A 66-year-old man with obesity and mild hypertension controlled with a diuretic presents with increasing nocturia and excessive thirst. He has no other urinary symptoms and denies any visual problems. His mother had diabetes and died at age 85 years from a heart attack. His only other concern is a recurrent fungal infection on his feet. His blood pressure in the office today is 135/85 mm Hg and his finger-stick blood sugar is 220 mg/dL. Physical exam findings confirm tinea pedis (Figure 228-1). A monofilament test demonstrates normal sensation in his feet.
Patient with diabetes and tinea pedis being tested with a monofilament for sensation. (Reproduced with permission from Richard P. Usatine, MD.)
You explain that based on his elevated blood sugar, he has diabetes mellitus. You order a fasting blood sugar, lipid profile, serum electrolytes, creatinine, and hemoglobin A1c. You ask him to return next week for a more complete examination, review of his test results, and diabetes education. You encourage him and his wife to consider meeting with a nutritionist, and briefly review treatment options, including diet, exercise, and metformin, as well as a possible need to improve his blood pressure control or switch to another agent. You suggest a nonprescription antifungal cream and will see if he needs additional treatment for his feet at follow-up. The patient is referred to an ophthalmologist, who finds diabetic nonproliferative retinopathy (Figure 228-2).
Nonproliferative diabetic retinopathy, with scattered intraretinal dot-blot and flame hemorrhages, along with macular exudates. Macular exudates can be related to diabetic macular edema, which accounts for a large portion of poor vision and disability secondary to diabetic retinopathy. (Reproduced with permission from Andrew Sanchez, COA.)
Diabetes is a group of disorders caused by a complex interaction between genetic susceptibility, environmental factors, and personal lifestyle choices that share the phenotype of hyperglycemia. Type 2 diabetes mellitus (DM) is a heterogeneous group of chronic disorders caused by a progressive insulin secretory defect and increased glucose production in the setting of insulin resistance.
Prevalence—In the United States, 29.1 million adults and children (9.3% of the population), including 21 million who have been diagnosed, have diabetes (2014).1 This includes about 1 in 400 children and adolescents and 25.9% of people age 65 years and older. Type 2 DM is the most common form, accounting for more than 90% of cases.
Incidence—In the United States in 2012, there were 1.7 million new cases among individuals 20 years of age and older.
Highest rates of diabetes, in decreasing order, are in American Indians/Alaska Natives (15.9%), non-Hispanic blacks (13.2%), ...