Diabetes Mellitus (DM) is defined by high glucose (sugar) in the blood (“mellitus” means “honey”). It was known to ancient Greeks (who tasted their urine to make the diagnosis). There are two main types of diabetes, Type-1 (DM-1) and Type-2 (DM-2). However, some people with diabetes can’t be easily categorized (so some clinicians say “DM-1.5”).
DM-1 usually begins in childhood (but not always!). It’s an auto-immune disease; for unknown reasons, the immune system attacks & destroys beta-cells of the pancreas. These cells make insulin, which our bodies use to move glucose from the blood stream into all our other organs’ cells (except brain cells, which manage on their own). So glucose levels in the blood are high, and many types of cells can’t function well.
DM-2 usually begins in adulthood. The pancreas still makes plenty of insulin, but the body becomes resistant to it, so the insulin doesn’t work well. This is usually caused by obesity; with today’s obesity epidemic, more and more people are developing DM-2 in childhood. The result is the same as with DM-1, lots of sugar in the blood, not enough for our cells.
The main difference between DM-1 and DM-2 is that patients with DM-1 have no insulin, so the only treatment is to inject it. Patients with DM-2 can take a variety of medications that decrease insulin resistance, or that nudge the pancreas to make more insulin. Of course, the best treatment for DM-2 is weight-loss, along with diet control and exercise; together, such strategies can completely control (or sort of “cure”) diabetes.
Another difference is that without any insulin, patients with DM-1 can get ketoacidosis. Too much acid accumulates in the blood, which can progress very quickly, and be fatal. Ketoacidosis usually occurs when a person first gets DM-1, since they’re not on treatment then (or later, if they stop insulin). It also occurs when a DM-1 patient gets an infection, or major stress, or becomes pregnant.
If there’s never been ketoacidosis, we don’t usually care too much whether an adult patient has DM-1 or DM-2. We start them on treatment we normally would for DM-2. If oral medication is no help, they may have DM-1, but at any rate, we depend on insulin. If diet & oral medication helps but not enough, we add insulin. In my practice, the thinner the patient, the more I encourage them to begin insulin soon.
Diabetes antibody tests don’t help a lot to distinguish DM-1 from DM-2, because there are several, & many people who will never develop diabetes may test positive. A test for C-peptide only helps if the protein isn’t found, meaning no insulin in the body, meaning DM-1. But we can’t do the test if the patient has already begun insulin, & many DM-1 patients still have C-peptide early on. The main way we try to distinguish is: if patient is Fat, they’re likely DM-2. If they’re Thin (& weight loss won’t help), we can still try oral medications, but they’re likely to need insulin.
When glucose is very high, patients may feel symptoms such as thirst, causing them to drink a lot, and pee a lot. There may be fatigue, vision may become blurry. But unfortunately, most patients with abnormally high glucose have no symptoms at all. I say “unfortunately,” because many think that since they don’t feel bad, nothing’s wrong, so they ignore their diet & don’t take their medications. Then, after 10-20 years, permanent complications develop:
- Kidney failure (requiring dialysis for life)
- Heart attacks & strokes
- Foot ulcers that don’t heal, get gangrene, require amputation
- Impotence (for some, this is the scariest of all)
If you want an idea, search Google images for “diabetes foot gangrene”.
We determine if diabetes is well-controlled or not by lab tests for glucose (sugar). We can see how it is on an empty stomach, or after a meal. But the best measurement is called glycolated (or glycosylated) hemoglobin A1C, which we call just “A1C” for short. Ranges are as follows:
- A1C <5.7 = No problems with glucose
- 5.7 – 6.4 = More risk of developing diabetes
- 6.5 – 7.0 = Diabetes, well-controlled
- 7.0 – 7.5 (or 8.0) = Not well-controlled (but OK for the elderly)
- A1C >8.0 = Poorly-controlled diabetes
We usually diagnose “diabetes” if either the fasting glucose is >126, or the A1C is >6.5, on two occasions (or one of each). People also talk of “pre-diabetes” if fasting glucose is 100 – 126, or if the A1C is 5.7 – 6.4. But in my mind, that medicalizes a condition that may never cause problems. So for those values, I simply say, “More risk of someday getting diabetes than other people.” Young people need to control their glucose more than the older, because they have more years to develop complications. In pregnancy, for the sake of the baby, glucose levels need to be as low as possible (“gestational diabetes” means diabetes during pregnancy, based on lower glucose values, usually treated with insulin, but then no diabetes after birth).
Then there’s Hypoglycemia, which means low blood sugar. This can only be caused by too much insulin, or too much of certain oral diabetic medications (but not all of them). Hypoglycemia can be immediately life-threatening, so it’s often a fine line between controlling diabetes, and avoiding very low glucose (<50 = too low, <30 = critical, risk of seizures or death). Symptoms of Hypoglycemia include:
- While Awake: Sudden attack of shakiness, sweating, heart palpitations
- While Awake: Mental dullness or confusion (especially after many years of insulin)
- Asleep: Nightmares, awaking drenched in sweat, bed partner reports very restless sleep
Treatment for Hypoglycemia is 1) immediately eat glucose tablets or hard candy; 2) then eat a decent meal. Family members should have the injectable antidote glucagon they learn to use. Nighttime hypoglycemia is the most dangerous of all, because you’re asleep & can’t realize it. There’s a phenomenon “dead in bed” which speaks for itself.
On a happier note, it’s usually not so hard for people with diabetes to learn to control their sugar levels, and live long happy lives. The main factor is that they be motivated.