Diabetes Mellitus self study Flashcards
What is Type 1 diabetes mellitus (DM) caused by?
What are the typical symptoms of Type 1 DM?
Explain the effects of type 1 DM on the body and why they occur.
A patient with typical Type 1 diabetes presents with
- Weight loss
- Polyuria
- Polydipsia
The metabolic derangement that is present can become life threatening in a very short time (days). There are also long term vascular and other complications (years)
Type 1 diabetes (insulin dependent diabetes mellitus, IDDM, formerly known as juvenile onset diabetes) Is caused by a lack of insulin because of destruction of B-cells (almost undoubtedly by an auto-immune response). This makes Type 1 diabetes a relatively homogeneous condition. In the absence of insulin, glucose cannot be taken up by the insulin sensitive transporters of muscle and adipose cells and cells “starve” even though there is glucose in the blood. Metabolic derangement is widespread as the substrate storing effects of insulin are absent and the actions of the other counter regulatory hormones (especially of glucagon) are unopposed. Consequently, gluconeogenesis, proteolysis and fatty acid release from adipose tissue are increased resulting in high circulating glucose, amino acid and fatty acid levels. Glucose produced by gluconeogenesis adds to the already high circulating glucose levels. Amino acids are used for gluconeogenesis; fatty acids are used to supply energy for gluconeogenesis and to produce ketone bodies (alternative energy source) by the liver.
attached is pg 188 of course notes
Because of the high levels of ketone body production in type 1 DM, ____ _____ is common.
metabolic acidosis
How is Type 1 DM diagnosed?
How are the metabolic consequences of insulin lack reversed?
In the presence of high circulating blood glucose levels, the occurrence of polyuria, polydipsia, and polyphagia (excessive hunger) is strongly suggestive of diabetes.
- Elevated fasting blood glucose is, of course, diagnostic. 2. A glucose tolerance test is frequently ordered to confirm a diagnosis.
The metabolic consequences of insulin lack are reversed by exogenous insulin.
The goal in treatment of diabetes is to maintain blood glucose concentration as normal as possible for as much time as possible.
What 3 thing does this require balancing?
Requires balancing:
a. daily diet
b. energy expenditure (activity level/exercise)
c. administration of exogenous insulin
Insulin preparations with different time courses and duration of action can be combined to meet individual needs and physiology.
All of the long-term complications of diabetes are thought to be consequences of _______.
hyperglycemia
What are the chronic complications of DM? Why do they occur?
a. One mechanism contributing to the pathology that results is osmotic damage caused by alternative utilization of glucose by certain cells, including high level of sorbitol production by the polyol pathway.
b. Another mechanism is non-enzymatic glycosylation of intra- and extracellular as well as membrane proteins. Advanced glycosylation end-products are formed that influence protein and cell functions.
c. One of the proteins that can be glycosylated is hemoglobin (Hb). The glycosylated is called HbA1c and it is used as a measure of the long term (3 months) average of blood glucose concentration. It is thus the best measure of the success of long-term blood glucose maintenance.
If the proper balance between diet, energy expenditure and insulin administration is NOT maintained there is a danger of hypoglycemia and its consequences.
What are the consequences/symptoms of hypoglycemia? How may it be quickly reversed?
Episodic monitoring of blood glucose levels and episodic administration of insulin is not as effective in maintaining homeostasis as is the body’s physiological mechanisms.
a. Very low blood glucose concentration is life threatening within a very short time.
b. Hypoglycemia can be quickly reversed by oral ingestion of glucose, and diabetics may keep different sources of glucose within close reach for such emergencies.
What is the fundamental issue in Type 2 DM? What additional issue may be present in this disease?
One fundamental problem is that target cell response to insulin is abnormal (sometimes referred to as “insulin resistance”).
A second problem can occur with the B-cells (too few of them or they are unable to secrete insulin in a normal manner when a stimulus for release is present).
What are the 2 types of insulin resistances that may be present in type 2 DM?
What are the consequences of each?
Type 2 diabetes is thus a much more heterogeneous problem than is Type 1 diabetes. There can be hepatic insulin resistance and peripheral insulin resistance of fat and muscle cells. With peripheral insulin resistance, the cells of the body become less sensitive to the glucose-lowering effects of insulin and thus there is a failure of the target tissues to take up glucose and lower circulating glucose levels. Normal blood levels of insulin become inadequate to keep blood glucose in a normal range (relative insulin deficiency). The liver helps regulate glucose levels by reducing its secretion of glucose in the presence of insulin. Hepatic insulin resistance results in reduced glycogen synthesis and storage and a failure to suppress glucose production and release into the blood.
What are the risk factors for type 2 DM? (7 of them)
It is clear that there is a genetic component to the occurrence of Type 2 diabetes (or at least the susceptibility to its occurrence) and that obesity is a contributing factor
Risk factors for type 2 diabetes:
- Genetics
- Obesity
- Diet
- Age (especially over 45)
- Ethnicity/race (prevalence is greater for Hispanics, blacks, Native Americans, and Asians)
- History of gestational diabetes (elevated blood glucose that occurs in non-diabetic pregnant women)
- The presence of metabolic syndrome, an increasingly common condition characterized by the presence of a group of metabolic risk factors in one person
What risk factors are included in metabolic syndrome?
a. Abdominal obesity
b. Atherogenic dyslipidemia (blood fat disorders — high triglycerides, low HDL cholesterol and high LDL cholesterol — that foster plaque buildups in artery walls)
c. Elevated blood pressure
d. Mild insulin resistance or glucose intolerance
e. Prothrombotic state (i.e., high fibrinogen or plasminogen activator inhibitor–1 in the blood)
f. Proinflammatory state (i.e., elevated C-reactive protein in the blood)
What are the treatment options for type 2 diabetics?
Many (BUT not ALL) Type 2 diabetic patients can control their hyperglycemia by controlling their diets and reducing their weight.
There are now a number of oral drugs that can reduce the hyperglycemia of Type 2 diabetics.
Some Type 2 diabetic DO REQUIRE insulin injections.
Why do Type 2 diabetics typically not experience ketoacidosis?
Type 2 diabetics do not typically experience ketoacidosis (and the dire consequences of this condition). It is thought that they produce enough insulin to prevent the release of glucose by the liver (but not enough to promote glucose uptake to avoid hyperglycemia).
Describe the following parameters for Type 1 and Type 2 DM:
synonyms
age at diagnosis
body weight
islet antibodies?
insulin requirement
insulin secretion
insullin resistance
