Endocrine and Diabetic Complications Overview

Endocrine Overview

• The endocrine system is composed of tissues that secrete hormones, which are chemical messengers that regulate growth and function within the body.

Diabetic Complications

• Autonomic neuropathy includes dizziness and syncope.
• Eye complications include retinopathy, cataracts, and glaucoma.
• Microangiopathy includes cerebral infarcts, hemorrhage.
• Atherosclerosis in the heart includes ischemic heart disease, myocardial infarct.
• Disorders of gastrointestinal motility include delayed gastric emptying, diarrhea, constipation.
• Genitourinary tract complications include bladder stasis and infection, erectile dysfunction in males.
• Nephropathy includes glomerulosclerosis, chronic kidney disease.
• Atherosclerosis in the lower legs includes peripheral vascular disease, gangrene, and infections.
• Somatic neuropathy includes abnormal sensory and motor function, foot ulcers.
• Microvascular, Macrovascular, and Foot ulcers/infection are the major categories of complications.
• Tight control of blood glucose, normal lipid levels, and control of hypertension are essential for preventing diabetic complications.

Diabetic Neuropathies

• Somatic neuropathy (peripheral neuropathy) is characterized by diminished perception of vibration, pain, and temperature, and hypersensitivity to light touch, occasionally with severe burning pain.
• Autonomic neuropathy causes defects in vasomotor and cardiac responses, inability to empty the bladder, impaired motility of the gastrointestinal tract, and sexual dysfunction.

Diabetic Nephropathy

• Leading cause of renal disease.
• Risk factors include predisposition, hypertension, smoking, poor glycemic control, and hyperlipidemia.
• Glomerular effects occur due to basement membrane damage of the blood vessels, leading to increased urine albumin.
• Prevention involves glycemic control, hypertension control, hyperlipidemia treatment, and smoking cessation.

Diabetic Retinopathy

• Leading cause of blindness in diabetes.
• Retinal abnormalities can result in hemorrhage and abnormal blood vessel growth.
• Risk factors and prevention include hypertension, smoking, poor glycemic control, and hyperlipidemia.
• Annual eye examinations are recommended.

Macrovascular Complications

• Includes coronary artery disease, cerebrovascular disease, and peripheral vascular disease.
• Risk factors include obesity, hypertension, hyperglycemia, hyperinsulinemia, and systemic inflammation.
• Aggressive management of cardiovascular risk factors is crucial, particularly in cases of metabolic syndrome.

Foot Ulcers

• The most common complication leading to hospitalization.
• Caused by neuropathy, leading to a lack of sensation to injury, and vascular insufficiency.

Infections

• Infections occur at a higher rate in diabetic patients, impacting soft tissue, osteomyelitis, urinary tract, pyelonephritis, and candidiasis.
• These infections result from impaired circulation (macro and micro), hyperglycemia, and sensory deficits.

Pharmacology for Diabetes

• Primary goal is to prevent long-term complications.
• Tight control of blood glucose level is important.
• Controlling blood pressure and blood lipids is also crucial to prevent chronic complications.

Type I Diabetes

• Physical activity of 150 minutes per week is recommended.
• Insulin replacement is essential.
• Management of hypertension is crucial.
• An ACE inhibitor (e.g., lisinopril) or an ARB (e.g., losartan) can reduce the risk of diabetic nephropathy.
• Dyslipidemia can be managed using statins (e.g., atorvastatin).
• Comprehensive management plan: integrated program of diet, self-monitoring of blood glucose, exercise, and insulin replacement.

Dietary Measures

• No ideal percentage of calories from carbohydrates, fat, or protein has been established.
• Macronutrient distribution for each individual is based on their current eating patterns, preferences, and goals.
• Substituting low-glycemic-load foods (complex carbohydrates) for higher-glycemic-load foods may modestly improve glycemic control.

Type II Diabetes

• Similar management plan to Type I, including comprehensive management of hypertension, nephropathy, retinopathy, neuropathy, and dyslipidemias.
• Glycemic control is achieved through modified diet, physical activity, and drug therapy.

Monitoring Treatment

• Self-Monitoring of Blood Glucose (SMBG) is a key element.
• Common target values: 80-130 mg/dL before meals, < 180 mg/dL one to two hours after meals.
• Continuous glucose monitoring is available through glucose monitoring systems and insulin pumps.

Hemoglobin A1c

• Also known as glycosylated hemoglobin or glycated hemoglobin.
• Provides an index of average glucose levels over the prior two to three months.
• An A1c target of below 7% is generally recommended.
• A goal below 8% may be appropriate for individuals with a history of severe hypoglycemia, limited life expectancy, or advanced microvascular or macrovascular complications.

Insulin

• Preparations: “High alert” agents.
• Sources: Recombinant DNA technology.
  • Human insulin: Identical to insulin produced by the human pancreas.
  • Human insulin analogs: Modified forms of human insulin with the same pharmacologic actions but different time courses.

Insulin Types

• Short-duration, rapid-acting: Insulin lispro, Insulin aspart, Insulin glulisine.
• Short-duration, slower-acting: Regular insulin.
• Intermediate duration: Neutral protamine Hagedorn (NPH) insulin, Insulin detemir.
• Long duration: Insulin glargine.

Short-Duration, Rapid-Acting Insulin

• Insulin Lispro: rapid-acting analog of regular insulin, administered immediately before or after eating.
• Onset: 15-30 minutes after subcutaneous injection.
• Peak: 0.5-2.5 hours.
• Duration: 3-6 hours.

Short-Duration, Slower-Acting Insulin

• Regular insulin: Unmodified human insulin, available in four routes: subQ injection, subQ infusion, IM injection (rare), and oral inhalation (approved but not currently used).
• Effects: Begin in 30 to 60 minutes.
• Peak: 1-5 hours.
• Duration: Up to 10 hours.

Intermediate-Duration Insulin

• Neutral Protamine Hagedorn (NPH): injected twice or three times daily for glycemic control between meals and during the night.
• NPH insulin is the only one suitable for mixing with short-acting insulins.
• Allergic reactions are possible.
• NPH insulins are cloudy suspensions that must be agitated before administration.
• Administered: Subcutaneous injection only.

Long-Duration Insulin

• Insulin Glargine [Lantus]: modified human insulin with a prolonged duration of action (up to 24 hours).
• Dosing: Once-daily subcutaneous injection for adults and children with Type I diabetes and adults with Type II diabetes.
• Never given intravenously.

Insulin Appearance

• Clear, colorless solutions (except for NPH insulins, which are cloudy suspensions).
• Inspect insulin vials and discard any abnormal insulin.

Insulin Concentrations

• Most common: 100 units/mL (U-100).
• Other concentrations: 200 units/mL (U-200), 300 units/mL (U-300), and 500 units/mL (U-500).

Mixing Insulins

• NPH insulin with short-acting insulins.
• Short-acting insulin drawn first (clear before cloudy).

Insulin Administration

• Subcutaneous injection: syringe and needle, pen injectors, jet injectors.
• Subcutaneous infusion: portable insulin pumps and implantable insulin pumps.
• Intravenous infusion.
• Inhalation.

Insulin Storage

• Unopened vials: stored under refrigeration until needed.
• Insulin should not be frozen.
• Opened Insulin: Kept up to one month without significant loss of activity if stored in the refrigerator.
• Keep out of direct sunlight and extreme heat.
• Insulin mixtures in vials: stable for one month at room temperature and three months under refrigeration.
• Mixtures in prefilled syringes: stored in a refrigerator for at least one week, stored vertically with the needle pointing up.

Insulin Therapeutic Uses

• Principal indication: Diabetes mellitus (DM)
• Required: All patients with Type I DM and many patients with Type II DM.
• IV insulin: Used for diabetic ketoacidosis.
• Gestational diabetes.
• Hyperkalemia: Promotes uptake of potassium into cells.
• Helps diagnose: Growth hormone (GH) deficiency.

Achieving Optimal Glucose Control

• Requires careful attention to all elements of the treatment program (diet, exercise, insulin replacement therapy).
• Defined glycemic target.
• Dosing: based on food intake, activity, and stress.
• Self-monitoring of blood glucose: according to the patient’s individualized management plan.
• Patient motivation, education, and participation: Essential for diabetes management success.

Complications of Insulin Treatment

• Hypoglycemia: Blood glucose below 70 mg/dL as insulin levels exceed needs.
• Lipohypertrophy: Accumulation of fat tissue at insulin injection sites.
• Allergic reactions.
• Hypokalemia: Low potassium levels.
• Drug interactions: Hypoglycemic agents, hyperglycemic agents, and beta-adrenergic blocking agents (mask symptoms of hypoglycemia).

Oral Antidiabetic Agents

• Biguanides: Metformin.
• Sulfonylureas: First and second-generation agents.
• Thiazolidinediones (glitazones): Rosiglitazone, Pioglitazone.
• Meglitinides (glinides): Repaglinide, Nateglinide.

Biguanides—Metformin

• Mechanism of action:
  • Inhibits glucose production by the liver.
  • Increases glucose uptake in target tissue.
  • Reduces glucose absorption in the gut.
• Drug of choice for initial therapy in most patients with Type II diabetes.
• Used as monotherapy or in combination with other agents.
• May delay the development of Type II diabetes in high-risk individuals.
• Contraindicated in renal insufficiency.
• Adverse effects: Most common are gastrointestinal (GI) disturbances.
  • Vitamin B12 levels can decrease and should be monitored.
  • Lactic acidosis (rare but potentially fatal complication).
• Drug interactions:
  • Alcohol: Minimize intake to reduce lactic acidosis.
  • Contrast dyes: Discontinue medicine one to two days before dye studies.

Sulfonylureas

• First oral agent available.
• Used as monotherapy or in combination with other agents.
• Mechanism of action:
  • Promotes insulin release from the pancreatic islets.
  • Only for Type II diabetes.
  • First-generation: older agents.
  • Second-generation: more potent, lower doses, fewer and milder drug-drug interactions.
  • Second-generation agents are preferred due to these advantages.
• Major side effects:
  • Hypoglycemia (dose-dependent reduction, regardless of glucose level).
  • Weight gain.
• Drug interactions:
  • Alcohol: Disulfiram-type reaction (palpitations, nausea).
  • Other medicines producing hypoglycemia.
  • Beta-blockers: Mask hypoglycemic responses.

Thyroid Hormones

• Two major functions:
  • Metabolism: Increases metabolism of target cells.
  • Growth and development: Promotes maturation in infancy and childhood.
• Produces two active hormones:
  • Triiodothyronine (T3): Synthetic T3: Liothyronine.
  • Thyroxine (T4, tetraiodothyronine): Synthetic T4: Levothyroxine.

Thyroid Hormone Actions

• Increase in thyroid hormone levels leads to:
  • Metabolic rate increase.
  • Cardiovascular function increase: increased heart rate and contractility.
  • Gastrointestinal function increase: increased motility.
  • Neuromuscular effects: Increased reactivity of the sympathetic nervous system and muscle tone.

Thyroid Function Tests

• Serum thyroid-stimulating hormone (TSH): Screening and diagnosis of hypothyroidism (elevated TSH is an indicator).
• Serum T4 test: Measures total T4 or free T4.
• Serum T3 test: Measures total T3 or free T3.

Hypothyroidism

• Severe deficiency of thyroid hormone.

This quiz explores the functions of the endocrine system and the various complications associated with diabetes. It delves into specific conditions resulting from both microvascular and macrovascular damage due to diabetes, such as neuropathy and nephropathy. Test your knowledge on how these complications affect different body systems.