Diabetes Mellitus

Don’t confuse diabetes insipidus with diabetes mellitus:

Diabetes insipidus has to do with a lack of ADH (vasopressin) produced in the posterior pituitary gland and the -pressin drugs were the solution.  The treatment was the -pressin drugs to replace the ADH.  Sound unfamiliar? Need a refresher? Check out the post about posterior pituitary hormones.

Diabetes Mellitus on the other hand has to do with the lack of insulin or the bodies reaction to the insulin.

Glucose Control

Let’s first review glucose control in the body.

What increases the blood glucose level?

• The intake of glucose will increase blood sugar.
• Glucagon converts glycogen in the liver to glucose, increasing blood sugar.
• Corticosteroids cause gluconeogenesis, to make sure the heart and brain have enough energy in a stressful situation and blood sugar gets elevated.

What decreases the blood glucose level?

• Insulin produced in the pancreas.
• Exogenous/injectable insulin.
• Oral hypoglycemic agents.

If any of this is unfamiliar, read how blood sugar levels are regulated in the body.

Insulin Dependent Diabetes Mellitus (Type 1 aka Juvenile Onset)

An insulin dependent diabetic (also known as type 1) is typically juvenile onset diabetes as it starts at a young age. This individual has a different appearance than the type 2 individual. If you look at the physical appearance, you’ll see they have less weight and are underweight. As opposed to the type 2 diabetic that is typically overweight.

The pancreas of a type-1 diabetic is not producing an adequate amount of insulin so they will require insulin.  A type 1 diabetic can lead to the most severe form of complications, such as diabetic ketoacidosis. When these patients are admitted into the ICU, they have ketone bodies forming in their bloodstream and their blood pH is dropping. The normal pH is about ~7.35 and we could find these patients with a pH below 7.0 and if that goes on for too long, they will die. A very unique form of therapy will be utilized: An insulin drip will be administered with an IV bag. (This is why it’s called insulin dependent).

• Also known as: juvenile onset and Type 1
• Most severe form of DM
• Complications include diabetic ketoacidosis
• Decreased synthesis and release of insulin from pancreas

Non-Insulin Dependent Diabetes Mellitus (Type 2 Diabetes; Adult onset)

This is known as adult onset diabetes and type 2 diabetes. This diabetes usually develops later on in life and they are usually overweight.  It’s not the diabetes that makes them overweight, but the chronic excess consumption of fats leads them to being diabetic.

There’s a couple theories behind this (at least): They have functional beta cells in the pancreas that could produce insulin but there’s a decreased production amount of it AND/OR the peripheral cells have lost their sensitivity to the insulin. So those are the two theories we have to work with at the moment. The brain and heart don’t require insulin to drive sugar into the cell but the rest of the body does.

These group of patients will be put on a special diet and their weight must be brought down but that alone rarely works. These group of individuals may be called “non-insulin dependent” but they may take insulin to bring their insulin levels up, so that’s why it’s more commonly called type 2 diabetes.

Recap

• Also known as Adult Onset DM and Type 2 DM
• Usually overweight
• Functional beta cells in pancreas and/or decrease sensitivity of peripheral cells to insulin
• No ketoacidosis associated

Consequences of Diabetes Mellitus

If you’re not in diabetic ketoacidosis, there’s usually no consequences. You may run to the bathroom a lot more than usual because the sugar is osmotticaly dragging water along with it into the urine.  However in the long term, if the blood sugar level is out of control, there’s very grave consequences such as:

• Cardiac Disease
• Renal Disease
• Blindness
• Peripheral Vascular Disease
• Polyneuropathy (losing sensation and feeling)
• Gangrene
  • Gangrene is an infection caused by an anaerobic organism. Usually it starts at the very bottom of their feet. There’s lots of wear and tear at the bottom of the feet. Skin is the protectant between your body and the outside world. Peripheral vascular disease (a lack of oxygen and nutrients) exists in these individuals meaning there’s a lack of oxygen and nutrients circulating in these extremities.  Eventually from the wear and tear, a tiny hole will develop in their foot.  Anaerobic bacteria will sneak into that hole and it will grow there.  It will work through the skin layer and once it hits the muscle, there isn’t an antibiotic available to treat this infection and the only option is amputation to stop the spread of the infection.
  • Some individuals don’t seek medical care and it goes up the leg and a below the knee amputation may occur. Some individuals still don’t seek medical care and it will go even further up and they may have an above the knee amputation.
  • Why do the individuals wait so long to come in? Because they probably have polyneuropathy and can’t feel that anything is wrong. As a result these individuals are instructed to check their feet at least 3-4x a week and visually inspect to see if there’s anything going on.