Page 1 of 2
Rubella (German Measles)
Abd El-Salam Dawood MD
Pediatric Cardiologist
FIBMS-Ped FIBMS-PedCard
Essentials of diagnosis & typical features
History of rubella vaccination usually absent.
Prodromal nonspecific respiratory symptoms
and adenopathy (postauricular and occipital).
Maculopapular rash beginning on face,
rapidly spreading to the entire body, and
disappearing by fourth day.
Few systemic symptoms.
Congenital Infection.
Retarded growth, development.
Cataracts, retinopathy.
Purpuric “blueberry muffin” rash at birth,
jaundice, thrombocytopenia.
Deafness.
Congenital heart defect.
General Considerations
If it were not teratogenic, rubella would be of little
clinical importance. Clinical diagnosis is difficult in
some cases because of its variable expression. In
one study, over 80% of infections were subclinical.
Because of inadequate vaccination, outbreaks now
occur in adolescents or adults. Rubella is transmitted
by aerosolized respiratory secretions. Patients are
infectious 5 days before until 5 days after the rash.
Congenital rubella, in infants both of unimmunized
women and of women who have apparently been
reinfected in pregnancy, is now rare.
Clinical Findings:
The incubation period is 14–21 days. The
nondistinctive signs may make exposure history
unreliable. A history of immunization makes rubella
unlikely but still possible. Congenital rubella usually
follows maternal infection in the first trimester.
A. Symptoms and signs:
1. Infection in children—Young children may only
have rash. Older patients often have a nonspecific
prodrome of low-grade fever, ocular pain, sore throat,
and
myalgia.
Postauricular
and
suboccipital
adenopathy
(sometimes
generalized)
is
characteristic. This often precedes the rash or may
occur without rash. The rash consists of
erythematous discrete maculopapules beginning on
the face. A “slapped-cheek” appearance or pruritus
may occur. Scarlatiniform or morbilliform rash
variants may occur. The rash spreads quickly to the
trunk and extremities after it fades from the face; it is
gone by the fourth day. Enanthem is usually absent.
2. Congenital infection—More than 80% of women
infected in the first 4 months of gestation are
delivered of affected infants; congenital disease
occurs in less than 5% of women infected later in
pregnancy. Later infections can result in isolated
defects, such as deafness. The main manifestations
are as follows:
a. Growth retardation. Between 50% and 85% of
infants are small at birth and remain so.
b. Cardiac anomalies. Pulmonary artery stenosis,
patent ductus arteriosus, ventricular septal defect.
c. Ocular anomalies. Cataracts, microphthalmia,
glaucoma, retinitis.
d. Deafness.
e. Cerebral disorders. Chronic encephalitis.
f.
Hematologic disorders. Thrombocytopenia,
dermal nests of extramedullary hematopoiesis or
purpura (“blueberry muffin” rash), lymphopenia.
g.
Others.
Hepatitis,
osteomyelitis,
immune
disorders, malabsorption, diabetes.
B. Laboratory findings:
Leukopenia is common, and platelet counts may be
low. Congenital infection is associated with low
platelet counts, abnormal liver function tests,
hemolytic anemia, pleocytosis, and very high rubella
IgM antibody titers. Total serum IgM is elevated, and
IgA and IgG levels may be depressed.
C. Imaging:
Pneumonitis and bone metaphysial longitudinal
lucencies may be present in x-rays of children with
congenital infection.
Diagnosis & Differential Diagnosis:
Page 2 of 2
Virus may be isolated from throat or urine from 1
week before to 2 weeks after onset of rash. Children
with congenital infection are infectious for months.
The virus laboratory must be notified that rubella is
suspected. Serologic diagnosis is best made by
demonstrating a fourfold rise in antibody titer
between specimens drawn 1–2 weeks apart. The first
should be drawn promptly, because titers increase
rapidly after onset of rash. Both specimens must be
tested simultaneously by a single laboratory. Specific
IgM antibody can be measured by immunoassay.
Because the decision to terminate a pregnancy is
usually based on serologic results, testing must be
done carefully.
Rubella may resemble infections due to enterovirus,
adenovirus, measles, EBV, roseola, parvovirus,
Toxoplasma
gondii,
and
Mycoplasma.
Drug
reactions may also mimic rubella. Because public
health implications are great, sporadic suspected
cases should be confirmed serologically or
virologically.
Congenital rubella must be differentiated from
congenital CMV infection, toxoplasmosis, and
syphilis.
Complications & Sequelae
A. Arthralgia and arthritis:
Both occur more often in adult women. Polyarticular
involvement (fingers, knees, wrists), lasting a few
days to weeks, is typical. Frank arthritis occurs in a
small percentage of patients. It may resemble acute
rheumatoid arthritis.
B. Encephalitis:
With an incidence of about 1:6000, this is a
nonspecific parainfectious encephalitis associated
with a low mortality rate. A syndrome resembling
subacute sclerosing panencephalitis has also been
described in congenital rubella.
C. Rubella in pregnancy:
Infection in the mother is self-limited and not severe.
Prevention:
Rubella is one of the infections that potentially could
be eradicated. Standard prenatal care should include
rubella antibody testing. Seropositive mothers are at
no risk; seronegative mothers are vaccinated after
delivery.
A pregnant woman possibly exposed to rubella
should be tested immediately; if seropositive, she is
immune and need not worry. If she is seronegative,
a second specimen should be drawn in 4 weeks, and
both specimens should be tested simultaneously.
Seroconversion in the first trimester suggests high
fetal risk; such women require counseling regarding
therapeutic abortion.
When pregnancy termination is not an option, some
experts recommend intramuscular administration of
20 mL of immune globulin within 72 hours after
exposure in an attempt to prevent infection. (This
negates the value of subsequent antibody testing.)
The efficacy of this practice is unknown.
Treatment & Prognosis:
Symptomatic therapy is sufficient. Arthritis may
improve with administration of anti-inflammatory
agents. The prognosis is excellent in all children and
adults but poor in congenitally infected infants, in
whom most defects are irreversible or progressive.
The severe cognitive defects seem to correlate
closely in these infants with the degree of growth
failure.