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NR601 FINAL EXAM STUDY GUIDE
Week 5: Glucose metabolism disorders
Types of DM
- Type 1 - severe insulin deficiency resulting in reduction or absence of
functioning beta cells in the pancreatic islets of Langerhans. Autoimmune disorder which immune system attacks beta cells of the pancreas. This leads to hyperglycemia due to altered metabolism of lipids, carbs, and proteins. Initial s/s of hyperglycemia. Subjective findings- polyuria, polydipsia, nocturnal enuresis and polyphagia with paradoxical weight loss, visual changes and fatigue. Objective-dehydration (poor skin turgor and dry mucous), wt loss despite normal/increase appetite, reduction in muscle mass. DKA-fatigue, cramping, abnormal breathing
**3 main ways someone with diabetes will present before diagnosed:
Acute, subacute, and asymptomatic.--Acute- This is the most severe presenting situation and can be life threatening for both type I and type II diabetes. This individual becomes very sick over a relatively short period of time, usually only a couple of days. Now symptoms will include things like nausea, vomiting, and abdominal pain and this often results in severe dehydration, and as such the individual may even become confused or unconscious as a result. In type I diabetes, this is known as diabetic ketoacidosis, or DKA for short. And it is how about 30% of individuals with type I diabetes will initially present before diagnosis. In type II diabetes, the acute presentation has a much longer name. It's known as hyperosmolar nonketotic state, or HHNS for short, and it's much less common than DKA as it's the initial presentation for only about 2% of individuals with type II diabetes. Now the difference between DKA and HHNS has to do with the difference between the underlying mechanisms of type I diabetes and type II diabetes. Now the most important difference is that in DKA the individual will become acidotic due to the production of ketoacids, hence the name diabetic ketoacidosis as opposed to hyperosmolar nonketotic state where ketoacids are not produced. 1 / 4
2 --Subacute- mild to moderate presentation that occurs over a period of weeks to months. And these individuals or maybe someone close to them notice that they are generally just not feeling as well as they normally do and they may experience symptoms of fatigue, increased thirst, frequent urination, or even weight loss. Now, once again this can occur with either type I or type II diabetes. And in type I diabetes, this is the most common form of presentation before diagnosis, accounting for about 70% of individuals with type I diabetes. In type II diabetes, this is also common, however the predominant symptoms are a little bit more vague and weight loss is less common.--Asymptomatic- individuals with diabetes can present is through asymptomatic screening tests. So type II diabetes affects nearly 10% of the population, and due to this high prevalence, potentially severe complications, and the relative ease of treatment, most adults, especially those with the risk factors of type II diabetes should be routinely screened for the disease. And this is the most common means by which type II diabetes is diagnosed. However, it's rare for the diagnosis of type I diabetes as routine screening for type I diabetes is not usually performed.
- Type 2 - Type 2 DM is characterized by the abnormal secretion of insulin,
resistance to the action of insulin in the target tissues, and/or an inadequate response at the level of the insulin receptor.in Type II diabetes as well as drug-induced and gestational diabetes, the pancreas continues to secrete insulin. However, it's the cells throughout the body that are unable to adequately respond to it. So in a sense, these mechanisms inhibit the second step in the insulin pathway. And this is known as insulin resistance, which can be thought of as A patient may, however, present with pruritus, fatigue, neuropathic complaints such as numbness and tingling, or blurred vision. More likely to have HHNS (Hyperosmolar hyperglycemic nonketotic syndrome) which is similar to DKA.a relative insulin deficiency. 2 / 4
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- Prediabetic - fasting glucose consistently elevated above the normal range
but less than 100-125. Impaired glucose tolerance (IGT) state of hyperglycemia where 2 hr post glucose load glycemic level is 140-199.RANDOM glucose test cannot be used to diagnose pre-diabetes. Needs to be fasting or two-hour glucose tolerance test. A1c greater than 5.7%.Fasting blood glucose greater than 100 but less than 126. OGTT greater than 140 but less than 200.Diagnostic criteria- Diagnosis is made in combination of BOTH presentation and diagnostic tests. So first, if an individual has symptoms of diabetes, whether acute or subacute, then only one positive test, either the blood glucose or the hemoglobin A1C is necessary for the diagnosis of diabetes mellitus. However, if the individual is asymptomatic, then a diagnosis of diabetes mellitus requires two positive tests that are separated by at least one week of time.there are 4 lab-based criteria to confirm DM: A1C, random plasma glucose, fasting plasma glucose, and 2-hr post load plasma glucose • AIC of 6.5 or higher=diabetes • of hyperglycemia or a hyperglycemic crisis • Fasting plasma glucose level of 126 or higher on TWO occasions(fasting is defined as no caloric intake for at least 8 hrs • 2 hour glucose tolerance test- 2-hour post load plasma glucose level of 200 or higher during an OGTT, following consumption of a glucose load containing the equivalent of 75g of anhydrous glucose dissolved in water (OGTT is also used to screen for diabetes during pregnancy) *** In the absence of unequivocal hyperglycemia results should be confirmed by repeat testing on a new blood sample without delay, preferably using the same type of test.***
• *All above-but confirmation of type 2 diabetes mellitus requires: two
fasting blood glucoses ≥126 mg/dL or two random blood glucoses ≥200 mg/dL.• You do not screen for type 1 diabetes but you do screen for type 2 if an individual is overweight or obese, regardless of age, and for all adults aged Random plasma glucose level of 200 WITH classic symptoms 3 / 4
4 45 years and older. Tests should be repeated at a minimum of 3 year intervals • . As the blood glucose levels in the body rise, this is sensed by the beta cells in the pancreas which secrete the hormone insulin. And insulin then acts on cells throughout the body to take the glucose from the blood up and remove it from the bloodstream or store it in the form of glycogen and thus lower the blood glucose levels. So in diabetes mellitus, regardless of the type, this insulin pathway is not working properly, therefore the body is not able to lower blood glucose levels. And this results in increased blood glucose levels known as hyperglycemia, which is the characteristic finding of diabetes mellitus. Now a side effect of hyperglycemia is a proccess known as glycosylation, which is the non-enzymatic attachment of glucose to proteins. And one protein that this occurs with that is of importance in diabetes mellitus is the protein hemoglobin which is located within red blood cells. And in the presence of hyperglycemia, glucose will attach itself to an abnormally high percentage of hemoglobin within the red blood cells.And this is known as glycosylated hemoglobin, or hemoglobin A1C, and it's the hyperglycemia and the hemoglobin A1C that are tested for in the blood to aid in the diagnosis of diabetes mellitus Initial Treatment-
Type 1- FIRST LINE: INSULIN. The initial goal of treatment for type 1 DM is
to normalize the elevated blood glucose level. This is best accomplished by
intensive insulin regimens to achieve the following goals: plasma glucose
levels of 80 to 130 mg/dL before meals, peak postprandial (1–2 hours after the beginning of a meal) glucose levels of less than 180 mg/dL, and an A1C below 7% for adults with type 1 DM. A comprehensive treatment plan requires exogenous insulin, frequent self-monitoring of blood glucose (SMBG), medical nutrition therapy, regular exercise, continuing education in prevention and treatment of diabetic complications, and the periodic reassessment of treatment goals. (Type 1A: insulin dependent, Type 1B: variably insulin dependent). The ADA Standards of medical care in diabetes states that the majority of patients with type 1 DM, should be treated with multiple daily injections of prandial insulin and daily basal insulin or with a continuous subcutaneous insulin infusion pump.INITIATION OF INSULIN THERAPY IN NEWLY DIAGNOSED TYPE 1 DM,
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