In a 16-year-old with diabetes mellitus and an A1C of 12%, which complication is at greatest risk?

• A. Nephropathy
• B. Ketoacidosis
• C. Retinopathy
• D. Neuropathy

Answer: (C)

Chronic high blood sugar damages the small vessels throughout the body, especially in the retina. In a teenager with an A1C around 12%, the retina’s fragile microvasculature is particularly vulnerable, so diabetic retinopathy becomes the complication they’re most at risk for. The high glucose level leads to retinal capillary changes—thickened basement membranes, microaneurysms, leakage, and ischemia—that can progress from mild, nonproliferative changes to more severe, vision-threatening stages if control isn’t improved. While ketoacidosis is an acute, life-threatening issue in type 1 diabetes, and nephropathy and neuropathy are important long-term concerns, retinopathy is the most likely long-term complication in the setting of sustained poor glycemic control and requires early screening and tight glucose management.