T4 - Endocrine Assessment Flashcards
What is necessary for maintaining a normal glucose level?
A balance between glucose usage and endogenous production or dietary carbohydrate intake.
Which organ is the primary source of endogenous glucose production?
The liver, via glycogenolysis and gluconeogenesis.
What percentage of the glucose released by the liver is metabolized by insulin-insensitive tissues?
70-80%.
When does a transition from exogenous glucose usage to endogenous production occur after eating?
2-4 hours after eating, when glucose usage exceeds production.
What is fundamental for maintaining normal blood glucose during the transition from exogenous usage to endogenous production?
Diminished insulin production.
What hormones make up the glucose counterregulatory system?
Glucagon, epinephrine, growth hormone, and cortisol.
What is the primary role of glucagon in glucose regulation?
Glucagon stimulates glycogenolysis and gluconeogenesis, while inhibiting glycolysis.
What is the prevalence of diabetes mellitus among adults?
Diabetes mellitus affects 1 in 10 adults.
What are the primary causes of diabetes mellitus?
It results from either an inadequate supply of insulin or an inadequate tissue response to insulin.
What are the consequences of untreated diabetes mellitus?
Increased circulating glucose levels leading to eventual microvascular and macrovascular complications.
What causes Type 1a diabetes?
Type 1a diabetes is caused by T-cell–mediated autoimmune destruction of β cells within pancreatic islets, resulting in minimal or absent circulating insulin levels.
How does Type 2 diabetes develop?
Type 2 diabetes results from defects in insulin receptors and post-receptor intracellular signaling pathways, and it is not immune mediated.
What percentage of all diabetes mellitus cases does Type 1 diabetes account for?
Type 1 diabetes accounts for 5-10% of all diabetes mellitus cases.
At what age is Type 1 diabetes usually diagnosed?
Type 1 diabetes is usually diagnosed before age 40.
What is the exact autoimmune cause of Type 1a diabetes?
The exact autoimmune cause of Type 1a diabetes is unknown.
What precedes the onset of symptoms in Type 1 diabetes?
A long pre-clinical period (9-13 years) of B-cell antigen production precedes the onset of symptoms.
How much B-cell function is typically lost before hyperglycemia occurs in Type 1 diabetes?
At least 80-90% of B-cell function is lost before hyperglycemia ensues.
What percentage of all diabetes mellitus cases does Type 2 diabetes account for?
Type 2 diabetes accounts for over 90% of all diabetes mellitus cases.
How has the prevalence of Type 2 diabetes changed in recent years?
Type 2 diabetes is increasingly seen in younger patients and children over the past decade.
How long before diagnosis is Type 2 diabetes typically present but underrecognized?
Type 2 diabetes is normally present 4-7 years before it is diagnosed.
What occurs in the initial stages of Type 2 diabetes?
Insensitivity to insulin on peripheral tissues leads to increased pancreatic insulin secretion.
What are the three main abnormalities seen in Type 2 diabetes?
Increased hepatic glucose release due to a reduction in insulin’s inhibitory effect on the liver, impaired insulin secretion, and insufficient glucose uptake in peripheral tissues.
What are some causes of insulin resistance in DM2?
Causes include abnormal insulin molecules, circulating insulin antagonists, and insulin receptor defects.
What acquired and contributing factors are associated with insulin resistance in DM2?
Obesity and sedentary lifestyle.
Diabetes Diagnostic Criteria chart
How does exercise and weight loss benefit individuals with diabetes?
Exercise and weight loss can improve hepatic and peripheral insulin sensitivity, leading to better blood glucose control.
What is the primary mechanism of action of Metformin in diabetes management?
Metformin, a biguanide, enhances glucose transport into tissues.
What are the effects of Metformin on triglyceride (TGL) and low-density lipoprotein (LDL) levels?
Metformin decreases triglyceride (TGL) and low-density lipoprotein (LDL) levels.
What is the mechanism of action of Sulfonylureas in diabetes management?
Sulfonylureas stimulate insulin secretion and enhance glucose transport into tissues.
Why are Sulfonylureas not effective in the long term for some diabetic patient
Due to diabetic progressive loss of B cell function, Sulfonylureas are not effective in the long term.
What are some common side effects of Sulfonylureas?
Common side effects include hypoglycemia, weight gain, and potential cardiac effects.
Treatment chart
In what cases is insulin necessary for diabetes management?
Insulin is necessary in all cases of Type 1 diabetes (DM1) and in approximately 30% of cases of Type 2 diabetes (DM2).
What are the categories of insulin based on duration of action?
Insulin is categorized into rapid-acting (e.g., Lispro, Aspart),
short-acting (regular),
basal/intermediate-acting (e.g., NPH, Lente), and
long-acting (e.g., Ultralente, Glargine).
What is the most dangerous complication associated with insulin therapy?
Hypoglycemia is the most dangerous complication.
What factors can exacerbate hypoglycemia?
Exacerbating factors include alcohol (ETOH), metformin, sulfonylureas, ACE inhibitors (ACE-I’s), monoamine oxidase inhibitors (MAOI’s), and non-selective beta-blockers (BB’s).
What can repetitive hypoglycemic episodes lead to?
Repetitive hypoglycemic episodes can lead to “hypoglycemia unawareness,” where the patient becomes desensitized to hypoglycemia and doesn’t show autonomic symptoms. Neuroglycopenia may ensue, leading to symptoms such as fatigue, confusion, headache, seizures, coma
What is the treatment for hypoglycemia?
PO or IV glucose (may give SQ or IM if unconscious)
Plasma insulin levels graph and chart
What is the mortality rate associated with decompensated DM?
Decompensated DM carries a mortality rate of 1-2%.
In which type of diabetes is Diabetic Ketoacidosis (DKA) more common, and what often triggers it?
DKA is more prevalent in DM1 and is frequently triggered by infection or illness.
What happens when glucose levels exceed the renal reabsorption threshold in diabetes?
Elevated glucose levels surpass the renal reabsorption threshold, leading to osmotic diuresis and subsequent hypovolemia.
What metabolic coupling in the liver can result in excessive production of ketoacids during DKA?
The tight metabolic coupling of gluconeogenesis and ketogenesis in the liver can lead to overproduction of ketoacids during DKA.
Features of DKA chart
What is the loading dose and infusion rate for insulin in diabetic emergencies?
The loading dose is 0.1 units/kg of Regular insulin, followed by a low-dose infusion at 0.1 units/kg/hr.
What electrolytes should be supplemented in diabetic emergencies?
Electrolyte supplements should include potassium (K+), phosphorus, magnesium (Mg), and sodium.
What caution should be exercised when correcting glucose levels in diabetic emergencies?
Correction of glucose without simultaneous correction of sodium may result in cerebral edema.
What are the key characteristics of Hyperosmolar Hyperglycemic State (HHS)?
HHS is characterized by severe hyperglycemia, hyperosmolarity, and dehydration. It typically occurs in individuals with DM2 over 60 years old. It evolves over days to weeks with persistent glucosuric diuresis.
What symptoms are associated with Hyperosmolar Hyperglycemic State (HHS)?
Symptoms include polyuria, polydipsia, hypovolemia, hypotension, tachycardia, and organ hypoperfusion. Hyperosmolarity can lead to coma. Patients may exhibit some degree of acidosis but not to the extent seen in DKA.
How is Hyperosmolar Hyperglycemic State (HHS) treated?
Treatment involves fluid resuscitation, insulin bolus and infusion, and electrolyte supplementation. The mortality rate ranges from 10-20%.
What characterizes microvascular complications in diabetes?
Microvascular complications involve nonocclusive microcirculatory disease with impaired blood flow autoregulation.
What are the key features of diabetic nephropathy?
Diabetic nephropathy affects 30-40% of DM1 and 5-10% of DM2 patients, leading to end-stage renal disease (ESRD). Kidneys develop glomerulosclerosis, arteriosclerosis, and tubulointerstitial disease. Symptoms include hypertension, proteinuria, peripheral edema, and decreased glomerular filtration rate (GFR).
How does the progression of diabetic nephropathy affect electrolyte balance?
When GFR falls below 15-20, kidneys no longer effectively clear potassium, leading to hyperkalemia and acidosis. ACE inhibitors can slow the progression of proteinuria and the rate of GFR decline.
What treatment options are available for end-stage renal disease (ESRD) in diabetic patients?
Treatment options for ESRD include hemodialysis (HD), peritoneal dialysis (PD), and kidney transplant. Combined kidney-pancreas transplant may prevent recurrent nephropathy.
What characterizes Peripheral Neuropathy in diabetes?
Peripheral Neuropathy typically presents as a distal symmetric diffuse sensorimotor polyneuropathy.
- Starts in the toes and feet and progressing proximally. It involves the loss of large sensory and motor fibers, reducing light touch and proprioception
- Loss of small nerve fibers, decreasing pain and temperature perception, leading to neuropathic pain
- Ulcers can develop from unnoticed mechanical and traumatic injuries, resulting in significant morbidity from recurrent infections and amputation wounds.
What are the features and treatment options for Peripheral Neuropathy?
Treatment involves optimal glucose control, NSAIDs, antidepressants, and anticonvulsants.
What are the characteristics and management strategies for Retinopathy in diabetes?
Retinopathy is characterized by microvascular changes, including vessel occlusion, dilation, increased permeability, and microaneurysms.
Visual impairment can range from color loss to blindness.
Glycemic control and blood pressure control can reduce the progression of retinopathy.
What characterizes Autonomic Neuropathy in diabetes?
Autonomic Neuropathy can affect any part of the Autonomic Nervous System (ANS) and is caused by damaged vasoconstrictor fibers, impaired baroreceptors, and ineffective cardiovascular activity.
What cardiovascular symptoms are associated with Autonomic Neuropathy?
Cardiovascular symptoms include abnormal heart rate control and vascular dynamics, resting tachycardia, loss of heart rate variability, and progression to orthostatic hypotension and dysrhythmias.
What gastrointestinal symptoms and treatments are associated with Autonomic Neuropathy?
Gastrointestinal symptoms include decreased gastric secretions and motility, eventually leading to gastroparesis. Symptoms include nausea, vomiting, early satiety, bloating, and epigastric pain. Treatment involves glucose control, consuming small meals, and using prokinetics.
What cardiovascular considerations are important in autonomic neuropathy?
Autonomic neuropathy can lead to silent ischemia. Stress tests may be necessary for patients with multiple cardiac risk factors and poor exercise tolerance.
Why is meticulous attention to hydration and renal function crucial in autonomic neuropathy?
Hydration status should be carefully monitored, nephrotoxins should be avoided, and renal blood flow should be preserved to prevent complications in the renal system.
How does autonomic neuropathy impact perioperative care?
Autonomic neuropathy predisposes patients to perioperative dysrhythmias and hypotension, requiring careful management during surgical procedures.
What considerations should be made regarding gastrointestinal symptoms and autonomic neuropathy?
Gastroparesis may increase the risk of aspiration regardless of NPO (nothing by mouth) status. Patients with autonomic neuropathy should avoid hypoglycemic medications and noninsulin injectables.
What characterizes Insulinoma?
Insulinoma is a rare, benign pancreatic islet tumor that secretes insulin. It occurs more frequently in women than men, typically in the 50s-60s age range.
How is Insulinoma diagnosed?
Diagnosis is based on Whipple triad: hypoglycemia with fasting, glucose levels below 50 with symptoms, and symptom relief with glucose intake.
Diagnosis is confirmed by inappropriately high insulin levels during a 48-72 hour fast.
What are the treatment options for Insulinoma?
Preoperatively, diazoxide may be used to inhibit insulin release from beta cells.
Other treatment options include verapamil, phenytoin, propranolol, glucocorticoids, and octreotide.
Surgery is curative.
What precautions should be taken during surgery for Insulinoma?
Intraoperative hypoglycemia can occur, followed by hyperglycemia once the tumor is removed. Tight glycemic control is essential during and after surgery.
What are the anatomical features of the thyroid gland?
The thyroid gland weighs approximately 20g and consists of two lobes joined by an isthmus.
It is located anteriorly and laterally to the trachea, with the upper border just below the cricoid cartilage.
The parathyroid glands are situated on the posterior aspect of each lobe.
How is the thyroid gland innervated?
The thyroid gland is innervated by the adrenergic and cholinergic nervous systems, with a rich capillary network permeating the gland.
What important structures are in close proximity to the thyroid gland?
The recurrent laryngeal nerve and the external motor branch of the superior laryngeal nerve are in close proximity to the thyroid gland.
What are the components and functions of the thyroid gland?
The thyroid gland is composed of follicles filled with thyroglobulin, an iodinated glycoprotein and substrate for thyroid hormone synthesis. Additionally, it contains parafollicular C cells, which produce calcitonin.
How is the availability of thyroid hormones affected by iodine?
Production of normal quantities of thyroid hormones depends on the availability of exogenous iodine, primarily obtained from the diet.
What is the process of thyroid hormone synthesis?
Iodine is reduced to iodide in the gastrointestinal tract, rapidly absorbed into the blood, and transported into thyroid follicular cells.
The binding of iodide to thyroglobulin is catalyzed by an iodinase enzyme, yielding inactive monoiodotyrosine and diiodotyrosine.
About 25% of monoiodotyrosine and diiodotyrosine undergo coupling with thyroid peroxidase to form active triiodothyronine (T3) and thyroxine (T4).
What factors contribute to the stability of thyroid hormone levels?
The thyroid gland contains a large store of hormones and has a low turnover rate, which protects against depletion if hormone synthesis is impaired.