Microbiology

Question 1

Targetoid, migrating erythematous rash (concentric rings) w/ flu-like sx followed by asymmetric arthralgia, carditis, ataxic gait.

Dx? Agent? Transmission? Tx?

Answer 1

Dx: Lyme Disease
Cause: Borrelia burgdorferi
Vector: Ixodes deer tick
Tx: Doxycyline (a tetracycline)

Question 2

Naked, single stranded DNA virus
Spread by respiratory droplets
Responsible for Fifth’s Disease/Slapped Cheek Disease/Erythema Infectiosum

Agent?

Answer 2

Parvovirus B19

Question 3

Joint pain and a red rash on the cheeks that later spread to the shoulders, chest, and upper limbs in a blotchy, reticulated (lacy) fashion.

Dx? Agent? Complications?

Answer 3

Dx: Fifths Disease/Slapped Cheek disease/Erythema infectiosum
Agent: Parvovirus B19

Sequelae:

• Transient aplastic crisis (especially in sickle cell pts.)
• Hydrops fetalis (fetus of pregnant women exposed in first trimester dies of cardiac failure secondary to severe anemia)

Question 4

Herpesvirus (HHV-4)
Enveloped
Linear DNA

Transmission via respiratory droplets & saliva
Monospot test postitive / Positive heterophile antibody test

Dx? Pathology? Presentation? Complications?

Answer 4

Dx: Epstein-Barr Virus
Pathology: Infects B-cells via CD21 receptor

Presentation:

1. Fever
2. Pharyngitis
3. Hepatosplenomegaly
4. Lymphadenopathy

Complications:

1. Splenic rupture
2. Maculopapular rash following amoxicillin administration
3. Burkitt Lymphoma
4. Nasopharyngeal carcinoma
5. B & T cell lymphoma