P3.209: Kawasaki Disease in an Infant: Unmasking a Complex Diagnosis Amid Viral Symptoms

Introduction: Kawasaki disease (KD) is a systemic vasculitis primarily affecting children under 5 years old. Diagnosing KD in neonates and young infants is challenging due to its variable and often subtle presentation. Early symptoms often overlap with viral illnesses, making diagnosis difficult. Untreated, KD can lead to severe complications, including coronary artery aneurysms (CAA). This case report discusses a 2-month-old infant who initially presented with viral-like symptoms but later developed features of KD.

Case Description: A 2-month-old female with no significant past medical history presented with constipation, vomiting, and fever. Initial evaluation ruled out gastrointestinal obstruction or intussusception, and a viral infection was suspected. She returned with a fever of 102.3°F, a rash starting around her mouth that spread to her body, mild conjunctivitis, cough, congestion, fussiness, and decreased oral intake. Laboratory results showed elevated CRP and AST, with viral studies positive for rhinovirus/enterovirus.

Due to persistent fever and fussiness, a full sepsis workup was completed, revealing mild pleocytosis in cerebrospinal fluid, but bacterial cultures remained negative. Over the course of her hospitalization, the patient’s condition improved. By day 7, the fever resolved, the rash nearly disappeared, and there was no further fussiness. Oral intake normalized, and the symptoms were attributed to a viral illness due to the improvement.

However, on day 9 of illness, the patient became febrile again. The development of recurrent fever and persistently elevated inflammatory markers led to further investigation, including an echocardiogram, which revealed multiple coronary artery aneurysms. The diagnosis of Kawasaki disease with giant coronary artery aneurysms was confirmed.

Treatment with high-dose aspirin, IVIG, and anticoagulation was initiated. Pulse steroids and infliximab were added due to the severity of the coronary involvement.

Discussion: This case highlights the diagnostic difficulty of KD in neonates and young infants, where initial symptoms can resemble viral infections. The patient’s early presentation with fever, rash, and conjunctivitis suggested a viral illness, especially given the positive rhinovirus test. However, the development of recurrent fever and elevated inflammatory markers raised suspicion for KD. An echocardiogram confirmed coronary artery aneurysms, which is diagnostic of KD.

KD requires early recognition and treatment to prevent severe complications like coronary artery aneurysms. IVIG and aspirin are first-line treatments, with additional immunosuppressive therapy needed in severe cases.

Conclusion: Kawasaki disease should be considered in the differential diagnosis of infants with persistent fever and nonspecific symptoms, even when initial signs suggest a viral infection. Early diagnosis and treatment are crucial to prevent long-term cardiovascular complications and improve patient outcomes.