AdvancedPathophysiologyExam238pages

Advanced Pathophysiology Overview

Endocrine System Overview

• The endocrine system includes various endocrine glands that produce hormones and secrete them into surrounding fluids.

Types of Hormones

Peptide Hormones

• Derived from protein structures, water-soluble.

• Synthesized as prohormones and stored in secretory granules.

• Example: Proinsulin (synthesizes 60-70 units/day, uses ~50%).

Amine Hormones

• Derived from the amino acid tyrosine (e.g. thyroid hormones T3 and T4).

Steroid Hormones

• Fat-soluble and derived from cholesterol.

• Not stored; released as they are produced.

Alterations of Anterior Pituitary

Pituitary Adenomas

• Slow-growing tumors in the pituitary gland, mostly benign. Can be classified as:

  • Benign Adenoma

  • Invasive Adenoma

  • Carcinomas

• Most common: Prolactinoma, which secretes prolactin causing amenorrhea, infertility, nonpuerperal milk production in women, erectile dysfunction, and osteopenia in men.

Alterations of the Posterior Pituitary

Diabetes Insipidus

• Condition of inadequate antidiuretic hormone (ADH) leading to high serum osmolarity and low urine osmolarity.

Syndrome of Inappropriate Antidiuretic Hormone (SIADH)

• Overproduction of ADH, causing hyponatremia and weight gain (not due to edema).

Pancreatic Dysfunction

• Diabetes Mellitus involves the dysfunction of the pancreas with insulin being the key hormone for fuel storage.

• Fuel sources managed include:

  • Carbohydrates/Glucose - Rapid energy source.

  • Fats/Triglycerides - Major energy needs.

  • Proteins/Amino Acids - Stimulate protein synthesis.

Diabetes Mellitus Types

Type 1 Diabetes Mellitus (DMT1)

• Genetic predisposition (90%) with environmental factors.

• Autoantibodies against beta cells.

• C-Peptide test for beta cell function.

• Complication: Diabetic Ketoacidosis (DKA).

Type 2 Diabetes Mellitus (DMT2)

• Caused primarily by obesity and associated with insulin resistance.

• Complication: Hyperosmolar Hyperglycemic Nonketotic State (no ketones).

• Initial signs include increased post-prandial glucose and later loss of basal control.

Insulin Adjustment Effects

Somogyi Effect

• Hypoglycemia followed by rebound hyperglycemia, prevalent in type 1 diabetes.

• Check blood glucose at 3 AM if low; decrease insulin dosage at night.

Dawn Phenomenon

• Early morning glucose elevation without nocturnal hypoglycemia due to growth hormone elevation.

• Check 3 AM glucose; if high, adjust insulin dosage or timing.

Thyroid Function

• Thyroid hormone affects every cell, influencing metabolic rate.

• Gland makes, stores, and releases thyroid hormone on demand.

• Iodine from the GI tract is crucial for synthesizing thyroid hormones (T4 and T3).

• Operates on a negative feedback system.

Hypothyroidism vs. Hyperthyroidism

Hypothyroidism

• Most commonly caused by Hashimoto's autoimmune condition, leading to lower thyroxine.

• TSH: High; T3/T4: Low.

Hyperthyroidism

• Most commonly caused by Graves Disease, causing excessive thyroxine production.

• TSH: Low; T3/T4: High.

Parathyroid Function

• PTH and Vitamin D maintain plasma calcium levels.

• Hyperparathyroidism leads to excessive calcium.

• Hypoparathyroidism results in low calcium levels.

Adrenal Gland Overview

Adrenal Zones

• Zona Glomerulosa: Produces aldosterone.

• Zona Fasciculate: Produces cortisol.

• Zona Reticularis: Produces sex hormones.

• Medulla: Responsible for catecholamine production (e.g., pheochromocytoma).

Hyperaldosteronism

• Causes hypertension, hypokalemia, and hypernatremia; assessed via aldosterone to renin ratio.

Hypoaldosteronism

• Hyperkalemia with no alternative cause.

Glucocorticoids and Cushing's Syndrome

Cushing Syndrome

• Chronic excessive cortisol regardless of cause, often from glucocorticoid administration.

Cushing Disease

• Excess pituitary ACTH from adenomas affecting cortisol secretion.

Addison's Disease

• Results in low levels of mineralocorticoids (aldosterone), glucocorticoids (cortisol), and sex hormones.

• Symptoms include extreme fatigue, low blood pressure, hyperpigmentation, and salt craving.

Cancer Overview

Tumor Markers

• Hormones, enzymes, genes, and antigens in blood/other fluids that indicate cancer presence or progression (e.g., PSA, CA-125).

Signs and Symptoms of Cancer

• Common symptoms include fatigue, pain, cachexia, anemia, leukopenia, and thrombocytopenia.

Specific Cancer Types

Leukemias

• Malignant disorders characterized by excessive production of leukocytes leading to bone marrow overcrowding.

• Classified by cell origin: Myeloid or lymphoid, and progression: acute or chronic.

Immune System Basics

Innate Immunity

• First line: skin; second line: inflammatory response.

Adaptive Immunity

• Involves B and T lymphocytes responding to pathogens.

Hypersensitivity Reactions

• Type 1: IGE mediated (allergies).

• Type 2: Antigen/antibody surface marker reaction.

• Type 3: Immune complex diseases (e.g., lupus).

• Type 4: Delayed response not antibody-related (e.g., TB test).

Cardiovascular Overview

Cardiac Function

• Right heart: pulmonary circulation; left heart: systemic circulation.

• Systole (ventricular contraction) and diastole (atrial contraction) describe hearts' operating states.

Myocardial Infarction

• STEMI (ST elevation indicates extensive myocardial damage), NSTEMI (elevation without ST segment changes).

Valvular Diseases

• Aortic stenosis and mitral regurgitation lead to significant heart complications.

Vascular Pathology

Aneurysms

• True aneurysms affect all layers of the arterial wall; false aneurysms are hematomas.

Peripheral Disease

• Chronically obstructed arteries leading to ischemia and pain during exertion.