Kawasaki Disease

, David G. I. Scott² and Chetan Mukhtyar²

(1)

Department of Rheumatology, Ipswich Hospital NHS Trust, Ipswich, UK

(2)

Department of Rheumatology, Norfolk and Norwich University Hospital, Norwich, UK

11.1 Introduction

Kawasaki disease was first recognized in 1967 as an acute febrile mucocutaneous syndrome, but coronary arterial involvement was not recognized until 1973 [1]. In a study of 20 patients who had coronary angiography following abatement of their initial febrile illness, 12 of the 20 were found to have abnormal coronary angiograms with evidence of coronary aneurysms. Until this time, Kawasaki disease was thought to be a benign illness.

11.2 Definition and Classification

The Chapel Hill consensus conference defined Kawasaki disease as “Arteritis associated with the mucocutaneous lymph node syndrome and predominantly affecting medium and small arteries. Coronary arteries are often involved. Aorta and large arteries may be involved. Usually occurs in infants and young children” [2].

The original diagnostic criteria for KD were developed by the Japanese in 1984. These have been revised by the European League against Rheumatism and the Paediatric Rheumatology European Society (Table 11.1) [3].

Table 11.1

EULAR/PReS classification criteria for Kawasaki disease

Fever persisting for at least 5 days (mandatory criterion) plus any four of the following features:

Changes in peripheral extremities or perineal area

Polymorphous exanthema

Bilateral conjunctival injection

Changes of lips and oral cavity: injection of oral and phalangeal mucosa

Cervical lymphadenopathy

From Ozen et al. [3], with permission from BMJ Publishing Group Ltd

11.3 Epidemiology

Kawasaki disease is predominantly a disease affecting children less than 4 years of age. It is more prevalent in the Japanese and other Far Eastern ethnic populations than in the Caucasian population, but occurs worldwide. The annual incidence in Japan is 240/100,000 children under 5 years of age [4]. In England the incidence is about 14.6/100,000 children less than 5 years of age from the Indian subcontinent and 4.6/100,000 in Caucasian White [5]. The annual incidence appears to be rising in various parts of the world as reported from Canada [6], India [7] and Japan [4]. There seems to be a predilection for the boys with a ratio of 1.5:1. There is a seasonal variation in the extra-tropical regions with highest incidence from January to March in the northern hemisphere [8].

11.4 Etiology

The etiology of KD is unknown. In Japan epidemics have been documented suggesting an infectious etiology probably respiratory, but no specific viral or bacterial infection has so far been identified. There are similarities between KD and toxic shock syndrome which has led to the suggestion that superantigen activation is responsible for KD.

11.5 Clinical Features

Children with Kawasaki disease are usually less than 5 years of age. They have a persistent fever and are extremely irritable.

It is important to recognize that the clinical features can appear sequentially and there will be children who do not develop all the features of the disease. There are no ethnic variations in the clinical presentation.

11.5.1 Mucosal

Mucosal inflammation can involve the lips and the oral cavity. Labial involvement can vary from mild erythema to fissuring, peeling, and bleeding. The glossitis of Kawasaki disease has been likened to a strawberry tongue. Cervical lymphadenopathy is usually unilateral. The glands do not suppurate, are not tender, and classically enlarge to >1.5 cm in diameter.

11.5.2 Cutaneous

An erythematous rash of the palms and soles appears within 5 days of the fever (Fig. 11.1). The rash desquamates during the convalescent stage. Typically, patients with Kawasaki disease develop erythema at the site of a previous BCG vaccination.

Figure 11.1

Desquamating rash in child with Kawasaki disease

11.5.3 Ophthalmic

Painless, nonexudative bilateral bulbar conjunctivitis may be associated with an iridocylitis. It usually resolves rapidly and does not leave sequelae.

11.5.4 Cardiovascular

Coronary aneurysms occur in up to 9 % of patients treated with IVIg in Japan. The coronary arteries are the most common site of aneurysm formation, but they can occur in any large artery (1 % of cases). Following treatment, the aneurysms may regress.

Valvular heart disease occurs in 1 % patients, with mitral regurgitation being the most common. The heart sounds may be faint, suggestive of pericardial effusion (Fig. 11.2). Pericarditis occurs in 13 % patients. A gallop rhythm is occasionally present.

Figure 11.2

Chest X-ray showing enlarged in heart in child with Kawasaki disease

11.6 Laboratory Features

There are no diagnostic tests for Kawasaki disease. The full blood count shows a neutrophilia and a thrombocytosis. The ESR and CRP are typically elevated. There can be a nonspecific transaminitis and urine analysis may show leucocytes and protein.

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