Learning about diabetes can be overwhelming, but understanding the basics of the disease and its complications is crucial for patients, caregivers, and medical students alike. In this article, we’ll break down the essentials of diabetes mellitus, including the differences between type 1 and type 2 diabetes, and dive into the serious complication known as diabetic ketoacidosis (DKA).
What is Diabetes Mellitus?
Diabetes mellitus is a chronic medical condition where the body struggles to move glucose (a type of sugar) from the bloodstream into the cells. This results in high blood glucose levels while the body’s cells are starved for energy, even though glucose is abundant in the blood.
The Role of Insulin and Glucagon
The body regulates blood glucose levels using two key hormones:
- Insulin: Lowers blood glucose by helping cells absorb glucose.
- Glucagon: Raises blood glucose by prompting the liver to release stored glucose.
Both hormones are produced in the pancreas within clusters of cells called the islets of Langerhans. Insulin is secreted by beta cells, while glucagon is secreted by alpha cells.
Types of Diabetes Mellitus
Diabetes mellitus is broadly classified into two main types: Type 1 and Type 2.
Type 1 Diabetes Mellitus
What Causes Type 1 Diabetes?
Type 1 diabetes is an autoimmune disease where the body’s own immune system attacks and destroys the insulin-producing beta cells in the pancreas. This process is driven by T cells that have lost “self-tolerance” and mistakenly target beta cell antigens.
Genetic Factors
A major genetic component involves the human leukocyte antigen (HLA) system—specifically, the HLA-DR3 and HLA-DR4 genes. While these genes increase the risk, not everyone with them develops diabetes.
Symptoms of Type 1 Diabetes
Uncontrolled type 1 diabetes leads to four classic symptoms:
- Polyphagia: Excessive hunger due to cells being starved of energy.
- Glycosuria: Glucose in the urine as high blood sugar spills into the kidneys.
- Polyuria: Excessive urination because glucose draws water into the urine.
- Polydipsia: Excessive thirst caused by dehydration from polyuria.
Weight loss is also common, as the body breaks down fat (lipolysis) and muscle for energy.
Treatment
People with type 1 diabetes require lifelong insulin therapy to regulate blood glucose and allow their cells to use glucose for energy.
Type 2 Diabetes Mellitus
Type 2 diabetes, which accounts for about 90% of all diabetes cases, involves insulin resistance—where the body’s cells don’t respond properly to insulin—or a relative lack of insulin production. (Note: The article focuses more on type 1, but it’s important to recognize the distinction.)
Diabetic Ketoacidosis (DKA): A Serious Complication
What is Diabetic Ketoacidosis?
Diabetic ketoacidosis (DKA) is a potentially life-threatening complication, most commonly associated with type 1 diabetes. It occurs when the body, lacking insulin, breaks down fat for energy, leading to the production of ketone bodies (acetoacetic acid and beta hydroxybutyric acid).
How Does DKA Happen?
Without insulin, glucose can’t enter cells, so the body turns to fat for fuel. The liver converts fatty acids into ketone bodies, which are acidic. This process acidifies the blood—a condition known as ketoacidosis.
Key Features of DKA
- Kussmaul Respiration: Deep, labored breathing as the body tries to expel carbon dioxide and reduce blood acidity.
- Electrolyte Imbalance: Acidic blood leads to increased potassium outside cells (hyperkalemia), but overall body potassium stores drop over time.
- High Anion Gap: Due to the accumulation of ketoacids in the blood.
Triggers of DKA
DKA can develop even in people receiving insulin therapy, especially during periods of stress (such as infection). Stress hormones like epinephrine increase glucagon, tipping the balance and causing a cascade leading to DKA.
Key Takeaways
- Diabetes mellitus is characterized by high blood sugar due to issues with insulin production or response.
- Type 1 diabetes is an autoimmune disorder leading to insulin deficiency, while type 2 diabetes involves insulin resistance.
- Classic symptoms of uncontrolled diabetes include polyphagia, glycosuria, polyuria, and polydipsia.
- Diabetic ketoacidosis (DKA) is a dangerous complication, especially in type 1 diabetes, and requires urgent medical attention.
Final Thoughts
Understanding the differences between type 1 and type 2 diabetes, as well as recognizing the signs of DKA, is crucial for effective management and prevention of complications. If you suspect you have symptoms of diabetes or DKA, consult a healthcare professional immediately.
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