Kawasaki disease is an illness that makes the blood vessels in the body swell and become inflamed. The exact cause of Kawasaki disease is unknown. Because it causes a high fever and swelling of the lymph nodes, Kawasaki disease is thought to be related to an infection. It may occur in children who have a genetic predisposition to the disease. The disease is not contagious.
The symptoms of Kawasaki disease often go away on their own, and the child recovers. Without medical evaluation and treatment however, serious complications may develop and not be initially recognized.
Kawasaki disease more commonly affects children younger than 5 years old, with the majority of children being less than 2 years old. Kawasaki disease, however, can affect older children as well. The disease occurs more often among boys. It is more commonly seen in the winter and spring months
In the starting stage of the disease the endothelial cells and the vascular media becomes edematous but the internal lamina of the blood vessels remains unchanged. An influx of the neutrophils occurs which leads to the formation of the CD 8+ lymphocytes and immunoglobulin A producing plasma cells. The inflammatory cells secreate the various cytokines such as tumour necrosis factor, vascular endothelial growth factor, monocyte chemotactic and activating factor interleukins such as IL1, IL4, IL 6 and matrix metalloproteinases primarily by theMMP3 and MMP9 that targets the endothelial cells and result in the events that lead to fragmentation of the internal elastic lamina and vascular damage.
In severely affected vessels, the media develops inflammation with necrosis of smooth muscle cells. The internal and external elastic laminae can split, leading to aneurysms.
Over the next few weeks to months, the active inflammatory cells are replaced by fibroblasts and monocytes, and fibrous connective tissue begins to form within the vessel wall. The intima proliferates and thickens. The vessel wall eventually becomes narrowed or occluded owing to stenosis or a thrombus. Cardiovascular death may occur from a myocardial infarction secondary to thrombosis of a coronary aneurysm or from rupture of a large coronary aneurysm. The period during of the greatest vascular damage is when a concomitant progressive increase in the serum platelet count occurs, and this is the point of the illness when the risk of death is most significant.
There are two forms of KD: complete and incomplete. Diagnosis of complete KD requires fever of at least 5 days' duration along with 4 or 5 of the principal clinical features. The principal clinical features are as follows:
Extremity changes
Polymorphous rash
Oropharyngeal changes
Bilateral, nonexudative, limbic sparing, painless bulbar conjunctival injection
Acute unilateral nonpurulent cervical lymphadenopathy with lymph node diameter greater than 1.5 cm
The acronym "FEBRILE" is used to remember the criteria as follows:
Fever
Enanthem (mucous membrane rash)
Bulbar conjunctivitis
Rash
Internal organ involvement (not part of the criteria)
Lymphadenopathy
Extremity changes
The following amounts are checked in the blood and urine
Electrocardiogram:
Left ventricular hypertrophy is seen
Left bundle branch is also seen
Chest xray:
It shows enlarged left ventricle
Dilatation of the ascending aorta
Calcification is also shown by xray on lateral view
Doppler:
Measurement of severity of stenosis
Detection of associated aortic regurgitation
Cardiac catheterisation:
May be used to measure the gradient between left ventricle and aorta.it measures pressure on both the sides of the aortic valve.
Echocardiogram:
Echocardiogram (heart ultrasound) is the best non-invasive way to evaluate the aortic valve anatomy and function
The prognosis is excellent when appropriate treatment is given to the patient at their earlier stages.
Prevention:
Since the disease does not spread by human contact the prevention of the disease is impossible.
