C h a p t e r 1 9
Disorders of Cardiac Function
481
Japan, the disease affects children of many races, occurs
worldwide, and is increasing in frequency.
The disease is characterized by a vasculitis that
begins in the small vessels (i.e., arterioles, venules, and
capillaries) and progresses to involve some of the larger
arteries, such as the coronaries. The exact etiology and
pathogenesis of the disease remain unknown, but it is
thought to be of immunologic origin.
94,95
Immunologic
abnormalities, including increased activation of helper
T cells and increased levels of immune mediators and
antibodies that destroy endothelial cells, have been
detected during the acute phase of the disease. It has
been hypothesized that some unknown antigen, pos-
sibly a common infectious agent, triggers the immune
response in a genetically predisposed child.
Manifestations and Clinical Course
The course of the disease is triphasic and includes an
acute febrile phase that lasts approximately 7 to 14 days,
a subacute phase that follows the acute phase and lasts
from days 10 through 24, and a convalescent phase that
follows the subacute stage and continues until the signs
of the acute-phase inflammatory response have subsided
and the signs of the illness have disappeared.
34,35,67–69
The
acute phase
begins with an abrupt onset of fever,
followed by bilateral conjunctivitis, usually without exu-
dates; erythema of the oral and pharyngeal mucosa with
“strawberry tongue” and dry, fissured lips; redness and
swelling of the hands and feet; rash of various forms;
and enlarged cervical lymph nodes. The fever typically is
high, reaching 40°C (104°F) or more; has an erratic spik-
ing pattern; is unresponsive to antibiotics; and persists for
5 or more days.
94
The conjunctivitis begins shortly after
the onset of fever, persists throughout the febrile course
of the disease, and may last as long as 3 to 5 weeks.
The
subacute phase
begins with abatement of the
fever and lasts until all signs of the disease have disap-
peared. During the subacute phase, desquamation (i.e.,
peeling) of the skin of the fingers and toe tips begins and
progresses to involve the entire surface of the palms and
soles. Patchy peeling of skin areas other than the hands
and feet may occur in some children. The convalescent
stage persists from the complete resolution of symptoms
until all signs of inflammation have disappeared. This
usually takes approximately 8 weeks.
In addition to the major manifestations that occur
during the acute stage of the illness, there are several
associated, less specific characteristics of the disease,
including arthritis, urethritis and pyuria, gastrointes-
tinal manifestations (e.g., diarrhea, abdominal pain),
and hepatitis. Arthritis is more common in girls and
may occur early in the illness along with the fever and
other acute manifestations of the disease or during the
2nd or 3rd week, generally affecting the hands, knees,
ankles, or toes.
96,97
Central nervous system involvement
occurs in almost all children and is characterized by pro-
nounced irritability and lability of mood.
Cardiac involvement is the most important mani-
festation of Kawasaki disease. Coronary artery abnor-
malities develop in approximately 20% of children,
manifested by coronary artery dilation and aneurysm
formation as seen on 2D echocardiography.
96,97
The
manifestations of coronary artery involvement include
signs and symptoms of myocardial ischemia or, rarely,
overt myocardial infarction or rupture of a coronary
aneurysm. Pericarditis, myocarditis, endocarditis, heart
failure, and arrhythmias also may develop.
Diagnosis andTreatment
No specific diagnostic test for Kawasaki disease is avail-
able; therefore, the diagnosis is made on clinical grounds
following published guidelines.
98
The guidelines specify
fever persisting at least 5 days or more without another
source in association with at least four principal fea-
tures, including oral changes that may include erythema
or cracking of the lips, strawberry tongue, and erythema
of the oral mucosa; bilateral, nonexudative conjuncti-
vitis; rash of various forms (maculopapular, erythema
multiforme, or scarlatiniform) with accentuation in the
groin region; erythema and swelling of the hands or feet
with desquamation of fingers and toes 1 to 3 weeks after
onset of illness; and cervical lymphadenopathy, often
unilateral, with at least one node that is 1.5 cm in size.
98
Chest radiographs, ECG tests, and 2D echocardiogra-
phy are used to detect coronary artery involvement and
follow its progress. Coronary angiography may be used
to determine the extent of coronary artery involvement.
Intravenous gamma globulin and aspirin are consid-
ered the best therapies for prevention of coronary artery
abnormalities in children with Kawasaki disease. During
the acute phase of the illness, aspirin usually is given in
larger doses (80 to 100 mg/kg/day divided in four doses)
for its anti-inflammatory and antipyretic effects. After
the fever is controlled, the aspirin dose is lowered (3 to
5 mg/kg/day, single dose), and the drug is given for 6 to
8 weeks for its anti–platelet-aggregating effects.
95,98
Recommendations for cardiac follow-up evaluation
(i.e., stress testing and sometimes coronary angiogra-
phy) are based on the level of coronary artery changes.
Anticoagulant therapy may be recommended for chil-
dren with multiple or large coronary aneurysms. Some
restrictions in activities such as competitive sports may
be advised for children with significant coronary artery
abnormalities.
95
SUMMARY CONCEPTS
■■
Congenital heart defects arise during fetal
heart development, which occurs during weeks
3 through 8 after conception, and reflect the
stage of development at the time the causative
event occurred. Several factors contribute to
the development of congenital heart defects,
including genetic and chromosomal influences,
viruses, and environmental agents such as drugs
and radiation.
(continued)
