4.4 ACUTE MYOCARDITIS

Question 1

Anatomy

Answer 1

(1) Three layers of the heart: Epicardium, Myocardium, Endocardium

Question 2

Pathophysiology

Answer 2

(1) Myocarditis is defined as inflammation of the myocardium
(2) Caused by a number of viral and bacterial agents
(a) Viruses: Influenza, Epstein Barr, Hepatitis B, HIV
(b) Bacteria: Beta-Hemolytic strep (cause of Rheumatic fever), Lyme, Neisseria meningitides
(3) Non-Infectious causes:
(a) Alcohol
(b) Cocaine
(c) Medications: PCN, cephalosporin, sulfonamides, diuretics
(d) Insect bites
(e) Snake bites
(f) Inflammatory bowel disease
(g) Celiac disease
(h) Sarcoidosis
(4) Frequently will be accompanied by pericarditis due to the large amount
of inflammation spreading out to the pericardium

Question 3

c. Symptoms and Physical Findings

Answer 3

(1) Fever
(2) SINUS TACHYCARDIA out of proportion to TEMPATURE
(3) Retrosternal chest pain
(4) Excessive fatigue or exercise intolerance
(5) S3, S4
(6) Pericardial friction rub if pericarditis is also present
(7) Clinical illness may overshadow clinical signs of myocardial dysfunction
(8) In severe cases signs of progressive congestive heart failure may be seen

Question 4

Differential Diagnosis

Answer 4

(1) AMI
(2) Unstable angina
(3) PE
(4) Aortic dissection
(5) Esophageal rupture
(6) Pericarditis
(7) Pericardial effusion
(8) Pneumonia

Question 5

Labs/Studies/EKG

Answer 5

(1) CARDIAC ENZYMES (troponin, CK-MB) will be positive (This is what distinguishes myocarditis from pericarditis)
(2) CBC: will have an elevated WBC because of infection and inflammation
(3) ESR or Sedimentation rate (marker of inflammation) will be elevated
(4) C-reactive protein (marker of inflammation) will be elevated
(5) EKG: may show signs of pericarditis with diffuse ST-segment elevation
(6) Echocardiogram is performed in all patients to look at heart function
(7) Cardiovascular Magnetic Resonance imaging
(8) Endomyocardial biopsy is the confirmatory test performed for diagnosis

Question 6

Treatment

Answer 6

(1) In idiopathic and viral myocarditis treatment is supportive and symptom
directed (Rest, fluids, pain control with morphine)
(2) AVOID NSAIDS as it is not effective and can worsen heart failure symptoms if they have them
(3) In Meningococcemia or Rheumatic fever use directed antibiotic therapy
(4) Manage congestive heart failure with diuretics

Question 7

Initial Care

Answer 7

(1) Stabilize and transfer to higher level of care
(2) Initiate Morphine therapy for pain
(3) Avoid all alcohol
(4) Restrict activity if cannot get them to a higher level of care right away.

Question 8

Complications

Answer 8

(1) AMI

(2) CHF