may show evidence of ventricular dysfunction or, occasionally, arrhythmia due to myocarditis. Echocardiogram may show subtle coronary artery changes or, later, true aneurysms. Ultrasound or computerized tomography may show hydrops (enlargement) of the gallbladder. Urinalysis may show white blood cells and protein in the urine (pyuria and proteinuria) without evidence of bacterial growth. Lumbar puncture may show evidence of aseptic meningitis. Angiography was historically used to detect coronary artery aneurysms, and remains the gold standard for their detection, but is rarely used today unless coronary artery aneurysms have already been detected by echocardiography. Biopsy is rarely performed, as it is not necessary for diagnosis. Subtypes Based on clinical findings, a diagnostic distinction may be made between the 'classic' / 'typical' presentation of Kawasaki disease and 'incomplete' / 'atypical' presentation of a "suspected" form of the disease. Regarding 'incomplete' / 'atypical' presentation, American Heart Association guidelines state that Kawasaki disease "should be considered in the differential diagnosis of prolonged unexplained fever in childhood associated with any of the principal clinical features of the disease, and the diagnosis can be considered confirmed when coronary artery aneurysms are identified in such patients by echocardiography." A further distinction between 'incomplete' and 'atypical' subtypes may also be made in the presence of non-typical symptoms. Case definition For study purposes, including vaccine safety monitoring, an international case definition has been proposed to categorize 'definite' (i.e. complete/incomplete), 'probable' and 'possible' cases of Kawasaki disease. Differential diagnosis The broadness of the differential diagnosis is a challenge to timely diagnosis of Kawasaki disease. Infectious and noninfectious conditions requiring consideration include: measles and other viral infections (e.g. adenovirus, enterovirus); staphylococcal and streptococcal toxin-mediated diseases such as scarlet fever and toxic shock syndrome; drug hypersensitivity reactions (including Stevens Johnson syndrome); systemic onset juvenile idiopathic arthritis; Rocky Mountain spotted fever or other rickettsial infections; and leptospirosis. Infectious conditions that can mimic Kawasaki disease include periorbital cellulitis, peritonsillar abscess, retropharyngeal abscess, cervical lymphadenitis, parvovirus B19, mononucleosis, rheumatic fever, meningitis, staphylococcal scalded skin syndrome, toxic epidermal necrolysis, and Lyme disease. Kawasaki-like disease temporally associated with COVID-19 In 2020, reports of a Kawasaki-like disease following exposure to SARS-CoV-2, the virus responsible for COVID-19, emerged in the US and Europe. The World Health Organization is examining possible links with COVID-19. This emerging condition was named 'paediatric multisystem inflammatory syndrome' by the Royal College of Paediatrics and Child Health, and 'multisystem inflammatory syndrome in children' by the