An Unanticipated Worsening of Glycemic Control Following a Mild COVID-19 Infection

We describe a case of acute-onset worsening of a patient's previously well-controlled type 2 diabetes mellitus (T2DM) following his recovery from a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. A 78-year-old male with a three-year medical history of well-controlled T2DM (controlled by diet and metformin) presented to the outpatient clinic to discuss his regularly scheduled six-month lab work. He mentioned having a mild coronavirus disease 2019 (COVID-19) infection lasting one week which required no medical treatment approximately two months before his current visit. His labs, taken one week prior to his current visit, were notable for fasting hyperglycemia, 301mg/dL, and an elevated hemoglobin A_1C (HbA_1C), 11%. A fasting blood glucose level was recorded at his current in-office visit and was found to be 403mg/dL. These findings were not anticipated - our patient reported no change in his meals, medications, or exercise routines. The only notable change he reported between visits was his COVID-19 infection. This case report explores the link between this virus and our patient's exacerbation of his previously well-controlled T2DM. Whether it be through insulin resistance or deficiency (or another unknown mechanism), our patient's prior novel COVID-19 infection could potentially be associated with his unprecedented altered glucose metabolism.