubella causes a flu-like disease. A pink or light red rash appears on the face that spreads to the trunk and limbs and usually fades after 3 days. This is why it is often called the 3-day measles.

• There may be a low-grade fever, lymphadenopathy, joint pain, headache, and conjunctivitis.

• It is a common childhood illness and is usually mild. Complications are rare.

• It is transmitted by airborne droplets from the upper respiratory tract of an infected individual.

• Rubella can affect individuals of any age.

• The virus can pass though the pregnant woman’s bloodstream to infect her fetus, causing congenital rubella syndrome.

EPIDEMIOLOGY

• A person can transmit the disease from 1 week before the rash until 1–2 weeks after the rash disappears.

• After infection there is usually a lifelong immunity.

• There is no carrier state and the virus exists entirely in active human cases.

• Rubella has an incubation period of 2–3 weeks.

• Risk of congenital rubella syndrome is greater with more severe consequences if maternal infection occurs in the first trimester (>50% risk). The risk decreases during the subsequent trimesters.

• The virus may persist in infected infants and may be a source of infection to other infants and to pregnant female contacts.

RISK FACTORS

• Not being vaccinated against rubella

• Exposure to active rubella virus

GENERAL PREVENTION

• The measles-mumps-rubella (MMR) vaccine is usually given to children before they reach school age and is highly effective in preventing rubella.

• Women who are of childbearing age can be tested to see if they have immunity to rubella. If they are not immune they can be vaccinated. Women who are pregnant should not be vaccinated, nor should those who are immunocompromised.

ETIOLOGY

Caused by the rubella virus, a togavirus that is enveloped and has a single stranded RNA genome.

COMMONLY ASSOCIATED CONDITIONS

Findings of congenital rubella syndrome include:

• Miscarriage or stillbirth, prematurity, low birth weight

• Cataracts

• Congenital heart defects (ventricular septal defects, patent ductus arteriosus, pulmonic stenosis, coarctation of the aorta)

• Deafness

• Ear infection (otitis media)

• Encephalitis

• Growth retardation

• Mental retardation in 10–20%

• Microcephaly

• Transient arthritis in adolescents and adults

• Hepatitis

• Hepatosplenomegaly

• Thrombocytopenia

• Obstructive jaundice

• Radiolucent bone disease

• Pigmentary retinopathy with salt-and-pepper changes

• Glaucoma

• Purpura

• Diabetes mellitus in 20% of adults

• Thyroid dysfunction in 5%

• Progressive panencephalitis

• Non-affective psychosis

DIAGNOSIS

HISTORY

Exposure to someone with rubella

PHYSICAL EXAM

• External examination including skin to identify characteristic rash

• Prenatal screening with ultrasound, amniocentesis, cordocentesis, or chorionic villous sampling

• Ultrasound assesses for fetal hydrops, bowel hyperechogenicity, and intrauterine growth retardation.

DIAGNOSTIC TESTS & INTERPRETATION

Diagnostic Procedures/Other

• Nasal or throat swab for viral culture and rubella serology. The presence of IgM antibodies along with, or a short time after, the characteristic rash confirms the diagnosis.

• Serological investigation typically employs enzyme-linked immunosorbent assays (ELISA), hemoagglutination inhibition test (HI), or the immunofluorescent antibody assay (IFA)

• Centers for Disease Control classification criteria for congenital rubella syndrome:

– Congenital rubella syndrome case: Infants that present one or, in the majority of cases, more than one of these following clinical signs or symptoms:

– Cataracts/congenital glaucoma, congenital heart disease (most commonly patent ductus arteriosus or peripheral pulmonic stenosis), hearing impairment, pigmentary retinopathy.

– Purpura, hepatosplenomegaly, jaundice, microcephaly, developmental delay, meningoencephalitis, radiolucent bone disease.

– Suspected case: Clinical signs are evident but without the satisfactory criteria to be defined as a probable case.

– Probable case: A case without laboratory confirmation, that has any of the 2 findings listed in category 1 of the clinical description or one finding from category 1 and one from 2, and lacks evidence of any other etiology.

– Confirmed case: Clinical evidence and laboratory confirmation.

– Infection only: Laboratory evidence of infection, without any clinical symptoms or signs.

TREATMENT

ADDITIONAL TREATMENT

General Measures

• There is no specific treatment for rubella. Supportive treatment as needed.

• Immune globulin therapy to exposed mothers does not prevent fetal rubella infection.

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

Based on degree and nature of manifestations

PROGNOSIS

• Acquired rubella is usually a mild infection without sequelae.

• Congenital rubella syndrome is chronic and incurable; many its manifestations, such as cataract and diabetes, can be treated.

ADDITIONAL READING

• CDC. MMWR rubella and congenital rubella syndrome, United States,1994–1997. MMWR Morb Mortal Wkly Rep 1997;46(16):350–354.

• De Santis M, Cavaliere AF, Straface G, et al. Rubella infection in pregnancy. Reprod Toxicol 2006;21(4):390–398.

• Richardson M, Elliman D, Maguire H, et al. Evidence base of incubation periods, periods of infectiousness and exclusion policies for the control of communicable diseases in schools and preschools. Pediatr Infec Dis J 2001;20(4):380–391.

• Siegel M, Fuerst HT, Guinee VF. Rubella epidemicity and embryopathy. Results of a long-term prospective study. Am J Dis Child 1971;121(6):469–473.

CODES

ICD9

• 056.79 Rubella with other specified complications

• 647.50 Rubella of mother, complicating pregnancy, childbirth, or the puerperium, unspecified as to episode of care

• 771.0 Congenital rubella

CLINICAL PEARLS

• Risk of congenital rubella syndrome is greater with more severe consequences if maternal infection occurs in the first trimester (>50% risk).

• Ocular manifestations of congenital rubella syndrome include cataracts, pigmentary retinopathy, and glaucoma.

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