Rheumatic Fever - Answers A systemic inflammatory disease, triggered by a pharyngeal infection with
Group A β-hemolytic streptococci (strep pyogeni)
Mechanism of Rheumatic Fever - Answers - In genetically susceptible individuals, the infection results in
production of antibodies that cross-react with cardiac antigens (streptococcal M antigen can stimulate B
cells which are cross reactive with cardiac myosin)
- This cross-reactivity is a Type II hypersensitivity reaction
Rheumatic Fever Epidemiology: - Answers Children (ages 5~15 years)
Decreasing incidence in the United States
Rheumatic Fever Clinical Findings - Answers - Symptoms occur 2~3 weeks after a pharyngeal infection
- Lab: elevated antistreptolysin O (ASO) titers
- Jones criteria
Jones Criteria - Answers Diagnosis requires: two major or one major and two minor
Treatment for Rheumatic Fever: aspirin, corticosteroid and antibiotics
Major Jones Criteria - Answers Migratory polyarthritis (~75%)
Pancarditis (~35%)
Subcutaneous nodules (~10%)
Skin rash (erythema marginatum) (~10%)
Sydenham chorea (jerking movements affecting primarily the face, feet)
Minor Jones Criteria - Answers Fever
Arthralgias
Positive culture for Group A Strep, ↑ ASO titer
Erythrocyte sedimentation rate (ESR), ↑ C reactive protein, leukocytosis
Previous rheumatic fever or inactive heart disease
Acute Rheumatic Heart Disease - Answers A heart disease characterized by pancarditis (inflammation of
the pericardium, myocardium and endocardium)
,Includes myocarditis, fibrinous pericarditis, and rheumatic endocarditis
Myocarditis - Answers - Aschoff body: fibrinoid necrosis surrounded by macrophages (Anitschkow cells),
lymphocytes, and plasma cells
- May lead to cardiac failure
- Is the cause of most deaths occurring during the early stages of acute rheumatic fever
Fibrinous pericarditis may result in - Answers Pericardial, pleural
Rheumatic endocarditis - Answers - Leads to valvular damage involving mitral and aortic valves
- Fibrin vegetations along the lines of closure
- MacCallum plaques: left atrial endocardial thickening
Infectious Bacterial Endocarditis - Answers Bacterial infection of the cardiac valves, characterized by
vegetations on the valve leaflets
Infectious Bacterial Endocarditis Risk Factors - Answers rheumatic heart disease, mitral valve prolapse,
bicuspid aortic valve, degenerative calcific aortic stenosis, congenital heart disease, artificial valves,
indwelling catheters, dental procedures, immunosuppression, IV drug abuse
Infectious Bacterial Endocarditis Acute Endocarditis - Answers - High virulence organism: Staphylococcus
aureus (introduced through the skin)
- Can colonize a normal valve
- Produces large destructive vegetations
- Prognosis: poor, mortality = 50%
Infectious Bacterial Endocarditis Subacute Endocarditis - Answers - Low virulence organism:
Streptococcus group viridans
- Usually colonize a previously damaged valve
Infectious Bacterial Endocarditis Clinical Presentation: - Answers - Fever, chills, weight loss, and cardiac
murmur
- Systemic emboli
- Roth spots: retinal emboli
- Osler nodes: painful, red subcutaneous nodules on the fingers and toes (caused by emboli and an
immunologic reaction)
- Janeway lesions: painless, red lesions on the palms and soles (are caused by septic emboli)
, Infectious Bacterial Endocarditis Diagnosis: - Answers Serial blood cultures
Infectious Bacterial Endocarditis Treatment: - Answers - IV High dose antibiotics (two to six weeks)
- Surgical removal of the valve
- A removed valve is usually replaced with an artificial valve
Infectious Bacterial Endocarditis Complications - Answers - Valve damage resulting in insufficiency and
CHF
- Myocardial abscess
- Dehiscence of an artificial heart valve
Roth spot - Answers Is a white-centered hemorrhage
Ex. of Infectious Bacterial Endocarditis
Osler's nodes - Answers Painful, erythematous nodules
Ex. of Infectious Bacterial Endocarditis
Valvular Heart Disease - Answers - Occurs often as a late result of rheumatic fever
- May be secondary to a variety of other inflammatory processes
- May be congenital
- Each of the four valves can be defective
- Disease can be stenosis or regurgitation
Stenosis - Answers Valve will not open all the way; it is harder to force blood through it
Regurgitation - Answers Valve will not close all the way; it leaks when it should be closed
Mitral Valve Stenosis Diseases Etiology - Answers Most commonly caused by chronic rheumatic heart
disease
Physical examination: Opening snap, diastolic rumbling murmur
Mitral Valve Stenosis Diseases Clinical Manifestations - Answers Dyspnea; orthopnea; left atrial
enlargement; mid-to late diastolic murmur