diease

Kawasaki Syndrome


OVERVIEW OF Kawasaki Syndrome :

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.


EPIDEMIOLOGY :

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


CAUSES :

The etiology is inknown. There has been a strong doubt that the etiology of Kawasaki syndrome is infectious. No single infectious agents has been implicated. The autoimmune reactions and genetic predisposition have been suggested as possible etiologic factors.

 

Infection:

Kawasoki  that raise concern for an infectious etiology include the occurrence of epidemics primarily in late winter and spring with 3 year intervals and the geographic spread of the disease occurs. The person to person transmission is possible.

 

Some authors have proposed a controversial association of KD with recent carpet shampooing, flooding, the use of a humidifier in the room of a child with an antecedent respiratory illness, and locations near bodies of water. These data have led to a waterborne vector hypothesis.

The overall clinical presentation of patients with KD is similar to that of patients with a viral or superantigenic disease. However, investigations have shown that the immune response in KD is oligoclonal, which is seen as a response to a conventional antigen, rather than polyclonal, as would be found in a superantigen-driven response.

Over the years, multiple infectious agents have been implicated; however, to date, no single microbial agent has surfaced as the prevailing cause. Suspected pathogens and infections have included the following:

Parvovirus B19

Neisseria meningitidis

Bacterial toxin–mediated superantigens

Mycoplasma pneumoniae

Klebsiella pneumoniae

Adenovirus

Cytomegalovirus

Parainfluenza type 3 virus

Rotavirus

Measles

Epstein-Barr virus

Human lymphotropic virus

Mite-associated bacteria

Tick-borne diseases

Rickettsia

Propionibacterium acnes

Using light and electron microscopy, researchers have identified cytoplasmic inclusion bodies containing RNA in 85% of acute- and late-stage KD fatalities and 25% of adult controls. Based on this finding, it is hypothesized that the KD infective agent could be a ubiquitous RNA virus that results in asymptomatic infection in most individuals, but leads to KD in a subset of genetically predisposed individuals. It is also possible that many infectious agents trigger one final common pathway in susceptible hosts, which leads to KD.

Genetic factors associated with Kawasaki disease

A genetic predilection to KD has long been suspected. Siblings of affected children have a 10-20 times higher probability of developing KD than the general population, and children in Japan whose parents had KD seem to have a more severe form of the disease and to be more susceptible to recurrence.  This risk of 2 family members having KD is greatest in twins, for whom the rate is approximately 13%.

Aortic aneurysm:

Aorta is an organ that mediates the flow of blood to the vital organs such as brain and heart. Such dilatation of the blood vessels is called Aneurysm.

 

If it is left untreated it might leads to severe complications such as inflammation of the blood vessels. This can cause severe damage because it affects the coronary arteries, the blood vessels that supply blood to the heart muscle causing aortic arteries aneurysm to develop. An aneurysm is a ballooning out of a damaged and weakened blood vessel wall. The treatment within the first 10 days of illness significantly decreases the risk of aneurysms.


PATHOPHYSIOLOGY :

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.

 


COMMON CLINICAL SIGNS AND SYMPTOMS :

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


DIAGNOSTIC :

The following amounts are checked in the blood and urine

  • Albumin 3 g/dL or less
  • Anemia for age
  • Elevated ALT level
  • Platelets >450,000 (after 7 days of fever)
  • WBC count 15,000/mm3 or greater
  • Urine WBC 10/hpf or greater

 

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


TREATMENT AND PROGNOSIS :

Intravenous immunoglobulin prepared from the purified combination of the gamma globulin and aspirin are the main aim of the treatment.

The resistance Kawasaki disease can be treated with the  Corticosteroids, Infliximab,

Cyclophosphamide. Methotrexate and Ulinastatin. 

In addition to the Aspirin other anticoagulants such as clopidogrel, dipyridamole , warfarin and heparin.


PROGNOSIS :

The prognosis is excellent when appropriate treatment is given to the patient at their earlier stages.

 


PREVENTION :

Prevention:

Since the disease does not spread by human contact the prevention of the disease is impossible.