Pathophysiology — B.Pharmacy 2nd Semester
Pathophysiology is the study of the functional changes associated with disease and injury. It bridges basic sciences (anatomy, physiology, biochemistry) with clinical pharmacy, helping pharmacists understand why diseases occur and how drugs can correct the underlying pathology.
Unit 1: Basic Principles of Cell Injury and Adaptation
Causes of Cell Injury
- Hypoxia: Insufficient oxygen supply (ischemia, anemia, respiratory failure)
- Physical agents: Trauma, temperature extremes, radiation, electric shock
- Chemical agents: Poisons, drugs, alcohol, environmental pollutants
- Biological agents: Viruses, bacteria, fungi, parasites
- Immunological reactions: Autoimmune diseases, hypersensitivity reactions
- Genetic defects: Inborn errors of metabolism, chromosomal abnormalities
- Nutritional imbalances: Deficiencies or excesses of nutrients
Cellular Adaptations
- Atrophy: Decrease in cell size (disuse, denervation, decreased blood supply)
- Hypertrophy: Increase in cell size (cardiac hypertrophy in hypertension)
- Hyperplasia: Increase in cell number (endometrial hyperplasia)
- Metaplasia: Replacement of one cell type by another (smokers’ bronchial epithelium)
- Dysplasia: Disordered cell growth (precancerous changes)
Unit 2: Inflammation
Acute Inflammation
A rapid, short-duration response to tissue injury characterized by the cardinal signs: rubor (redness), calor (heat), tumor (swelling), dolor (pain), and functio laesa (loss of function).
Chemical Mediators of Inflammation
- Histamine: Released from mast cells — vasodilation, increased vascular permeability
- Prostaglandins: Produced from arachidonic acid by COX enzymes — pain, fever, vasodilation
- Leukotrienes: Produced by lipoxygenase pathway — bronchoconstriction, chemotaxis
- Cytokines (IL-1, TNF-α): Pro-inflammatory mediators — fever, acute phase response
- Complement system: C3a, C5a — opsonization, chemotaxis, membrane attack complex
Chronic Inflammation
Prolonged inflammation (weeks to months) characterized by simultaneous tissue destruction, inflammation, and repair. Involves macrophages, lymphocytes, and fibroblasts.
Unit 3: Cardiovascular Pathophysiology
Hypertension
Sustained elevation of blood pressure (≥140/90 mmHg). Risk factors include obesity, high sodium intake, stress, smoking, family history. Complications: heart failure, stroke, renal failure, retinopathy.
Atherosclerosis
Progressive arterial disease involving lipid accumulation, inflammation, and fibrous plaque formation in vessel walls. Leading cause of coronary artery disease and stroke.
Heart Failure
The heart’s inability to pump sufficient blood to meet the body’s metabolic demands. Can be left-sided (pulmonary congestion) or right-sided (systemic congestion).
Unit 4: Respiratory Pathophysiology
Asthma
Chronic inflammatory airway disease characterized by reversible airway obstruction, bronchial hyperresponsiveness, and inflammation. Triggers include allergens, exercise, cold air, and pollutants.
COPD (Chronic Obstructive Pulmonary Disease)
Progressive, irreversible airflow limitation. Includes chronic bronchitis (excessive mucus production) and emphysema (destruction of alveolar walls). Primary cause: smoking.
Unit 5: Diabetes Mellitus
Type 1 Diabetes
Autoimmune destruction of pancreatic β-cells leading to absolute insulin deficiency. Onset typically in childhood/adolescence. Requires insulin therapy.
Type 2 Diabetes
Characterized by insulin resistance and relative insulin deficiency. Associated with obesity, sedentary lifestyle, and genetic predisposition. Most common form (~90% of cases).
Complications of Diabetes
- Microvascular: Retinopathy, nephropathy, neuropathy
- Macrovascular: Coronary artery disease, stroke, peripheral vascular disease
- Acute: Diabetic ketoacidosis (DKA), hyperosmolar hyperglycemic state (HHS)
Important Exam Questions
- Explain the types of cellular adaptations with examples
- Describe the chemical mediators of acute inflammation
- Differentiate between Type 1 and Type 2 diabetes mellitus
- Explain the pathophysiology of atherosclerosis
- Write about the pathophysiology of asthma
- Describe the pathophysiology of hypertension and its complications