THU382 It’s Not What It Seems - Metformin Induced Severe Lactic Acidosis Mimicking Euglycemic Diabetic Ketoacidosis
Authors: Shaukat Mishal , Memon Rahat , Mack Margaret , Galarza Emma , Saeed Rehan 
Published: October 2023

Abstract
Disclosure: M. Shaukat: None. R. Memon: None. M. Mack: None. E. Galarza: None. R. Saeed: None.
Diabetic Ketoacidosis (DKA) is a life-threatening complication and, occasionally, the initial presentation of Diabetes Mellitus (DM). DKA can rarely present without elevated blood glucose levels, known as Euglycemic DKA, now typically associated with SGLT-2 inhibitors. Metformin is known to cause lactic acidosis but has not been reliably associated with euglycemic DKA. We present a case of metformin-associated lactic acidosis with renal failure and ketosis mimicking euglycemic DKA. Case: 82-year-old female with a history of DM type 2 on metformin and hypertension presented to the Emergency Department (ED) with complaints of presyncope, vomiting and generalized weakness for two weeks. In the ED, her temp. was 90.3 F and BP was 66/28 mmHg. Her labs revealed a potassium of 5.4mmol/L, bicarbonate 5 mmol/L, Creatinine 3.68 mg/dL (baseline 0.7mg/dL), Anion gap (AG) 45mmol/L, Lactate 25.1 mmol/L and Beta-hydroxybutyrate of 21.4 mg/dL. CT Scan of the chest and abdomen showed a 2 cm liver mass and pancreatitis. She was taken to the ICU and started on antibiotics, IV fluids, and vasopressors. The following day, her lactate was 13.5mg/dL, AG was 37mmol/L and Beta-hydroxybutyrate increased to 53.5mg/dL. Her blood sugars remained between 140-180mg/dL and her hemoglobin A1c was in the prediabetic range at 6.1%. She was thought to be in metformin induced euglycemic diabetic ketoacidosis and was started on an insulin drip with 5% Dextrose and 0.45% Normal Saline. Nephrology was consulted and she underwent hemodialysis for metformin toxicity. She remained on the insulin drip for 48 hours after which she was successfully weaned off. She currently remains off on any antidiabetic medication and is doing well. Discussion: DKA is a life-threatening complication of DM that presents as hyperglycemia, ketonemia, and AGMA. Euglycemic DKA is distinguished by blood glucose levels less than 250mg/dL and is usually seen with pregnancy, fasting states and use of SGLT-2 inhibitors. Previous cases of metformin-associated lactic acidosis (MALA) and concurrent euglycemic DKA have been reported, out of which several patients were concurrently on SGLT-2 inhibitors. After a thorough literature review, we were unable to determine a causal mechanism linking metformin and euglycemic DKA. In the reported cases, we believe that renal failure from various causes precipitated MALA due to decrease metformin clearance, with ketosis caused by starvation and exacerbated by metformin-induced inhibition of hepatic gluconeogenesis, further aggravated by an increase in stress hormones resulting in increased insulin resistance and ultimately leading to the development of the severe ketoacidosis. Even though this phenomenon has previously been referred to as “Metformin-induced euglycemic DKA”, we believe that this is more akin to a mimic, rather than true DKA.
Presentation: Thursday, June 15, 2023