
Kawasaki Disease: Do You Know the Signs?
Kawasaki disease, also known as mucocutaneous lymph node syndrome or infantile polyarteritis,[1] is a relatively uncommon autoimmune illness of unknown etiology that involves inflammation of small and medium-sized blood vessels (vasculitis), including the coronary arteries. It primarily affects children younger than 5 years (average age, 2 years[2]), most often boys[2,3] of Asian and Pacific Island descent, although any race or ethnicity can be affected.[1,2,3] This acute febrile illness has an estimated incidence of 9 to 19 per 100,000 children[4] (age, <5 years) and often occurs in localized outbreaks in the late winter or spring.[1,4-6] Strawberry tongue is one of the early signs of this syndrome.
In addition to strawberry tongue, the patient shown demonstrates other changes in the oral cavity, including red and swollen lips and pharyngeal erythema.
Kawasaki Disease: Do You Know the Signs?
Kawasaki disease is a systemic illness. The mnemonic FEBRILE can be used to define the criteria for its diagnosis: Fever, Extremity changes, Bulbar conjunctivitis, Rash, Internal organ involvement (not one of the required diagnostic criteria), Lymphadenopathy, and Exanthem.
Signs of Kawasaki disease include fever (>39°C [>102.2°F]) of more than 5 days' duration that is unresponsive to antipyretics and antibiotics, as well as the following[1-4]:
- Ocular signs: bulbar conjunctivae
- Oral signs: strawberry tongue, redness within the mouth or the pharynx, red or cracked lips
- Skin signs: morbilliform (measles-like), maculopapular (red patches and bumps), erythematous (red skin), or target-like rash (shown); skin peeling may occur in the convalescent stage of the illness
Kawasaki Disease: Do You Know the Signs?
Other signs of Kawasaki disease include the following[1-4]:
- Extremity signs: firm swelling of the hands and feet, which may include the fingers and toes, with redness of the palms and soles; periungual desquamation (peeling of skin around the fingernails, as shown) and linear nail creases (Beau's lines) may occur during the convalescent stage of the illness
- Lymphadenopathy: swollen lymph glands (diameter ≥1.5 cm), often on one side of the neck (cervical region)
Kawasaki Disease: Do You Know the Signs?
In its 2017 Scientific Statement, the American Heart Association designated principal clinical features that lead to a diagnosis of classic Kawasaki disease. These include the presence of fever for at least 5 days, in combination with at least 4 of 5 other principal features. In addition to these principal clinical features, other clinical findings may include cardiovascular disorders such as myocarditis, pericarditis, and coronary artery aneurysms; pulmonary infiltrates or nodules; arthritis or arthralgia; gastrointestinal disorders such as hepatitis, pancreatitis, and gallbladder hydrops; aseptic meningitis or facial nerve palsy; urethritis or hydrocele; and anterior uveitis, among others.[7]
Kawasaki Disease: Do You Know the Signs?
Kawasaki disease is recognized as the leading cause of acquired heart disease in children,[4] with as many as 1 in 4 patients developing aneurysms in their coronary arteries.[1] Although this condition was initially thought to be benign, subsequent fatalities in untreated children revealed complete thrombotic occlusion of coronary artery aneurysms (arrow), with myocardial infarction as the immediate cause of death; about 1 in 100 patients will die of cardiac complications.[1] Fortunately, Kawasaki disease is usually self-limited—generally lasting 10-14 days in its acute phase—and is treatable. Most children fully recover from the acute phase and require no further treatment.[2,3]
Kawasaki Disease: Do You Know the Signs?
The clinical manifestations and stages of Kawasaki disease are shown. Not all signs and symptoms may be present in all cases[1,3,4]; some features may appear and disappear before others arise. In published reports, some patients have incomplete or atypical clinical presentations. The two findings that are most commonly absent are cervical lymphadenopathy and polymorphous rash.
What other condition may present similarly to Kawasaki disease?
- Retropharyngeal abscess or cellulitis
- Group A beta-hemolytic streptococcal infection
- Rocky Mountain spotted fever
- Juvenile idiopathic arthritis
- All of the above
Kawasaki Disease: Do You Know the Signs?
Answer: E. All of the above[3]
Because of the systemic involvement of Kawasaki disease, its presentation can be similar to that of a number of other diseases. The nonspecific finding of fever for several days (≥5 days) generally makes clinicians think of infectious etiologies. Ocular signs may include bulbar conjunctival congestion in both eyes that appears within a few days of the first fever and usually lasts several weeks.
The patient shown presented with red and swollen eyes, without any indication of pus or drainage.
Kawasaki Disease: Do You Know the Signs?
Oral signs appear within the first few days after the fever appears. These changes include "strawberry tongue," which is characterized by redness and swelling of the tongue, prominent papillae, and vertical cracking and bleeding. By itself, strawberry tongue is insufficient for a diagnosis of Kawasaki disease, in that it can also appear in patients with scarlet fever, which is a streptococcal infection.
Kawasaki Disease: Do You Know the Signs?
Shown are physical exam findings from a patient diagnosed with Kawasaki disease who presented with (A) conjunctival injection; (B) strawberry tongue; (C) erythematous papular rash; (D) edematous feet with bilateral desquamation.
Which of the following tests are specific in the diagnosis of Kawasaki disease?
- Erythrocyte sedimentation rate (ESR)
- C-reactive protein (CRP) levels
- Complete blood count (CBC)
- Antinuclear antibody levels (ANA)
- None of the above; it is a clinical diagnosis
Kawasaki Disease: Do You Know the Signs?
Answer: E. None of the above; it is a clinical diagnosis
No test has been found to be specific in the diagnosis of Kawasaki disease.[1,2] Initially, acute-phase reactants (ie, ESR and levels of CRP and alpha1-antitrypsin) are almost universally elevated; levels usually return to baseline 6-10 weeks after the onset of the illness. Other laboratory studies may include levels of serum albumin and transaminase, as well as urinalysis (which may show pus or proteinuria).[1] However, the presence of certain urine proteins (eg, filamin C, meprin A) in patients with Kawasaki disease has the potential to improve diagnostic accuracy[8]: These proteins appear to exhibit superior diagnostic performance compared with more commonly used markers of disease. Research has shown that more than one pathway of the complement system may be involved. Factors B and C5a measured earlier in the disease process may be useful biomarkers.[5]
The image depicts a patient who presented with a rash that began as perineal erythema and desquamation. This rash is typically followed by macular, morbilliform, or targetoid skin lesions of the trunk and extremities. Hand swelling is also an early sign of this condition.
Kawasaki Disease: Do You Know the Signs?
Additional symptoms of Kawasaki disease include joint pain, diarrhea, vomiting, abdominal pain, pneumonitis, and general irritability.[1,3] In children who undergo lumbar puncture (shown) for suspected meningitis, 50% show evidence of aseptic meningitis with a predominance of mononuclear cells, along with normal glucose and protein levels. In patients with joint involvement, synovial fluid obtained from arthrocentesis shows a high white blood cell count (range, 125,000-300,000/μL), with normal glucose levels and negative culture results.
Kawasaki Disease: Do You Know the Signs?
Within 2 weeks of the onset of the illness, patients may present with gallbladder hydrops (shown), which may be the result of periportal inflammation that travels to the cystic duct. In this right upper quadrant sonogram, note the size of the gallbladder (A) as compared with the size of the inferior vena cava (B).
Which of the following is a complication of delayed diagnosis or treatment in Kawasaki disease?
- Sepsis
- Coronary artery aneurysms
- Encephalitis
- Arthritis
- Vision loss
Kawasaki Disease: Do You Know the Signs?
Answer: B. Coronary artery aneurysms
The main treatment goal in patients with Kawasaki disease is to prevent coronary artery aneurysms and other cardiac complications.[3,8] Kawasaki disease is one of the leading causes of acquired heart disease in children. Electrocardiography, echocardiography, and other tests or procedures can aid in identifying damage to the coronary arteries and heart.[3] Vascular inflammation is most pronounced in the cardiac vessels, which makes coronary artery aneurysms (shown) a serious consequence of this disease. Vasculitis can also occur in veins, capillaries, small arterioles, and larger arteries. In the earliest stages of Kawasaki disease, the endothelial cells and the vascular media become edematous, but the internal elastic lamina remains intact. The inflammatory cells secrete various cytokines that result in a cascade of events that eventuates in fragmentation of the internal elastic lamina and vascular damage.
Kawasaki Disease: Do You Know the Signs?
Kawasaki disease is treated in the hospital with medications. The usual therapy consists of high doses of aspirin and intravenous immunoglobulin (IVIG), but anticoagulants (eg, warfarin) may be administered if an aneurysm is present.[1,3] Hospitalization and starting IVIG 2 g/kg in a single infusion within the first 7 days of symptoms have been shown to reduce the prevalence of coronary artery abnormalities.[9] The exact mechanism by which IVIG acts in treating Kawasaki disease is not known, but it is presumed to be related to an anti-inflammatory effect. Research into potential additional or alternative options in the treatment of this disease remains ongoing. One such phase III clinical trial used the addition of a TNF-alpha inhibitor, infliximab, to the standard therapies. The study showed that the addition of infliximab to standard treatment may reduce the duration of the febrile state and decrease inflammatory markers, coronary artery inflammation, and IVIG reactions.[10]
Kawasaki Disease: Do You Know the Signs?
How should you monitor patients after treatment?
- Coronary angiography
- Computed tomography (CT)
- Cardiac magnetic resonance imaging (MRI)
- Echocardiography
- No further monitoring is required
Kawasaki Disease: Do You Know the Signs?
Answer: D. Echocardiography
All patients who have received treatment should be reevaluated within 1 week of hospital discharge.[11] Obtain a repeat echocardiogram 21-28 days after the onset of fever. If baseline echocardiographic studies and those obtained at 3-4 weeks do not show any evidence of coronary aneurysms, further echocardiography is usually unnecessary, as are activity restrictions or medications beyond 3 months after the initial illness. However, repeat echocardiography at 1 year (and every 1-2 years thereafter[1]) and cardiovascular risk assessment at 5-year intervals are optimal.[8] Patients who have received IVIG should wait 11 months before receiving measles and chickenpox vaccinations.[3]
Post-treatment echocardiogram in a 3-month-old boy with Kawasaki disease shows ectasia of the left coronary artery and worsened dilatation of the right coronary artery.
Kawasaki Disease: Do You Know the Signs?
In February 2015, the American Heart Association and the American Stroke Association convened the Eleventh International Kawasaki Disease Symposium in Honolulu, Hawaii. Since its inception in 1984, this conference has been held every 3 years in the United States, Japan, or Taiwan. Topics covered in the multidisciplinary discussions included global epidemiology, genetics, pathophysiology, novel and new therapies, potential diagnostic and prognostic markers, and newer imaging techniques, as well as psychosocial issues, guidelines, and nursing practices. The American Heart Association updated its Scientific Statement on Kawasaki Disease in 2017.[7]
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