References:
- Wong’s Nursing Care of Infants and Children, 11th Edition, ISBN 978-0-323-54939-4, by Marilyn J. Hockenberry, David Wilson, and Cheryl C. Rodgers (Ch. 29, pp. 1298–1302)
Kawasaki Disease (KD) is an acute systemic vasculitis of unknown cause. The illness is self-limiting and resolves in 6 to 8 weeks. Without treatment, however, approximately 20% to 25% of children develop cardiac sequelae. Damage to the coronary arteries (the blood vessels that supply the heart muscle) is the most common sequelae and involves dilation of the coronary arteries and/or coronary artery aneurysm formation.
- The population at most risk for heart involvement are infants younger than 1 year of age.
- The incidence of KD is 1.5 to 1.7 times more frequent in males than females, with 76% of cases found in children younger than 5 years of age.
Pathophysiology
KD involves widespread inflammation of the small and medium-sized blood vessels, with the coronary arteries being the most susceptible to damage.
- In the acute stage, progressive inflammation of the small vessels (capillaries, venules, arterioles) along with pancarditis, as reflected in clinical signs and symptoms and laboratory test results (CRP, ESR).
- The vasculitis can progress to the medium-sized muscular arteries, potentially damaging the walls of the vessels and leading to the formation of coronary artery aneurysms in some children. Initial evidence of enlargement of the coronary arteries by echocardiogram can be detected as early as day 7 of illness. Affected vessels can continue to enlarge for several weeks and generally reach their largest diameter approximately 4 to 6 weeks from the onset of fever.
- Decreased LV function can be observed on echocardiogram, but clinical signs of heart failure are rarely observed in children (some children still present with cardiogenic shock/severe ventricular dysfunction). LV function usually improves after the administration of IV immune globulin.
Clinical Manifestations
- Acute Phase:
- Abrupt onset of fever unresponsive to antibiotics and antipyretics.
- Reddened bulbar conjunctivae, with clearing around the iris (limbal sparing) is most commonly associated with KD.
- Inflammation of the pharynx and the oral mucosa develops, with red, cracked lips and the characteristic “strawberry tongue” (i.e., the normal coating of the tongue sloughs off, leaving the large papillae exposed, so the tongue resembles a strawberry).
- Polymorphic rash; most commonly accentuated in the perineum, and is never vesicular. Desquamation may occur in the groin area.
- Edema of the hands and feet; a common presentation in children involves “not wanting to walk”.
- Lymphadenopathy (at least one node ≥1.5 cm), commonly cervical can be observed. The node is not usually very tender or red.
- Subacute Phase:
- Resolution of fever, lasting until all outward clinical signs of KD have disappeared.
- Periungual desquamation—peeling that begins under the fingertips and toes—of the hands and feet can occur in this period.
- A temporary arthritis may be evident during this phase, and can affect the larger weight-bearing joints.
- Irritability persists.
- Convalescent Phase:
- All outward signs have mostly resolved, but laboratory values (CRP, ESR) are still abnormal.
- Thrombocytosis may still be present.
- Arthritis may still be present.
- Coronary complications remain a concern as coronary dimensions peak 4 to 6 weeks from the onset of illness.
- This phase ends once all blood values return to normal (6 to 8 weeks after onset).
- The child returns to normal in terms of temperament, energy, and appetite.
Cardiac Involvement
The development of coronary artery aneurysms and the potential for myocardial infarction in children with aneurysm formation is the most serious complication of KD. MI can result from thrombotic occlusion or stenotic occlusion of a coronary aneurysm. Symptoms include abdominal pain, vomiting, restlessness, inconsolable crying, pallor, and shock. Complaints of actual chest pain or pressure are more typical in older children.
Diagnostic Evaluation
No specific diagnostic tests exist for KD. Its diagnosis is based on clinical findings and associated laboratory results that support the diagnosis.
- Fever for at least five days is a requirement for the diagnosis.
- At least four of the five following symptoms must be present:
- Changes in extremities: (acute) erythema of the palms and soles, edema of hands and feet; (subacute) periungual peeling of fingers and toes in second and third week.
- Polymorphous exanthem
- Bilateral bulbar conjunctival injection without exudate
- Changes in the lips and oral cavity— erythema and cracking of lips, strawberry tongue, diffuse injection of oral and pharyngeal mucosae
- Cervical lymphadenopathy (nodes >1.5 cm in diameter), usually unilateral
- If without clinical symptoms, but coronary artery abnormalities are present, a diagnosis can still be made.
- If four or more principal features are present, diagnosis can be made on the fourth day of illness.
Therapeutic Management
The standard treatment is a single large infusion of high-dose IVIG (2 g/kg over 8 to 12 hours) along with salicylate therapy (e.g., aspirin [acetylsalicylic acid]) has been shown to reduce the duration of fever and the incidence of coronary artery abnormalities when given within the first 10 days of illness and optimally within the first 7 days.
- Retreatment with IVIG is recommended if the child has persistent or recrudescent fever without other cause 36 hours after the completion of the initial dose of IVIG.
- Aspirin is given initially in an anti-inflammatory dosage (80 to 100 mg/kg/day in divided doses every 6 hours) to control fever and symptoms of inflammation.
- Aspirin doses are decreased to an antiplatelet dosage (3 to 5 mg/kg/day) once the child has been afebrile for 48 to 72 hours. Low-dose aspirin therapy is discontinued once the platelet count has returned to normal. However, in the presence of coronary abnormalities, low-dose salicylate (antiplatelet) therapy is continued indefinitely.
- Additional anticoagulation therapy, such as clopidogrel or warfarin, may be used in moderate or giant coronary enlargement, respectively. The goal is to reach an international normalized ratio level of 2.0 to 3.0.
Prognosis
Most children with KD recover fully after treatment. When cardiovascular complications occur, however, serious morbidity may result. Death occurs rarely (<0.1% to 0.2%) and is almost always a result of ischemia caused by coronary thrombosis or stenosis. Long-term testing and monitoring for children with coronary abnormalities is recommended.
Nursing Care Management
Inpatient care focuses on symptomatic relief, emotional support, diagnostic assistance, medication administration, and education of the child and family.
- In the initial phase of illness, the nurse must monitor the child’s cardiac status carefully.
- Intake and output and daily weight measurements are recorded.
- Assess frequently for signs of heart failure (e.g., decreased urinary output, gallop rhythm, tachycardia, respiratory distress).
- Cardiac monitoring, ECG, and echocardiogram are recorded during the infusion of IVIG (because of the large fluid load) for children younger than 1 year of age and in any child with cardiac symptoms.
- The child may require sedation for echocardiography as the child must remain still for up to 1 hour to obtain adequate visualization of the coronary arteries and cardiac structures and function.
- Symptomatic relief:
- Skin discomfort: application of cool cloths and unscented lotions and use of soft, loose clothing
- Mucosal inflammation: mouth care (e.g., lubricating ointment to lips)
- Offer clear liquids and soft foods and monitor temperature carefully.
- Fever: document temperature prior to aspirin therapy; high temperatures may warrant the addition of acetaminophen to the high-dose aspirin.
- Arthritis: passive range-of-motion exercises, most easily done during the child’s bath.
- IVIG Administration: the same protocol as any blood product should be followed. Frequent vital signs monitoring should be performed.
- Watch for allergic reactions.
- Monitor cardiac status because of the large fluid volume being administered to patients who may have subclinical myocarditis or diminished LV function.
- Check patency of the IV line because extravasation can result in tissue damage.
- Patient Irritability is perhaps the most challenging problem. A quiet environment that promotes adequate rest should be secured.
- Parental support should be given in their effort to comfort an often inconsolable child.
- Parents need to understand that irritability is a hallmark of KD and that they need not feel guilty or embarrassed about their child’s behavior.
Discharge Teaching
Parents need accurate information about the usual course of KD, including the importance of follow-up monitoring and the circumstances under which they should contact their practitioner.
- Irritability is likely to persist for up to 2 months after the onset of symptoms.
- Peeling of the hands and feet is painless and occurs primarily in the second and third weeks. This is typically periungunal and begins first on the fingers then on the feet.
- Arthritis, especially of the larger weight-bearing joints, may persist for several weeks. Stiffness is typically present in the mornings, during cold weather, and after naps. Passive range-of-motion exercises in the bathtub are often helpful in increasing flexibility.
- Educate parents about recrudescent illness after discharge. Persistent or recrudescent fever 48 hours after the initiation of IVIG infusion would prompt reevaluation and retreatment with IVIG. instruct the parents to take the child’s temperature daily after discharge and to contact their physician or practitioner if there is any increase in temperature.
- Also instruct parents about the administration of salicylates and, if the child is receiving high dosages, make them aware of the signs of aspirin toxicity: ringing in the ears (tinnitus), head ache, dizziness, and confusion. The main side effect of low-dose aspirin is easy bruising. In addition, stop the aspirin and notify the practitioner if the child is exposed to chickenpox or influenza because of the drug’s possible association with Reye syndrome.
- Parents should understand the unlikely but real possibility of myocardial infarction and the signs and symptoms of cardiac ischemia in a child. They should be taught cardiopulmonary resuscitation.
- Children with coronary abnormalities may require indefinite antiplatelet therapy with low-dose aspirin or other coagulants. These children should avoid contact sports and have yearly influenza vaccines. The administration of IVIG will require delaying the measles-mumps-rubella and varicella vaccines by 11 months after administration because the body might not produce the appropriate number of antibodies.