P2.221: Bilateral Axillary Masses in an Infant: An Incomplete Diagnosis

Introduction: Incomplete or atypical Kawasaki Disease (KD) is a challenging entity in pediatrics which requires a high index of suspicion for diagnosis. We present the case of a patient with an unusual clinical finding following a prior, undiagnosed episode of incomplete KD.

Case Description: A five-month-old female is brought to her PCP for new bilateral, pulsatile axillary masses noted by her parents. An ultrasound showed bilateral axillary aneurysms containing thrombus (Figure 1). The infant was transferred to the ED and ultimately admitted.

Additional imaging was obtained, including echocardiography and CT angiography, which showed multiple coronary artery aneurysms and redemonstrated the axillary aneurysms (Figure 2). The infant was started on aspirin and enoxaparin. She is doing well following discharge with no reported issues due to the axillary or cardiac aneurysms.

Three months prior to this presentation, the infant had an ~ 8-day febrile illness with symptoms including: fever, cough, diarrhea, and rash. Initial testing was significant for a urinalysis with large leukocyte esterase and WBC, and she was treated for a presumed UTI. She worsened at home on oral antibiotics and was admitted to a community hospital ICU with concern for sepsis. Urine culture did not grow any organisms. Additional testing at that time revealed leukocytosis, elevated inflammatory markers, anemia, and hypoalbuminemia. She defervesced after several days, and she was discharged home without any apparent complications.

Discussion: The infant’s multiple aneurysms suggest that her prior prolonged febrile illness was an episode of incomplete KD. Incomplete KD refers to the clinical presentation of KD which has 5 days of fever but fewer than four of the other principal clinical criteria (rash, conjunctivitis, mucosal changes, extremity changes, cervical lymphadenopathy). This patient had fever and rash without any other clinical criteria, consistent with incomplete KD. The pattern of laboratory values was also consistent.

Kawasaki Disease is most common between the ages of 6 months to 5 years, and it is very rare under the age of 3 months. Several studies have suggested that infants under the age of 6 months not only present more commonly with incomplete KD, but they are also at higher risk of coronary artery aneurysms and death. Typical mucosal and lymph node findings are also less common in this age group.

Like in Kawasaki Disease, the treatment for incomplete KD consists of IVIG and aspirin during the acute phase of the disease to reduce the risk of aneurysm development. Our patient did not receive the treatment during the initial illness and therefore was at risk for complications.

Conclusion: Pediatricians must maintain a high index of suspicion for Kawasaki Disease, especially in infants given the higher frequency of incomplete KD. Early recognition and treatment can prevent severe complications, such as those seen in this case.