Kawasaki Disease with Retropharyngeal Edema: A Comprehensive Case Series Analysis
Kawasaki disease (KD) is a systemic vasculitis predominantly affecting children under five years of age. While its classical diagnostic criteria—including fever, conjunctival injection, oral mucosal changes, polymorphous rash, extremity changes, and cervical lymphadenopathy—are well-established, the disease’s ability to mimic infectious conditions complicates timely diagnosis. This case series, spanning 24 patients managed at a tertiary pediatric referral center between 2007 and 2018, highlights the unique challenges and clinical features of KD presenting with retropharyngeal edema (RPE), a manifestation increasingly recognized as a mimic of deep neck infections.
Clinical Presentation and Diagnostic Challenges
All 24 patients initially presented with fever and neck-related symptoms such as pain, tenderness, torticollis, or restricted neck mobility. None exhibited upper airway obstruction signs like stridor, distinguishing them from typical retropharyngeal abscess cases. Crucially, none met the complete KD diagnostic criteria at initial presentation. Instead, symptoms overlapped with cervical lymphadenitis or pyogenic abscesses, leading to initial management with broad-spectrum antibiotics. However, all cases proved refractory to antibiotic therapy, prompting reevaluation.
As the clinical course evolved, 12 patients eventually met complete KD criteria by the time intravenous immunoglobulin (IVIG) therapy was initiated. The remaining 12 exhibited incomplete KD, defined by fever plus only two or three clinical criteria. For these cases, ancillary laboratory and imaging findings became pivotal. Over 50% of patients demonstrated hypoalbuminemia (1000 nmol/L), thrombocytosis (>500,000 platelets/mL), and normocytic normochromic anemia. Elevated alanine transaminase (ALT) levels and coronary abnormalities on echocardiography further supported the diagnosis. Five patients had echocardiographic evidence of coronary artery abnormalities, with one developing a persistent coronary aneurysm requiring long-term anticoagulation.
Radiological Findings and Differential Diagnosis
Imaging played a critical role in distinguishing KD-associated RPE from infectious etiologies. Twenty-two patients underwent computed tomography (CT) scans, while two received neck ultrasonography. CT findings consistently revealed long-segment RPE without rim-enhancing fluid collections, contrasting with the discrete abscess cavities typical of bacterial infections. Generalized cervical lymphadenopathy predominantly involved level II lymph nodes (upper internal jugular chain), sparing levels III–IV (middle and lower chains). These patterns align with prior studies describing KD-related cervical inflammation as diffuse and non-suppurative.
One patient underwent fine-needle aspiration of a suspected abscess, yielding 1.5 mL of necrotic material with negative bacterial cultures. This finding, coupled with unresponsiveness to antibiotics, reinforced the non-infectious inflammatory nature of the condition. The absence of purulent material and lack of microbiological growth helped exclude bacterial abscesses, redirecting focus toward systemic inflammatory processes like KD.
Therapeutic Response and Outcomes
All patients received IVIG, with rapid resolution of fever and neck symptoms in every case. This therapeutic response validated the diagnosis retrospectively, particularly for incomplete KD cases. The timing of IVIG administration varied, as initiation depended on the emergence of KD criteria or supportive laboratory markers. Notably, the single case of coronary aneurysm occurred in a patient with delayed diagnosis, underscoring the importance of early intervention.
Key Laboratory and Imaging Insights
Hypoalbuminemia and thrombocytosis emerged as consistent laboratory hallmarks, observed in over half the cohort. These markers, alongside elevated ALT and inflammatory markers, provided critical diagnostic clues when clinical criteria were incomplete. The American Heart Association’s guidelines for incomplete KD were instrumental in guiding treatment decisions, emphasizing the integration of laboratory and echocardiographic data.
Imaging protocols highlighted the utility of CT in delineating RPE characteristics. The absence of rim enhancement and the presence of diffuse phlegmon helped differentiate KD from bacterial abscesses. Ultrasonography, though less frequently used, offered a radiation-free alternative for assessing cervical lymphadenopathy. However, its inability to fully evaluate retropharyngeal spaces limited its utility compared to CT.
Avoiding Unnecessary Interventions
The series underscores the risks of invasive procedures in KD mimics. Surgical exploration or aspiration, often indicated for suspected abscesses, were avoided in 23 cases due to evolving clinical and laboratory evidence supporting KD. The rapid response to IVIG further obviated the need for such interventions, emphasizing the importance of clinical vigilance and serial reassessment.
Long-Term Implications
With 23 patients recovering without coronary sequelae, the series reinforces the favorable prognosis of KD when treated promptly. The lone case of coronary aneurysm highlights the necessity of echocardiographic monitoring, particularly in high-risk or incompletely treated patients. Long-term anticoagulation in this patient illustrates the potential cardiovascular burden of delayed diagnosis.
Conclusion
This case series elucidates the diagnostic and therapeutic nuances of KD presenting with RPE. Key takeaways include:
- Clinical Mimicry: KD with RPE closely resembles deep neck infections, necessitating a high index of suspicion in antibiotic-unresponsive cases.
- Ancillary Markers: Hypoalbuminemia, thrombocytosis, and elevated CRP/ALT are critical in diagnosing incomplete KD.
- Imaging Patterns: Diffuse RPE without abscess formation on CT supports KD over bacterial etiologies.
- Therapeutic Response: Rapid improvement with IVIG confirms the diagnosis and avoids unnecessary surgeries.
Early recognition of KD in children with neck complaints requires integration of clinical, laboratory, and imaging data. Future research should prospectively validate imaging criteria and refine protocols for differentiating KD from infections, ultimately reducing diagnostic delays and improving outcomes.
doi.org/10.1097/CM9.0000000000000321
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