Congenital rubella syndrome (CRS) can occur in a
developing fetus of a pregnant woman who has
contracted rubella (GERMAN MEASLES), usually in the
first trimester.
It was discovered in 1941 by Australian
ophthalmologist Norman McAlister Gregg.
The molecular basis for the causation of congenital
rubella syndrome are not yet completely clear, but in
vitro studies with cell lines showed that rubella virus
has an apoptotic effect on certain cell types.
Congenital rubella occurs when the rubella virus in the mother
affects the developing baby at a critical time, in the first 3
months of pregnancy. After the fourth month, the mother's
rubella infection is less likely to harm the developing baby.
The number of babies born with congenital rubella has
decreased dramatically since the introduction of the rubella
vaccine.
Pregnant women who are not vaccinated for rubella and who
have not had the disease in the past risk infecting themselves
and their unborn baby. .
If infection occurs 0–28 days before conception, the
infant has a 43% chance of being affected.
If the infection occurs 0–12 weeks after conception,
the chance increases to 51%.
If the infection occurs 13–26 weeks after conception,
the chance is 23% of the infant being affected by the
disease.
Infants are not generally affected if rubella is
contracted during the third trimester, or 26–40 weeks
after conception.
The classic triad for congenital rubella syndrome is:
Sensorineural deafness (58% of patients)
Eye abnormalities especially pigmentary
retinopathy, cataract and microphthalmia (43% of
patients).
Congenital heart disease — especially pulmonary artery
stenosis and patent ductus arteriosus (50% of patients).
Spleen, liver, or bone marrow problems (some of which
may disappear shortly after birth)
Intellectual disability
Small head size (microcephaly)
Eye defects
Low birth weight
Thrombocytopenic purpura
Splenomegaly
Children who have been exposed to rubella in the womb
should also be watched closely as they age for any
indication of:
Developmental delay
Autism spectrum disorders
Schizophrenia
Growth retardation
Learning disabilities
Diabetes mellitus
Glaucoma
Classical Triad
Cataract
Cardiac abnormalities
Deafness
Other manifestations
Growth retardation
Rash
Hepatosplenomegaly
Jaundice
Meningoencephalitis
CNS defects lead to moderate to profound
mental retardation
Congenital Cataract:
Pearly white nuclear opacification
Frequently a dense cataract is seen centrally or
anteriorly
Sometimes complete cataract / cortex may liquefy
Histopathology:
Lens is usually microspherophakic.
Frequently, there is accompanying liquefaction
and necrosis of lens. The iris is often bowed
forward by the lens.
Live virus may be recovered from the lens as late
3 yrs after birth
Cataract removal may be complicated by excessive
post operative inflammation caused by release of
these live virus
Ocular Manifestations of CRS
Other Ocular Manifestations:
1. Diffuse pigmentary retinopathy
2. Microphthalmos
3. Corneal clouding (Transient/Permanent)
4. Glaucoma
5. CHARGE Association
Ocular Manifestations of CRS
Isolation of rubella virus
Most frequently isolated from nasopharyngeal secretions
Can be cultured from blood, urine, CSF, lens tissue, etc.
Serial rubella-specific IgG levels at 3, 6, and 12 months
Rubella-specific IgG antibodies that persist at higher concentration or longer duration than expected from
passive transfer of maternal antibody
Maternal rubella antibody- half-life= 1 month, should decrease by 4 to 8 fold by 3 months of age and should
disappear by 6 to 12 months
Can delay diagnosis
Presence of rubella-specific haemagglutination inhibition (HAI) after nine
months of age
Demonstration of rubella-specific IgM antibodies
Demonstration of Rubella antibodies of IgM in a new born is diagnostic value. As IgM group do not cross the
placenta and they are produce in the infected fetus.
Most useful in infants younger than 2 months, but may persist for up to 12 months
False- negative-20% of infected infants tested for rubella IgM may not detectable titers before 1 month.
If clinically consistent and test negative after birth, should be retested at 1 month
False- positive- rheumatoid factor, viral infections (EBV, IM, parvovirus), and heterophile antibodies
Treatment is supportive. Provide vision screening and hearing screening for
asymptomatic newborns.
Treatment of symptomatic newborns is as follows:
Provide careful evaluation of the eyes and ophthalmology referral for babies with
corneal clouding, cataract, and retinopathy. Corneal clouding may indicate infantile
glaucoma.
Babies with congenital rubella syndrome who develop respiratory distress may
require supportive treatment in the ICU.
Hepatosplenomegaly is monitored clinically. No intervention is required.
Patients with hyperbilirubinemia may require phototherapy or exchange transfusions
if jaundice is severe to prevent kernicterus.
True hemorrhagic difficulties have not been a major problem; however, IVIG may be
considered in infants who develop severe thrombocytopenia. Corticosteroids are not
indicated.
Infants who have a rubella-related heart abnormality should be carefully observed for
signs of congestive heart failure. Echocardiography may be essential for diagnosis of
heart defects.
Surgical treatment may be required for congenital heart
anomalies, including patent ductus arteriosus (PDA),
coarctation of aorta, ventricular septal defect (VSD), atrial
septal defect (ASD), and pulmonary artery stenosis.
Surgical treatment may be required for eye defects such as
glaucoma, cataract, and retinal neovascularization.
The cataractous lens (usually a nuclear type cataract) may serve
as an infectious reservoir of live virus. Pregnant health care
workers should not be allowed to care for children undergoing
surgery for cataract secondary to suspected or confirmed CRS.
Because of the associated systemic disease, children with CRS
may be at an increased risk for general anesthesia.
Children with CRS have a high risk of postoperative
complications, including:
Corneal edema and corneal opacification
Secondary glaucoma
Intense inflammation, uveitis
May require prolonged postoperative steroids
Probably best to avoid primary implantation of IOL’s
Rubella vaccine is given to children at 15
months of age as a part of the MMR
(measles-mumps-rubella) immunization.
The vaccine is live and attenuated and
confers lifelong immunity.
Given to children 09 and 15 months and
again between 3-6 years of age