Diabetes

Diabetes Mellitus (DM) is described in the earliest medical texts. From the Egyptians to Hippocrates and Galen, all were concerned with a disease in which the flesh dissolved into water. In other words, a condition in which the (young) patient ate a great deal (polyphagia), drank water constantly (polydipsia), urinated frequently (polyuria), the urine was sweet (hence the name “mellitus”), lost weight visibly (cachexia), had breath that smelled like apples (ketone breath), and died within a short time.

While ancient physicians knew how to recognize this disease—which corresponds to today’s Type I diabetes—they did not know how to treat it, nor did they suspect the existence of another form of diabetes (Type II), which is common among middle-aged obese individuals. This form does not present as dramatically as Type I but, if left untreated, insidiously shortens life considerably, leading to myocardial infarction, blindness, gangrene of the lower limbs, kidney failure, and nerve damage (neuropathies).

Other types of diabetes have also been identified, notably gestational diabetes. In Type I DM, which has an autoimmune cause, the body attacks and destroys the insulin-producing cells of the pancreas, leading to a lack of this hormone in the blood. In Type II DM, caused by genetic factors and obesity, insulin production is either insufficient or there is resistance to its action. The absence of insulin or the inability to utilize it leads to elevated blood sugar levels (glycemia is the blood sugar level; when it exceeds normal levels, it is called hyperglycemia).

In diabetes, hyperglycemia is a constant feature; therefore, it is the clinical pathologist who diagnoses the disease in the laboratory and helps clarify its consequences. Thus, diabetes is defined by the blood glucose concentration. The condition is diagnosed when, on two separate occasions, a fasting blood glucose level exceeds 125 mg/dl or, 2 hours after ingesting 75 mg of glucose dissolved in water, exceeds 199 mg/dl.

Fasting blood glucose levels between 105 and 125 mg/dl may indicate a future risk of diabetes. Elevated blood sugar in people with diabetes binds to proteins and alters their function. This phenomenon, known as glycation, is responsible for kidney damage, blindness, and neuropathies. It also binds to hemoglobin, and measuring the glycated fraction of this protein (Glycated Hemoglobin – HbA1c) provides information about the diabetic’s blood glucose levels in the recent past. The higher the level, the more hyperglycemia there has been.

Currently, it is used not only for monitoring but also for diagnosis: HbA1c below 5.7%—normal; between 5.7 and 6.4%—prediabetes; 6.5% or higher—diabetes. In turn, the presence of trace amounts of albumin (microalbumin) indicates kidney damage. In Type I diabetes, insulin is the only treatment. In Type II diabetes, treatment involves diet (sugar-free and low in other carbohydrates) and medications that stimulate insulin production. Type I diabetes cannot be prevented. Type II diabetes, however, can be prevented or mitigated if obesity is avoided—starting in childhood!