Physician Assistant Exam: Type 1 and Type 2 Diabetes
As a more common problem, the Physician Assistant Exam (PANCE) will expect you to know the difference between type 1 and type 2 diabetes. Diabetes mellitus (DM) is due to abnormal insulin metabolism in the body. In type 1 diabetes mellitus, the pancreas doesn’t produce insulin, and in type 2, the body resists the actions of insulin.
In North America, the incidence and prevalence of diabetes mellitus has reached epidemic proportions. Diabetes is a leading cause of kidney disease and dialysis, and it increases the risk of developing coronary artery disease, hyperlipidemia, and peripheral vascular disease. It also increases total body inflammation.
Shared traits of type 1 and type 2 diabetes
Diabetes mellitus is diagnosed a few different ways:
The most common way is registering a fasting blood sugar of > 126 mg/dL two different times.
A postprandial (after-eating) glucose level of 200 mg/dL on two occasions is indicative of diabetes.
If someone is having symptoms of the three p’s — polyphagia (eating a lot), polydipsia (drinking a lot), and polyuria (voiding a lot) — diabetes is likely present.
Both type 1 and type 2 diabetes mellitus can affect the eyes (diabetic retinopathy), nerves (diabetic neuropathy), and kidneys (diabetic nephropathy). Here are some key points about these conditions:
Retinopathy: Because of the risk of retinopathy, a person with diabetes should see an ophthalmologist annually. Tight blood sugar control is important in reducing ophthalmologic risk.
Nephropathy: Diabetic nephropathy is the leading cause of kidney disease in this country (as Rich, a kidney doctor, can attest). It’s also the leading reason people with kidney disease need dialysis. About a third of people with type 1 diabetes go on to develop kidney disease; only about 10 percent of people with type 2 diabetes develop kidney disease.
Neuropathy: The neuropathy that diabetes causes can be debilitating. It’s typically a peripheral neuropathy, usually in a stocking-glove distribution. The condition can be so bad that it affects the person’s ability to walk and even drive a car, especially if he or she has no sensation of the feet touching the pedals.
Diabetic neuropathy is much more than a peripheral neuropathy; neuropathies can affect other areas of the body. Autonomic neuropathy related to diabetes can be difficult to treat. Basically, the sitting or supine blood pressure is high but drops big time when the person stands up.
Diabetic gastroparesis is also a significant problem with both types of diabetes. Problems with gastric and intestinal motility can lead to malnutrition as well as problems with labile blood sugars, due to the inconsistent digestion of carbohydrates.
Type 1 diabetes
In type 1 diabetes mellitus, the beta cells of the pancreas don’t produce insulin. Experts think that the failure of the beta cells to produce insulin may be an autoimmune phenomenon, perhaps stimulated by a viral process. Either way, the person needs insulin. Because type 1 diabetes is a failure of the body to make insulin, it’s diagnosed at a very young age.
When you think about the initial presentation of someone with type 1 diabetes, remember the three p’s: polyphagia, polydipsia, and polyuria. Despite all the eating and drinking, though, the person keeps losing weight. Without insulin, the body is in a catabolic state.
Here are the general points concerning type 1 diabetes:
The beta cells of the pancreas are not making insulin. Insulin levels are low, and the levels of the hormone glucagon (made by the gamma cells of the pancreas) are very high.
In addition to adhering to an insulin regimen, someone with type 1 diabetes needs to follow their blood glucose levels closely. Patients are often asked to keep a blood glucose diary and bring it with them during their clinic visits. You may ask a patient to check either preprandial or postprandial glucose levels.
Following a diabetic diet is important. Understanding how to count carbohydrates is also important, especially for people adjusting an insulin regimen. In general, roughly half of the diet should contain complex carbohydrates, and about a quarter of the diet should come from fat. The remaining quarter should be protein, although you may need to restrict protein if proteinuria or kidney disease is present.
A glycosylated hemoglobin (or Hgb A1c) is a test that measures how “sweet” the blood has been over the past 3 months. It’s been used to monitor compliance with an insulin or medication regimen, although some guidelines have proposed that the A1c also be used to diagnose diabetes. The goal Hgb A1c level is < 6.5 percent.
Treatment of type 1 diabetes is the administration of insulin, because the person’s pancreas isn’t secreting insulin. Many different insulin regimens are out there, and many seek to mimic what the insulin does physiologically. In people without type 1 diabetes, insulin is continually being secreted, and the secretion increases during a carbohydrate meal.
Type 2 diabetes
Type 2 diabetes mellitus is due to the body’s resistance to the actions of insulin. The pancreas is secreting insulin, but because of insulin resistance, the insulin can’t get into the cells to do its job. Experts think that the beta cells of the pancreas just wear out — the workload of pumping out insulin and trying to lower the blood glucose levels is too much.
The most common reason for insulin resistance is obesity. Unlike type 1 diabetes, type 2 diabetes is typically found in middle-aged or older adults, but with the current obesity epidemic in the United States, you see younger people being diagnosed with type 2 diabetes.
Metabolic syndrome isn’t diabetes per se, but it clearly increases the risk of developing type 2 diabetes. You’ll no doubt see a question about this in some form or fashion. Metabolic syndrome has several components: impaired fasting glucose, large waist circumference, hypertriglyceridemia with low cholesterol, and elevated blood pressure. Any three of these components are enough to diagnose metabolic syndrome.