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.