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Emergency and Acute Medicine – Kawasaki disease
Kawasaki disease is an acute, self-limited inflammatory illness involving multiple organ systems and is the leading cause of acquired heart disease in children in developed countries. It is a medium-vessel vasculitis with particular predilection for the coronary arteries. Acute cardiac complications include myocarditis, pericarditis, and coronary artery aneurysms, which may later progress to stenosis or thrombosis; giant aneurysms carry a risk of rupture. The disease progresses through three stages: an acute phase lasting 1–2 weeks characterized by fever and systemic inflammation; a subacute phase extending to approximately 4 weeks marked by desquamation, thrombocytosis, and the highest risk of sudden death from coronary involvement; and a convalescent phase lasting 6–8 weeks during which symptoms resolve and inflammatory markers normalize.
Epidemiologically, 80% of cases occur in children younger than 4 years, with a peak incidence between 1 and 2 years of age. The disease is rare in infants younger than 3 months, though adult cases have been reported. Males are affected more often than females, and children of Asian descent have the highest incidence, suggesting a genetic predisposition. Delayed diagnosis, prolonged fever, male sex, extremes of age, elevated inflammatory markers, anemia, hypoalbuminemia, and abnormal initial echocardiography increase the risk of coronary artery aneurysm formation. Approximately 10–15% of patients are resistant to standard therapy.
The etiology remains unknown, but the disease is thought to represent an abnormal immune response to an infectious trigger in genetically susceptible individuals. Seasonal clustering and epidemic patterns support this hypothesis, with increased incidence in winter and early spring.
Diagnosis is clinical. Classic Kawasaki disease is defined by fever lasting at least 5 days in combination with four of five features: bilateral nonexudative conjunctival injection, oral mucosal changes (such as strawberry tongue or cracked lips), polymorphous rash, extremity changes (erythema, edema, or desquamation), and cervical lymphadenopathy greater than 1.5 cm. Incomplete or atypical Kawasaki disease should be suspected in children with prolonged fever and fewer criteria accompanied by elevated ESR or CRP and supportive laboratory findings such as anemia, hypoalbuminemia, elevated ALT, leukocytosis, thrombocytosis after day 7, or sterile pyuria.
Clinical presentation typically includes abrupt onset of high, spiking fever persisting longer than 5 days. Children often appear irritable and ill. Ocular findings include conjunctivitis without exudate and photophobia. Oral findings include erythema, fissured lips, and strawberry tongue. Skin findings are variable and usually involve the trunk, while extremity changes include painful edema and erythema followed later by desquamation of the fingers and toes. Gastrointestinal symptoms such as vomiting, diarrhea, abdominal pain, and gallbladder hydrops may occur. Cardiac manifestations include myocarditis, pericarditis, heart failure, and, later, coronary artery aneurysms.
Evaluation requires a high index of suspicion in any febrile child with rash. Laboratory findings typically include elevated ESR and CRP, leukocytosis with left shift, normocytic anemia, thrombocytosis in the subacute phase, sterile pyuria, and mild transaminase elevation. Blood, urine, CSF, and throat cultures are negative. Echocardiography is essential to assess coronary artery involvement and should be performed at diagnosis, at 2–3 weeks, and again at 6–8 weeks. ECG may be indicated if myocardial involvement is suspected.
The differential diagnosis includes viral illnesses such as adenovirus, measles, Epstein–Barr virus, and influenza; bacterial infections such as scarlet fever, staphylococcal scalded skin syndrome, and rickettsial disease; immune-mediated conditions including Stevens–Johnson syndrome and serum sickness; and other vasculitides or connective tissue diseases.
Management focuses on early treatment to prevent cardiac complications. All patients meeting diagnostic criteria should be admitted. Initial therapy consists of intravenous immunoglobulin and high-dose aspirin, ideally within the first 10 days of illness, which reduces the incidence of coronary artery aneurysms from approximately 20–25% to 2–4%. Cardiology consultation is required, and myocardial infarction is treated similarly to adults if it occurs.
First-line treatment includes IVIG at 2 g/kg administered over 10–12 hours, with repeat dosing for persistent or recrudescent fever. High-dose aspirin is given during the acute phase for anti-inflammatory effect, followed by low-dose aspirin for antiplatelet therapy during the convalescent period. Patients who fail two doses of IVIG may require corticosteroids or other immunomodulatory therapies such as infliximab or cyclosporine.
All patients diagnosed with Kawasaki disease require hospitalization, while nontoxic children who do not meet diagnostic criteria may be discharged with close follow-up. Long-term cardiology follow-up is mandatory for monitoring coronary artery involvement.
Early recognition and treatment are critical, as prompt IVIG and aspirin therapy prevent coronary aneurysm formation in the vast majority of patients. Kawasaki disease should be strongly considered in children with persistent fever and repeated emergency visits, and incomplete presentations must not be overlooked.
Kawasaki disease is an acute, self-limited inflammatory illness involving multiple organ systems and is the leading cause of acquired heart disease in children in developed countries. It is a medium-vessel vasculitis with particular predilection for the coronary arteries. Acute cardiac complications include myocarditis, pericarditis, and coronary artery aneurysms, which may later progress to stenosis or thrombosis; giant aneurysms carry a risk of rupture. The disease progresses through three stages: an acute phase lasting 1–2 weeks characterized by fever and systemic inflammation; a subacute phase extending to approximately 4 weeks marked by desquamation, thrombocytosis, and the highest risk of sudden death from coronary involvement; and a convalescent phase lasting 6–8 weeks during which symptoms resolve and inflammatory markers normalize.
Epidemiologically, 80% of cases occur in children younger than 4 years, with a peak incidence between 1 and 2 years of age. The disease is rare in infants younger than 3 months, though adult cases have been reported. Males are affected more often than females, and children of Asian descent have the highest incidence, suggesting a genetic predisposition. Delayed diagnosis, prolonged fever, male sex, extremes of age, elevated inflammatory markers, anemia, hypoalbuminemia, and abnormal initial echocardiography increase the risk of coronary artery aneurysm formation. Approximately 10–15% of patients are resistant to standard therapy.
The etiology remains unknown, but the disease is thought to represent an abnormal immune response to an infectious trigger in genetically susceptible individuals. Seasonal clustering and epidemic patterns support this hypothesis, with increased incidence in winter and early spring.
Diagnosis is clinical. Classic Kawasaki disease is defined by fever lasting at least 5 days in combination with four of five features: bilateral nonexudative conjunctival injection, oral mucosal changes (such as strawberry tongue or cracked lips), polymorphous rash, extremity changes (erythema, edema, or desquamation), and cervical lymphadenopathy greater than 1.5 cm. Incomplete or atypical Kawasaki disease should be suspected in children with prolonged fever and fewer criteria accompanied by elevated ESR or CRP and supportive laboratory findings such as anemia, hypoalbuminemia, elevated ALT, leukocytosis, thrombocytosis after day 7, or sterile pyuria.
Clinical presentation typically includes abrupt onset of high, spiking fever persisting longer than 5 days. Children often appear irritable and ill. Ocular findings include conjunctivitis without exudate and photophobia. Oral findings include erythema, fissured lips, and strawberry tongue. Skin findings are variable and usually involve the trunk, while extremity changes include painful edema and erythema followed later by desquamation of the fingers and toes. Gastrointestinal symptoms such as vomiting, diarrhea, abdominal pain, and gallbladder hydrops may occur. Cardiac manifestations include myocarditis, pericarditis, heart failure, and, later, coronary artery aneurysms.
Evaluation requires a high index of suspicion in any febrile child with rash. Laboratory findings typically include elevated ESR and CRP, leukocytosis with left shift, normocytic anemia, thrombocytosis in the subacute phase, sterile pyuria, and mild transaminase elevation. Blood, urine, CSF, and throat cultures are negative. Echocardiography is essential to assess coronary artery involvement and should be performed at diagnosis, at 2–3 weeks, and again at 6–8 weeks. ECG may be indicated if myocardial involvement is suspected.
The differential diagnosis includes viral illnesses such as adenovirus, measles, Epstein–Barr virus, and influenza; bacterial infections such as scarlet fever, staphylococcal scalded skin syndrome, and rickettsial disease; immune-mediated conditions including Stevens–Johnson syndrome and serum sickness; and other vasculitides or connective tissue diseases.
Management focuses on early treatment to prevent cardiac complications. All patients meeting diagnostic criteria should be admitted. Initial therapy consists of intravenous immunoglobulin and high-dose aspirin, ideally within the first 10 days of illness, which reduces the incidence of coronary artery aneurysms from approximately 20–25% to 2–4%. Cardiology consultation is required, and myocardial infarction is treated similarly to adults if it occurs.
First-line treatment includes IVIG at 2 g/kg administered over 10–12 hours, with repeat dosing for persistent or recrudescent fever. High-dose aspirin is given during the acute phase for anti-inflammatory effect, followed by low-dose aspirin for antiplatelet therapy during the convalescent period. Patients who fail two doses of IVIG may require corticosteroids or other immunomodulatory therapies such as infliximab or cyclosporine.
All patients diagnosed with Kawasaki disease require hospitalization, while nontoxic children who do not meet diagnostic criteria may be discharged with close follow-up. Long-term cardiology follow-up is mandatory for monitoring coronary artery involvement.
Early recognition and treatment are critical, as prompt IVIG and aspirin therapy prevent coronary aneurysm formation in the vast majority of patients. Kawasaki disease should be strongly considered in children with persistent fever and repeated emergency visits, and incomplete presentations must not be overlooked.
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