A 12 months old child presents with an acute febrile illness. A full blood count, ESR and blood cultures are performed and the following results noted:
Hb 90 g/l, WBC 18.6 x 109/l, Platelet count 720 x 109/l and ESR 110 mm/hr.
The blood cultures show no growth after 7 days.
The blood film shows a normochromic, normocytic anaemia with marked rouleaux formation. The neutrophils show increased granulation and vacuolation. They also show cytoplasmic swelling, a characteristic feature of Kawasaki disease. A marked thrombocytosis is present.
Could the diagnosis be sepsis or could it be Kawasaki disease?
What is Kawasaki disease? In 1967, Tomisaku Kawasaki, a Japanese paediatrician, described 50 children with fever lasting for more than 5 days. The children had cervical lymphadenopathy, rash, bilateral non-exudative conjunctivitis, swelling of the hands and feet and inflammation of the oral mucosa. The children ranged in age from 6-12 months. Kawasaki disease is more common amongst males with a male-to-female ratio of 1.5:1.
The etiology of Kawasaki disease is still not understood. It is thought to be a multisystem vasculitic disorder. The onset of the fever is abrupt. It is a high, sustained fever, unresponsive to antibiotic therapy, lasting for a week or longer. During the acute phase, Kawasaki disease may cause medium and large vessel arteritis, arterial aneurysms, valvulitis and myocarditis. If untreated, approximately 20% of patients will develop coronary aneurysms. Kawasaki disease has surpassed rheumatic fever as the leading cause of heart disease in children less than 5 years of age.
The medical management of Kawasaki disease involves the use of intravenous gamma globulin as well as aspirin, which is used as an anti-inflammatory agent.
Kawasaki disease is diagnosed from a combination of clinical and haematological features. Bacterial sepsis must always be excluded. Scientists working with paediatric patients should be ever mindful of this potentially fatal disease.