P2.K215: Atypical Presentation of Kawasaki Disease: A Case Report

Introduction: Retropharyngeal abscesses (RPA) are typically preceded by upper respiratory infections and suppurative cervical lymphadenitis and can rapidly progress to life-threatening complications. Rarely, retropharyngeal involvement can be a presentation of Kawasaki Disease (KD). We present a unique scenario of a patient with RPA evolving into Kawasaki disease, providing further evidence of the multifaceted nature of KD.

Case Description: A 9-year-old healthy female was admitted with a 3-day history of left neck pain, swelling, difficulty swallowing, and fevers. Physical examination revealed a temperature of 39.3°C with trismus, soft tissue neck swelling, and enlarged cervical lymph nodes. Labs were notable for hemoglobin 11.3 g/dL, 17,400/µL white blood cells (neutrophils, 85%), 230/µL platelets, C-reactive protein (CRP) 166.30 mg/L, and procalcitonin 2.90 ng/mL. Liver and renal function were normal. Strep A PCR testing was negative. CT neck with contrast revealed a phlegmon/developing abscess in the prevertebral soft tissues. She was started on IV ampicillin-sulbactam and dexamethasone to assist with airway inflammation. Symptoms initially improved, then fever recurred at day 4. Thus, vancomycin was added for Methicillin-resistant Staphylococcus aureus coverage. Upon initiation, she developed facial and chest erythema and conjunctival injection, initially believed to be due to vancomycin infusion reaction, and she was treated with diphenhydramine and slowed antibiotic infusion rate. ENT attempted incision and drainage of the phlegmon however, no drainable fluid was found. Repeat CT demonstrated ongoing inflammation and lymphadenopathy but no abscess formation. Repeat blood culture had no growth.

The patient continued to have fevers on hospital day 6 and progressively developed non-exudative conjunctivitis, mucosal erythema, extremity swelling, and a generalized erythematous rash, leading to the consideration of KD. IVIG and moderate dose aspirin were started, resulting in rapid improvement of symptoms. Inflammatory markers improved and echocardiogram was normal. Follow-up included completing a 2-week course of antibiotics, low-dose aspirin, and outpatient Cardiology referral.

Discussion: Throughout this patient’s 12-day hospitalization, she developed symptoms of KD that were initially thought to be complications of her RPA and antibiotics. Once KD was considered, she responded rapidly to treatment with aspirin and IVIG. KD is a medium vessel vasculitis that can present with various symptoms, most commonly fever, rash, mucosal involvement, and lymphadenopathy. Although some studies report a < 5% presentation of deep neck infections with KD, physicians should consider KD in these patients if they are febrile and unresponsive to antibiotics.

Conclusion: Clinicians must maintain a high index of suspicion for KD, given the likelihood of atypical presentation. This case highlights the importance of considering KD in patients with febrile deep neck infections that do not respond to typical treatment. Both KD and RPAs can be serious and life-threatening; thus, timely diagnosis and effective management are crucial for good outcomes.