Acute Rheumatic Fever Flashcards
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Acute rheumatic fever (ARF) is a multisystem disease resulting from
an autoimmune reaction to infection with group A streptococcus
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manifestations resolve completely. The major exception is cardiac val-
vular damage (rheumatic heart disease [RHD]), which may persist after
the other features have disappeared.
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ARF and RHD are diseases of rich
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(ARF and RHD are diseases of poverty.)
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The virtual disappearance of ARF and reduction in the incidence of
RHD in industrialized countries during the twentieth century unfortunately was not replicated in developing countries, where these diseases
continue unabated
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is the most common cause of heart disease in
children in developing countries and is a major cause of mortality and
morbidity in adults as well
rheumatic heart disease
Some 95% of ARF
cases and RHD deaths now occur in developing countries, with particularly high rates in sub-Saharan Africa, Pacific nations, ______,
and South and Central Asia.
Australasia
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Unfortunately, the greatest
burden of disease is found in developing countries, most of which do
not have the resources, capacity, and/or interest to tackle this multifac-
eted disease
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ARF is mainly a disease of children age _____ years
5–14
High fever that last from 1-2 weeks, experiencing sore throat (tonsilitis)
ARF
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ARF
Initial episodes
become less common in older adolescents and young adults and are rare
in persons aged >30 years
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ARF
contrast, recurrent episodes of ARF remain
relatively common in adolescents and young adults. This pattern con-
trasts with the prevalence of RHD, which peaks between 25 and 40 years.
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There is no clear gender association for ARF, but RHD more commonly
affects females, sometimes up to twice as frequently as males.
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Risk factors
Overcrowded living
conditions
Poverty
Rural residence
Urban slum residence
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ORGANISM FACTORS
Based on currently available evidence, ARF is exclusively caused by infection of the upper respiratory tract with group A streptococci
Although classically, certain
_____ (particularly
types 1, 3, 5, 6, 14, 18, 19, 24, 27, and 29) were associated with ARF, in high-incidence regions, it is now thought that any strain of group
A streptococcus has the potential to cause ARF.
M-serotypes
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Approximately 3–6% of any population may be susceptible to ARF,
and this proportion does not vary dramatically between populations.
Findings of familial clustering of cases and concordance in mono-
zygotic twins—particularly for chorea—confirm that susceptibility to
ARF is an inherited characteristic, with 44% concordance in mono-
zygotic twins compared to 12% in dizygotic twins, and heritability
more recently estimated at 60%.
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Some human leukocyte antigen (HLA)
class II alleles, particularly HLA-DR7 and HLA-DR4, appear to be
associated with susceptibility,
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most widely accepted theory of rheumatic fever pathogenesis
is based on the concept of _____, whereby an immune
response targeted at streptococcal antigens (mainly thought to be on
the M protein and the N-acetylglucosamine of group A streptococcal
carbohydrate) also recognizes human tissues
molecular mimicry
crossreactive antibodies bind to endothelial cells on the heart valve, lead-
ing to activation of the adhesion molecule VCAM-1, with resulting
recruitment of activated lymphocytes and lysis of endothelial cells
in the presence of complement. The latter leads to release of peptides
including laminin, keratin, and ____, which, in turn, activates
cross-reactive T cells that invade the heart, amplifying the damage
and causing ____ spreading
tropomyosin
epitope
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Erythema marginatum
and subcutaneous nodules are now rare, being found in <5% of case
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Valvular damage is
the hallmark of rheumatic carditis. The ____ valve is almost always
affected, sometimes together with the aortic valve; isolated aortic valve
involvement is ____.
mitral
rare
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Damage to the pulmonary or tricuspid valves is
usually secondary to increased pulmonary pressures resulting from
left-sided valvular disease
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Early valvular damage leads to regurgitation. leaflet thickening, scarring, calcification, and valvular stenosis may develop
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Therefore, the char-
acteristic manifestation of carditis in previously unaffected individuals
is mitral regurgitation, always accompanied by aortic regurgitation
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(Therefore, the char-
acteristic manifestation of carditis in previously unaffected individuals
is mitral regurgitation, SOMETIMES accompanied by aortic regurgitation)
Myocardial inflammation may affect ____ conduction pathways,
leading to P-R interval prolongation (first-degree atrioventricular block
or rarely higher level block) and softening of the first heart sound
electrical
