Pediatric Rubella Clinical Presentation

Postnatal rubella

Rubella virus is transmitted from person to person via the aerosolized particles from the respiratory tract. A history of exposure may not be present. Individuals may acquire the infection from a completely asymptomatic patient or from an individual shedding the virus during the incubation period.

The incubation is usually 14-21 days after exposure to a person with rubella.

Prodromal symptoms are unusual in young children but are common in adolescents and adults.

The following signs and symptoms usually appear 1-5 days before the onset of rash:

• Eye pain on lateral and upward eye movement (a particularly troublesome complaint)
• Conjunctivitis
• Sore throat
• Headache
• General body aches
• Low-grade fever
• Chills
• Anorexia
• Nausea
• Tender lymphadenopathy (particularly posterior auricular and suboccipital lymph nodes)
• Forchheimer sign (an enanthem observed in 20% of patients with rubella during the prodromal period; can be present in some patients during the initial phase of the exanthem; consists of pinpoint or larger petechiae that usually occur on the soft palate)

Congenital rubella

Congenital rubella history focuses on the following:

• The number of weeks of pregnancy when maternal exposure to rubella occurred (The risk of congenital rubella syndrome is higher if maternal exposure occurs during the first trimester.)
• Maternal history of immunization or medical history of rubella
• Evidence of intrauterine growth retardation during pregnancy
• Manifestations suggestive of congenital rubella syndrome in a child

Physical findings are based on the type of rubella.

Rash

The exanthem of rubella consists of a discrete rose-pink maculopapular rash ranging from 1-4 mm. See the image below.

Rash in adults may be quite pruritic.

The synonym "3-day measles" derives from the typical course of rubella exanthem that starts initially on the face and neck and spreads centrifugally to the trunk and extremities within 24 hours. It then begins to fade on the face on the second day and disappears throughout the body by the end of the third day.

Temperature

Fever is usually not higher than 38.5°C (101.5°F).

Lymph nodes

Enlarged posterior auricular and suboccipital lymph nodes are usually found on physical examination.

Mouth

The Forchheimer sign may still be present on the soft palate.

The classic triad presentation of congenital rubella syndrome consists of the following:

• Sensorineural hearing loss is the most common manifestation of congenital rubella syndrome. It occurs in approximately 58% of patients. Studies have demonstrated that approximately 40% of patients with congenital rubella syndrome may present with deafness as the only abnormality without other manifestations. Hearing impairment may be bilateral or unilateral and may not be apparent until the second year of life.
• Ocular abnormalities including cataract, infantile glaucoma, and pigmentary retinopathy occur in approximately 43% of children with congenital rubella syndrome. Both eyes are affected in 80% of patients, and the most frequent findings are cataract and rubella retinopathy. Rubella retinopathy consists of a salt-and-pepper pigmentary change or a mottled, blotchy, irregular pigmentation, usually with the greatest density in the macula. The retinopathy is benign and nonprogressive and does not interfere with vision (in contrast to the cataract) unless choroid neovascularization develops in the macula.
• Congenital heart disease including patent ductus arteriosus (PDA) and pulmonary artery stenosis is present in 50% of infants infected in the first 2 months' gestation. Cardiac defects and deafness occur in all infants infected during the first 10 weeks of pregnancy and deafness alone is noted in one third of those infected at 13-16 weeks of gestation.

Other findings in congenital rubella syndrome include the following:

• Intrauterine growth retardation, prematurity, stillbirth, and abortion
• CNS abnormalities, including mental retardation, behavioral disorders, encephalographic abnormalities, hypotonia, meningoencephalitis, and microcephaly
• Hepatosplenomegaly
• Jaundice
• Hepatitis
• Skin manifestations, including blueberry muffin spots that represent dermal erythropoiesis and dermatoglyphic abnormalities
• Bone lesions, such as radiographic lucencies
• Endocrine disorders, including late manifestations in congenital rubella syndrome usually occurring in the second or third decade of life (eg, thyroid abnormalities, diabetes mellitus)
• Hematologic disorders, such as anemia and thrombocytopenic purpura

Table 2. Clinicopathologic Abnormalities in Congenital Rubella (Open Table in a new window)

Rubella and congenital rubella syndrome are caused by rubella virus. Only one antigenic type of rubella virus is available, and humans are the only natural hosts. The virus is spherical with a diameter of 50-70 nm, has a central core (ie, nucleocapsid), and is covered externally by a lipid-containing envelope. The nucleocapsid is composed of polypeptide (C protein) and a single-stranded RNA.

Its outer envelope is made up of glycosylated lipoprotein, which contains 2 virus-specific polypeptides (E1, E2) and a host-cell–derived lipid. These 2 envelope proteins comprise the spiked 5-nm to 6-nm surface projections that are observed on the outer membrane of rubella virus and are important for the virulence of the virus.

Monoclonal antibodies directed against epitopes of E1 and E2 have neutralizing activity. Protein E1 is the viral hemagglutinin that binds both hemagglutination-inhibiting and hemolysis-inhibiting antibodies.

Rubella virus is rapidly inactivated by 70% alcohol, ethylene oxide, formalin, ether, acetone, chloroform, free chlorine, deoxycholate, beta-propiolactone, ultraviolet light, extreme pH (< 6.8 or >8.1), heat (>56°C), and cold (from -10°C to -20°C). It is resistant to thimerosal and is stable at temperatures of -60°C or less.