Acquired heart disease and Kawasaki disease

Kawasaki disease (CD) is an acute febrile illness of early childhood, characterized by inflammation of medium-sized arteries. Most often, coronary vessels are affected, which increases the likelihood of coronary artery aneurysms and, consequently, sudden death. Such complications develop in approximately 25% of untreated cases; Appropriate medical effects reduce this risk by up to 3-5%.

Kawasaki disease is a major cause of acquired heart defects in developed countries. [1 - Newburger JW; Sleeper LA; McCrindle BW; Minich LL;Gersony W; Vetter VL; Atz AM; Li JS; Takahashi M; Baker AL; Colan SD; Mitchell PD; Klein GL; Sundel RP.Randomized trial of pulsed corticosteroid therapy for the primary treatment of Kawasaki disease. N Engl J Med. 2007;356 (7): 663-75]

It is worth pointing out that the incidence of CD in the continental US is about 25 per 100,000 children under the age of 5 years, while in Japan the incidence is estimated at about 250 per 100,000 children under the age of 5 years. The pathological condition is more often defined in children under 5 years old, with the majority of patients under 2 years old.However, Kawasaki disease can also affect older children. It is more common among boys, mostly developing in the winter and spring months.

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Impact of Kawasaki disease on the heart

BK is most often regarded as generalized vasculitis, which affects medium-sized arteries. Although vascular inflammation is most pronounced in the coronary vessels, veins, capillaries, small arterioles and large arteries can also become inflamed with the development of an appropriate clinic.

Kawasaki disease can affect the heart, causing the following complications:

• Aneurysms of the coronary arteries (or swelling of the arteries).
• Valve insufficiency (most often mitral valve regurgitation).
• The accumulation of fluid around the heart (effusion pericarditis).

Kawasaki disease is a major cause of acquired heart defects in children. As many as 25% of children with Kawasaki disease, the heart is affected, especially if not properly treated. Aneurysms of the coronary arteries, blood vessels that supply oxygen to the heart muscle, are the most important complication of Kawasaki disease. With the passage of the necessary treatment, the risk of coronary artery disease is reduced by about 5%.

In general, if changes in the coronary vessels did not develop within six to eight weeks after the onset of the disease, the risk of these changes is very low.

If a coronary aneurysm has occurred, the presence of long-term changes in the heart vessel depends on the size of the aneurysm - changes in the coronary artery can pass, remain unchanged or progress. Patients with large aneurysms are at risk of developing coronary artery clots or stenosis (narrowing) as the aneurysms heal.

Inflammation of the heart valve or heart muscle, often observed in the acute phase of the development of CD, can lead to such acquired heart defects as mitral or tricuspid valve insufficiency . Such pathological disorders can develop independently of coronary artery disease. Valvular apparatus dysfunction most often disappears when the underlying disease is eliminated, but the preservation and progression of a valve defect is sometimes observed. There is also late aortic or mitral insufficiency caused by thickening or deformation of the fibrous valves, with time intervals from several months to several years after the onset of Kawasaki disease. Some of these lesions require valve replacement.

It should be pointed out that acquired heart defects, unlike congenital ones, occur during a person's life and can develop at any age, in particular with CD - in early childhood from 2 to 5 years.

It was reported that in half of the patients with small coronary aneurysms and acquired heart defects, the changes disappear during the first year after the disease. Unfortunately, doctors can not give a reliable prediction of how exactly the disease will develop in a particular patient.

Regardless of the degree of damage to the coronary arteries and the valvular apparatus, the child will need to visit a pediatric cardiologist, both during the childhood and adulthood.

The reasons

The etiology of Kawasaki disease remains unknown. For a long time there was an assumption that the etiology of CD is infectious, that is, it is transmitted from one person to another. However, the involvement of a single infectious agent has not been proven. Also, autoimmune reactions and genetic predisposition have been proposed as possible etiological factors for CD.

Infection

The characteristics of CD that are of concern for infectious etiology include the appearance of epidemics, mainly in the late winter and spring, with three-year intervals, and the wave-like geographical distribution of these epidemics. BK is rare in children younger than 4 months, which suggests that maternal antibodies can provide passive immunity.

Epidemiological data claim, however, that the transmission of the disease from person to person is unlikely.

Some authors have suggested a controversial relationship with CD with recent carpet washing, the use of a humidifier in a child’s room, a recent respiratory illness, and places near water bodies. These data led to a hypothesis related to water.

Over the years of studying the disease, numerous infectious agents have been involved; however, to date, no pathogen has been detected as the main cause.

Genetic factors

Genetic susceptibility to BC has long been suspected. Brothers and sisters of affected children are 10-20 times more likely to develop CD than the general population. It is also noted that children in Japan whose parents are ill with CD have a more severe form of the disease and are more susceptible to relapses. This risk is highest in twins, for whom this figure is approximately 13%.

By 2014, 6 genetic loci were associated with BC, which was confirmed by general genomic studies. However, the etiology of CD remains quite complex, so these genetic factors are still only partially used for the diagnosis and treatment of the disease.

Video: What is Kawasaki disease? | Circulatory System and Disease | NCLEX-RN | Khan Academy

Diagnostics

There is no one specific test for determining Kawasaki disease. The doctor makes a diagnosis based on the signs and symptoms identified in the child. Laboratory tests can help with the definition of inflammation, blood rheology and other indicators. Prolonged fever (that is, more than five days and, as a rule, more than 38.5 centigrade) is often the first symptom that warns the doctor about the need to consider Kawasaki disease.

The main manifestations that help diagnose are as follows:

• Prolonged high temperature.
• A nonspecific red rash that often affects the groin area and can peel off.
• Red eyes or conjunctivitis.
• Very red lips and tongue.
• Enlarged lymph nodes on one side of the neck.
• Swollen, red hands and feet, which sometimes flaky skin.
• Soreness in the joints.
• Irritability and moodiness in children.

In some children, the gallbladder increases, and then there may be abdominal pain, sometimes accompanied by vomiting.

Other diseases and common viral infections may have the same symptoms. To determine if a child has Kawasaki disease, a doctor may order blood tests to identify:

• A recent streptococcal or viral infection.
• The body's immune response.

Additionally, a urine test can be performed.

These laboratory tests are quite informative, but the only way to diagnose Kawasaki disease is to have appropriate clinical criteria for most of the signs and symptoms listed above.

If the child determines the criteria for diagnosing Kawasaki disease, consult a cardiologist. The doctor of this specialty specifies the history of the disease and conducts a physical examination of the patient. Additionally, the patient is assigned electrocardiography (to assess the electrical conductivity of the heart) and echocardiography (ultrasound of the heart to determine the operation of the valve apparatus). Even if these tests are normal, the child is most often given treatment based on clinical symptoms and laboratory tests.

Kawasaki disease treatment

Treatment is usually carried out in a hospital setting and may take two to five days.

Therapy for BC involves the use of intravenous gamma globulin (IVHG), which is an infusion of intravenous infusion together with high-dose aspirin approximately every six hours. The medicine helps reduce swelling and inflammation in the blood vessels. IVHG can also reduce, but NOT eliminate, the risk of developing coronary aneurysms.

The drug is most effective during the first 10 days from the onset of the disease. The risk of developing coronary changes is reduced from 25% to less than 5% if the drug is used in the first 10 days of illness.

Minor acquired heart defects in CD can be eliminated independently in the case of effective treatment of the underlying disease. In rare cases, specific treatment is required in the form of surgery.

After discharge, the child will have to continue to take high doses of aspirin until the signs of inflammation and fever disappear.

• Children continue to take low-dose aspirin every day for six to eight weeks or more.
• The child will continue to undergo periodic check-ups with a cardiologist after Kawasaki disease resolves.

Parents are often concerned about the use of aspirin in children due to the occurrence of Reye's syndrome in the background of the use of this drug.

Reye's syndrome is an inflammatory process that affects the liver and brain, with it occurring more often in patients who use aspirin for a long time and have chicken pox or flu.

Some doctors suggest that if a child takes aspirin for a long period of time for any reason, he should be vaccinated against the flu to avoid developing the disease.

It is important to know that if a child is ill with chicken pox while taking aspirin, or someone from his family has chicken pox, then you should immediately contact your doctor for advice on further action.

Cardiac monitoring

The patient will continue to be monitored by a cardiologist after discharge. The first visits to the doctor, as a rule, pass in two weeks and six - eight weeks after discharge. If necessary, an echocardiogram and an electrocardiogram will be repeated, which will allow to check the condition of the valves and the coronary arteries in a child. If by six to eight weeks there are no signs of heart damage, then the patient’s risk of heart disease is extremely low.

In the absence of damage to the heart and blood vessels for six to eight weeks, the child will continue to visit a cardiologist every year or every few years. During these visits, the cardiologist may order additional blood tests to determine cholesterol and triglyceride levels.

Long Term Forecast

If there is no heart failure after one year from the date of the diagnosis of Kawasaki disease, then cardiologist visits to patients are performed annually or even every few years.

Patients with coronary aneurysms and acquired heart defects need periodic cardiological evaluation. The frequency of such visits varies depending on the degree of coronary changes and the magnitude of the valve lesion. Often these visits are scheduled once every 6-12 months.

With proper medical care, patients with defects and coronary changes usually have a good prognosis. Since coronary arteries and heart valves are affected in Kawasaki disease, it is advisable for patients and their families to practice a healthy lifestyle that helps prevent adult coronary heart disease in children and heart attacks and arrhythmias in children.

Video: Kawasaki disease: diagnosis and treatment | Circulatory System and Disease | NCLEX-RN | Khan Academy