Diabetes Mellitus Flashcards
Modern definition of diabetes mellitus
State of premature cardiovascular death that is associated with chronic hyperglycemia and may also be associated with blindness and renal failure
What is the cause of type 1 diabetes mellitus?
Autoimmune destruction of the insulin producing beta cells in the pancreatic islets of Langerhans
What is type 2 diabetes mellitus?
Diabetes usually associated with obesity in which there is metabolic resistance to insulin along with inadequate secretion of insulin
What are the consequences of hyperglycemia in diabetes?
Diabetic retinopathy and renal glomerular changes
What are the 4 Dx criteria for diabetes?
- HbA1c > 6.5% OR
- Fasting Plasma Glucose > 126 mg/dL OR
- 2-h plasma glucose > 200 mg/dL during an oral glucose tolerance test OR
- In a a patient with classic Syx of hyperlgycemia or hyperglycemic crisis, a random plasma glucose > 200 mg/dL
What are the two characteristics of T2DM?
Reduced tissue sensitivity to insulin and inadequate secretion of insulin from the pancreas
What is the cause of hyperglycemia in T2DM?
Failure of Betal cells to meet the body’s increased demand for insulin
What are the three greatest risk factors for T2DM?
- Obesity
- Diet
- Lack of Physical Activity
What is the genetic component of T2DM?
Multifactoral and multigenic inheritance
What is the next step that occurs after insulin resistance?
Increased hepatic glucose production and reduced glucose uptake by peripheral tissues (primarily muscles and adipose tissue)
When do blood glucose levels begin to rise in pre T2DM?
When beta cells fail
What are incretins?
Peptides secreted by the gut in response to meals that increase insulin secretion and decrease glucagon secretion
Describe the function of incretins in T2DM
The incretin effect is markedly reduced
What is the amyloid composed of in T2DM?
Amylin
What is the cause of T1DM?
Autoimmune destruction of the beta cells in the islets of Langerhans
Describe the general metabolic processes that occur in T1DM
Fat preferentially oxidized overproducing ketone bodies causing metabolic ketoacidosis
Hyperglycemia caused by unsuppressed hepatic glucose output and reduced glucose disposal in skeletal muscle and adipose tissue
Glucosuria leading to dehydration
What are two important factors that affect the molecular pathogenesis of T1DM?
Genetic and autoimmunity factors
A lymphocytic infiltrate is seen in and around the islets of Langerhans in a patient with T1DM. What is the Dx?
Insulitis
What is the most characteristic early lesion in the pancrease of T1DM?
Insulitis
What is a histological difference b/w T1 and T2DM?
T2 shows amyloidosis (amylin)
What are typical clinical characteristics of T1DM?
Severe ketoacidosis, polyuria, polydipsia, weightloss
What are the two major pathogenetic factors leading to the uvascular complications of diabetes?
Severity and chronicity of hyperglycemia
What is protein glycation and what role does it play in diabetes?
Glucose covalently bonds to proteins due to hyperglycemia. This can in turn cause proteins to function abnormally.
Describe what occurs in the aldose reductase pathway in hyperglycemia.
Glucose is shunted down this pathway creating sorbitol and depleting NADPH shifting the redox status
What accounts for more than half of the deaths among adult diabetics?
Cardiovascular disease (athersclerotic HD and ischemic stroke)
What are the three hypotheses contributing to cardiovascular disease in diabetes?
- Direct effects of diabetes or hyperglycemia on arterial wall
- Side effects of diabetic Tx
- Exacerbation of general risk factors for atherosclerosis (dyslipoproteinemia, HTN, hypercoagulability)
What are characteristic uvascular changes in diabetes?
Arteriolosclerosis and capillary basement membrane thickening
What is the typical pathology that occurs in a kidney with diabetic nephropathy?
Kimmelstiel-Wilson disease or nodular glomerulosclerosis
What are the most common nervous sytem effects of diabetes?
Neuropathy affecting sensory and autonomic nerve dysfn.
Why are UTIs common in diabetes?
Glucose in the urine provides enriched culture medium
What is a fatal fungal lung infection associated with diabetes?
Mucormycosis
