lec 1 Flashcards
Rheumatic fever Definition
acute inflammatory disease
immunologically
multisystem
Rheumatic fever متى ببلش
few weeks after an episode of group A streptococcal pharyngitis
Rheumatic fever نسبة الناس يلي بصير عندهم
3% of infected patients with streptococcal pharyngitis
Etiology of Rheumatic fever
Group A β-hemolytic streptococcal infections( pharyngitis or skin)
Rheumatic fever occurs mainly among
children (most often) and adolescents but may be seen in adults (20%)
Mortality of Rheumatic fever
less than 1%
Acute rheumatic fever is
hypersensitivity reaction
endothelium is
valvular self antigen
myosin
myocardial self antigen
M proteins) cross-react with
- myosin
2. endothelium
antibodies and CD4+ T cells directed against
group A streptococcal molecules (M proteins)
Pathogenesis of Antibody
activate complement →recruit Fc-receptor bearing cells ( e.g neutrophils and macrophages)
Pathogenesis of CD 4 +T cells
Stimulated CD 4 +T cells cytokine
production macrophage activation ( seen
within Aschoff bodies).
clinical signs of acute carditis
– pericardial friction rub (by auscultation)
– arrhythmias (ECG)
– myocarditis , if sever cardiac dilation →
functional mitral insufficiency CHF.
Laboratory tests
• ↑White blood cell count
•↑ ESR, CRP, Ferritin
• Serum titers of antibodies against one or
more streptococcal antigens (ASO) usually are
elevated.
• cultures for streptococci are ?? negative
cultures for streptococci are
negative
antibodies against one or more streptococcal antigens
ASO) usually are elevated.
Diagnosis of acute rheumatic fever is made based on
serologic elevated ASO titer+ Jones criteria
Jones criteria
– Carditis
– Migratory polyarthritis of large joints
– Subcutaneous nodules
– Erythematous annular rash (erythema marginatum) in the skin
– Sydenham chorea, a neurologic disorder characterized by involuntary purposeless, rapid movements
minor criteria
– fever
– arthralgia
– elevated blood levels of acute phase reactants.
Morphology
discrete inflammatory foci Anitschkow cells Aschoff bodies Pancarditis Pancarditis morphological features: – The pericardium
( pathognomonic for rheumatic fever )
Aschoff bodies
Anitschkow cells
activated macrophages
Anitschkow cells morphology
have abundant
cytoplasm and nuclei with chromatin that is centrally condensed into a slender, wavy ribbon (so-called “caterpillar cells”)
Pancarditis morphological features:
– The pericardium
fibrinous exudate, which generally resolves without sequelae مضاعفات
Pancarditis morphological features ;
The myocardial
Aschoff bodies within the interstitial connective tissue
Pancarditis morphological features:
endocardium
Valve involvement results in fibrinoid necrosis and fibrin deposition
vegetations—verrucae—that cause little disturbance in cardiac
function
(Aschoff bodies can be found in
any of the three layers of the heart)
chronic rheumatic carditis (RHD) بسبب
Initial attack→ generation of immunologic
memory→ reactivation with any subsequent streptococcal infection
chronic rheumatic carditis (RHD) اكتر جزء بنصاب
Valvular disease تحديدا mitral valves
in Chronic rheumatic heart disease Valve cusps and leaflets become permanently
thickened and retracted.
Chronic rheumatic heart disease is
characterized by
acute inflammation (Aschoff bodies) and subsequent (fibrosis) scarring
Morphology of CRHD
Neovascularization and diffuse fibrosis
Fibrous bridging
Fibrous bridging across the valvular commissures and calcification create
fishmouth” or “buttonhole” stenoses.
the mitral valves exhibit
leaflet thickening,
– commissural fusion and shortening,
– thickening and fusion of the chordae tendineae .
The most important functional consequence of rheumatic heart disease is
valvular stenosis (mainly) and regurgitation
Which valves stenosis
mitral valve alone is involved in 70% .
mitral and aortic 25%
tricuspid valve is less involved
the pulmonic valve almost always escapes injury
Clinical Consequences
27+28
