Myocarditis

Question 1

What is myocarditis?

Answer 1

Inflammation of the myocardium with myocyte necrosis and degeneration

Question 2

Biopsy of a heart is shown. What is the Dx? Describe the pathogenesis of this condition

Answer 2

Viral myocarditis

1. Acute myocardial necrosis from direct damage from virus
2. T cells and macros infiltrate the myocardium
3. Signs of HF develop

Question 3

What are the two most common viruses to infect the heart? Describe the pathogenesis of their infection. Why are children commonly affected?

Answer 3

Coxsackievirus and adenovirus

1. Both enter cardiac myocytes after binding to the coxsackie-adenovirus receptor
2. The have high levels of CAR

Question 4

1. What are the innate anti-viral mechanisms in cardiomyocytes?
2. How can these mechanisms be inhibited?

Answer 4

1. Antiviral mechanisms mediated thru Janus kinase (JAK) and STAT pathways
2. Suppressors of cytokine signaling (SOCS) endcoded by humans. The more SOCS activated, the more likely coxsackie virus can infect

Question 5

What are the symptoms of viral myocarditis? What is the Tx? What condition is associated with a high incidence of viral myocarditis?

Answer 5

Generally asymptomatic; Supportive Tx only!; AIDS

Question 6

What are other agents that can cause myocarditis?

Answer 6

• Bacteria
• Rickettsia
• Fungi
• Toxoplasmosis
• Chagas (Trypanosoma Cruzi)

Question 7

What can cause granulomatous myocarditis?

Answer 7

• Mycobacteria
• Fungi
• Rheumatic Myocarditis
• Sarcoidosis

Question 8

What is hypersensitivity myocarditis caused by? Typical features?

Answer 8

Reaction to drugs; Eosinophils, lymphocytes, plasma cells, ABSENCE of myocyte necrosis

Question 9

A patient with SLE rapidly declines. Giant cells are shown on autopsy. What is the Dx? What other diseases are associated with this condition? What is the most effective treatment? What did the patient likely die from?

Answer 9

Giant cell myocarditis; Hyperthyroidism, thymoma; Cardiac transplantation; Congestive HF