Kawasaki disease

Alternative Names: Kawasaki syndrome, lymph node syndrome and mucocutaneous lymph node syndrome

Definition:
Kawasaki disease (KD) is an autoimmune disease that manifests as a systemic necrotizing medium-sized vessel vasculitis and is largely seen in children under five years of age. It affects many organ systems, mainly those including the blood vessels, skin, mucous membranes and lymph nodes; however, its most serious effect is on the heart where it can cause severe coronary artery aneurysms in untreated children. Without treatment, mortality may approach 1%, usually within six weeks of onset. With treatment, the mortality rate is less than 0.01% in the U.S. There is often a pre-existing viral infection that may play a role in its pathogenesis. The conjunctivae and oral mucosa, along with the epidermis (skin), become erythematous (red and inflamed). Edema is often seen in the hands and feet and one or both of the cervical lymph nodes are often enlarged. Also, a remittant fever, often 40? (104°F) or higher, is characteristic of the acute phase of the disease. In untreated children, the febrile period lasts on average approximately 10 days, but may range from five to 25 days. The disorder was first described in 1967 by Dr. Tomisaku Kawasaki in Japan.

Kawasaki disease affects boys more than girls with people of Asian ethnicity, particularly Japanese and Korean most susceptible as well as people of Afro-Caribbean ethnicity. The disease was rare in Caucasians until the last few decades and incidence rate fluctuates from country to country.

By far the highest incidence of Kawasaki disease occurs in Japan (175 per 100,000).

However its incidence in the United States is increasing. Kawasaki disease is predominantly a disease of young children, with 80% of patients younger than five years of age. Approximately 2,000-4,000 cases are identified in the United States each year.

In the United Kingdom, estimates of incidence rate vary because of the rarity of Kawasaki disease. However Kawasaki disease is believed to affect fewer than 1 in every 25,000 people.  Incidence of the disease doubled from 1991 to 2000 however, with 4 cases in per 100,000 children in 1991 compared with a rise of 8 cases per 100,000 in 2000.

Symptoms:
Kawasaki disease often begins with a high and persistent fever that is not very responsive to normal treatment with paracetamol (acetaminophen) or ibuprofen.The fever may persist steadily for up to two weeks and is normally accompanied by irritability. Affected children develop red eyes because of non-suppurative conjunctivitis, iritis and bilateral anterior uveitis  Inflammation of the mucous membranes in the mouth, along with erythema (redness), edema (swelling) with fissures (cracks in the lip surface), desquamation (peeling) and exsudation of the lips are also evident. The oropharynx mucosa has enanthema and the tongue maintains an unusual red appearance termed “strawberry tongue” (marked erythema with prominent gustative papillae). Keratic precipitates (detectable by a slit lamp but usually too small to be seen by the unaided eye), and swollen lymph nodes may also be present and can be the first manifestation of the disease. Rashes occur early in the disease, and the cutaneous rash observed in patients with KD is non-specific, polymorphic, non-itchy and normally observed up to the fifth day of fever. Cutaneous exanthema may comprise macular-papular erythematous and fissure lesions, the most common type, in addition to urticariform type rash, purpuric, multiform-like erythema. and peeling of the skin in the genital area, hands, and feet (especially around the nails and on the palms and soles) may occur in later phases. Some of these symptoms may come and go during the course of the illness. It is a syndrome affecting multiple organ systems, and in the acute stage of KD, systemic inflammatory changes are evident in many organs. Myocarditis, pericarditis, valvulitis, aseptic meningitis, pneumonitis, lymphadenitis, and hepatitis may be present and are manifested by the presence of inflammatory cells in the affected tissues. If left untreated, some symptoms will eventually relent, but coronary artery aneurysms will not improve, resulting in a significant risk of death or disability due to myocardial infarction (heart attack). If treated in a timely fashion, this risk can be mostly avoided and the course of illness cut short

*High-grade fever (greater than 39 °C or 102 °F; often as high as 40 °C or 104 °F),  The duration of fever is on average one to two weeks; in the absence of treatment, it may extend for three to four weeks. However, when appropriate therapy is started the fever is gone after two days.

*Red eyes (conjunctivitis) bilateral without pus or drainage, also known as “conjunctival injection”.

*Anterior uveitis.

*Bright red, chapped, or cracked lips.

*Red mucous membranes in the mouth.

*Strawberry tongue, white coating on the tongue or prominent red bumps (papillae) on the back of the tongue.

*Red palms of the hands and the soles of the feet.

*Peeling (desquamation) palms and soles (later in the illness); peeling may begin around the nails.

*Rash which may take many forms, non-specific, polymorphic, non-itchy, but not vesicle-bullous lesions, and appears on the trunk.

*Swollen lymph nodes (frequently only one lymph node is swollen, and is usually on one side), particularly in the neck area.

*Joint pain (arthralgia) and swelling, frequently symmetrical, Also arthritis can occur.

*Irritability.

*Tachycardia (rapid heart beat).

*Beau’s lines (transverse grooves on nails).

*May find breathing difficult

Causes:
Like all autoimmune diseases, the cause of Kawasaki disease is presumably the interaction of genetic and environmental factors, possibly including an infection. The specific cause is unknown, but current theories center primarily on immunological causes for the disease. Evidence increasingly points to an infectious etiology, but debate continues on whether the cause is a conventional antigenic substance or a superantigen. Children’s Hospital Boston reported that “[s]ome studies have found associations between the occurrence of Kawasaki disease and recent exposure to carpet cleaning or residence near a body of stagnant water; however, cause and effect have not been established.”

An association has been identified with a SNP in the ITPKC gene, which codes an enzyme that negatively regulates T-cell activation. An additional factor that suggests genetic susceptibility is the fact that regardless of where they are living, Japanese children are more likely than other children to contract the disease. The HLA-B51 serotype has been found to be associated with endemic instances of the disease

Risk Factors:
Three things are known to increase your child’s risk of developing Kawasaki disease, including:

Your ads will be inserted here by

Easy Plugin for AdSense.

Please go to the plugin admin page to
Paste your ad code OR
Suppress this ad slot.

*Age. Children under 5 years old are most at risk of Kawasaki disease.

*Sex. Boys are slightly more likely than girls are to develop Kawasaki disease.

*Ethnicity. Children of Asian descent, such as Japanese or Korean, have higher rates of Kawasaki disease.

Diagnosis:
Kawasaki disease can only be diagnosed clinically (i.e. by medical signs and symptoms). There exists no specific laboratory test for this condition. It is difficult to establish the diagnosis, especially early in the course of the illness, and frequently children are not diagnosed until they have seen several health care providers. Many other serious illnesses can cause similar symptoms, and must be considered in the differential diagnosis, including scarlet fever, toxic shock syndrome, juvenile idiopathic arthritis, and childhood mercury poisoning (infantile acrodynia).

Classically, five days of fever  plus four of five diagnostic criteria must be met in order to establish the diagnosis. The criteria are: (1) erythema of the lips or oral cavity or cracking of the lips; (2) rash on the trunk; (3) swelling or erythema of the hands or feet; (4) red eyes (conjunctival injection) (5) swollen lymph node in the neck of at least 15 millimeters.

Many children, especially infants, eventually diagnosed with Kawasaki disease do not exhibit all of the above criteria. In fact, many experts now recommend treating for Kawasaki disease even if only three days of fever have passed and at least three diagnostic criteria are present, especially if other tests reveal abnormalities consistent with Kawasaki disease. In addition, the diagnosis can be made purely by the detection of coronary artery aneurysms in the proper clinical setting.

Investigations:
A physical examination will demonstrate many of the features listed above.

Blood tests:
*Complete blood count (CBC) may reveal normocytic anemia and eventually thrombocytosis

*Erythrocyte sedimentation rate (ESR) will be elevated

*C-reactive protein (CRP) will be elevated

*Liver function tests may show evidence of hepatic inflammation and low serum albumin

Other optional tests
*Electrocardiogram may show evidence of ventricular dysfunction or, occasionally, arrhythmia due to myocarditis

*Echocardiogram may show subtle coronary artery changes or, later, true aneurysms.

*Ultrasound or computerized tomography may show hydrops (enlargement) of the gallbladder

*Urinalysis may show white blood cells and protein in the urine (pyuria and proteinuria) without evidence of bacterial growth

*Lumbar puncture may show evidence of aseptic meningitis

*Angiography was historically used to detect coronary artery aneurysms and remains the gold standard for their detection, but is rarely used today unless coronary artery aneurysms have already been detected by echocardiography.

Complications :
•Inflammation of the blood vessels (vasculitis)
•Inflammation of the heart muscle (myocarditis)
•Aneurysms in arteries that increase the risk of blood clots and heart attacks

Treatment :
Children with Kawasaki disease should be hospitalized and cared for by a physician who has experience with this disease. When in an academic medical center, care is often shared between pediatric cardiology and pediatric infectious disease specialists (although no specific infectious agent has been identified as yet). It is imperative that treatment be started as soon as the diagnosis is made to prevent damage to the coronary arteries.

Intravenous immunoglobulin (IVIG) is the standard treatment for Kawasaki disease[38] and is administered in high doses with marked improvement usually noted within 24 hours. If the fever does not respond, an additional dose may have to be considered. In rare cases, a third dose may be given to the child. IVIG by itself is most useful within the first seven days of onset of fever, in terms of preventing coronary artery aneurysm.

Salicylate therapy, particularly aspirin, remains an important part of the treatment (though questioned by some) but salicylates alone are not as effective as IVIG. Aspirin therapy is started at high doses until the fever subsides, and then is continued at a low dose when the patient returns home, usually for two months to prevent blood clots from forming. Except for Kawasaki disease and a few other indications, aspirin is otherwise normally not recommended for children due to its association with Reye’s syndrome. Because children with Kawasaki disease will be taking aspirin for up to several months, vaccination against varicella and influenza is required, as these infections are most likely to cause Reye’s syndrome.

Corticosteroids have also been used, especially when other treatments fail or symptoms recur, but in a randomized controlled trial, the addition of corticosteroid to immune globulin and aspirin did not improve outcome. Additionally, corticosteroid use in the setting of Kawasaki disease is associated with increased risk of coronary artery aneurysm, and so its use is generally contraindicated in this setting. In cases of kawasaki disease refractory to IVIG, cyclophosphamide and plasma exchange have been investigated as possible treatments, with variable outcomes.

There are also treatments for iritis and other eye symptoms. Another treatment may include the use of Infliximab (Remicade). Infliximab works by binding tumour necrosis factor alpha

Prognosis:
With early treatment, rapid recovery from the acute symptoms can be expected and the risk of coronary artery aneurysms greatly reduced. Untreated, the acute symptoms of Kawasaki disease are self-limited (i.e. the patient will recover eventually), but the risk of coronary artery involvement is much greater. Overall, about 2% of patients die from complications of coronary vasculitis. Patients who have had Kawasaki disease should have an echocardiogram initially every few weeks, and then every one or two years to screen for progression of cardiac involvement.

It is also not uncommon that a relapse of symptoms may occur soon after initial treatment with IVIG. This usually requires re-hospitalization and re-treatment. Treatment with IVIG can cause allergic and non-allergic acute reactions, aseptic meningitis, fluid overload and, rarely, other serious reactions. Overall, life-threatening complications resulting from therapy for Kawasaki disease are exceedingly rare, especially compared with the risk of non-treatment. There is also evidence that Kawasaki disease produces altered lipid metabolism that persists beyond clinical resolution of the disease.

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose

Resources:
http://en.wikipedia.org/wiki/Kawasaki_disease
http://www.bbc.co.uk/health/physical_health/conditions/kawasaki2.shtml
http://www.vaheart.com/kawasaki-disease/
http://www.mayoclinic.com/health/kawasaki-disease/DS00576/DSECTION=risk-factors

Enhanced by Zemanta

Leave a Reply

Your email address will not be published. Required fields are marked *