Diagnosis and treatment of Kawasaki disease

Diagnostic approaches

To verify the disease, the physician needs to carefully tally the patient's existing symptoms. There are two main forms of the pathology:

1. Classic variant. The diagnosis is confirmed if the child has a fever for 5 days or more, combined with at least 4 out of the 5 main clinical criteria.
2. Incomplete (atypical) variant. In situations where the full set of symptoms is absent, but instrumental examination (Echocardiography) reliably reveals damage to the heart and coronary arteries, the requirements for the clinical picture are reduced. In this case, the presence of fever and just 3 typical criteria is sufficient to confirm the diagnosis.

The most important diagnostic rule is the so-called red flag: if an infant (especially in the first year of life) suffers from prolonged, persistent fever, Kawasaki disease must definitely be included in the differential diagnosis.

Differential diagnosis

The difficulty in identifying Kawasaki disease is due to the fact that its clinical manifestations can mimic a number of other childhood diseases. Differential diagnosis is most often carried out with the following groups of pathologies:

• Infectious diseases: measles, scarlet fever, various forms of acute respiratory viral infections (ARVI).
• Rheumatologic pathologies: primarily, the systemic form of juvenile idiopathic arthritis (JIA).
• Allergic conditions: toxic-allergic syndrome.

Basic conservative therapy in the acute period

The basis of drug treatment in the acute phase is the combined use of intravenous immunoglobulin (IVIG) and acetylsalicylic acid (ASA). This regimen makes it possible to quickly reduce temperature, improve the child's well-being, and normalize laboratory parameters of inflammation.

Administration of IVIG:

• The drug is prescribed in a high course dose of 2 g per kilogram of the patient's body weight.
• There is a strict therapeutic window: the administration of immunoglobulin must occur within the first 7–10 days from the onset of symptoms. This reliably reduces the likelihood of coronary artery aneurysm formation.

Administration of ASA:

• In the acute stage, the drug is used in high anti-inflammatory dosages (from 30 to 80 mg/kg per day). The daily volume is divided into 4 doses.
• After the fever has persistently been absent for 48–72 hours, the dosage is reduced to an antiplatelet dose (from 2 to 5 mg/kg per day).
• If the coronary arteries are not affected, ASA is continued for 6–8 weeks. If vascular pathology is detected, therapy becomes prolonged.

Management of patients with coronary involvement

The long-term risk for patients who have had this disease is the development of coronary artery disease (CAD) and the occurrence of myocardial infarction at a young or even pediatric age. Further management tactics directly depend on how severely the vessels are damaged.

For drug prevention of thrombosis, the following are used:

• Antiplatelet agents: ASA monotherapy or its combination with dipyridamole or clopidogrel.
• Anticoagulants: low molecular weight heparins (LMWH) or warfarin are prescribed.

In severe cases, surgical treatment is indicated. It is performed if the patient has developed coronary artery stenosis, experienced a myocardial infarction associated with an aneurysm, or exhibits recurrent episodes of ischemia. Intervention methods include coronary artery bypass grafting (CABG) or various endovascular techniques.

Prognosis and mortality specifics

As a rule, the disease ends in complete recovery, but the final prognosis is closely related to the timing of therapy initiation. On average, coronary artery aneurysms form in 5–12% of cases. However, if treatment was started late (after the 10th day of fever), the risk of vascular complications sharply increases and reaches 25%.

Overall mortality rates are extremely low (0.01–0.1%), while the direct causes of death have a clear dependence on the stage of the pathological process:

1. In the acute period, life-threatening conditions are severe forms of myocarditis and the occurrence of fatal arrhythmias.
2. In the subacute period, the maximum danger is the rupture of a previously formed coronary artery aneurysm.
3. In the convalescence period, patient death may occur due to a myocardial infarction developing against the background of thrombosis in structurally altered vessels.

Class and exam questions

What else to study on this topic

• Clinical symptoms included in the 5 main diagnostic criteria
• Ultrasonic evaluation of coronary arteries according to Echocardiography
• Features of differential diagnosis with measles and scarlet fever
• Mechanism of vascular aneurysm formation in systemic vasculitis
• Indications for endovascular interventions in children

Other topics of «Chapter 9. Rheumatic Diseases»

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.