Pathopharmacology, Immunity, Inflammation, and Cellular Regulation Practice Flashcards

Fundamentals of Pathophysiology and COVID-19 Disease Model

Pathophysiology involves understanding the origin, development, clinical characteristics, and management of disease states.

• Etiology: The underlying cause or origin of a disorder or disease process.
• Pathogenesis: The step-by-step cellular and tissue-level development or mechanism of a disease from initial exposure to full clinical expression.
• Risk Factors: Attributes, environmental exposures, or genetic characteristics that increase the likelihood of developing a specific health condition.
  • Nonmodifiable Risk Factors: Factors that cannot be altered, including age, gender, ethnicity, and genetics.
  • Modifiable Risk Factors: Lifestyle and environmental factors that can be changed, such as body weight, alcohol consumption, smoking habits, and physical activity levels.
• Disease Prevention: Interventions aimed at halting disease development, progression, or complications.
• Manifestations: The observable objective signs and reported subjective symptoms of a disease state.
• Diagnostics: Laboratory tests, imaging, and procedures used to identify or confirm the presence of a disease.
• Clinical Course: The evolutionary sequence and timeline of a disease from onset through resolution, chronicity, or death.
• Prognosis: The predicted outcome, recovery likelihood, or expected course of a disease.
• Complications: Secondary adverse conditions or pathological processes arising as a direct result of an underlying disease or its treatment.

Application to Specific Pathological Conditions

Chronic Obstructive Pulmonary Disease (COPD)

• Etiology: Inhalation of chemical or environmental irritants over a prolonged period.
• Risk Factors: Cigarette smoking and hereditary factors (such as alpha-1 antitrypsin deficiency).
• Prevention: Avoiding exposure to cigarette smoke and atmospheric pollutants.
• Manifestations: Dyspnea on exertion, excessive sputum production, and chronic wheezing.
• Diagnostics: Pulmonary function tests (PFTs), arterial blood gas (ABG) analysis, and pulse oximetry.
• Complications: Severe hypoxia, acute or chronic respiratory failure, and secondary pneumonia.

Acquired Immunodeficiency Syndrome (AIDS)

• Etiology: Infection by the Human Immunodeficiency Virus (HIV).
• Risk Factors: Engaging in unprotected sexual intercourse with an infected individual or parenteral exposure to infected blood.
• Prevention: Practicing safe sex behaviors (e.g., barrier methods).
• Manifestations: Acute flu-like illness, HIV encephalopathy, and opportunistic infections such as Pneumocystis pneumonia.
• Diagnostics: Enzyme-linked immunosorbent assay (ELISA), Western Blot assay, rapid antigen tests, and absolute CD4+ / CD8+ T-cell blood counts.
• Complications: Severe opportunistic infections including tuberculosis, candidiasis, histoplasmosis, cryptosporidiosis, and toxoplasmosis.

Pneumonia

• Etiology: Aspiration of vomitus, fluid, or pathogenic microbes into the pulmonary tissue.
• Risk Factors: Prolonged immobility, inability to sit upright while eating, and dysphagia secondary to cerebrovascular accident (stroke).
• Prevention: Positioning patients upright during oral intake.
• Manifestations: High fever, severe dyspnea, central cyanosis, and coarse crackles audible in lung bases.
• Diagnostics: Chest X-ray, sputum culture and sensitivity (C&S), and diagnostic bronchoscopy.
• Complications: Acute respiratory failure, localized lung abscess formation, and systemic infection or sepsis.

Myocardial Infarction (MI)

• Etiology: Acute occlusion of blood flow within a coronary artery leading to localized cardiac muscle tissue ischemia and necrosis.
• Risk Factors: Positive family history, essential hypertension, cigarette smoking, psychological stress, and elevated serum cholesterol levels.
• Prevention: Adopting a healthy lifestyle featuring regular exercise, low-fat diet, and low-sodium diet.
• Manifestations: Severe retrosternal chest pain, nausea, diaphoresis, and radiation of pain down the left arm.
• Diagnostics: Cardiac enzyme assays (troponin, CK-MB), 12-lead electrocardiogram (ECG), and cardiac catheterization/angiography.
• Complications: Lethal cardiac arrhythmias, sudden cardiac arrest, ischemic cardiomyopathy, and acute heart failure.

Comprehensive COVID-19 Disease Profile

• Etiology: COronaVIrus Disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a single-stranded RNA virus belonging to the coronavirus family. It is highly contagious and transmitted via close physical contact primarily through inhaled respiratory droplets.
• Pathogenesis:
  • SARS-CoV-2 binds to angiotensin-converting enzyme 2 (ACE2) receptors to gain cellular entry.
  • ACE2 receptors are heavily expressed on pneumocytes, myocardial cells, cholangiocytes, enterocytes, and oral mucosal epithelial cells.
  • Viral entry triggers a severe systemic inflammatory response while the virus actively replicates inside the respiratory tract.
  • Cells expressing ACE2 receptors are selectively targeted, damaged, and destroyed by both viral replication and host immune responses.
  • Delta Variant: Demonstrates heightened virulence, leading to significantly more severe cellular damage and clinical disease.
  • Omicron Variant: Exhibits reduced intrinsic virulence but markedly increased transmissibility, resulting in higher viral load inhalation and rapid spread.
• Manifestations:
  • Objective Signs: Measured fever, productive or non-productive cough, and increased sputum volume.
  • Subjective Symptoms: Sore throat, systemic chills, complete loss of taste (ageusia), complete loss of smell (anosmia), generalized myalgia, severe headache, malaise/fatigue, and progressive dyspnea.
• Diagnostics:
  • Viral Detection: Nasopharyngeal swab specimens analyzed via molecular or antigen testing indicate current, acute infection.
  • Antibody Testing: Serological blood tests detect circulating antibodies indicating prior viral exposure or vaccination, but do not confirm acute, active infection.
• Clinical Course:
  • Highly variable. The incubation period spans up to 14 days following initial viral exposure, with most symptomatic cases emerging within 4 to 5 days post-exposure.
  • Mild Cases: Recovery occurs within approximately 2 weeks.
  • Severe Cases: Recovery requires 2 to 3 months. In catastrophic cases, irreversible multi-organ failure occurs, resulting in death.
  • Persistent Post-Acute Symptoms: Chronic fatigue, ongoing dyspnea, persistent retrosternal chest pain, chronic cough, and severe cognitive deficits ("brain fog").
• Prognosis:
  • Age: Advanced age strongly correlates with disease severity and higher overall mortality rates.
  • Comorbidities: Pre-existing underlying conditions (e.g., cardiovascular disease, diabetes) markedly increase the risk of adverse outcomes and severe disease.
  • Laboratory Prognostic Markers: Severe COVID-19 correlates with profound lymphopenia, impaired hepatic function (elevated AST/ALT), elevated inflammatory biomarkers (CRP, ESR, ferritin), and severe coagulation abnormalities (d-dimer elevation).
• Complications: Viral or secondary bacterial pneumonia, acute respiratory distress syndrome (ARDS) / respiratory failure, cardiac arrhythmias, direct myocardial injury, acute heart failure, venous thromboembolism (VTE) including extensive deep vein thrombosis (DVT) and pulmonary embolism (PE), and acute inflammatory encephalopathy.

Disease Prevention and Health Promotion

Health promotion and disease prevention strategies are divided into three distinct levels of clinical practice:

• Primary Prevention:
  • Goal: Prevents the onset of disease entirely by removing risk factors and reducing susceptibility.
  • Examples: Administration of mRNA COVID-19 vaccines, practicing consistent hand hygiene, wearing protective masks, social distancing, avoiding cigarette smoke exposure, practicing safe sex with barrier methods, and maintaining a low-fat, low-sodium diet coupled with regular physical exercise.
• Secondary Prevention:
  • Goal: Identifies and detects disease in its early, asymptomatic phase to allow prompt treatment and cure or to arrest clinical progression.
  • Examples: Routine nasopharyngeal viral screening, diagnostic blood pressure measurements, sitting upright while eating to prevent silent aspiration, or performing routine cancer screenings (e.g., Pap smears, mammograms).
• Tertiary Prevention:
  • Goal: Manages established, symptomatic disease to reduce severe complications, slow clinical progression, and restore optimal function.
  • Examples: Administering targeted therapeutic medications, cardiac or pulmonary rehabilitation programs, physical therapy following a stroke, and diligent glucose control to prevent diabetic microvascular damage.

Pharmacology Core Principles and Drug Evaluation

Drugs are defined as active chemicals introduced into biological systems to elicit a functional or therapeutic response.

Mechanisms of General Drug Action

1. Replacing or acting as a direct substitute for missing intracellular or extracellular chemicals.
2. Increasing or stimulating baseline cellular activities.
3. Depressing, slowing, or inhibiting specific cellular functions.
4. Interfering with the survival or functional pathways of foreign invading organisms or malignant cells.

Sources of Pharmaceuticals

• Plants: Serve as the primary source for the vast majority of alternative and complementary drug therapies, as well as foundational pharmaceutical compounds (e.g., digitalis, morphine).
• Animals: Used to extract functional biological products (e.g., insulin, thyroid hormones, antivenom).
• Synthetic Materials: Chemically engineered structures created in laboratory settings to optimize therapeutic efficacy and minimize toxic side effects.
• Inorganic Compounds: Basic chemical elements and compounds used for specific therapeutic actions (e.g., iron, lithium, aluminum hydroxide).

Alternative Therapies and Nursing Responsibilities

• Nurses must routinely and specifically query clients regarding their current use of alternative, complementary, or over-the-counter herbal therapies.
• Nurses must possess knowledge regarding active alternative therapies to thoroughly evaluate potential drug-drug interactions with prescribed pharmaceutical regimens.
• Nurses must educate clients that alternative therapies are not regulated by the Food and Drug Administration (FDA) in the same rigorous manner as prescription medications.

FDA Drug Development and Evaluation Process

1. Preclinical Trials: Investigative chemicals are administered to nonhuman living biological organisms (animal models) to assess active biological effects and evaluate clear toxicity margins.
2. Phase I Studies: Candidate chemicals are administered to small cohorts of healthy human volunteers to evaluate human pharmacokinetics, safety profiles, and metabolic pathways.
3. Phase II Studies: Drugs are tested on targeted cohorts of informed human patients who actively possess the specific disease or condition the drug is designed to treat.
4. Phase III Studies: The drug is evaluated across massive, diverse patient populations in multi-center clinical trials to establish therapeutic efficacy, monitor rare adverse effects, and evaluate safety against existing therapies.
5. FDA Approval: Upon successful completion of Phase III, the drug is formally approved by the FDA for commercial marketing to the general public.
6. Phase IV Studies: Ongoing, post-marketing surveillance wherein continuous evaluation of real-world drug performance, long-term safety, and rare adverse events is routinely conducted.

Pregnancy and Lactation Labeling Guidelines

Modern pharmaceutical evaluation replaces former lettered pregnancy categories with explicit, evidence-based risk summaries and clinical considerations:

• Pregnancy: Detailed risk summaries regarding fetal developmental harm based on human and animal data.
• Lactation: Comprehensive summaries regarding drug excretion into human breast milk and potential clinical effects on the nursing infant.
• Females and Males of Reproductive Potential: Guidelines outlining mandatory pregnancy testing, effective contraceptive requirements during therapy, and potential drug-induced infertility.

Controlled Substance Regulation and Schedules

The Controlled Substances Act of 1970 established federal control over the coding, distribution, and clinical administration of habit-forming medications. Oversight is maintained by the FDA and the Drug Enforcement Agency (DEA), a branch of the U.S. Department of Justice.

• Prescribing providers and dispensing pharmacists must maintain active registration with the DEA.
• Prescription, distribution, storage, and waste of controlled substances are subject to strict monitoring; institutional policies are often more stringent than federal laws.

Note on Schedule V: Limited quantities of specific C-V drugs may be purchased over-the-counter without a prescription directly from a licensed pharmacist. Purchasers must be at least 18 years of age, present valid government identification, and complete a pharmacy ledger recording the transaction.

Generic versus Brand (Trade) Names

• Generic Name: assigned to the active chemical compound during its initial development phase. Generic drugs are manufactured by companies focused solely on pharmaceutical production, contain the exact active chemical formula as the parent drug, and are generally far more cost-effective. Generic names are written in lowercase letters (unless beginning a sentence).
• Brand (Trade) Name: assigned by the specific pharmaceutical company that receives formal FDA approval to market the patented drug formulation. Multiple commercial companies may manufacture identical active generic drugs under completely different proprietary Brand Names. Brand Names are always capitalized.

Over-the-Counter (OTC) versus Behind-the-Counter (BTC) Drugs

• Over-the-Counter (OTC) Medications: Available without a prescription.
  • Risks: May mask early signs and symptoms of underlying disease, delaying proper medical diagnosis; can cause severe drug-drug interactions when taken alongside prescribed drugs; and carry significant potential for toxicity, severe organ damage, or fatal overdose if taken in excess of recommended limits.
• Behind-the-Counter (BTC) Medications: Available without a formal medical prescription, but subject to strict legal purchasing restrictions.
  • Requirements: Kept securely locked behind the pharmacy counter; sold in strictly limited quantities per individual over set timeframes; and require mandatory government identification checks and logged sales tracking (e.g., Pseudoephedrine).

Pharmacokinetics, Pharmacodynamics, and Pharmacogenomics

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            Pharmacogenomics

Pharmacokinetics (LADME)

Pharmacokinetics defines what the body does to the drug. It encompasses the mathematical and physiological processes governing drug movement through the body:

1. Liberation: The process by which the active drug ingredient is separated from its administrative carrier, vehicle, or excipient.
   • Active Ingredient: The actual chemical substance eliciting therapeutic action.
   • Vehicle (Carrier): A chemical medium that alters when and where the active drug is released into the body.
   • Excipient: Inactive substances added to stabilize, preserve, color, or add physical bulk to the pharmaceutical dosage form.
   • Formulations: Enteric coatings prevent dissolution within the acidic gastric environment; extended-release and delayed-release formulations alter liberation timing.
2. Absorption: The movement of the drug from its site of administration into the vascular system.
   • Route Impact: Enteral absorption is modified by gastric pH, intestinal motility, and the presence of food in the stomach.
   • First-Pass Effect: Orally ingested drugs are absorbed through the gastrointestinal mucosa and transported directly via the portal vein to the liver. Hepatic enzymes extensively metabolize a high percentage of the active drug before it reaches the systemic circulation, significantly lowering overall bioavailability.
   • Bypassing First-Pass: Routes such as intravenous (IV), intramuscular (IM), sublingual, transdermal, inhalational aerosol, and rectal suppository deliver the active drug directly into the systemic circulation, completely bypassing initial hepatic portal metabolism.
3. Distribution: The movement and transportation of drug molecules through body fluids to target tissues and receptor sites.
   • Influencing Factors: Regional tissue perfusion/circulation, cell membrane permeability, physiological barriers (e.g., Blood-Brain Barrier, Placental Barrier), and plasma protein binding (e.g., albumin binding).
4. Metabolism (Biotransformation): The chemical alteration of the drug molecule within biological systems.
   • Primary Organ: The Liver (hepatic system).
   • Evaluation: Hepatic function tests, including serum transaminases (AST/ALT).
5. Excretion: The physical removal of drug molecules or their active/inactive metabolites from the body.
   • Primary Organ: The Kidneys (renal system).
   • Evaluation: Renal function tests, including Blood Urea Nitrogen (BUN) and serum Creatinine.

Pharmacodynamics

Pharmacodynamics defines what the drug does to the body. It governs the pharmacological mechanism of action, therapeutic effects, and secondary adverse reactions.

• Receptors: Specialized functional protein areas located on cell membranes or within cytoplasm that bind with specific endogenous chemicals or exogenous drugs.
  • Agonists: Molecules that bind to and directly activate receptor sites, mimicking natural physiological responses.
  • Antagonists: Molecules that block or bind to receptor sites without activating them, preventing natural endogenous ligand binding.
  • Inverse Agonists: Molecules that bind to the same receptor site as an agonist but induce an opposite biological response.

Pharmacogenomics and Cytochrome P450 Systems

Pharmacogenomics studies how an individual's unique genetic composition dictates their metabolic and physiological response to pharmaceutical agents.

• Cytochrome P450 (CYP450) Enzyme Family: A massive superfamily of liver enzymes responsible for metabolizing approximately 75% of all clinical medications. At least 57 distinct functional genes code for these enzymes.
• CYP2D6: One of the most vital enzymes, responsible for biotransforming approximately 25% of all commonly prescribed clinical drugs.
• Enzyme Inducers: Substances that accelerate CYP450 enzyme synthesis or functional capacity.
  • Effect: Rapidly increases drug metabolism, resulting in markedly decreased bioavailability and lower plasma concentration. Leads to an increased risk of reduced therapeutic effect.
• Enzyme Inhibitors: Substances that inhibit or block CYP450 enzyme synthesis or functional activity.
  • Effect: Slows drug metabolism, resulting in increased bioavailability and abnormally high, persistent drug levels in the bloodstream. Leads to a high risk of adverse toxic effects.
  • Clinical Example: Grapefruit juice acts as a potent inhibitor of the CYP3A4 enzyme, markedly elevating serum levels of co-administered drugs.
• Genetic Variant Case: If a patient is genetically identified as a