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Congenital rubella syndrome

  1.  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.
  2.  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. .
  3.  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.
  4.  Rate of organ anomalies in CRS
  5.  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).
  6.  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
  7.  Extramedullary hematopoiesis, presents as a characteristic blueberry muffin rash
  8.  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
  9. Classical Triad  Cataract  Cardiac abnormalities  Deafness Other manifestations Growth retardation Rash Hepatosplenomegaly Jaundice Meningoencephalitis CNS defects lead to moderate to profound mental retardation
  10. 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
  11.  Other Ocular Manifestations: 1. Diffuse pigmentary retinopathy 2. Microphthalmos 3. Corneal clouding (Transient/Permanent) 4. Glaucoma 5. CHARGE Association Ocular Manifestations of CRS
  12. Diffuse Pigmentary Retinopathy / Salt-and-pepper retinopathy Cataract
  13.  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
  14.  Other causes of congenital infection:  cytomegalovirus,  toxoplasmosis,  herpes simplex,  varicella zoster, syphilis, parvovirus, human immunodeficiency virus, enteroviruses  Noninfectious processes:  neonatal hyperthyroidism  tuberous sclerosis  incontinentia pigmenti  Aicardi syndrome  hereditary congenital cataract with hypertrophic cardiomyopathy.
  15.  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.
  16.  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.
  17.  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
  18.  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