Kawasaki Disease (new) Flashcards
Kawasaki Disease is also called:
Mucocutaneous Lymph Node Syndrome or
Infantile Polyarteritis Nodosa
● An acute febrile illness in childhood, seen worldwide especially in Asian children.
● This was first discovered in Japan.
KD
What is a systemic inflammatory disorder manifesting as vasculitis with a predilection for the coronary arteries?
KD
Those with KD, 20-25% of untreated children develop what?
coronary artery
abnormalities (CAA) including aneurysms
<5% of children treated with this develop CAA
IVIg (Intravenous immune
globulin) develop CAA.
What is the leading cause of acquired heart disease in children?
KD
● If there is a progression of the Kawasaki disease, there will be mild transient dilatation in the tunica intima and media which usually resolves in 4-6 weeks, but for those <5% treated, they would still progress into aneurysms and CAAs.
● They will have subacute/ chronic vasculitis, luminal
myofibroblastic proliferation, and laminar nonocclusive thrombosis.
● If there is further progression with atherosclerotic risk factors, then calcification will happen which hardens the arteries, resulting in complex stenosis which leads to ischemic heart disease and myocardial infarction.
Etiology of KD
● Etiology is unknown
○ There are certain epidemiologic and clinical features that support an infectious origin although no single infectious agent is identified.
○ Usually if you ask these patients with Kawasaki disease, they would have mild fever weeks prior, cough, and colds coming from viral infections but at the end they cannot pinpoint the infectious origin.
● Genetic (polymorphism is the ITPKC gene, a T-cell regular)
● Higher in boys
● <5 years old
○ Rare if you catch Kawasaki disease in children more than 5 years old.
○ In younger children it is also quite difficult. That’s why we have another criteria for that one because for those who are less than 6 months old, they don’t
usually fulfill the criteria for Kawasaki disease.
● vasculitis that predominantly affects the medium-size arteries; while other areas include: axillary, subclavian, femoral, popliteal, and brachial arteries.
● There are phases in regards to your Kawasaki disease.
What are these phases?
1st phase
● 1st 2 weeks.
● neutrophilic necrotizing arteritis that begins in the endothelium and moves through the coronary wall.
Saccular aneurysms may form from this arteritis.
2nd phase
● Weeks to years.
● subacute/chronic vasculitis driven by lymphocytes, plasma cells, and eosinophils, which may result in fusiform aneurysms.
3rd phase
● affected by the subacute/chronic vasculitis then develop smooth muscle cell myofibroblasts, which cause progressive stenosis.
Clinical Manifestations of KD
● Fever (>38C) not responsive to antipyretics; if w/o treatment lasts 1-2 weeks.
● Most of the viral infections or bacterial infections are when you give antipyretics, initially there is a little resolution but
after an hour of giving your antipyretics some of the viral or bacterial infections will increase again.
● Others would have GI and respiratory symptoms
● Clinical features that are not consistent with KD include exudative conjunctivitis, exudative pharyngitis, generalized lymphadenopathy
● Discrete oral lesions (ulceration or exudative pharyngitis), splenomegaly, and bullous, petechial, or vesicular rashes.
● Myocarditis: tachycardia disproportionate to fever, with diminished left ventricular systolic function
● KD present in cardiogenic shock (KD shock syndrome), with greatly diminished left ventricular function
● Pericarditis with a small pericardial effusion
● Mitral regurgitation of at least mild severity is evident on echocardiography in 10-25% of patients at presentation but diminishes over time, except among rare patients with coronary aneurysms and ischemic heart disease.
● Coronary Artery Abnormalities develops in 25% on 2nd-3rd week and are usually asymptomatic
● Large giant aneurysms are at greatest risk of thrombosis or stenosis, angina, and myocardial infarction.
Clinical phases
● Acute Febrile: fever and other acute signs of illness and usually lasts 1-2 weeks
● Subacute Phase: desquamation, thrombocytosis development of CAA, and the highest risk of sudden death in patients who develop aneurysms; it generally lasts 3 weeks.
● Convalescent Phase: clinical signs of illness have
disappeared and continue until the erythrocyte sedimentation
rate (ESR) returns to normal, typically 6-8 weeks.
CLASSIC CLINICAL CRITERIA
● Fever persisting for at least 3 days
● Pus
● At least 4 of the following principle features
○ Extremity Changes - Erythema of palms soles, edema of hands/feet, periungual peeling of fingers, toes in 2-3 weeks
○ Rash - Polymorphous exanthema, NOT
bullous/vesicular
○ Changes in lips and oral cavity - Erythema, cracked lips, strawberry tongue, diffuse injection of oral and pharyngeal mucosa
○ Conjunctival injection - Bilateral, bulbur sparing limbus, non-purulent
○ Cervical lymphadenopathy >1.5 cm in diameter, most of the time its bilateral, but some of them can have unilateral lymphadenopathy
● Supplemental laboratory criteria
○ Hypoalbuminemia - <3.0 mg/dL
○ Alanine aminotransferase (ALT) - Elevation above reference range (varies by laboratory)
○ Anemia for age - Decreased in hemoglobin before reference range for age
○ Leukocytosis - White blood cells >15,000/mm3
○ Sterile pyuria (urinalysis) - ≥ 10 WBC/HPF (high power field); no bacterial infection when culture is done
○ Thrombocytosis after 7 days - Platelets >
450,000/mm3
Laboratory for KD
● NO DIAGNOSTIC TEST FOR KD.
● WBC elevated (neutrophilic predominance)
● Normocytic normochromic anemia
● Platelet: 1st week Normal; 2-3rd week >1M
● ESR and CRP elevated
● Sterile (pyuria)
● Diagnosis of KD leads to 2D echo
2D ECHO
● Coronary artery dimensions, adjusted for BSA (z scores), may be increased in the 1st few weeks
● The AHA z-score classification system is as follows:
○ No involvement: always < 2
○ Dilation only: 2 to <2.5; or initially <2, a decrease in z score during follow-up >= 1
○ Small aneurysm: >=2.5 to <5
○ Medium aneurysm: >=5 to <10 , and absolute dimension <8 mm
○ Large or giant aneurysm: >=10, or absolute dimension >=8 mm
● Echocardiography
○ At diagnosis and again after 1-2 weeks; if normal: 6-8 weeks after
○ If with abnormalities: more frequent
● So again your clinical diagnosis of fever of at least 4 days and at least 4 of the 5 principles characteristic of the illness and the diagnosis of Kawasaki’s disease should be made in 10 days and ideally within 7 days of fever onset to improve coronary outcomes
DDx
● Usually viral infections such as adenoviruses, measles, and scarlet fever
○ Each has different types of rash
○ Usually nonspecific
○ Conjunctival injections, lymph nodes,
○ For measles, take note of the 3 Cs
■ Conjunctivitis, cough, and coryza
■ Also lymphadenopathy
■ In roseola, it starts with the trunk
■ But in measles, it usually starts in the head then progresses down then ends with the extremities
● In Kawasaki’s diseases, it appears in any part of the body
● In scarlet fever, it is typical with “slapped cheek” appearance and rashes
○ “Sand paper” feel on the skin
DIAGNOSIS: ATYPICAL OR INCOMPLETE
KAWASAKI’S DISEASE
● Mostly seen in infants (highest likelihood to have CAA)
● Patients have persistent fever but <4 of the 5 characteristic clinical signs
● Lab 2D echo assist in the diagnosis
○ Must fulfill 3 of the 5 clinical characteristic signs
● Is recommended that any infant age <=6 months with fever for >=7 days without explanation undergo echocardiography to assess the coronary arteries
