From type 2 to type 1 diabetes: A case report on the diagnostic challenges in an older adult

Type 1 diabetes (T1D) is an autoimmune disease that targets the pancreatic beta cells, leading to insulin deficiency. Meanwhile, Type 2 diabetes (T2D) is primarily characterised by insulin resistance leading to decreased insulin production. Although younger individuals are commonly affected by T1D, an increasing number of cases are being reported in older adults. The overlapping features of T1D and T2D can make distinguishing between them difficult. Misdiagnosis of T1D as T2D may cause a delay in insulin administration, increasing the risk of diabetic ketoacidosis (DKA). This case report highlights the diagnostic challenges in identifying T1D in a 72-year-old female, referred to as Mrs Q, who presented with hyperglycaemic symptoms. On assessment in the emergency department, Mrs Q was initially diagnosed with T2D based solely on her blood glucose reading. She was commenced on oral hypoglycaemic agents; however, her blood glucose level remained elevated despite therapy. Given her poor response to the medications, further evaluation was undertaken. An antibody panel revealed that Mrs Q was positive for anti-glutamic acid decarboxylase and islet antigen 2 antibodies, confirming the diagnosis of T1D. Insulin was promptly administered to prevent the onset of diabetic ketoacidosis. This case report highlights the importance of keeping T1D as a differential diagnosis for older adults who present with hyperglycaemia, to ensure the right treatment approach is undertaken and to avoid adverse outcomes such as DKA.