What is Kawasaki disease?
Kawasaki disease (KD), also known as mucocutaneous lymph node syndrome and infantile periarteritis nodosa, is a disease commonly seen in children under the age of five, however, it can affect people of all ages and involves the inflammation of all of the arteries (blood vessels) in the body. It is an acute febrile vasculitic syndrome wherein inflammation typically affects the medium-sized coronary arteries, these are responsible for supplying blood to the heart.
The original name for Kawasaki disease, being mucocutaneous lymph node syndrome is rather descriptive due to the fact that the condition is characterised by changes in the mucous membranes lining the mouth, throat, nose and lips, as well as tender and enlarged lymph nodes.
**My Med Memo - Lymph nodes are tiny glands that resemble the shape of beans and are located throughout the body. Lymph nodes are responsible for transporting waste material, nutrients and fluid, known as lymph fluid, between the bloodstream and tissues in the body. The lymphatic system forms a vital part of the body’s immune system, being the system of defence against infection and illness.
The common signs and symptoms that help in identifying Kawasaki disease include peeling skin, prolonged high fever and strawberry tongue (red and inflamed bumpy tongue). The condition is easily treated with a generally positive prognosis for most as the majority of cases (generally children) will recover through treatment without any severe issues developing. Rarely, if left untreated, death due to coronary artery aneurysm (CAA) and resulting heart attack (myocardial infarction) may occur.
The KDF (Kawasaki Disease Foundation) has reported that roughly 80% of patients with Kawasaki disease are younger than five years old. Children who are older and teenagers are less commonly affected. Children who are younger than six months old are not normally affected either as they may still have the protection of antibodies transmitted to them by their mother during pregnancy.
The disease tends to be seen more commonly in boys, as girls are 1.5 times less likely to develop Kawasaki disease.
The following article explores Kawasaki disease, starting from the symptoms and working through the causes, diagnosis and treatment and finally ending with the prognosis. Keep in mind that this information is not that of a professional opinion that should act as a substitute for personalised medical care. If you suspect you or your child are ill, then seek the prognosis of a general practitioner or medical professional. Never self-diagnose.
What are the symptoms of Kawasaki disease?
The signs and symptoms of KD (Kawasaki disease) will typically develop and manifest over a period of six weeks and can be categorised into three phases. These are described as follows:
Phase 1 – Acute phase during weeks one and two
During this stage, the symptoms tend to appear rapidly and are often severe.
High temperature (fever)
A prolonged fever is the most common and the very first symptom of KD, your child will normally have a temperature of 38℃ (100.4℉) or higher, often reaching 40℃ (104℉).
This fever can often progress rapidly and appear without warning and will not respond to medicines such as antibiotics that are typically used to aid in reducing the fever. Other medications that are ineffective include:
If your child has a fever, they may also become very irritable. The fever tends to be prolonged, lasting more than four or five days. In some cases, fever can persist for more than 11 days if not treated. In rare cases, the fever can last for more than three or four weeks.
A blotchy, red rash may develop on the skin. This rash will typically begin around the genitals and then spread to the arms, legs, torso and eventually the face. The spots of the rash are normally raised and red, however blistering does not occur.
Feet and hands
The toes and fingers may become hard or red and slightly swollen if your child is infected with Kawasaki disease. Your child may also note that their feet and hands feel tender and are extremely painful when touched or when weight is applied to these areas. This often makes children reluctant to crawl or walk.
This symptom refers to a condition wherein the eyes become red and often swollen. Both eyes are normally affected, although it is important to bear in mind that pain is not associated with conjunctival injection.
Unlike the more common conjunctival infection (also known as pink eye), which involves the cell layer that covers the white area of one’s eye, known as the conjunctiva, fluid will not leak from your child’s eyes when suffering from conjunctival injection.
Tongue, throat, lips and mouth
Your child’s lips may become cracked, dry or red and even swell which can result in cracking, peeling and bleeding. The inside of their throat and mouth will also swell up and the tongue will become red, swollen and bumpy, resembling a strawberry, hence the name for this symptom is strawberry tongue.
Inflamed lymph glands
By gently feeling your child’s neck, it may be possible for you to feel inflamed lumps, these could be lymph glands that are swollen.
Just to recap:
**My Med Memo - Lymph nodes are tiny glands that resemble the shape of beans and are located throughout the body. Lymph nodes are responsible for transporting waste material, nutrients and fluid, known as lymph fluid between the bloodstream and tissues in the body. The lymphatic system forms a vital part of the body’s immune system being the system of defence against infection and illness.
The lymph glands may swell to more than 1.5 centimetres in width (0.6 inches) and may feel firm and slightly painful when pushing on them.
Phase 2 – Sub-acute phase during weeks two to four
During the second phase of Kawasaki disease, symptoms will typically lessen in their severity, however, the symptoms experienced tend to last longer. A high temperature will generally subside, but there may still be some irritability in your child’s behaviour as a result of the pain associated with the condition.
The symptoms that can occur during phase two include:
- Abdominal pain
- Peeling of the skin on the toes and fingers (this peeling can sometimes occur on the soles of your child’s feet or on the palms of their hands)
- Pus/discharge in urine
- Lacking energy and feeling drowsy, generally lethargic
- Swollen joints and joint pain
- Jaundice (this condition refers to the yellowing of skin and eyes)
The complications that are associated with Kawasaki disease are more prone to developing during stage two. One such complication includes the development of a coronary artery aneurism (CAA), this condition refers to a bulge developing in a blood vessel that supplies the heart with blood. Complications will be discussed in more detail later on.
Phase 3 – Convalescent phase during weeks four to six
Pronounced “kon-vuh-les-uh nt”, convalescent refers to a period of regaining strength and recovering from an illness.
With this definition in mind, during phase three your child will start to recover from Kawasaki disease through treatment.
During this phase, the symptoms will lessen and start to improve, and eventually, disappear. During this phase, your child may show signs of fatigue and lack energy.
While complications associated with Kawasaki disease may still develop during this stage, it is less likely than during stage two.
When to see a doctor
If you notice that your child is experiencing a fever that persists for longer than a period of three days, then you should contact your doctor. If your child has a fever as well as four of the below symptoms, then it is vital that you make an appointment to see your doctor immediately. These signs include:
- Strawberry tongue (red, swollen and bumpy tongue)
- Redness of the eyes
- Peeling skin
- Rash on the body (begins in genital regions and spreads)
- Redness on the soles of feet or palms of hands
- Swollen lymph glands
If Kawasaki disease is treated within a period of ten days from the onset of the initial symptoms, this can reduce the risk of complications developing.
Are there any unusual symptoms and signs of Kawasaki disease?
The symptoms that are described above are often resolved without any complications occurring, even in cases where the condition is left untreated (although seeking treatment is highly recommended).
Some of the less common, yet potentially fatal, symptoms of Kawasaki disease include:
- Pericarditis – This refers to the inflammation of the heart lining
- Arthritis – This is the inflammation of the joints
- Meningitis – This is a condition that involves the inflammation of the spinal cord and covering of the brain
- Heart complications such as heart attack (myocardial infarction) and heart disease
The prognosis of patients who suffer from complications or symptoms is dependent on the specific complication and its severity.
What causes Kawasaki disease?
The exact cause of Kawasaki disease has not been properly identified as yet, however, experts believe that the condition is a result of an infection. A person’s genetics may also have a role to play in the development of the disease. These causes are further explained below:
Due to the symptoms of KD (Kawasaki disease) being similar to the signs associated with an infection, it is thought that either a virus or bacteria may have a role to play in the disease. However, there has not been any specific viral or bacterial cause identified yet.
The below points are facts that are known regarding the condition, each one explaining why a virus or bacteria may be the cause:
- Kawasaki disease is not contagious, and therefore, cannot be passed from one patient or child to another. This factor makes the chances of the cause being a virus only and not a bacterial infection, highly unlikely.
- Babies who are younger than six months old are not infected by the disease, although in some cases, extremely young children are at risk.
- This finding suggests that newborns have some kind of protection given to them by their mothers in the form of antibodies, this transference of antibodies occurs either during pregnancy, birth or through breastfeeding. Antibodies are blood proteins that are created in response to threats entering the body, these proteins help to combat disease and infection.
- Adults and older children are less likely to develop the condition, this means that they may be immune to the cause of Kawasaki disease. While a number of people will be exposed to the disease, only a small number of these will develop any symptoms.
There are findings that suggest that children who are diagnosed with Kawasaki disease may have some kind of genetic predisposition. This means that they may have inherited genes from their mother or father which may raise their risk of being infected.
Another theory notes that instead of one single gene being responsible for the development of Kawasaki disease, a number of genes may be to blame, with each one of the responsible genes increasing your child’s chances of the condition developing ever so slightly.
Kawasaki disease is commonly seen in children living in Northeast Asia, and in Korea and Japan in particular. This finding strongly suggests that genes have a role to play.
One theory indicates that the disease itself may be an autoimmune condition. This means that the immune system recognises healthy organisms as pathogens and attacks them, in turn, attacking a number of healthy cells, organs and tissues in the body.
Another theory notes that the cause of Kawasaki disease may be the result of a reaction to specific environmental factors such as toxins, chemicals or pollutants or medications.
Identifying the exact cause of the condition will provide a platform for effective diagnosis and treatment and possibly the development of a vaccine if need be.
What are the complications of Kawasaki disease?
Through prompt and effective treatment, most instances of Kawasaki disease undergo full recovery. But, this does not mean that some complications may not develop.
Most of the complications that are related to Kawasaki disease are directly related to a child’s heart and occur due to the inflammatory side effects that Kawasaki has on a child’s blood vessels.
The inflammatory response that Kawasaki disease has on the blood vessels responsible for supplying blood to a child’s heart, known as the coronary arteries, may result in a portion of the wall of an artery weakening.
When blood passes through this weakened section, the blood pressure can cause a bulge (or dilation) in the artery, this bulge is known as a coronary artery aneurysm (CAA).
In some cases, the aneurysm will heal over time by itself, however, in other cases, a thrombosis (i.e. a blood clot) can form. A blood clot is an accumulation of fibrin and platelets found in the blood that stops the body from bleeding. When an aneurysm exists, creating a bulge in the artery, this allows for blood to accumulate in that section. When a blood clot forms inside of the artery, this can lead to significant issues due to blood flow being decreased as a result.
A blood clot can result in either:
- Heart disease – This is an umbrella term for any kind of condition that has an effect on the heart. In this case, heart disease develops as a result of the heart being deprived of oxygen due to a blood clot blocking the oxygen-rich blood from reaching the heart.
- A heart attack – This refers to a condition wherein the muscle of the heart stops as a result of oxygen deprivation. It is a sudden occurrence of a blood clot that leads to the death of a section of the heart muscle that is often fatal.
In some rare cases of Kawasaki disease, the aneurysm can rupture (burst) which can result in internal bleeding.
Another possible complication is the risk of other major arteries being affected. These include the main blood vessel found in the upper section of the arm known as the brachial artery or the main blood vessel found in the upper section of the thigh known as the femoral artery. If these arteries are affected, this can result in limb threatening conditions as the arm or leg is deprived of blood.
Risk factors associated with Kawasaki disease
Roughly 25 percent of children suffering from Kawasaki disease will not receive treatment as a result of misdiagnosis or no diagnosis at all, this can result in heart-related issues developing in the future.
The risk of complications developing is greatly reduced for children when they receive IVIG (intravenous immunoglobulin) for the treatment of Kawasaki disease. This will be discussed further in the section on treatment.
The complications of Kawasaki disease that are heart-related are often severe and can even be fatal in roughly 1 percent of cases. Children who are younger than one year of age are seen to have a greater risk of severe complications developing due to their bodies lack of maturity and strength.
Complications of Kawasaki disease seen later in life
If there are any heart complications present as a complication associated with Kawasaki disease, this may increase your child’s risk of cardiovascular issues developing later in life. These complications include conditions such as heart disease and heart attack.
Should any complications develop during the disease, it will be recommended that the patient attend follow-up appointments in order for the condition and any subsequent complications to be monitored and controlled. They will likely be seen by a heart specialist known as a cardiologist. He or she will advise on the likelihood of the patient developing any further heart issues.
How is Kawasaki disease diagnosed?
The diagnosis of Kawasaki disease does not consist of one single test. The doctor is likely to confirm the disease through examining your child’s symptoms by means of a physical examination.
Your child is likely to be diagnosed with Kawasaki disease if he or she has a temperature of 38℃ (100.4℉) or higher as well as four or more of the below key symptoms:
- Changes in the mouth or throat – These changes include cracked or dry lips and strawberry tongue (red, bumpy and inflamed tongue).
- Conjunctival infection present in both of the eyes – This is a condition where the white areas of the eyes are swollen and red.
- Changes in the feet and hands – These changes include painful or swollen feet or hands, as well as peeling or red skin on the palms or soles.
- Lymph nodes – The lymph nodes will become swollen located in the neck.
- Rash – This rash will typically develop in the genital regions and then spread to the torso and limbs.
Your child’s skin on his or her toes and fingers may become hard or red and their feet and hands may also swell up. It is also possible for your child’s feet and hands to become painful and tender when touched or walked on, thus making walking or crawling difficult.
Some cases of Kawasaki disease are diagnosed especially if your child does not have at least four of the key symptoms of Kawasaki disease. This may be a case in incomplete or atypical Kawasaki disease.
It is possible that your child may require additional tests in order for a number of other conditions that may be causing the symptoms to be ruled out.
The possible conditions that may be causing similar symptoms include:
- Measles – This is an extremely infectious virus that results in a fever as well as distinctive reddish-brown spots on the body that manifest in the form of a rash.
- Scarlet fever - This condition is a bacterial infection seen commonly in children and is characterised by a pink and red rash on the body.
- Glandular fever – This refers to a viral infection that results in swollen lymph nodes (glands) and fever.
- Viral meningitis – This condition infects the protective membranes surrounding the spinal cord and brain and results in the inflammation of these areas.
- Toxic shock syndrome (TSS) – This life-threatening condition occurs as a result of a number of bacterial infections and is rarely seen.
- Stevens-Johnson syndrome – This is an extremely severe allergic reaction to certain medications.
- Lupus – This is an autoimmune disorder that can result in a number of symptoms which include a rash, joint pain and fatigue.
There are a number of tests that can be conducted during the initial seven to ten days of Kawasaki disease that aid in an accurate diagnosis, these include:
- Blood tests – A blood test will involve your doctor drawing a sample of blood from the affected child and sending it to a laboratory for analysis. A blood test for Kawasaki disease will include one that looks at a number of white blood cells or the platelet count.
- If the white blood cells are increased this often indicates the presence of infection as the WBC (white blood cells) form a vital part of the immune system in helping the body to fight off infection and illness.
- A platelet count measures the number of platelets present in the blood, these are blood clotting agents which the body uses to stop an injury site from bleeding. If the platelet amount is higher than normal, this may indicate the presence of a blood clot.
- Urine sample – This test will allow for the doctor to examine the urine for white blood cells.
- Lumbar puncture – This procedure involves inserting a needle into the lower area of your child’s spine in order for a sample of the spinal (cerebrospinal) fluid to be taken. This test is able to detect severe infection such as meningitis or disorders affecting the central nervous system (CNS).
If these tests are conducted individually, they may not be conclusive, however, when they are combined with the identification of a number of the symptoms listed above, this can help in confirming the diagnosis.
As previously stated, the complications of Kawasaki disease will normally have an affect on the heart. This may mean that your child needs additional tests to be conducted in order for the function of their heart to be monitored.
These tests may include:
- ECG (electrocardiogram) – This procedure involves measuring the heart’s activity of electric pulses through the use of electrodes (flat and round metal discs with sticky pads that stick to the skin) that are attached to the legs, arms and chest. This will aid in identifying any damage done to the heart or issues with the rhythm of the heart.
- Echocardiogram – This procedure uses sound waves to create images from the inside of the heart that allow the specialist to detect any issues with the function or structure of the heart.
There are a number of heart abnormalities that may be detected during the first two weeks of Kawasaki disease, which is the acute phase of the condition. Some of these heart conditions include:
- Myocarditis – This is a condition that refers to the inflammation of the heart muscle
- Tachycardia – This condition refers to an abnormally fast resting heart rate
- Pericardial effusion – This refers to fluid collecting in the heart
In roughly 25 percent of children with Kawasaki disease, the child’s blood vessels found around their heart, known as the coronary arteries, are slightly widened.
In the majority of cases, these abnormalities will resolve within six to eight weeks from the initial onset of symptoms, although, it is also possible for further complications to arise during this time.
How is Kawasaki's disease treated?
The treatment for Kawasaki disease will typically involve your child having to stay in the hospital for a short duration in order to prevent any complications from arising. The best prognosis is possible through early detection and treatment.
If the condition is not treated in the initial stages, your child’s hospital stay may be longer and their risk of complications developing may also increase.
There are two main treatments for Kawasaki disease, these are:
- IVIG (intravenous immunoglobulin)
These treatments are explained further below:
It is likely that the doctor will prescribe aspirin for your child. Children under the age of 16 are not normally given aspirin, but this specific disease calls for this medication to be administered. It is vital to note that you should not give your child aspirin without a prescription or recommendation from your doctor to do so.
Aspirin can have a number of side effects in children when it is not administered correctly, one of these side effects includes Reye’s syndrome. This is a condition that results in liver damage, confusion and swelling of the brain that is potentially life-threatening.
Your doctor will normally warn you against giving your child aspirin for the treatment of a fever associated with another condition, specifically if it’s caused by a virus, for example, chickenpox.
Aspirin is a part of a class of drugs known as NSAIDs, non-steroidal anti-inflammatory drugs and is used in the treatment of Kawasaki disease due to the following reasons:
- Easing of discomfort and pain
- Reducing fever
- Reducing swelling when given in higher doses
- Preventing the formation of blood clots due to aspirin being an antiplatelet, this means that aspirin reduces the ability of platelets to join together and form blood clots.
The dosage and duration of aspirin administration will be dependent on the symptoms. It is likely that your doctor will give your child a higher dose until the fever has subsided.
A lower dose of aspirin will typically be prescribed for six or eight weeks thereafter. This dosage will aid in reducing any blood clots present due to any issues that are developing within the blood vessels supplying the heart with blood.
Research conducted on the use of aspirin for the treatment of Kawasaki disease was unable to find evidence to support the use of the drug. However, there is also no evidence to suggest any issues arising from the treatment.
What is known is that aspirin aids in preventing heart complications through acting as an antiplatelet and an anti-inflammatory agent.
IVIG (intravenous immunoglobin)
This form of treatment is administered intravenously. The solution consists of antibodies that have been taken from a number of healthy donors. The solution will be injected into your child’s vein.
Just to recap, antibodies, also known as immunoglobins, are proteins produced by the immune system to help in fighting off any pathogen and other organisms carrying disease. Thus, when your child is given IVIG their immune system is boosted which helps their body to combat the disease.
Research conducted has found that IVIG administration for Kawasaki disease is able to reduce a child’s fever and their risk of developing any heart issues.
The specific immunoglobin that is used for the treatment of Kawasaki disease is known as gamma globin.
When your child receives intravenous immunoglobin, their symptoms will typically improve in a period of 36 hours. If the fever has not improved after this time, they may be given another dose of gamma immunoglobin.
These are forms of medication that consist of powerful chemicals known as hormones. Hormones are vital for the functioning of the body and have a large impact on the activity of organs and tissues in the body. Corticosteroids are able to mimic the effects of natural hormones produced by the adrenal glands in the body and aid in suppressing any inflammation associated with disease and infection.
These kinds of drugs are often administered if a second dose of immunoglobin was ineffective. Should your child have a high risk of developing heart complications, it is likely that your doctor will give him or her corticosteroids as a part of the initial treatment.
Research is still trying to identify the effects of corticosteroids when used for the treatment of Kawasaki disease. These results have previously been inconsistent, however, there have been findings that suggest these when used initially, these drugs reduce the need for a second dosage of.
Once your child has been discharged from the hospital, your doctor will give you advice on how to look after him or her at home. This home-care often involves ensuring they are comfortable and drink enough fluids. Any medication that your child was given while admitted should be continued once you return home as per the treating doctor’s instructions.
It is likely that your doctor, should he or she see fit, will warn you on the signs to look out for regarding the development of complications.
You will need to schedule a follow-up appointment with your doctor for your child to be monitored. During this visit, your doctor may conduct an ultrasound of your child’s heart, this is known as an echocardiogram. This will help your doctor to see any abnormalities, if none are present, then the dosage of aspirin will normally be discontinued.
Some of the symptoms of Kawasaki disease may only occur between weeks three and four, one of these being peeling skin. A full recovery from the disease may take up to six weeks.
Monitoring heart conditions
If there are any signs of heart conditions associated with Kawasaki disease, then your doctor may suggest a number of follow-up appointments in which he or she will perform tests on the heart at consistent intervals, these are often conducted between six and weights weeks after Kawasaki disease has begun, and again after a period of six months to ensure no further complications have manifested as well as to monitor any previously detected issues.
Should your child continue to develop heart issues as a result of Kawasaki disease, then your doctor may refer your child to a specialist in heart conditions in children known as a paediatric cardiologist.
If your child has a CAA (coronary artery aneurysm - this is the abnormal dilation of the coronary artery caused by Kawasaki disease), their treatment plan may consist of:
- Coronary artery angioplasty – Pronounced, “AN-jee-o-plas-tee”, this is a procedure to opening the clogged arteries of the heart by inserting a small balloon that will inflate once in place and thus, widen the artery, return the blood flow back to normal and hopefully prevent further blockage.
- Stent placement – Angioplasty is often combined with a procedure known as stent placement which involves placing a tiny mesh tube made of wire inside the artery, this tube is called a stent and helps to prop open the artery and decrease the chances of further blockage.
- CABG (Coronary artery bypass graft) – This procedure is a type of operation that involves improving blood flow to the heart. This is done through redirecting the blood around a narrowed or diseased artery through grafting a small section of a blood vessel taken from the leg, arm or chest in order to use this as an alternate route. The replacement blood vessels will be sewn in and used to redirect the blood flow past the blockage or narrowing.
- Anticoagulant drugs – Aspirin, warfarin (Jantoven, Coumadin), clopidogrel (Plavix), as well as heparin, are drugs that aid in the prevention of the formation of clots as they have blood thinning properties which inhibit the joining of platelets that cause blood clots.
Wait before vaccinating your child for another condition
Should your child have been administered with immunoglobin for the treatment of Kawasaki disease, it is advised that you wait for at least eleven months before your child is vaccinated against measles or chickenpox. This is due to the fact that gamma globin is able to affect the efficiency of these vaccinations and the vaccines prompting the production of antibodies to fight off future diseases.
What is the prognosis for children with Kawasaki's disease?
Generally, Kawasaki disease will resolve through early treatment within four to eight weeks, after which, you can expect a full recovery.
Bear in mind, this is not always the outcome for every child. In some rare cases, Kawasaki disease can be a life-threatening condition as a result of the formation of blood clots in the heart arteries and widening of these arteries. These issues can lead to a number of heart complications and issues, some of which, if not treated promptly and regularly monitored, can be fatal.
Aneurysms forming in the coronary arteries (heart arteries) may occur during childhood or even later on in life, during adulthood as a result of the disease.
Children whose echocardiograms have not shown any widening of the heart arteries often have the best prognosis.
If you child develops any heart complications, he or she will need to be closely monitored. Children who are younger than six months old and show signs of heart issues will need highly attentive care and ongoing monitoring as they are the most at risk of further complications arising.
Researchers are currently investigating various methods that may be able to detect the risk children may have for heart issues such as the aneurysms developing in the coronary arteries. There are various studies and research teams exploring several criteria for the abnormal variant manifestations of Kawasaki disease as these cases are deemed atypical. The more research is done on these topics, the more accurate the diagnosis and in turn, the more effective the treatment.
As with most illnesses, when your child is diagnosed early, the risk of complications arising is significantly decreased. It is vital that you recognise the signs and symptoms of Kawasaki disease and make an appointment to see your doctor if you feel your child may be ill.
Can Kawasaki's disease be prevented?
Due to the fact that the exact cause of the condition is yet to be identified, there are currently no measures in place that have been known to prevent the occurrence of the disease. This makes the early detection of the disease vital in preventing further complications.
What is the difference between Kawasaki's disease and Kawasaki's syndrome?
Both the terms Kawasaki disease and Kawasaki’s disease refer to the same syndrome.
Why is it called Kawasaki disease?
Kawasaki disease was initially described by Japanese paediatrician Tomisaku Kawasaki during the 1960s and as such, is named after him.
The first case was therefore reported in Japan, since then, a number of cases have been seen in several countries globally.
Is Kawasaki's disease contagious?
There is no evidence that suggests Kawasaki disease to be contagious.