Makindo Medical Notes

Related Subjects: |Herpes Varicella-Zoster (Shingles) Infection |Chickenpox Varicella Infection |Varicella Cerebral Vasculopathy |Herpes Viruses |Herpes Zoster Ophthalmicus (HZO) Shingles |MonkeyPox |Mumps |Measles |Rubella (German Measles) |Epstein-Barr Virus infection

Rubella infection typically causes a mild exanthematous illness with little clinical significance in most individuals. However, if contracted during the first trimester of pregnancy, it can lead to severe congenital abnormalities such as cataracts, cardiac anomalies, and sensorineural hearing loss.

About

• Also known as German measles (described by German physicians) and should not be confused with rubeola (measles).
• Caused by an RNA virus, with an incubation period of 14-21 days. Rubella epidemics tend to occur every decade.
• Transmission is through respiratory aerosols. The peak incidence is typically in individuals around 15 years old.
• Rubella is a vaccine-preventable disease, significantly reduced by widespread immunization.

Clinical Presentation

• Infection may be subclinical, but individuals can still shed the virus and infect others.
• Fever is usually mild and transient, lasting only on the first day of symptoms.
• Other symptoms include malaise, lethargy, coryza (runny nose), and conjunctivitis.
• Lymphadenopathy (swollen lymph nodes) is common, particularly in the posterior cervical, posterior auricular, and suboccipital regions.
• A characteristic red or pink maculopapular rash appears, often starting on the face and spreading to the trunk and limbs.
• Small petechial lesions, called Forchheimer spots, may appear on the soft palate.
• Rubella is contagious for up to 2 weeks, starting from 7 days before the rash appears until 7 days after.

Rubella Rash

Complications

• Fetal infection: Rubella infection during pregnancy, particularly in the first trimester, can cause severe congenital anomalies (see below).
• Encephalitis: Occurs in approximately 1 in 5,000 cases, with a mortality rate of 30-50% in severe cases.
• Transient arthritis: Often affects the hands and small joints, particularly in adults, and resolves without long-term damage.
• Transient hepatitis: Mild liver inflammation may occur, especially in adults.

Rubella in Pregnancy

• Rubella infection during the first trimester poses the highest risk to the fetus and can result in Congenital Rubella Syndrome (CRS).
• Potential congenital defects include:
  • Congenital heart defects: Patent ductus arteriosus (PDA) and ventricular septal defects (VSD) are common.
  • Ocular abnormalities: Cataracts and microphthalmia.
  • Sensorineural hearing loss: One of the most common long-term complications.
  • Neurological issues: Microcephaly, developmental delays, and encephalitis.
  • Other systemic effects: Hepatosplenomegaly, myocarditis, interstitial pneumonia, and bone lesions.
• Rubella infection in the third trimester is generally less harmful to the fetus, though risks still exist.

Investigations

• Serology: A rising rubella-specific IgG titer in paired samples taken 2 weeks apart confirms recent infection. Detection of rubella-specific IgM indicates acute infection.
• A fourfold increase in rubella IgG antibodies between acute and convalescent phases can confirm infection or reinfection.
• Viral isolation from nasopharyngeal secretions can confirm acute rubella infection, particularly during pregnancy.

Management

• Prevention: Rubella vaccination, as part of the Measles, Mumps, and Rubella (MMR) vaccine, is the most effective way to prevent rubella.
• Preconception care: Women planning to conceive should have their rubella immunity checked. Vaccination is recommended for non-immune women before pregnancy, as live vaccines are contraindicated during pregnancy.
• During pregnancy: If a woman is exposed to rubella, serology (IgM and IgG) should be performed to assess for infection or immunity. Immunoglobulin may be offered in some cases to reduce the risk of CRS, though efficacy is limited.
• Supportive care: There is no specific treatment for rubella. Management is supportive, including antipyretics for fever and analgesics for joint pain.
• Congenital Rubella Syndrome: Management of CRS focuses on addressing the specific complications (e.g., cardiac surgery for heart defects, hearing aids or cochlear implants for hearing loss).