Understanding Diabetes Mellitus: Causes, Symptoms, and Types

Diabetes is a very common disease, affecting nearly 10 percent of the population. More than 25 percent, or one in four people, over the age of 65 have diabetes. But what exactly is diabetes mellitus? Let's explore this condition through a couple of scenarios.

Joe's Story: A Case of Type 1 Diabetes

Meet Joe, a 15-year-old boy who hasn't been feeling well for the past few months. Joe has been more tired and fatigued than usual, and he has lost some weight despite being a skinny guy to begin with. His mother noticed that Joe has been carrying around a water bottle everywhere and drinking liters of water daily. Joe acknowledges this, saying he has been more thirsty than usual and has been urinating frequently.

Bruce's Story: A Case of Type 2 Diabetes

Now, let's contrast Joe with Bruce, a 45-year-old gentleman. Bruce feels pretty good overall, although he has packed on a few extra pounds around the waist. During his annual physical, the doctor recommends routine screening, which includes checking his blood sugar. Despite having no symptoms, Bruce's blood sugar levels are found to be high.

Understanding Hyperglycemia and Diabetes

Both Joe and Bruce have very high blood sugar, a condition known as hyperglycemia, and are diagnosed with diabetes. But how can such different situations result from the same disease? To answer this question, we need to understand what diabetes mellitus is.

What is Diabetes Mellitus?

Diabetes mellitus is a group of disorders characterized by the body's inability to regulate its blood sugar levels. The main type of sugar the body uses is glucose. This disregulation results in high blood sugar or hyperglycemia.

The Role of Insulin and Glucagon

To get a better idea, let's look at a simple diagram. Imagine a blood vessel with blood flowing through it, containing glucose. Glucose is the body's preferred source of energy, obtained from the foods we eat and stored primarily in the liver.

Two hormones regulate blood sugar levels: insulin and glucagon. When glucose levels are high, the pancreas releases insulin, which stops the release of glucose from the liver into the blood and helps cells absorb glucose. This decreases blood sugar levels. However, when blood sugar levels are low, the pancreas releases glucagon, which causes the liver to release stored glucose into the blood and stops insulin production, increasing blood sugar levels.

What Happens in Diabetes?

In diabetes, insulin is either not produced or not functioning properly. As a result, glucagon's effect is amplified, leading to increased blood glucose levels. Despite high blood sugar levels, glucose can't enter the cells, causing the body to think it's starving.

Starvation in the Face of Plenty: An Analogy

To illustrate, imagine a water main bringing water to houses. If a pipe from the main to a house gets clogged, the house can't receive water despite plenty of water in the main. Similarly, without insulin, glucose can't enter cells despite high blood sugar levels.

Different Types of Diabetes

Diabetes mellitus is a group of diseases with different underlying mechanisms, leading to varied presentations.

Type 1 Diabetes

Joe's case is typical of type 1 diabetes, where the body doesn't produce any insulin, resulting in high blood sugar.

Type 2 Diabetes

Bruce's case is characteristic of type 2 diabetes, where the body produces insulin, but the cells' receptors are not sensitive to it, leading to high blood sugar levels.

Conclusion

Understanding diabetes mellitus requires recognizing the different types and their underlying mechanisms. Whether it's the lack of insulin production in type 1 diabetes or the reduced sensitivity to insulin in type 2 diabetes, both result in hyperglycemia. By understanding these differences, we can better manage and treat this common disease.