Rubella (Virus)

Question 1

What are the 5 classic childhood exanthems? What is an exanthem?

Answer 1

Exanthems are widespread rashes throughout the body. The 5 classic childhood exanthems are Rubella, Chicken Pox, Roseola, Measels, and Fifth Disease.

Question 2

What kind of virus is Rubella? (in terms of family and what area of the body it infects)

Answer 2

It is in the family of togaviruses however, it is a respiratory virus and does not cause readily detectable cytopathologic effects.

Question 3

What is maternal rubella associated with? When does the mother have to be infected for congenital rubella to present?

Answer 3

Congenital cataracts and other severe congenital defects, including deafness. This happens in females infected w/ Rubella in the first trimester.

Question 4

What are the family characteristics of togavirus and under which does Rubella fall under?

Answer 4

Togaviruses are enveloped, icosahedral, and subdivided into two genera: alhpavirus and rubivirus, rubella is part of the rubivirus genera.

Question 5

Describe the rash for Rubella, and how does this relate to the rash seen in measels?

Answer 5

It is a macular rash that begins in the forehead and works its way down. Measels will start below the ears and behind the neck and work its way down and then eventually back up to cover the face.

Question 6

What are the vector and hosts of rubella? How is Rubella transferred?

Answer 6

There are no vectors, and the host is humans. Transferred via respiratory droplets or transplacental.

Question 7

What are the diseases caused by Rubella called?

Answer 7

“German Measles” and “Congenital Rubella Syndrome” or CRS.

Question 8

What kind of vaccine is available for Rubella?

Answer 8

Live, attenuated vaccine.

Question 9

What are the symptoms of CRS and when do these symptoms most severe? Define the congenital rubella triad.

Answer 9

Congenital Rubella Syndrome is most serious in the first 16 weeks of gestation and will still be a problem until the 20th week. It will present as patent ductus arteriosis, pulmonary stenosis, cataracts, microencephalopathy, mental retardation and deafness. Cataracts is the most tell-tale sign. Triad: Patent ductus arteriosis (PDA), cataracts and deafness.

Question 10

Child 3-4 months old presenting with cataracts, immediately we should be thinking of…?

Answer 10

Congenital Rubella Syndrome, the mother has been infected with rubella while child is in utero. It is extremely uncommon for a child that young to present with cataracts.

Question 11

What is are 3 common but non-specific manifestation of rubella in an infant?

Answer 11

Deafness, patent ductus arteriosis, pulmonary stenosis.

Question 12

Rubella virus presenting in the first trimester is considered…?

Answer 12

Teratogenic, because in the first trimester is when the organs begin to develop.

Question 13

How is one vaccinated for Rubella?

Answer 13

Via the MMR vaccine, the Measles, Mumps and Rubella vaccine all three are covered in the live attenuated MMR vaccine.

Question 14

Generally speaking how does Rubella and Measles differ in their clinical presentation besides the rash differences?

Answer 14

Measles will make you a lot sicker than Rubella, and Rubella will present with lymphadenopathy which is not as apparent in Measles.

Question 15

Describe the path of rubella infection

Answer 15

It gets into the body via the upper respiratory tract, spreads to the lymph nodes (and causes lymphadenopathy) and the monocyte-macrophage system, virimia and this can result in infection of other tissues and the mild rash.

Question 16

How can Rubella be transferred?

Answer 16

A person can shed the virus via respiratory droplets 2 weeks before symptoms present and 2 weeks after the onset of the rash.

Question 17

What causes the rash and the arthralgia associated with rubella?

Answer 17

Immune complexes made in response to the virimia of Rubella.

Question 18

How does rubella spread to the fetus?

Answer 18

If mother lacks the antibody to rubella the virus can spread to the placenta and replicate there, then spread to the fetal blood supply.

Question 19

How does rubella cause malformations and teratogenicity in the baby?

Answer 19

It is not cytolytic but the general growth/mitosis and chromosomal structure of the fetal cells can be altered. It depends on what tissues and what time the virus infects to determine the extent of the damage.

Question 20

How does rubella present in children clinically?

Answer 20

It is generally benign, the maculopapular or macular rash and swollen lymph nodes are the extent of it.

Question 21

Rubella infection in adults presents how?

Answer 21

Bone and joint pain and rarely thrombocytopenia or post infectious encephalopathy, this is from cell mediated immunity and HS rxns.

Question 22

Mortality rate of infants infected with rubella in utero?

Answer 22

High mortality rate within the first year.

Question 23

How can we identify Rubella infection?

Answer 23

The presence is detected via RT-PCR detection of viral RNA, and then the dx is confirmed via antirubella specific IgM. x4 increase in specific IgG’s can indicate recent infection.

Question 24

When is the MMR vaccine administered? What does it do?

Answer 24

At 2 years of age. It promotes both humural and cell-mediated immunity.

Question 25

Describe the structure and characteristics of the Rubella Virus?

Answer 25

Enveloped virus with an icosahedral capsid. Positive strand ssRNA. Under the family of “Togavirus.”

Question 26

Describe the infection process of Rubella from the incubation period to the extent of the disease?

Answer 26

14-21 day incubation period, then prodrome (malaise and low grade fever), then maculopapular rash (lasts for 3 days).

Question 27

Describe the skin and musculoskeletal defects?

Answer 27

Skin: Purpuric “Blueberry Muffin” rash (dermal erythropoeisis – also seen in CMV).
Bone: Radiolucent bone lesions can be seen.

Question 28

What is the classic finding in the MOTHER who is infected with Rubella?

Answer 28

Post auricural and Sub-occipital lymphadenopathy.