Understanding Kawasaki Disease: Diagnosis, Pathophysiology, and Treatment

1. Good Morning  Morning Report July 2, 2013

2. Semantic Qualifiers

3. Illness Script • Predisposing Conditions • Age, gender, preceding events (trauma, viral illness, etc), medication use, past medical history (diagnoses, surgeries, etc) • Pathophysiological Insult • What is physically happening in the body, organisms involved, etc. • Clinical Manifestations • Signs and symptoms • Labs and imaging

4. Differential Diagnosis** • What other diagnoses would you consider in a patient with suspected Kawasaki Disease?

5. Predisposing Conditions • Which country has the highest prevalence of Kawasaki Disease? • Japan (10x that of US) • In the US, which ethnicity is most commonly affected? Least commonly? • Most common in Asians and Pacific Islanders • Least common in caucasians • Age • Median = 2yo • 76% of cases in <5yo • Male:Female = 3:2 • Which seasons are you more likely to see patients present with KD? • Seasonal peaks in winter and spring

6. Pathophysiology • Complete etiology is unknown, but features suggest an infectious source. • Generalized vasculitis • Affects all blood vessels throughout the body • Which specific vessels are affected in KD? • Preferentially involves the coronary arteries • Process • Initial neutrophil influx  • Large mononuclear cells w/lymphocytes and plasma cells  • Active inflammation  • Progressive fibrosis and scar formation

7. Clinical Manifestations • You are seeing a patient with multiple days of fever as well as a rash and some other non-focal symptoms. How many days of fever must be present before diagnosing a patient with KD? • What are the other 5 criteria used to diagnose KD?

8. Conjunctivitis** • Bilateral bulbar injection • No exudate • Painless • Limbic sparing • Shortly after fever starts

9. Rash** • Various forms • Nonspecific, diffuse with scattered macules & erythematous papules • Occasionally scarlatiniform, erythroderma, erythemamultiforme, • uriticarial, or a fine micropustular eruption • Not bullous of vesicular • Often involves diaper area • Within 5d of fever

10. Adenopathy** • Least common feature • Anterior cervical triangle • Usually unilateral • > 1.5 cm • Firm, nontender • No overlying erythema

11. Strawberry Tongue** • Changes of the lips and oral cavity • Strawberry tongue • Cracked, red, swollen, bleeding lips • Diffuse erythema of oral mucosa • Oral ulcers and exudates are not seen

12. Hands and Feet** • Erythema of palms and soles • Firm, sometimes painful induration of the hands and feet • Later desquamation that usually begins in periungal region (2-3 weeks after fever onset)

13. Clinical Manifestations** “C R A S H”

14. Other** • Arthritis/arthralgias that involve multiple joints • In children, what behavioral complaint do parents often give? • Irritability*** • GI complaints • Diarrhea • Vomiting • Abdominal pain • Hepatomegaly and jaundice • What abnormal finding may be seen on abdominal imaging (esp. RUQ) • Acalculous distension of gallbladder…hydrops of the gallbladder

15. Labs** • What would your CBC look like? • Leukocytosis • Majority with WBC > 15,000 • Predominance of immature and mature granulocytes • Anemia • Thrombocytosis…with platelet counts 500-1000 x 103 • Elevated ESR (>40 mm/hr) and CRP (>3mg/dL) • Mild to moderate elevation of LFTs • Mild hyperbilirubinemia • What abnormality could you see on the UA and urine culture? • Sterile pyuria…+WBC • Negative cultures • Aseptic meningitis (if CSF obtained)

16. Treatment** • High-dose aspirin (80-100mg/kg/day divided QID) during acute phase of illness  • 3-5mg/kg/day until no evidence of coronary changes by 6-8 • weeks • Continued aspirin therapy if coronary changes present • IVIG • 2g/kg/dose (up to 2-3 doses depending on fever) • Children treated with IVIG and ASA had faster resolution of • fever and fewer coronary abnormalities than those treated • with ASA alone • Refractory KD…treatment is controversial

17. Cardiac Complications** • Coronary artery aneurysm (identified on echo within 1-2mo of diagnosis) • 20-25% of untreated patients; 5% of treated patients • Resolution within 1-2 years in approximately 50% • Myocardial infarction • Principal cause of death • Most occur within 1 year of disease onset but can occur • years later • Myocarditis • Valvulitis • Pericarditis with effusion

18. Echocardiogram** • When should you obtain an echo on patients with suspected Kawasaki disease? • Obtain on all patients with suspected Kawasaki • At diagnosis • Follow-up…usually at 2 weeks and 6 weeks after diagnosis

19. Follow-Up

20. Atypical Kawasaki

21. Thanks  • No noon conference today!