Signs and Symptoms of Diabetes
Analysis of the signs and symptoms of diabetes mellitus helps in understanding and remembering them. Many of the features are common to both type 1 and type 2 diseases. Some are specific to one or the other disorder. Many are the direct or indirect result of a higher-than-normal level of glucose in the blood. Others are due to deficient action of insulin in cells and tissues. Despite overlap of most of the signs and symptoms there are often differences in their frequency and severity between the two disease types.
High Blood Sugar Symptoms
Four of the cardinal signs of uncontrolled diabetes mellitus that can be explained by hyperglycemia are the following:
The excessive urination is the result of spillage of glucose from the blood into the urine with water following in accordance with the law of osmosis. The medical term for this phenomenon is osmotic diuresis. The increased thirst is an indirect effect of the blood sugar elevation. It is the body’s response to hypovolemia from increased fluid loss. The decreased fluid volume stimulates the thirst center in the brain. That in turn leads to an increased craving for and intake of fluids.
Elevated blood glucose and osmosis are also the reasons for blurred vision after at least days or weeks of high blood glucose levels. With persistent elevations glucose diffuses into the lens of the eye. The subsequent movement of water causes a change in the shape of the eye structure. That alters the optical properties of the eye and results in blurred vision.
It is noteworthy that transient blurred vision can also occur with improvement of glycemic control. The reason is, as the blood glucose level falls and sugar moves out of the lens fluid shifts occur in the opposite direction, resulting in a reverse change in the shape of the lens. That opposite effect still alters the optical properties of the eye resulting in blurred vision. It is usually the near vision that is affected.
Although overweight and obesity are risk factors for insulin resistance and type 2 diabetes mellitus, unexplained weight loss is often a symptom of the development of the disease. It can be the result of fluid losses due to polyuria. But can also be due to deficient insulin secretion or insulin resistance.
Signs of High Blood Sugar
Signs of diabetes mellitus due to elevations in the blood glucose are the following:
- tendency toward infections
- slow healing of sores and skin wounds
- evidence of peripheral neuropathy
There is an increased incidence of a variety of different infections in individuals with diabetes. The most common sites are the skin, urinary tract and vaginal tract of women. Skin infections can be primary or secondary to nonhealing sores or wounds. Yeast infections are the main ones which occur in the vaginal tract of women. Other common sites of infection are the ears, sinuses and gums. Disease of the gums is often a clue of underlying diabetes.
A number of factors are involved in recurring infections when diabetes is long-standing. But research has shown that acute elevations in blood sugar adversely affect several aspects of innate immune system function including inflammation which plays a major role in healing. It is not surprising then that many of the infections involve the barriers which the innate immune system defends.
Signs and symptoms of peripheral neuropathy oftentimes lead to the initial diagnosis of diabetes mellitus. According to research, long-standing elevations in blood sugar appear to cause damage to nerve fibers through a number of pathways.
Insulin-related Signs and Symptoms of Diabetes
Diabetes signs and symptoms that relate to insulin are the result of inadequate secretion of insulin or resistance to it. In either case the resulting reduction or absence of glucose entry into cells is the cause of most of the signs and symptoms. An exception though is the signs and symptoms of ketoacidosis which are partly due to deficient direct action of insulin on fat cells. The main insulin signs and symptoms of diabetes mellitus related to the direct or indirect actions of insulin are the following:
- weight loss
- feelings of generalized weakness
The increase craving for food which occurs with untreated or uncontrolled diabetes is due to deficient glucose in cells. All brain cells don’t need insulin to utilize glucose but the ones in the hunger center of the hypothalamus of the brain do. According to animal studies, when the amount of glucose in them is below normal they send out chemical signals which stimulate hunger. Additionally, the reduced glucose in the cells of the satiety center of the brain causes a decrease in their function to suppress appetite.
The actions of insulin which have a bearing on weight are the stimulation of anabolism and inhibition of catabolism. When insulin is lacking or deficient in its action the synthesis of fat tissue and the buildup of protein in muscle are less. At the same time, the breakdown of fat in adipose tissue and protein in muscle tissue are increased. The net result is weight loss or an underweight BMI. Weight loss due to this imbalance between buildup and breakdown is more common in type 2 diabetics.
Weight loss can also be a sign of type 1 diabetes but individuals with it are more likely to be underweight at the time of diagnosis. The reason for the latter is probably the fact that marked insulin deficiency develops early on with type 1 disease. This would cause an imbalance favoring breakdown over buildup. The result would be the failure to reach a normal weight.
The lack of sufficient glucose in muscle cells can account for the fatigue and generalized sense of weakness which many diabetics experience. After all, glucose is the main source of energy for cells.
Diabetic ketoacidosis symptoms and signs
Many of the signs and symptoms due to high blood sugar and insulin deficiency or resistance are present with DKA, but they are often more pronounced. Some additional ones usually associated with it are the following:
- abdominal pain
- a fruity smell to the breath
- a decreased appetite
- deep and rapid breathing (Kussmaul breathing)
- a rapid heart rate
- mental confusion
Nausea, vomiting, abdominal pain, decreased appetite and confusion are due to the toxic effects of the ketone bodies. The fruity odor to the breath is a result of increased acetone per se in the body. The rapid breathing is the body’s attempt to compensate for the acid buildup. The rapid heart rate might be due to excessive fluid loss, ketone bodies or a triggering cause such as infection. Fever might also be present if infection is a trigger. Some of the symptoms listed above, except for the breath odor, might also be due to the DKA trigger if there is one.