Kawasaki's disease

Question 1

KD - overview

Answer 1

1. Kawasaki disease is a systemic vasculitis that predominantly affects children between 6mo and 4y
2. An important but poorly understood cause of prolonged fever, rash and other features
3. May lead to development of coronary artery aneurysms, with risk of myocardial ischaemia, infarction and dysrhythmias
4. Results in coronary artery damage in 5% of untx and 5% of tx children - ?
5. Epi = commoner in boys; much more common in north-eastern Asians (Japanese, Koreans) but seen in all ethnic groups

Question 2

KD - diagnostic criteria

Answer 2

The diagnosis can be made in children with fever (>38.5*C) present for at least 5 days, without other explanation, in the presence of 4 of the 5
following criteria. Criteria may not be present at the same time (history is important) and misery is a very common feature.

1. Bilateral congestion of the ocular conjunctivae (94%): non-purulent.
2. Changes of the lips and oral cavity with at least one of the following: dryness, erythema, fissuring of lips (70%); strawberry tongue (71%); diffuse erythema of oral and pharyngeal mucosa without discrete lesions (70%).
3. Changes of the extremities with at least one of the following: erythema of palms and soles (80%); indurative oedema (67%); periungual desquamation of fingers and toes (29%).
4. Polymorphous exanthem (92%).
5. Non-suppurative cervical lymphadenopathy >1.5cm (42%).

Note: The percentage values indicate the proportion of patients manifesting this clinical sign within the first 10 days after onset of fever.

*Definition of fever?

Question 3

KD - ddx (3 main ones)

Answer 3

1. Streptococcal and staphylococcal toxin-mediated diseases
2. Viral infections (enterovirus, measles)
3. Drug reactions or Stevens–Johnson syndrome

Question 4

KD - ix

Answer 4

Bedside
1. Urinalysis (excluding UTI as cause of fever)

Bloods

2. FBE with differential WBC count (anaemia, leukocytosis, thrombocytosis in 3rd to 4th week, LFTs (elevated liver transaminases), coagulation studies (increased coagulability)
3. CRP, ESR (may be profoundly elevated)
4. Blood cultures (to exclude infection as a cause of fever)

Imaging
5. Echocardiography (at least twice: at initial presentation and, if negative, again at 6 - 8 weeks; aneurysms may be first seen from 7-21d post-onset of fever)
Note - ECG usually normal, but strain, ischaemia and/or infarct can be present

Question 5

KD - mx

Answer 5

1. Patients require admission to hospital if KD is diagnosed or strongly suspected.
2. Intravenous immunoglobulin (2 g/kg over 10 hours; preferably within the first 10 days of the illness but should also be given to patients diagnosed after 10 days of illness if there is evidence of ongoing inflammation - eg fever, raised ESR/CRP)
3. Aspirin 3 - 5 mg/kg once a day for at least 6 to 8 weeks. Some give a higher dose (10mg/kg 8 hourly for the first few days) but this probably adds nothing over immunoglobulin.
4. . Paediatric follow-up should be arranged on discharge.
5. At least one further echocardiogram should be performed at 6-8 weeks. If this is normal, no further examinations are needed.