Delayed Diagnosis of Kawasaki Disease
Vigilance can be the most difficult part of our job. After being inundated with kids who have all started back to school and swapped their various viruses with one another and now have new fevers (after having just got rid of their previous virus), it is easy to become complacent. So sometimes it is best to have some preset “alarms” that go off when certain criteria are met. For instance, set an alarm that gets your attention anytime someone presents with “Fever for 5 days.”
While “Fever for 5 days” may be due to numerous conditions and should make you ponder infectious as well as oncologic processes, the one that needs specific consideration is Kawasaki Disease. We have discussed Kawasaki Disease in the past (see Morsel), but this time let us focus on the aspects that may lead to a Delayed Diagnosis of Kawasaki Disease.
Kawasaki Disease (KD) Basics
- KD is an acute febrile vasculitis that occurs in children.
- It is the LEADING CAUSE OF ACQUIRED HEART DISEASE among children in North America and Japan.
- The cause is currently unknown.
- 85% of cases occur in children < 5 years of age (which means there are cases in older children).
- Recurrence rate is low (~4%).
It’s a Clinical Diagnosis
- The diagnosis of KD is considered confirmed by the presence of Fever for 5 or more days and 4 of the 5 following criteria, provided that the illness cannot be explained by other known disease (see Morsel for common mimics).
- Bilateral Conjunctival Injection
- Mucous Membrane Changes of the Upper Respiratory Tract: injected pharynx, fissured lips, strawberry tongue.
- Changes of the Peripheral Extermities: peripheral edema, peripheral erythema, periungual desquamation.
- Polymorphous Rash: it really can be almost any type of rash.
- Cervical Adenopathy
Incomplete Kawasaki Disease
- The child has prolonged fever, but only 2 or 3 of the characteristic features (so not a complete complement of criteria).
- While the child has an incomplete set of criteria, he/she has as the same risk for developing coronary artery aneurysms.
- When you are entertaining this possibility, lab values (ESR/CRP) can be helpful in risk stratify the patient.
- It may also be a case when you actually need an ECHO done in the ED to help determine the child’s management (See Newburger article for evaluation algorithm).
Timing is Everything
- 20% – 25% will go on to develop coronary artery aneurysms if untreated.
- Intravenous Immunoglobin (IVIG) in addition to Aspirin lower the rate of developing coronary artery aneurysms to 3% – 5%.
- The benefit of IVIG and Aspirin is seen if it is administered within the first 10 days of illness!
- When therapy is initiated after Day 10, the incidence of coronary artery aneurysms increases ~3 times (so 9%-15%).
- Vascular injury is evident as easly as 1 week after onset of fever.
- Ideally, treatment should be started on or before Day 7 of illness.
Potential Causes of Delayed Diagnosis of Kawasaki Disease
- The diagnostic characteristics are not specific and overlap with other entities.
- The diagnostic characteristics may be transient and do not have to be all present concurrently!
- Incomplete Kawasaki Disease – come on this isn’t even fair!
- Lack of vigilance!! We need to keep it on the DDx list!
Who is at greatest risk for having Delayed Diagnosis of Kawasaki Disease?
- Children < 6 months of age
- Children who present with < 4 criteria (Incomplete KD)
- Those who lived a greater distance from the clinical center – that makes sense. May have poorer access to care.
- Specific clinical centers also had higher rates of delayed diagnosis – perhaps pointing towards physicians not considering the Dx as much as other centers.
Moral of the Story:
Stay vigilant. When someone presents with a report of prolonged fever, reconsider Kawasaki Disease and be especially keen to revisit the potential of KD in those who are < 6 months and in those who Incomplete KD may be the diagnosis.
Minich LL, et al. Delayed Diagnosis of Kawasaki Disease: What are the Risk Factors? Pediatrics. 2007; 120: e1434 – e1440.
Newburger, JW. Diagnosis, Treatment, and Long-Term Management of Kawasaki Disease. Circulation. 2004;110:2747-2771.
Burns JC, et al. Kawasaki Disease: A Brief History. Pediatrics. 2000; 106: e27.