Micro: Myocarditis/Peri

Question 1

Why is acute (non-fulminant) myocarditis more lethal than fulminant myocarditis?

Answer 1

Acute is not as easily diagnosed and the disease progresses to an irreversible state more often.

Question 2

Name the 4 mechanisms by which cardiac myocytes can become damaged in myocarditis and an example of each.

Answer 2

1. Direct Damage by invading organism: Coxsackie B virus
2. Damage by the host’s CMI: Gram (-) bacteria with LPS causing massive immune reaction
3. Abs produced against an infection that cross-recognize cardiac myocytes by mistake: CMV infection
4. Cytotoxicity caused by circulating toxin: Diptheria

Question 3

Name 4 of the viruses that cause myocarditis and which is most common.

Answer 3

1. B19: Parvoviridae (most common)
2. HHV-6
3. Enteroviruses (Coxsackie B)
4. Adenovirus

Question 4

Name two tools used to Dx myocarditis. Which is the gold standard and which is on the rise.

Answer 4

1. Biopsy (gold standard)

2. PCR (on rise to becoming the test of choice)

Question 5

Which of the two tests is best to distinguish autoimmune from viral myocarditis?

Answer 5

PCR

Question 6

Most threatening cause of myocarditis in neonates.

Answer 6

Coxsackie B

Question 7

How does Coxsackie B enter cardiac myocytes and how does it cause damage?

Answer 7

Enters thru the Coxsackie-Adenovirus Receptor (CAR)

Uses Viral Protease 2A: cleaves dystrophin protein

Question 8

Name the cause of myocarditis in a child that presents with a rash on the face.

Answer 8

B19

-slapped cheek (Erythema Infectiosum)

Question 9

Most common cause of FATAL myocarditis.

Answer 9

C. diptheriae (Gram + rod)

Question 10

Most distinguishing feature of diphtheria and mechanism of cell damage.

Answer 10

Gray Pseudomembrane in the back of the throat.

Releases a toxin that inhibits Elongation Factor 2 preventing translation

Question 11

Bug and most common manifestation of Lyme Carditis. Treatment for this symptom.

Answer 11

Borrrelia burgdorferi

-causes AV block and may need a temporary pacemaker

Question 12

Cause of myocarditis in a patient that presents with a rash and edema around the eyes.

Answer 12

T. cruzi (chagas disease)

-this presentation is the Romana Sign (chagoma formation)

Question 13

How does T. cruzi cause damage to the heart muscle?

Answer 13

Parasite enters and replicates within cells. T-lymphocytes are activated and lyse the cells (CMI).

Question 14

How can myocarditis from chagas disease be detected in acute stages?

Answer 14

Thick-Thin blood smear

Question 15

Name the four most common causes of Pericarditis.

Answer 15

1. Viral
2. TB
3. Pneumococcal
4. Staphylococcal

Question 16

What are 4 characteristics that are very common upon presentation of pericarditis?

Answer 16

1. Pleuritic chest pain
2. High fever
3. Pericardial friction rub
4. EKG abnormalities

Question 17

Most common source of TB pericarditis.

Answer 17

Spread from lungs