Kawasaki disease is an illness that gives inflammation of the blood vessels in the whole body. It was first comprehensively described in Japan in 1967.
Though some children without treatment for Kawasaki Disease get better on their own, 15 to 25% have damage to the coronary arteries.
In Kawasaki, disease damage can occur to many arteries, but the coronary arteries are the most vulnerable, making Kawasaki disease a leading cause of childhood heart disease after birth.
Kawasaki Disease Nursing Diagnosis
What does Kawasaki Disease look like and how can we diagnose it?
There is no laboratory test that can diagnose Kawasaki disease with 100% surety. Instead, we use a collection of criteria developed by Dr. Kawasaki and described by the Centers for Disease Control (Table 1).
A child must have a fever for more than 5 days plus four of five findings from the criteria on physical exam, without evidence of another disease. Lips and mouth are often bright red, as are both eyes, usually without fluid or crusting.
The top layer of the tongue peels off, creating the appearance of “strawberry tongue,” which is red and glossy. Hands may be swollen and red. Kawasaki disease typically produces a rash as well, which is often worse in the groin area.
There can be swollen glands (lymphadenopathy), usually one gland in the neck measuring at least 1.5 cm (normally glands are less than 0.5 cm).
There are other clinical and laboratory findings that can support the diagnosis (Table 2). Children are often extremely irritable over the course of the entire illness.
Occasionally the diagnosis of Kawasaki disease is unclear and a spinal tap is done to evaluate for causes of fever; this can show mild inflammation of the spinal fluid (aseptic meningitis). One-third of patients have temporary joint pain (arthritis), usually in the small joints initially (fingers and toes), with progression to the large weight-bearing joints (knees, wrists, elbows, hips). Many children have diarrhea, nausea, and vomiting.
The gall bladder may be large and children may have abdominal pain. The diagnostic criteria in Table 1 should be viewed only as a guideline, since some children develop coronary artery changes without meeting diagnostic criteria, referred to as “atypical Kawasaki disease”. The atypical disease is more common in infants, who often present with subtle or incomplete findings.
Kawasaki disease is a self–limiting illness, which means the symptoms go away on their own. However it may take 6-8 weeks for the symptoms to resolve and the laboratory results to return to normal, and the effects on the coronary arteries can last a lifetime. The illness can be divided into three stages: acute, subacute, and convalescent phases.
The acute phase starts with fever, which lasts for at least 5 days (an average of 11 days without treatment). Over the first week, the symptoms of Kawasaki disease in babies reveal themselves, but often one symptom appears as another disappears, making the diagnosis challenging, especially for children who see different physicians during the early days of their illness.
Kawasaki Disease Echo
An ultrasound of the heart (echocardiography or ECHO) is done at the time of diagnosis to look at the way the heart squeezes, and to get baseline measurements of the coronary arteries.
Some children may have mild or moderately decreased heart output due to poor contraction of the inflamed heart muscle; some may have a small amount of fluid around the heart (pericardial effusion). Very rarely, cardiac rhythm (electrical) disturbances may occur.
The subacute phase begins when the fever stops. However, many parts of the body are still affected by the disease.
During this stage one of the most characteristic symptoms of the Kawasaki disease in adults may be seen, peeling of the skin of the palms and soles beginning under the fingertips and toes (periungual desquamation).
Joint inflammation may also be present, usually affecting the larger weight-bearing joints in this phase. Laboratory studies reveal a high platelet count (one of the cells in the blood that helps to clot) and an increase in blood proteins that promote clotting.
The sedimentation rate, a blood test that shows the overall degree of inflammation, continues to be high and anemia (fewer red blood cells than usual) is common. Widening (dilation) or bubble formation (aneurysm) in the coronary arteries can be seen by echocardiogram in this phase.
The third is a convalescent-phase: the child continues to recover and labs return to normal. Although the child is usually feeling better, coronary aneurysms may continue to enlarge, reaching their biggest size 4 to 6 weeks from the first day of fever.
Kawasaki disease Heart Problems
Myocarditis: We know that during the acute phase of Kawasaki disease baby have at least some degree of heart muscle inflammation (myocarditis).
Most often the myocarditis cannot be detected in the child by exam or Kawasaki disease echocardiogram and is not clinically important, but occasionally children with acute Kawasaki disease can get heart failure.
Children with this type of heart failure have an increase in the heart rate higher then we would expect from fever alone, and echocardiography shows the heart does not squeeze as strongly.
The strength of the heart muscle usually gets better after Kawasaki Disease IVIG dose and is always temporary.
Valvulitis: In the acute phase of Kawasaki disease baby get inflammation of the heart valves that control the flow through the heart (valvulitis).
The early leakiness of the mitral valve (mitral regurgitation) is usually due to inflammation of the valve. Rarely mitral regurgitation occurs late after Kawasaki disease; it is usually because not enough blood is reaching the muscles that help to operate the valve because of coronary aneurysms.
Rarely a child may get leakiness of the aortic valve (aortic regurgitation) by the same mechanism; this might require surgery.
Coronary Artery Inflammation
Acute Phase: The most important complication of Kawasaki disease is the weakening of coronary arteries, the arteries that supply the heart itself.
Among children who are not treated with immunoglobulin (see below) in the acute phase, 15 to 25% have damage to their coronary arteries, either dilation (ectasia) or bubble formation (aneurysm) in one or more vessels.
The longer the fever, the more likely a child is to have aneurysms. In the acute phase of the illness, inflammation of the coronary arteries causes weakness in the vessel wall.
Subacute Phase: Over the next few weeks, the damaged vessel gets bigger in diameter, resulting in dilation or aneurysm formation. There are different criteria for what is defined as an abnormal coronary artery, based on the actual size, or the size adjusted for the size of the patient.
Children usually do not have coronary artery problems until the second week after the start of fever; however, coronary changes have been seen as early as the 7th day of illness. Blood vessels can continue to get larger through the 4th week, at which time they have generally reached their largest size.
Echocardiography is a good test for detecting both enlargement and aneurysm formation in the parts of the coronary arteries closest to the heart. Children have a high platelet count during the subacute phase of the illness.
Sluggish, swirling blood flow through enlarged coronary vessels, along with an elevated platelet count and increased blood clotting proteins, raises the risk of clotting. If blood clots form in the coronary arteries, they can cause a heart attack. Children with “giant aneurysms,” which measure more than 8 mm in internal diameter, are at greatest risk for clots.
Convalescent Phase and Late Effects: Over time, coronary aneurysms can heal and the amount of coronary artery dilation can become less. Most healing happens during the first year or two after the illness.
In half of the children with coronary aneurysms, the aneurysm actually heals back to normal size as cells multiply in the artery wall. The amount of healing (called “regression”) in an individual patient depends on the amount of damage – the larger the aneurysm, the less likely it is to return to its normal size.
Regardless of whether the artery becomes normal in size, the vessel wall is not truly “normal” due to thickening of vessel walls that occurs in during healing. We do not know whether such thickening will make it more likely for children to have early atherosclerotic coronary artery disease, the most common form of heart disease in adults and the cause of heart attacks.
Rarely, aneurysms can be seen in other arteries, such as those supplying the arms, legs, or kidneys (“peripheral artery aneurysms”). Peripheral artery aneurysms rarely cause significant problems and are usually seen only in children who also have giant coronary aneurysms.
Over the years following Kawasaki disease, tight (“stenotic”) areas may develop in damaged coronary arteries. These are usually at either the beginning or the end of aneurysms, possibly because of the way the vessel wall heals from the outside in.
The likelihood of having significant stenosis of a coronary artery increases over the years and is highest in children with giant aneurysms. These tight areas can cause a decrease in blood flow to the heart muscle.
If other blood vessels have not grown in to help, angina or a heart attack may occur. These coronary artery stenoses are not easily detectable on echocardiograms, so we perform stress testing or cardiac catheterization in children with significant aneurysms about a year after the illness and when symptoms or other testing show signs of inadequate blood flow to the heart muscle.
If an area of the coronary artery does become so tight a child has symptoms or there are signs of damage by testing, the patient’s cardiologist may recommend a procedure to open the coronary artery tightness by either cardiac catheterization or a coronary artery bypass operation.
The outcome after these types of procedures is generally excellent.
What causes Kawasaki disease?
The cause of Kawasaki disease is unknown. Many believe it is related to an infection, for several reasons.
First, Kawasaki disease is almost only seen in children; suggesting adults have developed an immunity to something that may be important in causing the disease.
Second, outbreaks are seen in certain geographic regions, and more cases happen in the late winter and early spring. Lastly, children with acute Kawasaki disease have an appearance that is similar in some ways to children with other infectious diseases like scarlet fever, and some viruses.
However, Kawasaki disease is not spread from person to person or “catching.” No bacteria or virus has ever been proven to cause Kawasaki disease, so some experts wonder whether there might be several infections at fault.
Genes may also play a role in Kawasaki disease:
- 1) individuals of Japanese origin, no matter where in the world they live, are more likely to get Kawasaki disease;
- 2) brothers and sisters of children with Kawasaki disease are more likely than other neighborhood children to get Kawasaki disease, and
- 3) some children of parents who had Kawasaki disease later have come down with the illness.
Some studies have found associations between Kawasaki disease and recent carpet cleaning and living near a body of stagnant water, but cause and effect have not been established. Kawasaki disease is also seen more commonly in children from higher socioeconomic groups.
How Do We Treat Kawasaki Disease?
Gamma Globulin. The use of intravenous immunoglobulin (IVIG dose) shortens the acute phase of Kawasaki disease somewhat and prevents much of the coronary damage.
This treatment is currently the standard of care in Kawasaki disease, in a dose of 2 g/kg through the vein over 8 to 12 hours.
In an NIH study, gamma globulin decreased the number of aneurysms by 3-5 times, when given in the first ten days of illness. For children who are diagnosed after the 10th day and continue to have a fever, IVIG still may be helpful.
Children who still have fever two days after IVIG may benefit from further treatments with IVIG.
Careful monitoring is necessary during the administration of gamma globulin because it rarely can cause an allergic-like reaction.
Aspirin: In the past, aspirin was used for Kawasaki disease because it decreases inflammation and lowers fever, as well as prevents blood clots.
Aspirin has never been shown in a study to decrease the risk of aneurysms. High doses of aspirin (20–25 mg/kg/dose every 6 hours) are used in the first few days to control fever.
After a child has no fever for 2 or 3 days, the dose is decreased to one that makes the blood “slippery” and less likely to clot, an “antiplatelet” dose (3–5 mg/kg/day).
Children continue to take low–dose aspirin through the convalescent phase and then stop unless they have coronary damage.
Treating children with aneurysms.
Children with coronary aneurysms require long-term therapy to decrease the chance of clotting in the aneurysm.
The chance of having a clot in the coronary arteries is greatest after the acute phase when the platelet count is high and there continues to be inflammation of the blood vessels. Aspirin therapy is the most common treatment for children with aneurysms.
If a patient has “giant aneurysms”, other medicines are used to thin the blood. Heparin or warfarin (Coumadin) effect proteins in the blood that promote clotting. Treatment with Coumadin requires monitoring with blood tests every month. Many children with giant aneurysms are treated with both Coumadin and aspirin.
Low molecular weight heparin is occasionally used instead of Coumadin; this treatment requires injections twice a day under the skin but does not require frequent blood testing. Newer drugs that affect the platelets, such as clopidogrel or Plavix, can also be used together with aspirin, through experience in children is still limited.
The medicines used to prevent clotting will depend on the cardiologist’s opinions about the risks and benefits of different treatment regimens for the individual child.
Because aspirin is associated with Reye’s syndrome, children who take daily aspirin should have yearly influenza vaccines.
If the child develops influenza or chickenpox, two viral illnesses especially associated with Reye’s syndrome and aspirin, aspirin must be stopped temporarily. Aspirin therapy also should not be given during the six weeks after a chicken pox vaccine.
For children with especially large aneurysms for whom aspirin therapy must be interrupted, we can use other antiplatelet agents in the short-term. When there is a blood clot in a coronary aneurysm, either as detected by echocardiography or by symptoms of a heart attack, special treatments are used to prevent further clotting, to dissolve the clot, and to protect the heart muscle.
These treatments are identical to those used in adults who have heart attacks.
Who gets Kawasaki disease?
The first cases of Kawasaki disease in the United States were described in the early 1970s. Japanese children have the highest risk of this illness, but Kawasaki disease occurs in all races.
Blacks have the second highest rate of occurrence, and white children follow. Eighty–five percent of cases occur in children under age 5 years, mostly in toddlers (1– to 2–year–olds). Infants often have atypical symptoms, without fulfilling diagnostic criteria; however, this age group (especially infant males) has the highest risk of developing severe coronary artery disease.
Recent research has also shown more coronary artery aneurysms in children older than 6 years. Males are more likely to get the disease than females.
We do not know exactly how many children in the United States develop Kawasaki disease each year, but estimates based upon hospital discharge summaries suggest that at least 2,000 to 3,000 cases occur annually. 0.3% of baby with Kawasaki disease die; almost all deaths are related to its effects on the heart.
We know Kawasaki disease can seriously affect the heart. Our ability to diagnose and treat Kawasaki disease has greatly improved in recent years. We have identified treatments that reduce the damage to the heart and have devised ways of close monitoring of cardiac status after the disease. Ongoing research is needed to learn more about the causes of this illness and how to prevent it.