C h a p t e r 1 9
Disorders of Cardiac Function
459
tissues to produce an autoimmune response through a
phenomenon called
molecular mimicry
33
(see Chapter
16). Although only a small percentage of persons with
untreated GAS pharyngitis develop RF, the incidence of
recurrence with a subsequent untreated infection is sub-
stantially greater. These observations and more recent
studies suggest a genetic predisposition to development
of the disease.
6
Clinical Features.
Rheumatic fever can manifest as an
acute, recurrent, or chronic disorder. The acute stage
of rheumatic fever includes a history of an initiating
streptococcal infection and subsequent development
of discrete inflammatory lesions seen on histopatho-
logic exam within the connective tissue elements of
the heart, blood vessels, joints, and subcutaneous tis-
sues. Within the heart these lesions are called Aschoff
bodies.
6
The recurrent phase usually involves extension
of the cardiac effects of the disease. The chronic phase
is characterized by permanent deformity of the heart
valves. Chronic rheumatic heart disease usually does
not appear until at least 10 years after the initial attack,
sometimes decades later.
Most persons with rheumatic fever have a history
of sore throat, headache, fever, abdominal pain, nau-
sea, vomiting, swollen glands (usually at the angle of
the jaw), and other signs and symptoms of streptococcal
infection. Other clinical features are related to the acute
inflammatory process and the structures involved in the
disease process. The course of the disease is character-
ized by a constellation of findings that includes cardi-
tis, migratory polyarthritis of the large joints, erythema
marginatum, subcutaneous nodules, and Sydenham
chorea.
6,35
Acute
rheumatic carditis
, which complicates the
acute phase of rheumatic fever, is a pancarditis involv-
ing all three layers of the heart. In some cases, the myo-
cardium can be so severely affected that the resulting
cardiac dilation causes functional mitral insufficiency
and even heart failure. Clinical features include pericar-
dial friction rubs, arrhythmias, and a new heart mur-
mur. Usually, both the pericarditis and myocarditis are
self-limited manifestations of the acute stage of the rheu-
matic fever. Involvement of the endocardium and val-
vular structures produces the permanent and disabling
effects of disease. Although any of the four valves can be
involved, the mitral and aortic valves are affected most
often. During the acute inflammatory stage, the valvular
structures become red and swollen, and small vegeta-
tive lesions develop on the valve leaflets. These changes
gradually proceed to the development of fibrous scar tis-
sue, which tends to contract and cause permanent defor-
mity of the valve leaflets and shortening of the chordae
tendineae. In some cases, the edges or commissures of
the valve leaflets fuse together as healing occurs.
Polyarthritis
is the most common manifestation of
rheumatic fever. It may be the only major diagnostic
criterion in adolescents and adults. The arthritis most
often involves larger joints, particularly the knees and
ankles, and is almost always migratory, affecting one
joint and then moving to another. Untreated, it lasts
approximately 4 weeks, but it typically responds within
48 hours to salicylates. Polyarthritis usually heals
completely.
Erythema marginatum
lesions are commonly seen on
the trunk or inner aspects of the upper arm and thigh,
but never on the face. These transitory skin lesions
occur early in the course of a rheumatic attack and usu-
ally with subcutaneous nodules, which are hard, pain-
less, and freely movable masses that usually occur over
the extensor muscles of the wrist, elbow, ankle, and
knee joints.
Chorea (i.e., Sydenham chorea) is the major central
nervous system manifestation of rheumatic fever. It is
rarely seen after 20 years of age. The onset is typically
insidious: the child often is fidgety, cries easily, drops
things, and walks clumsily. The choreiform movements
are spontaneous, rapid, jerking movements that interfere
with voluntary activities. Facial grimaces are common,
and speech may be affected. The chorea is self-limited,
usually running its course within a matter of weeks or
months, but recurrences are not uncommon.
Diagnosis.
Diagnosis of acute rheumatic fever is made
using serologic evidence of GAS infection along with
a consideration of the cardinal symptoms and clinical
manifestations or Jones criteria, which were developed
to assist in standardizing the diagnosis of RF. Serologic
tests for streptococcal antibodies (antistreptolysin O
and antideoxyribonuclease B) can provide retrospective
confirmation of recent streptococcal infection in persons
thought to have rheumatic fever. Laboratory markers
of acute inflammation include an elevated white blood
cell count, erythrocyte sedimentation rate (ESR), and
C-reactive protein (CRP). The Jones criteria divide the
clinical features of RF into major and minor categories,
based on prevalence and specificity.
34,36
The presence
of two major signs (i.e., carditis, polyarthritis, chorea,
erythema marginatum, and subcutaneous nodules) or
one major and two minor signs (i.e., arthralgia, fever,
elevated ESR, CRP, or leukocyte count and prolonged
PR interval on EKG), accompanied by evidence of a
preceding GAS infection (antistreptolysin 0 antibodies,
positive throat culture for GAS) indicates a high prob-
ability of RF.
The use of echocardiography has enhanced the under-
standing of both acute and chronic RHD. It is useful in
assessing the severity of valvular stenosis and regurgi-
tation, chamber size and ventricular function, and the
presence and size of pleural effusions. Doppler ultraso-
nography may be useful in identifying cardiac lesions
in persons who do not show typical signs of cardiac
involvement during an attack of RF.
34,36
Treatment and Prevention.
It is important that GAS
infections be promptly diagnosed and treated to prevent
RF. The gold standard for detecting a GAS infection is a
throat culture. However, it takes 24 to 48 hours to pro-
duce a result, which may delay treatment. Rapid tests
for direct detection of GAS antigens are highly specific
for GAS infection but are limited in terms of their sensi-
tivity (i.e., the person may have a negative test result but
