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Rheumatic Fever and Heart Disease (PowerPoint)

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					Rheumatic Fever and Heart Disease
• Definition: rheumatic fever is an acute,
  immunologically mediated, multi-system
  inflammatory disease that follows, after a few
  weeks, an episode of group A streptococcal
  pharyngitis (3% of patients).

• The incidence and mortality of rheumatic fever
  has declined over the past 30 years (due to
  improved socioeconomic condition and rapid
  diagnosis and treatment of strep. pharyngitis.
      Rheumatic Fever: Heart
• Affect the heart during its acute phase 
  acute rheumatic carditis.

• Cause chronic valvular deformities (many
  years after the acute disease.
           Pathogenesis and Key Morphologic Changes of Acute
                         Rheumatic Heart Disease
Hypersensitivity
reaction induced by
group A strept. (ab.
Against protein M
Cross-reaction /
Autoimmune response
Morphology: Acute Rheumatic Fever

 • Inflammatory infiltrates occur in a wide
   range of tissues: synovium, joints, skin,
   heart.
 • Focal fibrinoid necrosis  mixed
   inflammatory reaction (diffuse or localized)
    Fibrosis (chronic rheumatic heart disease) .
        Acute Rheumatic Carditis
• Pancarditis (endo- myo- pericarditis).
• Multiple foci of inflammation within the connective
  tissue of the heart. (Aschoff bodies: central fibrinoid
  necrosis, surrounded by chronic mononuclear
  inflammatory infiltrate and occasional large
  histiocytes).
• Diffuse interstitial inflammatory infiltrates (may lead
  to generalized dilation of the cardiac chambers).
      Acute Rheumatic Carditis
• Pericardial involvement: fibrinous pericarditis,
  sometime associated with serous or
  serosanguinous effusion.
• Endocardium:
   – Mostly mitral and aortic valve.
   – Valves are edematous and thickened with foci of
     fibrinoid necrosis. (Aschoff nodules uncommon).
   – Verrucous endocarditis (small vegetations along lines
     of valve closure).
• Acute changes may resolve completely or progress
  to scarring and chronic valvular deformities.
Rheumatic Fever: Involvement of
        Other Organs
• Arthritis: large joints, self limited, no
  chronic deformities.
• Lung: uncommon, chronic interstitial
  inflammation and fibrinous pleuritis.
• Skin: skin nodules, erythema marginatum.
Chronic Rheumatic Heart Disease
• Irreversible deformity of one or more
  cardiac valves (previous acute valvulitis).
• Left side of heart > right.
• Reduction of diameter (stenosis), or
  improper closure (regurgitation), or both.
• May lead to cardiac failure (overload)
• May predispose to infective endocarditis.
  Chronic Rheumatic mitral valvulitis
• Stenosis > regurgitation.
• Females > males.
• In stenosis:
  –   Leaflets are thick, rigid, and interadherent.
  –   Dilatation and hypertrophy of left atrium.
  –   Mural thrombi may be present systemic emboli.
  –   Lungs are firm and heavy (chronic passive congestion).
  –   Right heart may be affected later.
• In regurgitation:
  – Retracted leaflets.
  – Left ventricular hypertrophy and dilatation.
      Chronic Aortic Valvulitis
• Males > females.
• Associated with mitral valvulitis.
• Aortic stenosis:
  – Valve cusps are thickened, firm and
    interadherent  rigid triangular channel.
  – Left ventricular hypertrophy.
  – Subsequent left ventricular failure and dilation.
• Aortic regurgitation: retraction of leaflets.
    Acute Rheumatic Fever: Clinical
• Occurs 10 days to 6 weeks after pharyngitis.
• ? Of genetic susceptibility.
• Peak incidence: 5-15 years.
• Pharyngeal culture may be negative, but anti
  streptolysin O (ASO) titer will be high.
• Arthritis: large joints, migratory.
• Acute carditis: pericardial friction rubs, weak heart
  sounds, tachycardia and arrhythmias.
  myocarditis  cardiac dilation  functional mitral
  valve insufficiency or even congestive heart failure.
 Major criteria for diagnosis of
       rheumatic fever
• Migratory polyarthritis: a temporary
  migrating inflammation of the large joints,
  usually starting in the legs and migrating
  upwards.
• Carditis: inflammation of the heart muscle
  which can manifest as congestive heart
  failure with shortness of breath, pericarditis
  with a rub, or a new heart murmur.
 Major criteria for diagnosis of
    rheumatic fever contd
• Subcutaneous nodules: painless, firm
  collections of collagen fibers over bones or
  tendons. They commonly appear on the
  back of the wrist, the outside elbow, and the
  front of the knees.
• Erythema marginatum: a long lasting rash
  that begins on the trunk or arms. This rash
  never starts on the face and it is made worse
  with heat.
 Major criteria for diagnosis of
    rheumatic fever contd
• Sydenham's chorea (St. Vitus' dance): a
  characteristic series of rapid movements
  without purpose of the face and arms. This
  can occur very late in the disease.
 Minor criteria for diagnosis of
       rheumatic fever
• Fever
• Arthralgia: Joint pain without swelling
• Raised Erythrocyte sedimentation rate or C
  reactive protein
• Leukocytosis
 Minor criteria for diagnosis of
       rheumatic fever
• ECG showing features of heart block
• evidence of Streptococcal infection:
  elevated or rising Antistreptolysin O titre or
  DNAase.[1].
• Previous episode of rheumatic fever or
  inactive heart disease
Chronic Rheumatic Carditis: Clinical

 • Manifestation after years or decades after
   the initial episode of rheumatic fever.
 • Signs and symptoms depend on which
   involved valve(s): cardiac murmurs,
   hypertrophy, dilation, congestive heart
   failure, arrhythmia, thromboembolic
   complications and infective endocarditis.
              A. Acute rheumatic mitral valvulitis superimposed on chronic rheumatic heart disease. Small vegetations (verrucae) are visible
              along the line of closure of the mitral valve leaflet (arrowheads). Previous episodes of rheumatic valvulitis have caused fibrous
              thickening and fusion of the tendinous cords.


Slide 13.34
              B. Microscopic appearance of an Aschoff body in a patient with acute
              rheumatic carditis. The myocardial interstitium has a circumscribed collection
              of mononuclear inflammatory cells, including some large histiocytes with
              prominent nucleoli, a prominent binuclear histiocyte, and central necrosis.




Slide 13.35
              C. & D. Mitral stenosis with diffuse fibrous thickening and distortion of the valve leaflets, commissural fusion (arrow in C),
              and thickening and shortening of the tendinous cords. Marked dilation of the left atrium is noted in the left atrial view ( C).



Slide 13.36
              D. Opened valve. Note the neovascularization of the anterior mitral leaflet (arrow).



Slide 13.37
              E. Surgically removed specimen of rheumatic aortic stenosis demonstrating
              thickening and distortion of the cusps with commissural fusion ( E from
              Schoen FJ, St. John-Sutton M:
              Contemporary issues in the pathology of valvular heart disease. Hum Pathol
              18:568, 1967.)
Slide 13.38
       Infective Endocarditis
• Definition: infection of the cardiac valves or
  mural surface of the endocardium, resulting
  in the formation of an adherent mass of
  thrombotic debris and organisms.
• Divided into:
  – Acute: high virulent organisms (staphylococcus
    aureus), infect even normal valves, progress
    rapidly, little local host reaction.
  – Subacute: infection of previously abnormal
    valves by organisms of low virulence (-
    hemolytic streptococci), progress slowly,
    induce local inflammatory reaction.
Infective Endocarditis: Etiology, Pathogenesis


  • Bacteremia: i.v. drug abusers, elsewhere infection,
    previous dental, surgical or interventional
    procedure (catheterization).
  • In some cases the source of bacteremia is occult.
  • Infective endocarditis is a particularly difficult
    infection to eradicate because of the avascular
    nature of the heart valves.
Infective Endocarditis: Risk Factors

• Cardiac abnormalities: chronic valvular
  diseases, high pressure shunts within the
  heart (small ventricular septal defects).
• Prosthetic heart valves.
• Intravenous drug abusers.
 Infective Endocarditis: Causative
            Organisms
• Most common of non prosthetic valves (50-60%):
 -Hemolytic (viridans) streptococci, which
  attack previously damaged valves.
• Staphylococcus attack healthy or deformed
  valves (10-20%).
• Prosthetic valve endocarditis is caused
  commonly by coagulase-negative
  staphylococci (e.g., S. epidermidis).
 Infective Endocarditis: Morphology

• Valvular vegetations containing bacteria or
  other organisms.
• Aortic and mitral valves are the most
  common sites. (right side valves in i.v.users)
• Vegetations may be single or multiple,
  involve one or more valve(s), differ in
  appearance according to the causative agent.
     Infective Acute Endocarditis:
              Morphology
• Vegetations: may obstruct valve orifice, lead to
  rupture of ( the leaflets, cordae tendineae, or
  papillary muscles), abscess in perivalvular tissue
  (ring abscess), friable vegetations may become
  systemic emboli infarcts + abscesses.
• Micro: large number of organisms + fibrin and
  blood cells. Neutrophilic inflammatory reaction
  occurs the infection extends beyond the avascular
  valves.
  Infective Subacute Endocarditis:
            Morphology
• Vegetations are firmer, less destructive, and
  ring abscess are uncommon.
• Micro: Granulation tissue is seen at the base
  of the vegetations, later: fibrosis,
  calcifications and chronic inflammatory
  infiltrates. Systemic emboli may develop
  but they don’t undergo suppuration.
         Infective Endocarditis: Clinical
• Onset: gradual or explosive (~organisms).
    – Low-grade fever, malaise, weight loss.
    – High fever, shaking chills.
• Cardiac murmurs.
• Enlargement of spleen, clubbing of digits (particularly in subacute cases).
• Systemic emboli (neurologic deficits, retinal abnormalities, necrosis of digits, and
  infarcts of the myocardium.
• Pulmonary emboli in right-sided endocarditis.
• Mycotic aneurysms.
• Petechiae (due to micro emboli or deposition of immune complexes.
• Renal lesions: renal infarcts and glomerulonephritis.
• Valvular regurgitation and congestive heart failure due to progressive valvular
  destruction.
• Blood culture for aerobic and anaerobic organisms is very important (only minority
  of cases remain negative).
      Endocarditis of the mitral valve (subacute, caused by Streptococcus viridens). The irregular, large friable vegetations are denoted by arrows.


Slide 13.40
   B. Acute endocarditis of a congenitally bicuspid aortic valve (caused by Staphylococcus aureus) with severe cuspal destruction and ring abscess (arrow).



Slide 13.41
       C. Histologic appearance of vegetation of endocarditis with extensive acute inflammatory cells and fibrin. Bacterial organisms were
       demonstrated by tissue Gram stain.




Slide 13.42
    D. Gross photograph illustrating healed endocarditis with perforations on bicuspid aortic valve



Slide 13.43
Nonbacterial Thrombotic Endocarditis
   NBTE (marantic endocarditis)
• Characterized by the deposition of small
  masses of fibrin, platelets, and other blood
  components on the leaflets of the cardiac
  valves (sterile).
• Pathogenesis/ association:
  – Subtle endothelial abnormalities.
  – Hypercoagulability.
  – Association with malignancy (50%).
Nonbacterial Thrombotic Endocarditis

• Gross:groups of small nodules on the lines
  of valve closure (similar to those of acute
  rheumatic fever), valve leaflets are normal.
• Aortic valve most common site.
• Micro: fibrin and platelets aggregates, no
  inflammation or fibrosis.
• Clinically asymptomatic, if large: may
  embolize, may become infected.
 (Libman-Sacks) endocarditis
• Less commonly, noninfective, verrucous
  (Libman-Sacks) endocarditis attributable
  to elevated levels of circulating immune
  complexes may occur in patients with
  systemic lupus erythematosus
  Diagrammatic comparison of the lesions in the four major forms of vegetative
  endocarditis. The rheumatic fever phase of RHD (rheumatic heart disease) is
  marked by a row of warty, small vegetations along the lines of closure of the
  valve leaflets. IE (infective endocarditis) is characterized by large, irregular
  masses on the valve cusps that can extend onto the cords (see Fig. 13–18 A).
  NBTE (nonbacterial thrombotic endocarditis) typically exhibits small, bland
  vegetations, usually attached at the line of closure. One or many may be
  present (see Fig. 13–20). LSE (Libman-Sacks endocarditis) has small or
  medium-sized vegetations on either or both sides of the valve leaflets.




Slide 13.44
Nonbacterial thrombotic endocarditis (NBTE).
A. Nearly complete row of thrombotic vegetations along the line of closure of
the mitral valve leaflets.
B. Photomicrograph of NBTE showing bland thrombus, with virtually no
inflammation in the valve cusp (c) or the thrombotic deposit. The thrombus is
only loosely attached to the cusp (arrow).
Slide 13.45
                  Pericarditis
• Primary: mostly viral, sometimes by other
  microorganisms (pyogenic bacteria, mycobacteria
  and fungi.
• Secondary to: acute myocardial infarction, cardiac
  surgery, or radiation to the mediastinum.
• Associated systemic disorders, mostly with
  uremia.
• Less common 2ndry causes: rheumatic fever, SLE,
  and metastatic malignancies (bloody effusions).
                Pericarditis
• Cause immediate hemodynamic
  complications, if significant effusion is
  present.
• Resolve without significant sequelae.
• Progress to chronic fibrosing process.
    Acute Pericarditis: Morphology
• In uremia, and acute rheumatic fever: the exudate is
  fibrinous and impart a shaggy irregular pericardial surface
  (bread and butter pericarditis).
• Viral pericarditis  fibrinous exudate.
• Acute bacterial pericarditis  fibrinopurulent pericarditis.
• Tuberculosis caseous materials.
• Pericardial metastases: irregular nodules.
• Exudate usually resolve unless there is excessive
  suppuration or caseation, where healing leads to chronic
  pericarditis.
Chronic Pericarditis: Morphology
• Ranges from delicates adhesions to dense
  fibrotic scars that obliterate the pericardial
  space.
• In extreme cases the heart can’t expand
  during diastole : constrictive pericarditis.
        Pericarditis: Clinical
• Atypical chest pain (worse on reclining).
• High pitch friction rub.
• Significant exudate cardiac tamponade 
  faint distant heart sounds, distended neck
  veins, declining cardiac output, and shock.
• Chronic constrictive pericarditis  venous
  distension and low cardiac output.
          Hemopericardium
• Accumulation of large amounts of blood in
  the pericardial space is called as
  hemopericardium.
• Hemopericardium can be seen in rupture of
  the myocardium secondary to acute
  myocardial infarction. It may also be seen
  in pericarditis especially when it is
  secondary to metastatic nodule in the
  pericardial space.
  Acute suppurative pericarditis
  as an extension from
  pneumonia. Extensive
  purulent exudate is evident in
  this in situ photograph.


Slide 13.56

				
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