Doctor's Notes on Diabetes (Mellitus, Type 1 and Type 2)
Diabetes (type 1 and type 2) is a disease where the body’s ability to produce or respond to the hormone insulin is impaired. Type 1 diabetes is when the body either stops insulin production or produces too little insulin to regulate blood glucose levels. It is usually diagnosed in children or adolescents. Symptoms may develop quickly. Other signs of type 1 disease may include urinary tract infections, dehydration and nausea/vomiting; untreated type 1 can cause coma or death. Type 2 diabetes is when the body is partially or completely unable to respond to insulin. It is usually diagnosed in adults (45 years and older); symptoms often develop very gradually. Signs and symptoms common to both types include excessive thirst, excessive hunger, excessive urination, fatigue and weight loss. Type 2 diabetes, untreated, can lead to nerve damage, blindness, kidney failure, hyperglycemic hyperosmolar nonketotic syndrome (extremely high levels of blood glucose, causing coma or death) and heart disease.
Type 1 diabetes is an autoimmune disease where the body’s immune system attacks the pancreatic cells that make insulin. Type 2 diabetes causes are less clear; however, such factors as genetics, obesity, high fat levels in the blood and the diet, high blood pressure, sedentary lifestyle, ethnicity, birthing a baby weighing more than 9 lbs. and aging may play a role in type 2 development.
Diabetes (Mellitus, Type 1 and Type 2) Symptoms
Symptoms of type 1 diabetes are often dramatic and come on very suddenly.
- Type 1 diabetes is usually recognized in childhood or early adolescence, often in association with an injury or illness (such as a virus or urinary tract infection).
- The extra stress can cause diabetic ketoacidosis (DKA).
Symptoms of type 2 diabetes are often subtle and may be attributed to aging or obesity.
- A person may have type 2 diabetes for many years without knowing it.
- People with type 2 diabetes can develop the hyperglycemic hyperosmolar nonketotic syndrome.
- Type 2 diabetes can be precipitated by steroids and stress.
- If not properly treated, type 2 diabetes can lead to complications such as blindness, kidney failure, heart disease, and nerve damage.
Common symptoms of both type 1 and type 2 diabetes include:
- Fatigue, or feeling constantly tired: In diabetes, the body is inefficient and sometimes unable to use glucose for fuel. The body switches over to metabolizing fat, partially or completely, as a fuel source. This process requires the body to use more energy. The end result is feeling fatigued or constantly tired.
- Unexplained weight loss: People with diabetes are unable to process many of the calories in the foods they eat. Thus, they may lose weight even though they eat an apparently appropriate or even an excessive amount of food. Losing sugar and water in the urine and the accompanying dehydration also contributes to weight loss.
- Excessive thirst (polydipsia): A person with diabetes develops high blood sugar levels, which overwhelms the kidney's ability to reabsorb the sugar as the blood is filtered to make urine. Excessive urine is made as the kidney spills the excess sugar. The body tries to counteract this by sending a signal to the brain to dilute the blood, which translates into thirst. The body encourages more water consumption to dilute the high blood sugar back to normal levels and to compensate for the water lost by excessive urination.
- Excessive urination (polyuria): Another way the body tries to rid the body of the extra sugar in the blood is to excrete it in the urine. This can also lead to dehydration because a large amount of water is necessary to excrete the sugar.
- Excessive eating (polyphagia): If the body is able, it will secrete more insulin in order to try to manage the excessive blood sugar levels. With type 2 diabetes, the body resists the action of insulin. One function of insulin is to stimulate hunger. Therefore, higher insulin levels lead to increased hunger. Despite eating more, the diabetic person may gain very little weight and may even lose weight.
- Poor wound healing: High blood sugar levels prevent white blood cells, which are important in defending the body against bacteria and also in cleaning up dead tissue and cells, from functioning normally. When these cells do not function properly, wounds take much longer to heal and become infected more frequently. Long-standing diabetes also is associated with thickening of blood vessels, which prevents good circulation, including the delivery of enough oxygen and other nutrients to body tissues.
- Infections: Certain infections -- such as frequent yeast infections of the genitals, dental infections, skin infections, and frequent urinary tract infections -- may result from suppression of the immune system by diabetes and by the presence of glucose in the tissues, which allows bacteria to grow. These infections can also be an indicator of poor blood sugar control in a person known to have diabetes.
- Altered mental status: Agitation, unexplained irritability, inattention, extreme lethargy, or confusion can all be signs of very high blood sugar, ketoacidosis, hyperosmolar hyperglycemia nonketotic syndrome, or hypoglycemia (low sugar). Thus, any of these in a diabetic patient merit the immediate assessment of blood glucose. Call your health-care professional or 911 for immediate attention by a medical professional.
- Blurry vision: Blurry vision is not specific for diabetes but is frequently present with high blood sugar levels.
Diabetes (Mellitus, Type 1 and Type 2) Causes
Type 1 diabetes: Type 1 diabetes is an autoimmune disease. The body's immune system specifically attacks the cells in the pancreas that produce insulin.
- A predisposition to develop type 1 diabetes may run in families, but genetic causes (a positive family history) are much more common for type 2 diabetes.
- Environmental factors, including common and unavoidable viral infections, may also contribute to type 1 diabetes.
- Type 1 diabetes is most common among people of non-Hispanic, Northern European descent (especially Finland and Sardinia), followed by African Americans, and Hispanic Americans. It is relatively rare among people of Asian descent.
- Type 1 diabetes is slightly more common in men than in women.
Type 2 diabetes: Type 2 diabetes has strong genetic links, so type 2 diabetes tends to run in families. Several genes have been linked to type 2 diabetes, and many are under study related to type 2 diabetes. Risk factors for developing type 2 diabetes include the following:
- High blood pressure
- High triglyceride (fat) levels in the blood
- Gestational diabetes or giving birth to a baby weighing more than 9 pounds
- High-fat diet
- High alcohol intake
- Sedentary lifestyle
- Obesity or being overweight
- Ethnicity, particularly when a close relative had type 2 diabetes or gestational diabetes. Certain groups (such as African Americans, Native Americans, Hispanic Americans, and Japanese Americans) have a greater risk of developing type 2 diabetes than non-Hispanic whites.
- Aging: Increasing age is a significant risk factor for type 2 diabetes. Risk begins to rise significantly at about age 45 years, and rises considerably after age 65 years.
People with diabetes know that carb-counting is important. That’s because carbohydrates (carbs) have a big impact on your blood sugar. But does it matter what carbs you’re counting? Absolutely. Not all carbs are equal. While you want to keep an eye on your total carb intake, it’s important to remember that some carbs are better for your overall health.
Carbs can be one of three things: sugars, starches, or fibers. Sugar can be found naturally, for example in milk and fruit, but it’s the added sugar you really want to avoid. Added sugar is what you’ll find in a cookie for example, but it’s often snuck into processed foods to preserve them and make them taste better. So it’s wise to steer clear of processed foods. Try to get most of your carbs from fiber and load up on the healthy carbs found in high-fiber foods like whole grain products and vegetables.
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.