Hyperglycemic Emergencies Associated With COVID-19 Vaccination: A Case Series and Discussion

CONTEXT: Hyperglycemic emergencies such as diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic syndrome (HHS) and new-onset diabetes mellitus (DM) have been reported in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Hyperglycemia is a predictor of poor prognosis in COVID-19 disease. OBJECTIVES: The objective of this work is to describe a case series of HHS and/or DKA likely triggered by the COVID-19 vaccine. The aim is to alert physicians of the potential hyperglycemic complications from the COVID-19 vaccination and to provide further insight into the underlying mechanism of the bidirectional relationship between SARS-CoV-2 and DM. CASE DESCRIPTIONS: All 3 patients developed HHS and/or DKA within 2 to 10 days of the COVID-19 vaccination. PCR testing for SARS-CoV-2 was negative and other clinical precipitating factors were excluded. Two patients had a history of type 2 DM (T2DM) with pre-admission HbA1c levels of 7.0% to 7.5% while 1 patient was newly diagnosed with T2DM during the hospitalization. They were each treated with insulin infusion and were discharged on subcutaneous insulin therapy. Due to the rapid resolution of the hyperglycemia, insulin was discontinued in all patients within 8 weeks and they remain well-controlled on oral DM medications. CONCLUSION: Severe hyperglycemia including HHS and DKA may be triggered by COVID-19 vaccination. Early evaluation and screening of patients with hyperglycemic symptoms after COVID-19 vaccination is recommended. The vaccine-induced hyperglycemia may provide further insight into the underlying pathogenesis caused by the SARS-CoV-2 infection itself. The underlying robust inflammatory response and “cytokine storm” may be the primary precipitant.