Diabetic ketoacidosis as a unique initial presentation of cystic fibrosis

Background: Cystic fibrosis–related diabetes (CFRD) is an increasingly common complication of CF as life expectancy of people with the condition increases. The pathophysiology differs from type 1 and type 2 diabetes. In CFRD, there is a reduced and delayed insulin response to carbohydrates while basal insulin is often spared. Many people with CF have abnormally high glucose levels at intermediate time points of an oral glucose tolerance test despite meeting conventional criteria for normal glucose tolerance. This pattern of transient postprandial hyperglycaemia also means that a normal HbA1c in persons with CF does not reliably exclude CFRD.1 Aggressive screening and early institution of insulin has been reported to be associated with reduced mortality, but there are differing opinions on whether good glycaemic control does modify the course of CF. For example, the rationale for treatment with insulin in CFRD may include reducing the impact on lung function and infection risk.1, 2 However, it is important to differentiate CFRD from other forms of diabetes as the insulin regime and treatment rationale are different.