Diabetic Ketoacidosis Triggered by Retropharyngeal Abscess Complicated by Descending Necrotizing Mediastinitis: A Case Report.

A 62-year-old woman with poorly controlled type 2 diabetes mellitus presented with a fever and altered consciousness. The patient was diagnosed with diabetic ketoacidosis (DKA) with a positive blood culture for group A Streptococcus. Although the source of infection was initially unclear, contrast-enhanced CT revealed a retropharyngeal abscess (RPA) and descending necrotizing mediastinitis (DNM) that required surgical drainage. RPA with DNM is rare and potentially fatal in adults and is often missed without high clinical suspicion. In severe DKA, altered mental status and hemodynamic instability may obscure the underlying infection, emphasizing the importance of a thorough evaluation.