Congenital rubella syndrome

Overview

Congenital Rubella Syndrome (CRS) is a serious condition that occurs in a fetus when a pregnant woman becomes infected with the rubella virus, especially during the first trimester. The virus crosses the placenta and disrupts fetal development, leading to a range of birth defects affecting the eyes, ears, heart, and brain. CRS is preventable through vaccination, and widespread immunization has significantly reduced its incidence worldwide. However, outbreaks still occur in areas with low vaccination coverage.

Causes

CRS is caused by in utero infection with the rubella virus, a single-stranded RNA virus from the Togaviridae family. The infection is transmitted from mother to fetus via the placenta. The risk and severity of CRS are highest when the mother contracts rubella during the first 12 weeks of pregnancy. After the 20th week, the risk of severe birth defects drops significantly, but mild effects may still occur.

Symptoms

The clinical features of CRS vary, but the classic triad includes:

• Sensorineural deafness: The most common manifestation

• Eye abnormalities: Such as cataracts, retinopathy, and microphthalmia

• Congenital heart defects: Particularly patent ductus arteriosus (PDA) and pulmonary artery stenosis

Other signs and complications may include:

• Microcephaly: Abnormally small head and brain development

• Intellectual disability or developmental delay

• Hepatosplenomegaly: Enlarged liver and spleen

• Bone lesions

• Thrombocytopenic purpura: Bruising or purplish spots due to low platelet counts ("blueberry muffin" rash)

• Low birth weight and failure to thrive

• Endocrine disorders: Such as type 1 diabetes or thyroid dysfunction (may appear later)

Diagnosis

Diagnosis of CRS is based on clinical findings, maternal history, and laboratory confirmation. Diagnostic steps include:

• Maternal history: Rubella infection or rash illness during early pregnancy

• Physical examination: Identification of characteristic birth defects

• Serologic tests: Detection of rubella-specific IgM antibodies in the infant's blood

• PCR testing: Detection of rubella RNA in nasopharyngeal, urine, or cerebrospinal fluid samples

• Ophthalmologic and audiologic exams: To assess vision and hearing impairments

• Cardiac evaluation: Echocardiogram to detect congenital heart defects

• Neuroimaging: For brain abnormalities and calcifications

Treatment

There is no specific antiviral treatment for CRS. Management is supportive and focused on treating individual symptoms and complications. Key components include:

• Hearing aids or cochlear implants: For sensorineural hearing loss

• Corrective eye surgery: For cataracts or other visual defects

• Cardiac surgery or medication: For congenital heart disease such as PDA

• Developmental therapies: Including physical, speech, and occupational therapy

• Special education services: For cognitive and learning support

• Endocrinologic care: Monitoring and managing diabetes or thyroid disorders

• Regular follow-up: With audiology, ophthalmology, cardiology, neurology, and developmental pediatrics

Prognosis

The prognosis of Congenital Rubella Syndrome depends on the severity and number of systems affected. Many children with CRS face lifelong challenges, including hearing impairment, vision loss, and developmental delays. With appropriate medical and educational support, some can achieve functional independence. However, severe multi-organ involvement can lead to significant disability or early mortality. The most effective approach to CRS is prevention through vaccination of women of childbearing age and maintaining high rubella immunization rates in the general population.