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Kawasaki Disease

  • Medical Author:
    John Mersch, MD, FAAP

    Dr. Mersch received his Bachelor of Arts degree from the University of California, San Diego, and prior to entering the University Of Southern California School Of Medicine, was a graduate student (attaining PhD candidate status) in Experimental Pathology at USC. He attended internship and residency at Children's Hospital Los Angeles.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

Kawasaki Disease Related Articles

What Is Kawasaki Disease?

Kawasaki disease is an acute illness associated with fevers that mainly affects previously healthy children between 6 months to 5 years of age. The diagnosis of Kawasaki disease is based on fever of at least five days' duration and a number of additional signs and symptoms, which often appear in sequences rather than all at once. Kawasaki disease is considered in any child with prolonged fever, regardless of other symptoms. Of note, Kawasaki disease is associated with a risk of developing critical widening of the arteries to the heart (coronary artery aneurysms) and subsequent heart attacks in untreated children. Kawasaki disease is currently the most common cause of acquired heart disease in children in the developed world.

The number of new cases per year (incidence) of Kawasaki disease remain highest in Japan, followed by Taiwan and then Korea, though the rates in Europe and North America are increasing. American children of Asian and Pacific Islander ethnic background have the highest rate of hospitalization.

Kawasaki disease was originally described in 1967 by a Japanese pediatrician, Dr. Tomisaku Kawasaki, and it was initially known as mucocutaneous lymph node syndrome (MCLNS).

What Causes Kawasaki Disease?

The cause of Kawasaki disease is not completely known. There are a number of theories regarding the cause, but so far, none have been proven. Some believe that the disease is caused by an infection since outbreaks are commonly clustered and appear similar to other infectious diseases (abrupt onset, fever, rapid resolution of symptoms within one to three weeks). It is thought that a bacterial toxin, acting as a disease trigger, initiates the disease. This toxin may come from common bacterial infections in children, such as Staphylococcus or Streptococcus.

What Are the Symptoms and Signs of Kawasaki Disease?

Kawasaki disease is the result of an acute inflammatory process of medium-size blood vessels (vasculitis) that affects multiple organs in otherwise healthy children. The diagnosis of the disease is based upon criteria below.

The child must have a fever of at least five days' duration (with exclusion of other causes of fever) and at least four of the following five clinical features:

  1. Bilateral nonpurulent conjunctival injection (red eyes without discharge)
  2. Changes in the lips and oral cavity (red and cracked lips, strawberry tongue)
  3. Rash (nonpetechial, nonblistering)
  4. Changes in the extremities (swelling of the hands or feet, red hands or feet, peeling of the skin of the palms or soles)
  5. Cervical lymphadenopathy (large lymph nodes of the neck, often unilateral): Lymph node size is often >1.5 cm.
  6. Or fewer of the above findings with evidence of coronary aneurysms or coronary enlargement seen on echocardiogram

Typically, a child with Kawasaki disease will have a sudden onset of moderate fever (101 F-103-plus F) that has no apparent source. The fever lasts longer than five days, and the child is irritable and generally appears ill. In addition to the fever, the above symptoms may develop in any order and duration. The diagnosis is made when the above criteria are met and there is no other explanation for the symptoms, such as strep throat or an acute drug reaction. Other physical findings may be present and support the diagnosis:

  1. sore muscles and joints;
  2. abdominal pain without vomiting or diarrhea;
  3. liver or gall bladder abnormalities;
  4. abnormal lung function;
  5. meningitis;
  6. hearing loss;
  7. Bell's palsy; and
  8. testicular swelling and discomfort.

Kawasaki disease can be divided into phases. The acute, early phase (fever and other major symptoms) lasting from five to 10 days and is followed by the subacute phase (development of coronary artery aneurysms) from 11-30 days. The convalescent phase (resolution of acute symptoms) lasts from four to six weeks. For untreated patients, some develop coronary artery aneurysms that often will result in an acute heart attack (myocardial infarction) from months to years after the diagnosis.

The clinical features of Kawasaki disease can be mistaken for other illnesses such as streptococcal or staphylococcal infections (scarlet fever or toxic shock syndrome), parasite or viral infections (leptospirosis, measles, or adenovirus), and drug reactions (Stevens-Johnson syndrome). Acute mercury poisoning (acrodynia) has many signs and symptoms of Kawasaki disease.

In addition, some patients, especially toddlers or older patients, may develop incomplete Kawasaki disease or atypical Kawasaki disease in which the child may not have the four characteristic clinical features described above. Diagnosis in these situations is much more difficult. Patients with atypical Kawasaki disease are more likely to develop coronary artery disease.

When Should I Seek Medical Care for Kawasaki Disease?

Most pediatricians and associated health care professionals like to be aware of any significant fever in any child, though a visit to the office may not be necessary. If your child has a fever that lasts longer than a few days, it is important to consult with your child's doctor. The fever associated with Kawasaki disease is generally 102 or higher. The doctor will probably want to evaluate your child to check for a source of the fever. If your child has fever and develops any of the common signs and symptoms of Kawasaki disease listed above, it is important to discuss this with your doctor immediately. Obviously, if your child appears dehydrated and is not passing urine normally, he/she needs to be evaluated urgently.

How Do Health Care Professionals Diagnose Kawasaki Disease?

There are no unique or specific tests seen in Kawasaki disease. There are, however, a number of blood, urine, and spinal fluid studies that support the clinical diagnosis. These might include throat cultures, urine cultures, and blood counts. All children with possible Kawasaki disease should have an electrocardiogram (ECG) and echocardiogram (ECHO) to evaluate the child's coronary arteries.

What Are Treatments for Kawasaki Disease?

Once Kawasaki disease is diagnosed, it is imperative to initiate treatment within 10 days of the onset of the child's fever. This is due to the fact that the damage to the coronary arteries usually occurs after the 10th day of illness during the subacute phase of the disease. The current recommended therapy includes admission to a hospital and administration of intravenous immunoglobulin (IVIG or gammaglobulin) and high-dose aspirin until the child's fever resolves, followed by low-dose aspirin for six to eight weeks until a normal echocardiogram has been obtained. If a child has any evidence of coronary artery abnormality, a pediatric cardiologist can continue to follow monitor the patient.

What Is the Prognosis for Kawasaki Disease? What Are Complications of Kawasaki Disease?

Kawasaki disease is the most common cause of acquired heart disease in children in the developed world. When diagnosed and treated early, the incidence of coronary artery lesions decreases from 20% to 5%. It is very uncommon for patients who have no evidence of coronary abnormalities at two to three months after the acute illness to develop coronary abnormalities. Patients with larger coronary lesions have the greatest risk, and it has been shown that patients with giant aneurysms (>8mm) have a highest risk of developing future heart attacks (myocardial infarctions). The long-term risk of patients with small aneurysms is currently unknown.

Kawasaki Disease & Vasculitis

Medium-vessel vasculitic disorders include polyarteritis nodosa (PAN), Kawasaki disease, and vasculitis of the central nervous system. PAN classically affects the medium- to small-sized arteries, and it mainly involves the vessels of the kidneys (renal vasculitis) and the gut. A variation of this condition may affect smaller vessels and is called microscopic polyangiitis or microscopic polyarteritis. Some association exists between hepatitis B infection and PAN.

Kawasaki disease is a type of medium- and small-vessel vasculitis affecting the arteries of the heart (coronary arteries) in children. It is associated with a generalized febrile infection of the children, which can cause vasculitis of the heart in the convalescence period of the illness.

Vasculitis of the central nervous system (CNS vasculitis or cerebral vasculitis) is a rare disease characterized by inflammation of the arteries of the brain and the spinal cord. This condition may sometimes be associated with some viral infections, Hodgkin's disease, syphilis, and amphetamine use. In some instances, no underlying cause can be identified.

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Reviewed on 11/20/2017
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