A 56-year-old Hispanic woman presents to her medical practitioner with symptoms of fatigue, increased thirst, frequent urination, and exercise intolerance with shortness of breath of many months’ duration. She does not get regular medical care and is unaware of any medical problems. Her family history is significant for obesity, diabetes, high blood pressure, and coronary artery disease in both parents and several siblings. She is not taking any medications. Five of her six children had a birthweight of over 9 pounds. Physical examination reveals a BMI (body mass index) of 34, blood pressure of 150/90 mm Hg, and evidence of mild peripheral neuropathy. Laboratory tests reveal a random blood sugar of 261 mg/dL; this is confirmed with a fasting plasma glucose of 192 mg/dL. A fasting lipid panel reveals total cholesterol 264 mg/dL, triglycerides 255 mg/dL, high-density lipoproteins 43 mg/dL, and low-density lipoproteins 170 mg/dL. What type of diabetes does this woman have? What further evaluations should be obtained? How would you treat her diabetes?
The endocrine pancreas in the adult human consists of approximately 1 million islets of Langerhans interspersed throughout the pancreatic gland. Within the islets, at least five hormone-producing cells are present (Table 41–1). Their hormone products include insulin, the storage and anabolic hormone of the body; islet amyloid polypeptide (IAPP, or amylin), which modulates appetite, gastric emptying, and glucagon and insulin secretion; glucagon, the hyperglycemic factor that mobilizes glycogen stores; somatostatin, a universal inhibitor of secretory cells; pancreatic peptide, a small protein that facilitates digestive processes by a mechanism not yet clarified; and ghrelin, a peptide known to increase pituitary growth hormone release.
TABLE 41–1Pancreatic islet cells and their secretory products. |Favorite Table|Download (.pdf) TABLE 41–1Pancreatic islet cells and their secretory products.
|Cell Types1 ||Approximate Percent of Islet Mass ||Secretory Products |
|Alpha (A) cell ||20 ||Glucagon, proglucagon |
|Beta (B) cell ||75 ||Insulin, C-peptide, proinsulin, amylin |
|Delta (D) cell ||3–5 ||Somatostatin |
|Epsilon cell ||< 1 ||Ghrelin |
Diabetes mellitus is defined as an elevated blood glucose associated with absent or inadequate pancreatic insulin secretion, with or without concurrent impairment of insulin action. The disease states underlying the diagnosis of diabetes mellitus are now classified into four categories: type 1, type 2, other, and gestational diabetes mellitus.
The hallmark of type 1 diabetes is selective beta cell (B cell) destruction and severe or absolute insulin deficiency. Type 1 diabetes is further subdivided into immune-mediated (type 1a) and idiopathic causes (type 1b). The immune form is the most common form of type 1 diabetes. Although most patients are younger than 30 years of age ...