SUN-557 - Ketosis-Prone Diabetes Mimicking Type 1 Diabetes in A Young Adult

Ketosis-prone diabetes (KPD) is a unique clinical entity that does not fit the classic phenotypes of type 1 or type 2 diabetes mellitus. KPD is defined as a syndrome in which patients with negative antibodies present with diabetic ketoacidosis, severe hyperglycemia, or ketosis resulting in severe β-cell dysfunction and new insulin requirements. Patients can demonstrate reversible β-cell dysfunction, leading to sustained glycemic improvement and insulin independence. We present the case of a patient initially diagnosed with type 2 diabetes mellitus (T2DM) who required high doses of insulin prior to a period of sustained insulin remission.

A 22-year-old male with no medical history presented with one week of polyuria, polydipsia, and blurred vision. He had a blood glucose level (BGL) of 421 mg/dL and no evidence of ketosis. Intravenous fluids and a basal-bolus insulin regimen were initiated. He reported an extensive family history of T2DM and admitted to a recent period of heavy alcohol intake. Hemoglobin A1c (HbA1c) could not be measured due to an undefined hemoglobin variant. Fructosamine level was elevated at 451 µmol/L, corresponding to an estimated HbA1c of 11–12%. On discharge, he was prescribed aspart 10 units with meals, glargine 30 units daily, and metformin 500 mg twice daily.

Over several months, the patient’s insulin requirements escalated to 60 units of glargine daily and 12 units of prandial aspart. Autoimmune testing showed a slight, clinically insignificant rise in GAD-65 antibodies (0.05 nmol/L). Subsequent continuous glucose monitoring (CGM) demonstrated glycemic variability that corresponded with recurrent, symptomatic hypoglycemia ( < 50mg/dL), leading to substantial reductions and eventual discontinuation of all insulin. The patient maintained euglycemia on CGM without insulin therapy and the device was discontinued due to false pressure induced hypoglycemia.

KPD is challenging to diagnose and remains underrecognized, especially in patients presenting with hyperglycemia and negative autoimmune markers. The Aβ classification system provides valuable diagnostic and prognostic guidelines for management. In this case, a lack of significant autoimmune markers, a strong family history of T2DM and a clinical course of severe hyperglycemia requiring high dose insulin with subsequent need for rapid insulin independence is consistent with the A⁻β⁺ subtype. Patients with A⁻β⁺ KPD demonstrate significant β-cell recovery and often sustained insulin independence, but relapse can occur during periods of physiologic stress. The exact pathophysiology of KPD remains unknown but is hypothesized to occur in susceptible patients due to defective energy production from impaired ketone oxidation and fatty acid utilization. Recognition and classification are essential to prevent unnecessary insulin administration and hypoglycemia.

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