Abstract
SUMMARY: A 77-year-old Japanese woman with a history of spinocerebellar degeneration, recently diagnosed with mild glucose intolerance managed by diet, sustained blunt chest trauma from a fall 7 days before admission. Three days prior, she developed general fatigue, thirst, and polydipsia. On arrival, she was unconscious, with unmeasurable blood pressure; heart rate of 112 beats/minute; and rectal temperature of 28°C. She presented with glucose levels of 1,125 mg/dL; β-hydroxybutyrate of 13,778 μmol/L; and arterial blood pH, 6.84, indicating severe diabetic ketoacidosis (DKA), likely triggered by traumatic hemothorax, and exhibited markedly elevated CA19-9 levels. External rewarming therapy was initiated along with vasopressor support, fluid resuscitation, continuous intravenous insulin infusion, and bicarbonate administration; subsequently, she regained consciousness. C-peptide depletion and positive islet-associated autoantibodies confirmed acute-onset type 1 diabetes mellitus. Although the CA19-9 level gradually decreased during hospitalization, it remained persistently above the reference range. Comprehensive imaging studies revealed no malignancy. Elevated CA19-9 levels were attributable to lung injury associated with traumatic hemothorax and multiple hepatic cysts. On hospital day 5, she was transferred to a general ward and resumed oral intake. Given the sustained improvement in glycemic control, she was transferred to another facility on hospital day 32. We report a rare case of acute-onset type 1 diabetes in an older patient who survived severe hypothermia and DKA secondary to traumatic hemothorax through intensive medical management. Appropriate and timely treatment can lead to favorable outcomes even in older patients with severe DKA and hypothermia. Furthermore, type 1 diabetes should be considered in elderly individuals presenting with newly developed glucose intolerance. LEARNING POINTS: Acute-onset type 1 diabetes mellitus can occur in older patients and may present with life-threatening complications, such as severe diabetic ketoacidosis (DKA) and hypothermia. Traumatic events, such as hemothorax from blunt chest trauma, can precipitate DKA even in patients with previously mild glucose intolerance. Intensive supportive care, including rewarming, insulin infusion, fluid resuscitation, vasopressors, and bicarbonate, can lead to recovery without the need for invasive interventions, such as CHDF or ECLS. Markedly elevated CA19-9 levels in the absence of malignancy may result from non-neoplastic conditions, such as lung injury and hepatic cysts, emphasizing the importance of thorough differential diagnosis. Positive islet autoantibodies and depleted C-peptide levels confirmed the diagnosis of acute-onset type 1 diabetes, reinforcing the need to consider autoimmune diabetes even in older patients with new-onset hyperglycemia.