Kawasaki Disease by Lucy Rubin and Dr. Lisa DiPietro.
Learning Objectives.
By the end of this video, the learner
will be able to explain the pathophysiology of Kawasaki
disease, recognize the clinical features
and diagnostic criteria, describe
the potential complications and discuss the important steps
in managing a child with Kawasaki disease.
Introduction.
Kawasaki disease is an acute systemic vasculitis
of children.
Approximately 3/4 of children presenting with acute disease
are younger than age 5, but Kawasaki disease
can occur in older children, as well.
Boys outnumber girls 1.3 to 1, and children of Asian ancestry
are at highest risk.
The cause of Kawasaki disease is unknown,
although most experts believe that Kawasaki disease reflects
an immune response to an unknown infectious trigger.
Kawasaki disease arteritis particularly
affects the coronary arteries, and coronary aneurysms
are caused by vascular infiltration first
of neutrophils, transitioning to large mononuclear cells
along with lymphocytes and plasma cells,
causing a weakening and dilatation of the vessel walls.
Clinical presentation and diagnosis.
The clinical presentation of Kawasaki disease
can be remembered by the mnemonic CRASH and burn.
C is for conjunctivitis, R is for rash,
A is for cervical adenopathy, S is for strawberry tongue,
H is for hands and feet, which is
to say swelling and erythema of those parts.
B is for burn, which is to say fever.
The diagnosis of classical Kawasaki disease
can be made clinically based on the following criteria.
Fever for five or more days and at least four
of the five clinical features from the CRASH mnemonic.
Conjunctivitis, which is typically
bilateral and nonpurulent.
Rash, which is a polymorphic rash that
can be seen on the trunk, extremities, and groin.
Adenopathy which is cervical and unilateral, with the node
being at least 1.5 centimeters in diameter.
Strawberry tongue, or erythema of the tongue
with prominent papillae, as well as erythema
of the oral mucosa and lips.
Changes in the hands and feet, which
may include swelling and erythema in the acute illness.
Periungual desquamation occurs two weeks after fever onset.
Patients who have less than four of the five
principal clinical criteria who have fever
with coronary abnormalities can have incomplete Kawasaki
disease.
For these patients, you can follow the American Heart
Association algorithm for evaluation of suspected
incomplete Kawasaki disease.
If the child has a fever for greater than or equal to 5
days with two or three of the principal clinical criteria,
or if an infant has a fever for greater than or equal to 7 days
without another explanation, the next step
is to assess laboratory tests.
C-reactive protein (CRP) and erythrocyte sedimentation rate
(ESR) are markers of inflammation.
If the CRP is greater than or equal to three milligrams
per deciliter and/or the ESR is greater than or equal to 40
millimeters per hour, assess for anemia, thrombocytosis,
hypoalbuminemia, elevated alanine aminotransferase,
or (ALT) leukocytosis, and white blood cells in the urine.
If the patient has three or more of those findings
or has a positive echocardiogram,
treatment should be initiated.
In the absence of those features,
the patient should be monitored clinically,
with repeat laboratory testing if the fever persists.
A patient with Kawasaki disease is
often very irritable and difficult to console.
In addition to the classic signs and symptoms,
they may also have involvement of the musculoskeletal, GI, GU,
respiratory, nervous and cardiovascular systems.
The most concerning potential complication
of Kawasaki disease is coronary artery aneurysm,
which occurs in about 25% of untreated patients.
With timely treatment, fewer than 5%
of children with Kawasaki disease develop aneurysms.
Given the wide range of potential clinical findings,
a comprehensive physical exam is essential.
Assess the general appearance of the child.
Is he irritable?
What are his vital signs?
Does he appeared dehydrated?
Inspect the skin, including the extremities and the perineum.
If a rash is present, describe it.
The rash of Kawasaki disease is most commonly maculopapular,
but may also be morbilliform, targetoid, or scarlatiniform.
It is never vesicular.
Are the hands and feet edemitous?
Are the palms and soles erythematous?
Is there any ischemia?
Complete a thorough HEENT exam.
Is there conjunctival injection?
Are the lips red or cracked?
Is the tongue red with prominent papillae?
Is the oral pharynx erythematous?
Is there a lymphadenopathy, and if so,
is it unilateral or bilateral?
How big are the nodes?
Are they tender?
If the lymphadenopathy is diffuse,
this is more suggestive of a viral illness.
It is also important to perform cardiac, respiratory,
and abdominal examinations, although the findings
may be nonspecific for Kawasaki disease.
Management.
All patients with Kawasaki disease
should have an echocardiogram to look for coronary aneurysms
or dilatation, as well as other potential cardiac
complications, such as pericardial effusion, valvular
regurgitation, or decreased left ventricular function.
While laboratory tests aren't necessary for diagnosis,
they can be helpful if the diagnosis is not certain.
Several abnormalities may be present,
including anemia, leukocytosis, thrombocytosis, elevated CRP
and ESR, hypoabluminemia, elevated ALT, sterile pyuria,
and CSF pleocytosis.
The mainstays of treatment for Kawasaki disease
are intravenous immunoglobulin (IVIG) and aspirin.
IVIG, which contains antibodies from donated blood,
should ideally be given as a one-time dose
within the first 10 days of the illness.
It works as an anti-inflammatory to decrease
the risk of aneurysms, as well as to lower fever.
Moderate to high dose aspirin is often
given until the patient has been afebrile for 48 to 72 hours,
followed by low dose aspirin for four to six weeks
or until aneurysms resolve.
Those patients who develop a fever after 36 hours
post IVIG treatment without another explanation
can have refractory Kawasaki disease,
and may be retreated with a second dose of IVIG
or other anti-inflammatory therapies
if Kawasaki disease is still the likely diagnosis.
Appropriate follow-up for uncomplicated Kawasaki disease
includes a repeat echocardiography
at one to two weeks and four to six weeks after treatment.
For patients with coronary artery aneurysms,
cardiologic follow-up and treatment,
including antithrombotic therapies,
are tailored to the severity of coronary involvement.
Summary.
In summary, Kawasaki disease is an acute systemic vasculitis
of childhood that presents with conjunctivitis,
rash, lymphadenopathy, changes in the oral pharynx,
and changes on the hands and feet.
The most concerning complication is coronary artery aneurysms.
An echocardiography should be performed on all patients.
Treatment includes IVIG and aspirin.
Patients with always normal coronary arteries
have no increase in cardiovascular mortality
compared with the general population.
Children with coronary artery aneurysms,
even those that remodel to normal,
require lifelong follow-up.
Thank you for watching this video on Kawasaki disease.