Diabetes Flashcards
What is diabetes mellitus?
A chronic disorder characterized by the impaired metabolism of glucose.
Diabetes is associated with what two conditions?
hyperglycemia and insulin deficiency
Describe Type I diabetes.
absolute insulin deficiency, secondary to autoimmune destruction of beta cells by T lymphocytes
FH less common
Describe Type II diabetes.
Relative insulin deficiency secondary to decreased response of peripheral tissue to insulin (insulin resistance) and beta cell dysfunction resulting in inadequate insulin secretion.
FH common
What are the differences histologically between Type I and Type II?
Type I: Histologically translated into chronic inflammation of the pancreatic islets.
Type II: Histologically, there is a decrease in beta cell mass and deposition of amyloid in the islets.
What percentage of diabetes is Type I vs Type II?
5% Type I Diabetes Mellitus
95% Type II Diabetes Mellitus
What is the age of onset for Type I?
Onset usually childhood and adolescence– bimodal distribution (ages 4-6, 10-14).
What is the age of onset for Type II?
Onset usually greater that age 40, however may occur earlier with obesity.
Clinical Presentation of Type I Diabetes
- Relative abrupt onset (days to weeks)
- Polyuria (increased urination) hypovolemia
- Polydypsia (increased thirst)
- Polyphagia (increased appetite)
- Weight loss
- Sudden onset of ketoacidosis, often precipitated by an acute illness.
Why does ketoacidosis occur in Type I Diabetes?
The lack of insulin and corresponding unopposed effect of glucagon leads to increased release of glucose via glycogenolysis and gluconeogenesis. Unopposed glucagon also leads to the release of free fatty acids from adipose tissue (lipolysis), producing ketone bodies and triggering the metabolic acidosis.
Clinical Presentation of Type II Diabetes
- Very slow onset, may be asymptomatic for years
- (often relatively mild) polyuria, polydipsia, polyphagia, weight loss, fatigue, skin changes. Patients may also present with chronic complications of diabetes
How do you screen for diabetes mellitus?
- Type I: no routine screening indicated
- Type II:
- Fasting plasma glucose (FPG)
- Glycosylated hemoglobin (A1C) every 3 yrs starting at 45 (earlier if obese BMI >25 and have one or more risk factors)
Ranges for Gycosylated Hemoglobin (A1C):
Normal : /= 6.5%
Ranges for Fasting Plasma Glucose (FPG):
Normal: /= 126
What are the chronic complications of both Type I and Type II diabetes?
- Retinopathy
- Neuropathy (Symmetric polyneuropathy/autonomic)
- Nephropathy
- Macroangiopathy (accelerated Atherosclerosis)
- Skin Abnormalities
Describe retinopathy for diabetes.
Retinopathy is a microvascular complication of diabetes. The small arteries of the retina are progressively damaged resulting in aneurysms, occlusions, leakage, and swelling. This initial stage of retinopathy is called the non-proliferative stage. The more advanced form of the disease is called proliferative diabetic retinopathy. Retinopathy becomes proliferative when abnormally fragile new blood vessels grow (proliferate) in the retina or the optic disc. This process is called neovascularization. These fragile new blood vessels often rupture, leading to hemorrhage and vision loss.
Describe neuropathy for diabetes.
An estimated 50 percent of patients with diabetes have some form of neuropathy. Although neuropathy is occasionally a presenting feature of diabetes, the highest rates of neuropathy are among people who have had the disease for at least 25 years. A wide variety of neuropathies can occur. Among the most common presentations are symmetric polyneuropathy and autonomic neuropathy.
Symmetric polyneuropathy
Distal symmetric sensorimotor polyneuropathy is the most common type of diabetic neuropathy and is often considered synonymous with the term diabetic neuropathy. It is characterized by a progressive loss of distal sensation correlating with loss of sensory axons, followed, in severe cases, by motor weakness and motor axonal loss. Classic “stocking-glove” sensory loss is typical in this disorder.
Autonomic Neuropathy
Diabetic autonomic neuropathy is a common complication of diabetes. Among the problems that can occur are postural hypotension, gastroparesis, constipation/diarrhea, and sexual dysfunction.
Describe Nephropathy.
Diabetic nephropathy is the leading cause of End Stage Renal Disease (ESRD) in the US. Diabetic nephropathy usually begins with microalbuminuria (renal loss of albumin). The disease progresses with a gradual decline in renal function
Macroangiopathy (Accelerated Atherosclerosis)
Atherosclerosis involving the coronary, cerebral, and peripheral (lower extremity) arteries is the predominant cause of diabetes-related mortality. Diabetes is an independent risk factor for accelerated atherosclerosis. Its association with vascular disease is not solely attributable to an increased prevalence of other recognized vascular risk factors such as hypertension, smoking, and dyslipidemia. Probably the most critical aspect of long term diabetes management is reducing the risk of atherosclerosis.
Skin Abnormalities.
Skin changes related to diabetes may sometimes be the presenting symptom in Type 2 diabetes.
Diabetic dermopathy, also known as shin spots, is a skin condition usually found on the lower legs of people with diabetes. It is thought to result from changes in the small blood vessels that supply the skin and from minor leakage of blood products from these vessels into the skin. Diabetic dermopathy is the most common skin finding in people with diabetes.
Other common dermatologic findings in diabetics include acanthosis nigricans and necrobiosis lipoidica diabeticorum.
