Diabetes mellitus may have a rapid or an insidious onset. In type 1 diabetes, signs and symptoms often arise suddenly. Type 2 diabetes usually develops more insidiously; its presence may be detected during a routine medical examination or when a patient seeks medical care for other reasons.
The most commonly identified signs and diabetes symptoms are often referred to as the three polys: ployuria (I.e. Excessive urination), oplydipsia (i.e. excessive thirst) and polyphagia (i.e. excessive hunger). These three symptoms are closely related to the hyperglycemia and glycosuria of diabetes.
Glucose is a small, osmotically active molecule. When blood glucose levels are sufficiently elevated, the amount of glucose filtered by the glomeruli of the kidney exceeds the amount that can be reabsorbed by the renal tubules; this results in glycosuria accompanied by large losses of water in the urine. Thirst results from the intracellular dehydration that occurs as blood glucose levels rise and water is pulled out of body cells, including those in the hypothalamic thirst center.
This early symptom may be easily overlooked in people with type 2 diabetes, particularly in those who have had a gradual increase in blood glucose levels. Polyphagia usually is not present in people with type 2 diabetes. In type 1 diabetes, it probably results from cellular starvation and the depletion of cellular stores of carbohydrates, fats, and proteins.
Weight loss despite normal or increased appetite is a common occurrence in people with uncontrolled type 1 diabetes.
The cause of weight loss is twofold. First, loss of body fluids results from osmotic diuresis. Vomiting may exaggerate the fluid loss in ketoacidosis. Second, body tissue is lost because the lack of insulin forces the body to use its fat stores and cellular proteins as sources of energy. In terms of weight loss, there often is a marked difference between type 2 diabetes and type 1 diabetes. Weight loss is a frequent phenomenon in people with uncontrolled type 1 diabetes, whereas many people with uncomplicated diabetes type 2often have problems with obesity.
Other signs and symptoms of hyperglycemia include recurrent blurred vision, fatigue, pareshesias and skin infections. In type 2 diabetes, these often are the symptoms that prompt a person to seek medical treatment.
Blurred vision develps as the lens and retina are exposed to hyperosmoloar fluids. Lowered plasma volume produces weakness and fatigue. Paresthesias reflect a temporary dysfunction of the peripheral sensory nerves. Chronic skin infections can occur and are more common in people with type 2 diabetes. Hyperglycemics and glycosuria favor the growth of yeast organisms. Pruritus and vulvovaginitis due to candida infections are common initioal complaints in women with diabetes. Balanitis secondary to candida infections can occur in men.
The diagnosis of diabetes mellitus is confirmed through the use of laboratory tests that measure blood glucose levels. Testing for diabetes should be considered in all individuals 45 years of age and older. Testing should be considered at a younger age in people who are obese, have a first degree relative with diabetes, are members of a high risk group, have delivered an infant weight more than 9 pounds or been diagnosed with GDM, have hypertension or hyperlipidemia, or have met the criteria for increased risk of diabetes on previous testing.