Kawasaki disease (KD) is an acute systemic vasculitis of unknown cause that mainly affects infants and children and can result in coronary artery complications if left untreated. A small subset of KD patients with fever and cervical lymphadenitis has been reported as node-first-presenting KD (NFKD). This type of KD commonly affects the older pediatric population with a more intense inflammatory process. Considering its unusual initial presentation, a delay in diagnosis and treatment increases the risk of coronary artery complications. Herein, we report the case of a 9-year-old female with fever and neck mass that rapidly deteriorated to shock status. A diagnosis of KD was made after the signs and symptoms fulfilled the principal diagnostic criteria. The patient’s heart failure and blood pressure improved dramatically after a single dose of intravenous immunoglobulin. This case reminds us that NFKD could be the initial manifestation of KDSS, which is a potentially fatal condition. We review the literature to identify the overlapping characteristics of NFKD and KDSS, and to highlight the importance of early recognition of atypical KD regardless of age. We conclude that unusually high C-reactive protein, neutrophilia, and thrombocytopenia serve as supplemental laboratory indicators for early identification of KDSS in patients with NFKD.

Background: Guillain-Barré syndrome (GBS) is an acute immune-mediated polyneuropathy often associated with autonomic dysfunction. Although transient cardiovascular instability is common, severe dysautonomia leading to cardiac arrest is rarely documented in children. Methods: We report the case of an 11-year-old previously healthy boy who initially presented with acute ophthalmoplegia and rapidly progressed to quadriplegia and areflexia. He developed fluctuating blood pressure and bradycardia, culminating in cardiac arrest due to asystole at 24 h after admission, requiring 17 min of resuscitation. Results: Electrophysiological studies confirmed a demyelinating polyneuropathy. Although intravenous immunoglobulin (IVIG) was initiated 5 h after admission, clinical improvement was achieved only after subsequent plasmapheresis on day 20, with the recovery of autonomic function by day 35. He was extubated on day 45 and discharged on day 83 with a near-complete recovery after prolonged intensive care and rehabilitation. Conclusion: This case highlights the potential for rapid and life-threatening autonomic instability in pediatric GBS. Unlike typical cases, the patient progressed to cardiac arrest within 24 h despite IVIG, highlighting the need to consider plasmapheresis for non-responders. Continuous hemodynamic monitoring is essential to prevent fatal outcomes, even in patients with initially mild or atypical presentations.