 |
|
|
|
Rheumatic Fever |
Back to Library |
Acute rheumatic fever is still an important
disease of children
in certain developing countries.
Rheumatic fever is an immune disorder that follows an infection
in children, usually a streptococcal tonsillitis or pharyngitis.
Certain strains of streptococci, especially group A ß-haemolytic
streptococci, produce particular antigens to which antibodies are
developed by certain susceptible individuals; these antibodies
may cross-react with host cardiac antigens.
The disease occurs mainly in children between the ages of 5 and
15 years, and was once prevalent in the UK, Europe and USA.
It
is now rare outside certain developing countries with low socioeconomic
standards. The disease is a systemic disorder which, in the acute
phase, presents with fever, malaise and, sometimes, synovitis and
polyserositis. However, the most important target organ is the heart.
Patients develop characteristic lesions (Aschoff's nodules).
Histology of the Aschoff's nodule.
The Aschoff's nodule is composed of an area of degenerate collagen,
surrounded by activated histiocytic cells and lymphoid cells. These
lesions stimulate fibroblast proliferation and lead to scarring.
Rheumatic fever causes a pancarditis in the acute phase
The components of the pancarditis are:
• Rheumatic pericarditis. Aschoff's nodules form in the
pericardium, associated with an acute pericarditis. The
acute inflammatory exudate is often predominantly of the
serous type (mainly fluid with comparatively little fibrin or
neutrophil components). The serous exudate can
produce a pericardial effusion, which may distend the
pericardial cavity.
• Rheumatic myocarditis. Aschoff's nodules developing
in the myocardium are associated with interstitial oedema
and mild inflammation, sometimes with muscle-fibre
necrosis. The myocarditis is usually clinically mild, but
may produce left ventricular failure.
• Rheumatic endocarditis. Aschoff's nodules may form
anywhere in the endocardium, producing slight
irregularity of the endocardial surface. However,
Aschoff's nodules in the valves lead to greater
irregularity, and there may be erosion of the overlying
endocardium, particularly at the points at which the
valves contact each other at the line of closure.
In these
sites, small aggregations of fibrin and platelets accumulate
to form small vegetations. The aortic and mitral valves are
most prone to develop severe lesions, probably because
of the higher pressures to which they are exposed and
the more vigorous and traumatic valve closure.
In the acute phase of rheumatic fever the greatest dangers to the
patient are the pericarditis and myocarditis; however, the main
morbidity of rheumatic fever is the long-term effects of the immune
damage causing chronic scarring of valves.
Numerous small vegetations are present on the mitral valve. |
|
|
Interested in translating health topics to somali language! |
|
|
|
|
We give here simplified and accurate information about the disease
Info@somalidoc.com |
DISCLAIMER: This website is provided for
general information and it's run by medical students for medical students only
and is not a substitute for professional medical advice. We are not responsible
or liable for any diagnosis or action made by a user based on the content of
this website. We are not liable for the contents of any external websites
listed, nor do we endorse any commercial product or service mentioned or advised
on any of the sites. Always consult your own doctor if you are in any way
concerned about your health |
