Chapter 12.
Diabetes Mellitus
Diabetes mellitus (DM), commonly known as diabetes, is a group of metabolic disorders characterized by the inability of the body to regulate the blood sugar (glucose) levels over a prolonged period. The sugars from food flow through the blood to provide energy for the cells. The extra glucose is stored by the liver. When there is a high level of sugars in the bloodstream, the pancreas (actually, the beta cells from the Islets of Langerhans in the pancreas) secretes insulin, a hormone which causes the liver to stop releasing sugars, and helps the cells to absorb the sugars. These two processes will help get rid of the surplus of sugars in the blood.
If the glucose level goes too low in the bloodstream, the alpha cells from the Islets of Langerhans in the pancreas produce glucagon, a hormone which stimulates the liver to release more glucose in the blood, making it available to the cells.
Insulin and glucagon have antagonistic (opposite) effects on the blood sugar level.
Symptoms of high blood sugar include frequent urination, increased thirst, and increased hunger. If left untreated, diabetes can cause many complications.
Acute complications can include diabetic ketoacidosis, hyperosmolar hyperglycemic state, or death. Serious long-term complications include cardiovascular disease, stroke, chronic kidney disease, foot ulcers, and damage to the eyes.
Diabetes is due to either the pancreas not producing enough insulin, or the cells of the body not responding properly to the insulin produced. There are three main types of diabetes mellitus:
Type 1 diabetes results from the pancreas’s failure to produce enough insulin due to loss of beta cells.
Type 2 diabetes begins with insulin resistance, a condition in which cells fail to respond to insulin properly. As the disease progresses, a lack of insulin may also develop. The most common cause is a combination of excessive body weight and insufficient exercise.
Gestational diabetes is a form of Type 2, and occurs when pregnant women without a previous history of diabetes develop high blood sugar levels.
Prevention and treatment involve maintaining a healthy diet, regular physical exercise, a normal body weight, and avoiding use of tobacco. Control of blood pressure and maintaining proper foot care are important for people with the disease.
Type 1 diabetes must be managed with insulin injections.
Type 2 diabetes may be treated with medications with or without insulin. Insulin and some oral medications can cause low blood sugar. Weight loss surgery in those with obesity is sometimes an effective measure in those with type 2 diabetes.
Gestational diabetes usually resolves after the birth of the baby.
Please watch the following videos:
- What is diabetes mellitus? | Endocrine system diseases | NCLEX-RN | Khan Academy (about 9 minutes)
- Pathophysiology – Type I diabetes | Endocrine system diseases | NCLEX-RN | Khan Academy (about 11 minutes)
- Pathophysiology – Type II diabetes | Endocrine system diseases | NCLEX-RN | Khan Academy (about 8 minutes)
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