The most common symptom my patients have of the onset of diabetes is: none!
Most of my patients are adults who I see on a regular basis, many of whom receive blood testing periodically. Patients who are at risk for diabetes – who are overweight or have a family history of diabetes – are often diagnosed on routine blood tests done for other reasons. Usually these patients exhibit no specific symptoms.
Historically, excess thirst, frequent urination, weight loss, and increased hunger have been cited as classic diagnostic signs. Sweet tasting urine is another, but modern day doctors rarely use this diagnostic test. (Most doctors don’t know how regular urine tastes, anyway.) The latin words, diabetes mellitus, mean “run-through honey.”
However, by the time a patient’s blood sugar is high enough to cause these symptoms, diabetes is usually quite advanced.
What causes thirst and frequent urination in a diabetic? The kidney normally is capable of absorbing all the glucose that flows through it. However, above a certain threshold, usually around a blood sugar of 200 to 300 mg/dL, the kidney can no longer absorb all the blood glucose, resulting in the sugar “spilling” into the urine. Glucose in the urine acts as a diuretic, causing increased volume of urination and therefore increased urinary frequency.
Because some of the calories from diet run right through a patient with diabetes, weight loss can occur, especially in children with Type I diabetes. Type I diabetic children tend to be thin and eat more to make up for what they are losing. Most Type II diabetics (which accounts for most adult diabetes) are overweight to begin with and may not exhibit weight loss. Some are happy if weight loss occurs and therefore delay seeking medical attention. Type II diabetes is no longer a disease limited to adults. Overweight teens and pre-teens are also at risk.
The current definition of diabetes is a fasting blood glucose reading of only 126 mg/dL, much lower than the level where patients exhibit the above symptoms. However, recognizing subtler symptoms of diabetes may lead to the diagnosis at blood sugar levels below those that produce thirst and frequent urination. Sometimes a patient will complain of fatigue (mental or physical). In women, recurrent vaginal yeast infections or a yeast skin rash under the breast may be associated with diabetes. Occasionally men complain of a yeast rash in the groin area. Some patients describe mild discomfort urinating or a change in vision.
The laboratory definition of diabetes has changed over the past few decades, with the threshold for diagnosis dropping lower and lower. Along with this, treatment goals for blood sugar now aim at normal or nearly normal blood glucose levels. With our improved understanding of how obesity leads to diabetes, insulin resistance is now recognized as a pre-diabetic condition.
Rather than wait for symptoms to occur, if you are at risk for diabetes, check with your doctor, who may want to perform simple blood testing. Or take advantage of your local health fair or chain pharmacies, who often offer free diabetic testing.
Copyright 2010 Cynthia J. Koelker, MD