(18.04) Never Too Old: Oldest Case of New onset Latent Autoimmune Diabetes in Adults Presenting with Diabetic Ketoacidosis in an 86 Year Old Adult Female

Introduction : Latent Autoimmune Diabetes of Adults (LADA) represents a subset of diabetes caused by beta-cell destruction. There are often clinical features of type 1 and type 2 diabetes. Diagnostic criteria established by the American Diabetes Association (ADA) are age over 30, presence of diabetes-associated autoantibodies, and absence of an insulin requirement for at least 6 months after diagnosis of diabetes.

Case(s) Description : An 86 year-old-female presented to the emergency department with altered mental status after having been found slumped over. She was at her baseline mentation one day prior. She had no known recent illness. Her medical history included hypothyroidism, Stage 2 chronic kidney disease, hyperlipidemia, and hypertension. She has no smoking or alcohol use history. She had no known family history of diabetes or autoimmune disease.
She had a heart rate of 94 BPM, BP 129/71 mmHg, a temperature of 37.4 degrees Celsius, and a respiration rate of 16. She weighed 54.4 kg (BMI 18.7 kg/m2). On physical exam she appeared toxic with dry mucous membranes. Her labs included a venous blood gas with pH 7.19, pCO2 51 mmHg, potassium 5.9 mmol/L, sodium 148 mmol/L, lactate 2.7 mmol/L, and the anion gap was 19 mmol/L. Serum glucose was 1107 mg/dL, serum CO2 was 18 mmol/L, and had an estimated glomular filtration rate of 22 mL/min/1.73m2. Beta-Hydroxybutryate was 5.6 mmol/L. White blood cells were 12.3 K/uL (84.6% neutrophils) and the remainder of cell lines were unremarkable. COVID-19 PCR testing was negative. Troponin was 28 pg/mL and downtrended to 26 pg/mL when reassessed. Electrocardiogram showed normal sinus rhythm with non-specific ST and T wave abnormalities.
She was given 4 L of lactated ringers intravenously, started on continuous insulin infusion, and admitted for diabetic ketoacidosis (DKA).
Further labs revealed an Hgb A1C 16.8%. Glutamic Acid Decarboxylase Antibody was elevated at 3.88 nmol/L. C-Peptide was 0.5 ng/dL with a blood glucose of 142 mg/dL
A CT Abdomen and Pelvis showed an atrophic pancreas with out other pancreatic lesions.
The patient started basal/bolus insulin. Her dosing at discharge was 12 units glargine at bedtime, 5 units lispro with meals, and a correction scale of 1 unit for every 50 mg/dL over 150 mg/dL.

Discussion : This case provides an opportunity to recognize that LADA can present late in life and with DKA. Although the average age of onset is over 30, current literature review suggests this to be the oldest patient presenting with new diagnosis of LADA in setting of DKA. This patient had no obvious precipitating factors or pancreatic lesions on imaging, though her atrophic pancreas suggests the processes may have been subclinical. Checking auto-antibodies and insulin reserve are critical in choosing the appropriate therapy prior to discharge because a clinician may choose an agent without recognizing the need for insulin. One of the diagnostic criteria by the ADA includes no insulin 6 months post diabetes diagnosis, but this case demonstrates that patients do not necessarily meet all diagnostic criteria on presentation, and that new a diagnosis of autoimmune diabetes can still occur in the elderly.