Inflammation: Acute and Chronic Responses

Inflammation

• A vascularized tissue's response to cell damage
• Characteristics: Inflammatory mediators, fluid, and leukocytes move from blood to extravascular tissue
• Purpose: Minimize damage, remove damaged tissue, promote new tissue growth
• Causes: Trauma, surgery, infection, hypoxia, ischemia

Acute Inflammation

• Short duration and self-limited
• Neutrophils are the first cells to arrive

Chronic Inflammation

• Lasts for weeks, months, or years
• Characterized by mononuclear cells, lymphocytes, and fibroblasts

Vascular Phase of Acute Inflammation

• Hemodynamic changes in the small blood vessels at the site of injury
• Vasodilation: Increased capillary pressure, fluid outflow, swelling, pain, and functional impairment
• Vasoconstriction: Minimizes blood loss, maintains blood flow, and blood pressure
• Vascular Changes:
  • Immediate transient response: Minor injury
  • Immediate sustained response: More severe injury, lasts several days, damages vessels
  • Delayed hemodynamic response: Increased capillary permeability, 4 to 24 hours after injury (e.g., sunburn)

Cellular Phase

• White blood cell activation
• Two types of leukocytes in acute inflammation:
  • Granulocytes: Neutrophils, basophils, and eosinophils
  • Monocytes: Largest white blood cell type

Phagocytosis

• Five steps:
  • Chemotaxis: Cell migration towards chemical stimulus
  • Adherence and Opsonization: Attachment to and recognition of foreign material
  • Ingestion: Receptor activation, engulfment of targeted material
  • Digestion: Fusion with lysosomes, breakdown of engulfed material
  • Intracellular Killing: Removal of foreign material

Cardinal Signs of Inflammation

• Rubor (redness)
• Tumor (swelling)
• Calor (heat)
• Dolor (pain)
• Functio laesa (loss of function)

Systemic Signs of Inflammation

• Fever
• Malaise (feeling unwell)

Inflammatory Mediators

• Increase body's response to injury
• Chemotaxis: Direct migration of a cell in response to a chemical stimulus

Plasma-Derived Mediators

• Kinin system: Causes pain
• Clotting system: Forms clots to prevent infection spread and stop bleeding
• Complement system: Causes vasodilation

Chemical Mediators

• Histamine: Released in response to trauma and immune reactions
• Serotonin: Similar actions to histamine

Arachidonic Acid Metabolites

• Prostaglandins: Induce inflammation, similar effects to histamine
• Leukotrienes: Similar functions to histamine

Nitric Oxide

• Produced by various cells, plays a role in inflammation
• Relaxes smooth muscle in vessel walls
• Regulates leukocyte movement

Inflammatory Exudates

• Serous exudate: Watery fluid, low protein content, plasma entering the site
• Hemorrhagic exudate: Severe tissue injury, blood vessel damage
• Membranous exudate: Forms on mucus membrane surfaces
• Purulent exudate: Contains pus
• Fibrinous exudate: Contains large amounts of fibrin

Granulomatous Inflammation

• Associated with:
  • Foreign bodies (splinters, sutures)
  • Microorganisms causing tuberculosis, syphilis, and deep fungal infections

Body's Protective Response

• Involves:
  • Inflammatory reaction
  • Immune response
  • Tissue repair

Manifestations of Inflammation

• Increased plasma proteins
• Increased skeletal muscle breakdown
• White blood cell alterations
• Fever

Fever Patterns

• Intermittent: Normal temperature between fevers
• Remittent: Temperature remains above normal, fluctuates more than 1 degree in 24 hours
• Sustained: Temperature remains above normal, fluctuates less than 1 degree in 24 hours
• Neurogenic: Caused by brain and spinal cord trauma

Dangers of Fever

• 1-degree increase leads to a 15-beat-per-minute increase in heart rate

Body Organ and Tissue Structure

• Parenchymal tissue: Contains the functioning cells of an organ or body part
• Stromal tissue: Supports connective tissue, blood vessels, and nerve fibers

Two Types of Healing

• Regeneration- replacement of injured cells with cells of the same type
• Repair - replacement of lost cells with connective tissue

Types of Hypersensitivity

• Type I - Immediate, IgE-mediated, mast cells degranulate, histamine release, examples: allergic reations, anaphylaxis,
• Type II - Antibody dependent cytotoxic, antibodies (IgM,IgG) attack antigens, examples: Rh disease, drug reactions, involves neutrophils, macrophages and IgG,IgM
• Type III - Immune complex medicated, antigen is not attached to cells, inflammatory response produces the damage, examples: lupus, serum sickness, Arthur's reaction
• Type IV - Cell-mediated hypersensitivity, T cells attack antigen, examples: Tuberculin test, allergic contact dermatitis

Transplant Reaction Types

• Hyperacute reactions: Occur immediately after transplantation
• Acute rejection: Occurs within a few months after transplantation

HIV and AIDS

• HIV: The virus
• AIDS: Manifestations of the infection
• Diagnosis:
  • ELISA: Initial screening test
  • Western blot: Confirmation test

Opportunistic Infections

• Respiratory diseases: Tuberculosis, pneumonia
• GI diseases: Thrush, protozoal infections, diarrhea
• Nervous system: AIDS dementia, Toxoplasmosis (neurological dysfunction)
• Malignancies: Kaposi's sarcoma (affects blood vessel lining)
• Wasting syndrome: Involuntary weight loss, weakness, fever

Ions

• Negative: Anions
• Positive: Cations

Body Fluid Functions

• Transport gases, nutrients, and waste
• Metabolic processes
• Maintain body function

Body Fluid Distribution

• Intracellular compartment: Inside the cell, 2/3 of body water, high potassium concentration
• Extracellular compartment: Outside the cell, 1/3 of body water, high sodium concentration

Fluid Exchange at Capillaries

• Four forces control water movement between capillaries and interstitial spaces
• Starling's Law of Capillaries: The volume reabsorbed equals the volume filtered

Edema (Fluid Accumulation)

• Occurs when filtration exceeds reabsorption
• Concerns: Increased diffusion distance, impaired function, blood vessel compression
• Common sites: Stomach, lungs, heart

Water Gain and Loss

• 2500 ml intake, 2500 ml output

Physiological Mechanisms Regulating Body Water

• Thirst: Primary regulator of water intake
• ADH (Antidiuretic Hormone): Regulates water output

Ways to Lose Water

• Insensible loss: Sweat, respiration
• Measurable loss: Urine, vomit, diarrhea

Sodium Regulation

• Kidney: Main regulator, monitors arterial pressure, retains sodium when pressure is low, eliminates it when pressure is high

Thirst Triggers

• Osmoreceptors in the hypothalamus

Types of Thirst

• Hypodipsia: Inability to sense thirst
• Polydipsia: Excessive thirst

Disorders of ADH Expression

• Diabetes insipidus: Excessive water loss in urine
• SIADH (Syndrome of Inappropriate Antidiuretic Hormone): Impaired negative feedback system regulating ADH release

Types of Diabetes Insipidus

• Central or neurogenic: Defect in ADH synthesis or release
• Nephrogenic: Kidneys do not respond to ADH

Disorders of Sodium and Water Balance

• Changes can be proportional (isotonic) or disproportionate (hypertonic or hypotonic)

Isotonic Fluid Volume Deficit (Hypovolemia)

• Water and electrolytes lost in equal proportions
• Causes: High salt intake
• Manifestations: Increased thirst, dry mucous membranes

Isotonic Fluid Volume Excess (Hypervolemia)

• Disproportionate intake or retention of water and sodium

Sodium Needs

• 500 mg per day

Importance of Sodium

• Maintains serum osmolality
• Acid-base balance
• Electrical impulse transmission
• Cell integrity (sodium-potassium pump)

Hyponatremia

• Low sodium levels

Types of Hyponatremia

• Hypertonic hyponatremia: Osmotic water shift due to high blood glucose
• Hypovolemic hypotonic hyponatremia: Most common, ECF loss due to sweating, vomiting, diarrhea
• Normovolemic hypotonic hyponatremia: Associated with SIADH, post-operative, high ADH levels
• Hypervolemic hypotonic hyponatremia: Least common

Hypernatremia

• High sodium levels
• Causes: Excessive sodium intake or water loss
• Euvolemic: Water from ICF shifts to ECF
• Hypovolemic: Water loss exceeds sodium loss
• Hypervolemic: Addition of hypertonic solution containing sodium and water

Potassium Distribution and Regulation

• Key role in muscle contraction and nerve impulse transmission
• Regulation:
  • Renal excretion: Main regulator, influenced by aldosterone
  • Cellular uptake, shifting between ICF and ECF

Disorders of Potassium Balance

• Hypokalemia: Low potassium levels
• Hyperkalemia: High potassium levels

Acid-Base Balance

• Normal pH: 7.35-7.45
• Regulation:
  • Buffers
  • Respiratory system (lungs)
  • Renal system (kidneys)

Acid-Base Disorders

• Primary: Initiating event
• Compensatory: Attempting to correct pH change

Types of Acid-Base Disorders

• Metabolic: Involves bicarbonate (HCO3-)
• Respiratory: Involves carbon dioxide (CO2)

Metabolic Acidosis

• Primary deficit of bicarbonate, decreased pH

Causes of Metabolic Acidosis

• Decreased kidney function
• Increased bicarbonate loss

Manifestations of Metabolic Acidosis

• Increased respiration
• Hyperkalemia

Metabolic Alkalosis

• Increased pH due to increased bicarbonate ions

Causes of Metabolic Alkalosis

• Loss of acids (e.g., vomiting)
• Increased bicarbonate retention

Respiratory Acidosis

• Increased CO2, carbonic acid, and decreased pH

Causes of Respiratory Acidosis

• Acute: Always accompanied by low oxygen
• Acute respiratory failure: Severe drop in pH, minimal change in bicarbonate

Respiratory Alkalosis

• Decreased CO2, carbonic acid deficit, and increased pH

Causes of Respiratory Alkalosis

• Panic attacks, fever, excessive stress

This quiz explores the mechanisms of inflammation, focusing on acute and chronic processes. It covers key characteristics, causes, and vascular changes involved in inflammatory responses. Test your knowledge on how the body reacts to cell damage and the role of different cells in inflammation.