Medical Student Pearl by Farhad Hossain

MD Candidate, Class of 2024

Dalhousie University

Reviewed by Dr. M McGraw

Copy Edited by Dr. J Vonkeman

Pdf Download: EMSJ Could it be Kawasaki Disease FHossain

Case Presentation

A 6-year-old female presents to the Emergency Department with a history of a fever over 5 days. She had initially visited the ED a few days ago, where croup was suspected, and she was administered a dose of dexamethasone with minimal improvement. On the day she was brought in for the second time her fever had peaked. Her mom reports increased fatigue and decreased PO intake over the duration, as well as rash.

On physical exam vitals were stable aside from an elevated temperature. Mucosal changes were observed inside her mouth and on her tongue, a non-pruritic rash was present over most of her body, and she had enlarged cervical nodes and an otitis media of the right ear. Further examination showed no pharyngitis, no conjunctivitis, lungs were clear, and heart sounds were normal.

Aside from previous croup and infections, she is otherwise healthy.

Labs yielded elevated CRP and WCC.

Given the clinical picture you consider Kawasaki Disease.

Kawasaki Disease

Kawasaki disease (KD) is an acute systemic vasculitis that mostly affects small and medium size vessels.^1-3 It is typically self-limited and usually presents in those under the age of 5.¹ Kawasaki disease is now the most common cause of acquired heart disease in children in developed countries due involvement of the coronary arteries.^4,5 There are no pathognomonic tests, so diagnosis is dependent on key clinical signs and exclusion of other diagnoses on the differential. A differential can include the following:

• Scarlett fever
• Peritonsillar abscess
• Group A Strep
• Rheumatic fever
• Measles

Etiology and Pathophysiology

While several theories have been proposed to explain the cause of KD, none have been definitively proven. Evidence suggests that genetic factors increase the predisposition of KD as siblings are more likely develop it than the general population, as well as those of Japanese descent.^3,4 The trigger for the disease has also been believed to be some viral or bacterial antigen that enters the body through mucosal surfaces such as the lung as roughly 40% of children diagnosed with KD tested positive for a viral pathogen.^1-4 Various cytokines and immune cascades lead to myocarditis and arteritis, eventually this may cause weak spot in the vessel that predisposes the formation of aneurysms.^2,4

Diagnosis

The diagnosis of KD is clinical and requires the presence of fever that has persisted for 5 or more days that is not better explained by another cause and 4/5 of the following:^1,3-6

• Extremity changes such as erythema of the palms/soles and desquamation of the fingers/toes
• An erythematous rash that is commonly a maculopapular eruption, but urticarial and multiforme-like rashes have been seen. The rash is usually diffuse and affects the trunk and extremities.
• Bilateral bulbar conjunctival injection with uveitis often observed.
• Changes to the oral mucosa include erythema, fissuring, strawberry tongue (erythema and prominent fungiform papillae), and diffuse erythema of the oral mucosa.
• Cervical adenopathy is usually unilateral and confined to the anterior cervical triangle but is the least common clinical finding observed.

Patients can meet the definition of typical or classical KD, but those who do not meet the set criteria can be diagnosed with incomplete KD based off of clinical, laboratory, and echocardiographic findings.⁶ The following figure shows the evaluation of suspected KD:⁶

Figure 1: Algorithm for the evaluation of typical Kawasaki Disease. Figure obtained from UpToDate.

Aside from measuring CRP, additional lab findings are assessed in those with incomplete KD. The evaluation of suspected incomplete KD is shown in the below figure:¹

Figure 2: Algorithm for the evaluation incomplete Kawasaki Disease. Figure obtained from McCrindle et al.

People with either complete or incomplete KD should receive an echocardiogram to assess for coronary artery aneurysm in the acute phase of the disease, as well as other cardiac abnormalities.¹ It is common for initial echocardiography to be normal, but it does establish a baseline for sequential scans.

Treatment

Treatment for KD should be initiated immediately if clinical criteria are met. It is treated with intravenous immunoglobulin (IVIG) and high dose aspirin.^1-6 The maximum dose of IVIG is 2 g/kg and it has been shown that increasing dose (up 2 kg/kg) reduces risk of CA aneurysms and duration of fever.^1,5 Aspirin, usually 30 to 100 mg/day divided into 4 doses, modifies the risk in KD leading to lower risk of thrombosis.^1,3,5 Studies have demonstrated that combining IVIG with corticosteroids has better effect on reducing coronary artery abnormalities in those who are refractory to initial therapy.^1,4 Disease modifying anti-rheumatic drugs and antibodies have been used to treat KD, but there is not enough evidence to recommend their use as treatment.³ Patients often start seeing improvements in 36 to 48 hours. Long term management depends on the patient and the risk of coronary events reaches a peak at 5 to 6 weeks after the acute phase.

Case Conclusion

The patient was started on amoxicillin 500 mg tid down in the Emergency Department for the otitis of the right ear and within 12 hours showed improvement. It was determined she met 3 of 5 criteria for KD along with the fever that persisted for 5 days, so an echocardiogram was ordered. Upon review of the echocardiogram there were no findings suggestive of KD. The patient was discharged with a script of amoxicillin and instructed to follow up with her family doctor if conditions worsen.

References

1. McCrindle BW, Rowley AH, Newburger JW, et al. Diagnosis, Treatment, and Long-Term Management of Kawasaki Disease: A Scientific Statement for Health Professionals From the American Heart Association. Circulation. 2017;135(17). doi:10.1161/CIR.0000000000000484
2. Noval Rivas M, Arditi M. Kawasaki disease: pathophysiology and insights from mouse models. Nat Rev Rheumatol. 2020;16(7):391-405. doi:10.1038/s41584-020-0426-0
3. Ramphul K, Mejias SG. Kawasaki disease: a comprehensive review. Arch Med Sci Atheroscler Dis. 2018;3(1):41-45. doi:10.5114/amsad.2018.74522
4. Owens AM, Plewa MC. Kawasaki Disease. In: StatPearls. StatPearls Publishing; 2023. Accessed March 30, 2023. http://www.ncbi.nlm.nih.gov/books/NBK537163/
5. Galuppo J, Kowker A, Rolfs J, Nicholas J, Schmidt E. Kawasaki disease: Shedding light on a mysterious diagnosis. J Am Acad Physician Assist. 2020;33(7):18-22. doi:10.1097/01.JAA.0000668792.41976.f2
6. Sundel R. Kawasaki disease: Clinical features and diagnosis. Post TW, ed. UpToDate.Waltham, MA: UpToDate Inc. UpToDate.com (Accessed on March 30, 2023)