Background: Kawasaki Disease(KD) is a challenging diagnosis at first presentation. Diagnosis relies on the 1993 American Heart Association(AHA) criteria of ≥5 days of fever with ≥4 of the following features: mucositis, cervical lymphadenopathy, non-suppurative conjunctivitis, swollen or desquamating extremities, polymorphous rash. Many present atypically and are not easily identified by the Emergency Department(ED) physician. This leads to delays in diagnosis and treatment of KD.
Aim: To reduce miss rates and overdiagnosis in the ED through identifying early clinical predictors for KD, within and out of the AHA criteria.
Methods: Retrospective case-controlled study on patients discharged with a diagnosis of KD at KK Women’s and Children’s Hospital (KKH) from April 2007 - December 2010. Patients admitted from the ED over the same period with initial diagnoses of KD, but with discharge diagnoses that stated otherwise formed the control group. We analysed the presentation patterns in both groups. Using multivariate logistic regression, we identified significant clinical predictors of KD.
Results: The diagnostic guidelines in the ED were neither specific nor sensitive, resulting in high overdiagnosis and miss rates, respectively. Of the patients admitted with the initial diagnosis of KD, 59.2% did not have KD. 44.3% and 29.1% of KD diagnoses were missed at first visit and during reattendences respectively. Miss rates were higher in infants than in older children(≥1 year old).
In older children, lymphadenopathy (OR1.79, p=0.013), non-suppurative conjunctivitis (OR2.22; p=0.001), irritability (OR2.24, p=0.005) and age (OR0.75, p<0.0001) were early predictors for true KD. With reattendances, lymphadenopathy (OR2.23, p=0.002), conjunctivitis (OR3.02, p<0.0001), irritability (OR1.86, p=0.040) and age (OR0.75, p<0.0001) remained significant, while changes in extremities (OR1.93, p=0.008) emerges as a useful predictor. No significant predictors were found for infants.
Conclusion: ED physicians should be aware of early predictors of KD. We advocate incorporating irritability into diagnostic guidelines for older children. These measures would reduce overdiagnosis and miss rates, permitting appropriate institution of early treatment.