2.) what is the pathophysiology of rheumatic fever/ rheumatic heart disease?
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2.) What is the Pathophysiology of Rheumatic Fever/ Rheumatic Heart Disease?. Organism Factors. Based on evidence, ARF is exclusively caused by URTI ( Group A Streptococci). - PowerPoint PPT PresentationTRANSCRIPT
2.) What is the Pathophysiology of Rheumatic Fever/ Rheumatic Heart Disease?
Organism Factors
• Based on evidence, ARF is exclusively caused by URTI ( Group A Streptococci).
• It has been postulated that a series of preceding streptococcal infections is needed to “prime” the immune system to the final infection that directly causes the disease.
The Immune Response
• Susceptible host encounters a group A streptococcus
• Auto immune reaction occurs• Leads to human tissue damage as a result of
cross-reactivity between epitopes on the organism and host.
Molecular mimicry
• Group A Streptococci- has epitopes present in the M protein
• Similar molecules – human myosin, tropomyosin, keratin, actin, laminin, vimentin, and NAG.
• Basis for Autoimmune response• T cell sensitization• T cells recalled following subsequent exposure
Valvular Damage
• Laminin- found in cardiac endothelium and is recognized by anti-myosin, anti-M protein, T cells.
• Antibodies to cardiac valve cross react with NAG
4.) What is the differential Diagnosis for the cause of Fever?
Infective Endocarditis
• Prototypic lesion- vegetation• Infection most commonly involves the heart
valve• Organisms that cause this generally enter the
bloodstream from mucosal surfaces, the skin, or sites of focal infection.
Infective Endocarditis
• Etiologies:– Health Care Associated – bacteremia arising from
IV catheterizations, nosocomial wound, UTI’s, chronic invasive procedures
– Prosthetic Valve endocarditis- intraoperative contamination
– Injection drug users-
Infective Endocarditis
• Highly variable clinical manifestations• Causative microorganism primarily responsible
for acute course incluse B-hemolytic streptococci, S. aureus, and Pneumococci.
• Febrile patient with valvular abnormalities or behavior pattern that predispose ( injection drug use)
• Bacteremia with organisms that frequently causes endocarditis
Infective Endocarditis
• 39.4-40 degrees Celcius fever for the acute course
• Fever may be blunted or absent in patients who are elderly or severely debilitated.