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Flashcards in Infections of the Heart Deck (26):
1

Infections of the Heart

  • Endocarditis
  • Myocarditis
  • Pericarditis

  • Endocarditis
    • Inflammation of the heart lining, or endocardium
    • Typically involves the valves
  • Myocarditis
    • Inflammation of the heart muscle
  • Pericarditis
    • Inflammation of the outside of the heart & sac

2

Bacterial (Infective) Endocarditis

  • General
  • Most common cause of infective endocarditis
  • Acute
  • Subacute
  • Histology
  • Major complications

  • General
    • Bacteria (or fungus) infects valve surfaces
    • Damages & destroys valves
    • Abnormal valve can act as nidus of infection
      • i.e. Stenotic, insufficient, bicuspid, prosthetic
      • Mitral & aortic most common
        • Tricuspid valve in IV drug abuse
  • Most common cause of infective endocarditis
    • Staphylococcus aureus
  • Acute
    • Normal valve
    • Highly virulent organism
    • Rapid course w/ high mortality
  • Subacute
    • Abnormal valve
    • Less virulent organism
    • Protracted course (weeks to months)
  • Histology
    • Acute inflammation
    • Inflammatory debris
    • Bacterial colonies
      • Staphylococcus epidermitis
      • Staphylococcus aureus
      • Pseudomonas aeruginosa
  • Major complications
    • Destruction / rupture of valve
    • Heart failure
    • Valve insufficiency
    • Septic embolic events
    • Subacute: valve fibrosis & stenosis

3

Bacterial (Infective) Endocarditis Classic Lesions

  • Septic emboli to other organs & tissues
  • Splinter hemorrhages
    • Subungual vascular lesion
  • Osler nodes
    • Painful red-purple nodules on fingers or toes
    • Occur around glomus body
  • Janeway lesions
    • Non-painful hemorrhagic lesions on palms & soles of feet
  • Roth spots
    • Retinal hemorrhages
  • Kidney abscesses
  • Brain infarcts

4

Rheumatic Heart Disease

  • Endocarditis
  • Myocarditis
  • Pericarditis
  • Pancarditis

  • Endocarditis
    • Vegetations on heart valve surfaces
  • Myocarditis
    • Inflammation of the myocardium (heart muscle cells)
    • Rare: <1% of patients get fulminant rheumatic fever w/ myocarditis
    • Achoff body: diagnostic myocardial lesion
      • Composed of t-cells, plasma cells, & activated macrophages
    • Anitschow cells: diagnostic cells
      • Activated, multinucleated macrophages w/ slender wave chromatin "caterpillar cells"
    • If someone dies from rheumatic fever, they typically have myocarditis
  • Pericarditis
    • Inflammation of the pericardium
  • Pancarditis
    • Involvement of epicardium, myocardium, & pericardium

5

Viral Myocarditis

  • Myocarditis
  • Due to...
  • Caused by...
  • Clinical features

  • Myocarditis
    • Inflammation of the myocardium
  • Almost exclusively due to infection
    • ​Viral: Coxsackie virus, Influenza virus
    • Chagas disease, Lyme diesease
  • Caused by...
    • Rheumatic heart disease (can cause death)
    • Immune reactions (lupus, rheumatic fever)
    • Transplant rejection
    • Drug reaction (eosinophilic)
  • Clinical features
    • Viral illness symptoms
    • Cardiac arrhythmia, palpitations
    • Dyspnea
    • Pre-cordial discomfort
    • Can progress rapidly to heart failure & death

6

Viral Myocarditis

  • Gross pathology
  • Microscopic pathology
  • Clinical pathology
  • Course & complications

  • Gross pathology
    • Pale, floppy myocardium
  • Microscopic pathology
    • Lymphocytic (or mixed) infiltrate
    • Myocyte necrosis
  • Clinical pathology
    • Elevated CK-MB & troponins
  • Course & complications
    • No sequelae
    • Symptoms w/ recovery
    • Chronic heart disease
    • Dilated cardiomyopathy
    • Death

7

Why do you see elevated cardiac enzymes in myocarditis?

Inflammatory cell death

8

Eosinophilic Myocarditis

  • Drug reaction
  • Chagas disease

  • Drug reaction (hypersensitivity)
    • Antibiotics, chemotherapeutics
    • Typically have a rash or other immune response
  • Chagas disease (protozoal infection)
    • Trypanosoma cruzi: American trypanosomiasis
    • "Kissing bug"
    • Most patients get caridac involvement
    • Can lead to immune-mediated myocarditis (Achalasia in GI path)

9

Giant Cell Myocarditis

  • Unusual varient of "garden variety" myocarditis
  • Mixed infiltrate w/ giant cells
  • More extensive myocyte necrosis
  • Aggressive course w/ poor prognosis

10

Myocarditis Summary

  • Lymphocytic
  • Eosinophilic
  • Giant cell
  • Requirements for pathology diagnosis

  • Lymphocytic
    • Viral, immune reactions
  • Eosinophilic
    • Hypersensitivity
  • Giant cell
    • Unique aggressive form
  • Requirements for pathology diagnosis
    • Inflammatoyr infiltrate
    • Myocyte damage &/or necrosis

11

Pericarditis

  • General
  • Clinical findings
  • Different types

  • General
    • Inflammation or infection of the epicardium &/or pericardium
    • Caused by a variety of conditions
    • Primary pericarditis is viral
    • Typically see accompanying fluid collection
  • Clinical findings
    • Chest pain
      • Sharp, retrosternal, radiates to back
      • Relieved by sitting up or leaning forward
      • Worsened w/ lying down
    • Friction rub on auscultation
    • Caridac tamponade
      • Life-threatening event
      • Fluid fills heart sac (usually >150 ml)
      • Beck's triad: jugular venous distention, hypotension, muffled heart sounds
      • Emergent treatment: pericardiocentesis
  • Different types
    • Serous
    • Fibrinous
    • Purulent (suppurative)
    • Hemorrhagic

12

Serous Pericarditis

  • General
  • Caused by...

  • Straw-colored pericardial effusion
  • Protein rich exudate
  • Caused by
    • SLE (lupus)
    • Rheumatic fever
    • Viral infection

13

Fibrinous Pericarditis

  • General
  • Caused by...

  • General
    • "Sticky" adherent fibrin strands on surface
    • Fibrin rich exudate
  • Caused by...
    • Post-pericardotomy syndrome after coronary artery bypass graft surgery
    • Acute myocardial infarction
    • Dressler's syndrome
    • Uremia (uremic pericarditis): renal failure

14

Purulent (Suppurative) Pericarditis

  • General
  • Caused by...

  • General
    • Thick yellow effusion (pus)
    • Inflammatory exudate
  • Caused by...
    • Infection

15

Hemorrhagic Pericarditis

  • General
  • Caused by...

  • General
    • Bloody inflammatory effusion
  • Caused by...
    • Tumor invasion of pericardium
    • Tuberculosis (chronic)
    • Bacterial infection

16

Pericarditis

  • Acute complications
  • Chronic complications

  • Acute complications
    • Cardiac tamponade
    • Cardiac arrhythmia
  • Chronic complications
    • Constrictive (restrictive) pericarditis
    • Scarring w/ adhesions

17

Scenario 1

  • 36-year-old chronic IV drug abuser
  • Osler node on right index finger
  • Splinter hemorrhages

  • Endocarditis
    • Infectious bacterial
    • Tricuspid valve
    • Pseudomonas, Staph. aureus

18

Scenario 2

  • 6-year-old w/ 4-day history of "sore throat" & rash
  • Didn't go to doctor
  • Collapses suddenly
  • Autopsy shows myocarditis

  • Rheumatic heart disease
    • Myocarditis & sudden death

19

Scenario 3

  • 25-year-old male dies suddenly in 3rd day of an influenza infection

  • Myocarditis
    • Infectious
    • Influenza virus

20

Scenario 4

  • 57-year-old woman receiving chemotherapy for breast cancer
  • Sudden new-onset cardiac arrhythmias
  • Myocardial biopsy shows eosinophilic infiltrate

  • Hypersensitivity myocarditis
    • Chemotherapy
    • Antibiotics

21

Scenario 5

  • 11-year-old dies dudenly after 36 hour course of apparent viral infection
  • Heart exam shows myocarditis w/ giant cells

  • Giant cell myocarditis
    • Unique aggressive form in younger patients

22

Scenario 6

  • 5-year-old w/ "sore throat" for 5 days collapses suddenly
  • Heart sounds are distant, JVD, hypotension
  • Therapeutic intervention?

  • Pericarditis w/ cardiac tamponade
    • Pericardiocentesis

23

Scenario 7

  • 65-year-old woman w/ chronic renal failure
  • Sudden onset of chest pain
  • Exam shows friction rub

  • Fibrinous pericarditis
    • Uremia

24

Scenario 8

  • 56-year-old alcoholic w/ pneumonia & sepsis
  • Acute substernal chest pain
  • Exam shows friction rub

  • Purulent (suppurative) pericarditis
    • Infection

25

Scenario 9

  • 68-year-old w/ advanced untreatable lung cancer
  • Now has signs & symptoms of pericarditis

  • Hemorrhagic pericarditis
    • Tumor invasion

26

Scenario 10

  • 54-year-old w/ recent CABG surgery
  • Sharp substernal chest pain & hypotension

  • Fibrinous pericarditis
    • Post-pericardotomy syndrome
    • Coronary artery bypass graft surgery
    • Dressler's syndrome