Kawasaki syndrome
Kawasaki disease, also known as lymph node
syndrome, mucocutaneous node disease, infantile polyarteritis and Kawasaki
syndrome, is a poorly understood self-limited vasculitis that affects many
organs, including the skin and mucous membranes, lymph nodes, blood vessel
walls, and the heart. It does not seem to be contagious. It was first
described in 1967 by Dr. Tomisaku Kawasaki in Japan.
Incidence, causes, and risk factors
By far, the highest incidence of Kawasaki disease occurs in Japan (175 per
100,000), though its incidence in the United States is increasing. Kawasaki
disease is predominantly a disease of young children, with 80% of patients
younger than 5 years of age. Additional risk factors in the United States
include Asian race and male sex.[citation needed]
The causative agent of Kawasaki disease is still unknown. However, current
etiological theories center primarily on immunological causes for the
disease. Much research is being performed to discover a definitive toxin or
antigenic substance, possibly a superantigen, that is the specific cause of
the disease. An unknown virus may play a role as an inciting factor as well.
The cardiac complications are, by far, the most important aspect of the
disease. Kawasaki disease can cause vasculitic changes (inflammation of
blood vessels) in the coronary arteries and subsequent coronary artery
aneurysms. These aneurysms can lead to myocardial infarction (heart attack)
even in young children. Overall, about 10–18% of children with Kawasaki
disease develop coronary artery aneurysms[2], with much higher prevalence
among patients who are not treated early in the course of illness. Kawasaki
disease is the most common cause of acquired heart disease among children in
the United States.
[edit] Symptoms
Kawasaki disease often begins with a high and persistent fever that is not
very responsive to normal doses of acetaminophen or ibuprofen. The fever may
persist steadily for up to two weeks and is normally accompanied by
irritability. Affected children develop red eyes, red mucous membranes in
the mouth, red cracked lips, a "strawberry tongue", iritis, keratic
precipitates (detectable by an ophthalmologist but usually too small to be
seen by the unaided eye), and swollen lymph nodes. Skin rashes occur early
in the disease, and peeling of the skin in the genital area, hands, and feet
(especially around the nails and on the palms and soles) may occur in later
phases. Some of these symptoms may come and go during the course of the
illness. If left untreated, the symptoms will eventually relent, but
coronary artery aneurysms will not improve, resulting in a significant risk
of death or disability due to myocardial infarction (heart attack). If
treated in a timely fashion, this risk can be mostly avoided and the course
of illness cut short.
* High-grade fever (greater than 39 °C or 102 °F; often as high as 40 °C or
104 °F) that normally lasts for more than a week if left untreated.
* Red eyes (conjunctivitis) without pus or drainage, also known as "conjunctival
injection"
* Bright red, chapped, or cracked lips
* Red mucous membranes in the mouth
* Strawberry tongue, white coating on the tongue or prominent red bumps
(papillae) on the back of the tongue
* Red palms of the hands and the soles of the feet
* Swollen hands and feet
* Rash which may take many forms, but not vesicular (blister-like), on the
trunk
* Swollen lymph nodes (frequently only one lymph node is swollen),
particularly in the neck area
* Joint pain (arthralgia) and swelling, frequently symmetrical
* Irritability
* Tachycardia (rapid heart beat)
* Peeling (desquamation) palms and soles (later in the illness); peeling may
begin around the nails
[edit] Signs and tests
A physical examination will demonstrate many of the features listed above.
Blood tests
* Complete blood count (CBC) may reveal normocytic anemia and eventually
thrombocytosis
* Erythrocyte sedimentation rate (ESR) will be elevated
* C-reactive protein (CRP) will be elevated
* Liver function tests may show evidence of hepatic inflammation and low
serum albumin
Other tests (may or may not be performed)
* Electrocardiogram may show evidence of ventricular dysfunction or,
occasionally, arrhythmia due to myocarditis
* Echocardiogram may show subtle coronary artery changes or, later, true
aneurysms.
* Ultrasound or computerized tomography may show hydrops (enlargement) of
the gallbladder
* Urinalysis may show white blood cells and protein in the urine (pyuria and
proteinuria) without evidence of bacterial growth
* Lumbar puncture may show evidence of aseptic meningitis
* Angiography was historically used to detect coronary artery aneurysms and
remains the gold standard for their detection, but is rarely used today
unless coronary artery aneurysms have already been detected by
echocardiography.
[edit] Diagnosis
Kawasaki disease can only be diagnosed clinically (by medical signs and
symptoms), as there exists no specific laboratory test that can tell if
someone has it. It is normally difficult to establish the diagnosis,
especially early in the course of illness, and frequently children are not
diagnosed until they have seen their doctor several times, or visited a
number of different health care providers. Many other serious illnesses can
cause similar symptoms, and must be considered in the differential
diagnosis, including scarlet fever, toxic shock syndrome, and juvenile
idiopathic arthritis.
Classically, five days of fever plus four of five diagnostic criteria must
be met in order to establish the diagnosis. The criteria are: (1) erythema
of the lips or oral cavity or cracking of the lips; (2) rash on the trunk;
(3) swelling or erythema of the hands or feet; (4) red eyes (conjunctival
injection) (5) swollen lymph node in the neck of at least 15 millimeters.
Many children, especially infants, eventually diagnosed with Kawasaki
disease do not exhibit all of the above criteria. In fact, many experts now
recommend treating for Kawasaki disease even if only three days of fever
have passed and at least three diagnostic criteria are present, especially
if other tests reveal abnormalities consistent with Kawasaki disease. In
addition, the diagnosis can be made purely by the detection of coronary
artery aneurysms in the proper clinical setting.
[edit] Treatment
Children with Kawasaki disease should be hospitalized and cared for by a
physician who has experience with this disease. When in an academic medical
center, care is often shared between pediatric cardiology and pediatric
infectious disease specialists, although no infectious agent has been
demonstrated. It is imperative that treatment be started as soon as the
diagnosis is made to prevent damage to the coronary arteries.
Intravenous immunoglobulin (IVIG) is the standard treatment for Kawasaki
disease and is administered in high doses with marked improvement usually
noted within 24 hours. If the fever does not respond, an additional dose may
have to be considered. IVIG by itself is most useful within the first 7 days
of onset of fever, in terms of preventing coronary artery aneurysm.
Salicylate therapy, particularly aspirin, remains an important part of the
treatment but salicylates alone are not as effective as Intravenous
immunoglobulin. Aspirin therapy is started at high doses until the fever
subsides, and then is continued at a low dose when the patient returns home,
usually for 2 months. Except for Kawasaki disease and a few other
indications, aspirin is otherwise normally not recommended for children due
to its association with Reye's syndrome.
Corticosteroids have also been used, especially when other treatments fail
or symptoms recur, but in a randomized controlled trial, the addition of
corticosteroid to immune globulin and aspirin did not improve outcome. [3]
The are also treatments for iritis and other eye symptoms.
[edit] Prognosis
With early treatment, rapid recovery from the acute symptoms can be expected
and the risk of coronary artery aneurysms greatly reduced. Untreated, the
acute symptoms of Kawasaki disease are self-limited (i.e. the patient will
recover eventually), but the risk of coronary artery involvement is much
greater. Overall, about 2% of patients die from complications of coronary
vasculitis. Patients who have had Kawasaki disease should have an
echocardiogram initially every few weeks, and then every 1–2 years to screen
for progression of cardiac involvement.
It is also not uncommon that a relapse of symptoms may occur soon after
initial treatment with IVIG. This usually requires re-hospitalization and
retreatment. Treatment with IVIG can cause allergic and non-allergic acute
reactions, aseptic meningitis, fluid overload and, rarely, other serious
reactions. Aspirin may increase the risk of bleeding from other causes and
may be associated with Reye's syndrome. Overall, life-threatening
complications resulting from therapy for Kawasaki disease are exceedingly
rare, especially compared with the risk of non-treatment.
If the treatment is given early after the symptoms are diagnosed and there
is a successful cure, there is a 0.2 percent chance of coronary artery
complications occurring later in the patients life. This data came from UCSF
Children's Hospital.
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