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Internal Medicine

Rubella

Rubella, also known as German measles or three-day measles, is an infection caused by the rubella virus.

Rubella, also known as German measles or three-day measles, is an infection caused by the rubella virus.

Epidemiology

  • Transmission: Air droplets via nasopharyngeal secretions (respiratory route) (80% infectivity)

Aetiology

  • Rubella
640px-rubella_virus_tem_b82-0203_lores
Transmission electron micrograph of rubella viruses | CDC/Dr. Erskine Palmer – http://phil.cdc.gov/PHIL_Images/08301998/00001/B82-0203_lores.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=821892

Clinical features

75% cases symptomatic

  • Incubation period: 14-21 days
  • Infective period: 7 days before & 5 days after appearance of rash

Children:

In children, rubella normally last two days
  • Generalised maculopapular rash “blueberry muffin rash“: Face → Trunk → Extremities
  • Febrile illness: Low fever of < 38.3 °C (101 °F)
  • Posterior cervical lymphadenopathy
  • Forchheimer spots (20% cases): Tiny red-coloured lesions in oropharynx or petechial haemorrhages on soft palate
Forchheimer spots appear in about 20% of patients with rubella with enanthem as small, red spots on the soft palate, occasionally preceding a rash. These spots are not specific to rubella and can be seen in cases of measles, scarlet fever, and other systemic infections | Fukuda, M., Harada, T., Shimizu, T., & Hiroshige, J. (2020). Forchheimer Spots in Rubella. Internal medicine (Tokyo, Japan), 59(13), 1673. https://doi.org/10.2169/internalmedicine.4368-19

Older children and adults:

  • Additional symptoms:
    • Swollen glands
    • Coryza (cold-like symptoms)
    • Arthritis/arthralgia (especially in young women)
  • Rare problems:
    • Brain inflammation
    • Ear infection

Late-onset complications:

  • Progressive rubella pancephalitis (PRP)
  • Type I Diabetes mellitus
  • Thyroiditis & hypothyroidism

Diagnosis

  • Isolated in:
    • Urin, blood, nasopharynx & CSF
      • For 2 weeks after rash onset
  • Serology:
    • Maternal: IgG & IgM titres
    • Neonate (Umbilical cord blood): IgG titre
640px-rubella_serology
Congenital rubella serology time-line | GrahamColmTalk – Public Domain, https://en.wikipedia.org/w/index.php?curid=14949036

Differential diagnosis:

Other viral illnesses associated with rash
  • Measles: Appears on 4th day over face and retroauricular in origin
  • Chicken pox: Appears on 1st day of fever, with centripetal distribution and pleomorphic appearance like dewdrops on a rose petal.
  • Erythema infectiosum: Rash on cheeks (slapped cheek appearance), and moves to trunk and extremities
  • Erythema subitum: Macules/maculopapular rash
  • Infectious mononucleosis: Associated with maculopapular rash
  • Roseola
rubella-measles-roseola

Management

  • Maternal termination of pregnancy
    • Unequivocal diagnosis of rubella in the first trimester of pregnancy is indicative
  • Droplet precautions (7 days after rash onset)
  • Prenatal counselling
  • Rubella immunization
    • All children and particularly all adolescent girls

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