Pneumonia (PNA) - Causes, Symptoms, and Treatments - PDF

Chapter 13: Pneumonia (PNA) - RSPT 2310 Objectives: - Recognize common characteristics, manifestations, and anatomic features of pneumonia. - Identify complications associated with different types of pneumonia. - Understand mechanisms that allow infectious organisms to enter the lower respiratory t...

Chapter 13: Pneumonia (PNA) - RSPT 2310 Objectives: - Recognize common characteristics, manifestations, and anatomic features of pneumonia. - Identify complications associated with different types of pneumonia. - Understand mechanisms that allow infectious organisms to enter the lower respiratory tract. - Differentiate pneumonia by classification (causative organism, origin, anatomic location). - Identify risk factors for antimicrobial resistance. Overview of Pneumonia (PNA): Pneumonia is an acute infection of the lung parenchyma caused by one or more pathogens. Classifications: - By causative organism: Bacterial, viral, fungal, or parasitic. - By acquisition: - Community-acquired pneumonia (CAP) - Hospital-acquired pneumonia (HAP) - Ventilator-associated pneumonia (VAP) - By anatomic location: - Lobar pneumonia - Bronchopneumonia - Interstitial pneumonia - By drug resistance: Some pathogens develop resistance, increasing mortality risk. Key Fact: - Pneumonia was the 8th leading cause of death in the U.S. in 2014. Mechanisms of Infection: - Organisms invade and colonize the respiratory tract when host defenses are compromised. - Entry via: - Inhalation of airborne particles - Aspiration of secretions - Hematogenous spread from infections elsewhere in the body Common Organisms: - Bacteria (most common) - Viruses - Atypical bacteria - Fungi - Parasites Bacterial Pneumonia: Causative Agents: - Typical Bacteria:  - Streptococcus pneumoniae (most common) - Staphylococcus aureus - Klebsiella pneumoniae - Haemophilus influenzae - Atypical Bacteria ("Walking Pneumonia"): - Mycoplasma pneumoniae (most common) - Legionella pneumophila (severe CAP) Gram Staining: - Gram-positive: Stains purple. - Gram-negative: Stains pink. - Types of Bacteria: - Aerobic: Requires oxygen. - Anaerobic: Cannot survive in oxygen. - Facultative Anaerobes: Can grow with or without oxygen. Morphology: - Cocci (round) - Bacilli (rod-shaped) - Spirilla (spiral-shaped) Signs & Symptoms: - Respiratory: - Productive cough - Adventitious breath sounds - Dull percussion over areas of consolidation - Cardiac: - Tachycardia or bradycardia - Fever: - High-grade (>101°F) - Observation: - Cyanosis - Altered mental status Sputum Characteristics: - Rust-colored - *Streptococcus pneumoniae* - Currant jelly - *Klebsiella pneumoniae* - Green - *Pseudomonas aeruginosa, Haemophilus influenzae* - Yellow - *Typical bacterial infections* - Foul-smelling - *Anaerobic infections* Risk Factors: - Age >65 years - Chronic lung diseases - Increased risk of microaspiration - Immunocompromising conditions - Metabolic disorders - Instrumentation of the respiratory tract - Recent viral infection (especially influenza) Complications: - Acute Respiratory Distress Syndrome (ARDS) - Bacteremia (blood infection) - Bronchiectasis - Lung abscess - Septic shock - Pleural effusion & pleurisy - Multi-organ failure Diagnostic Testing: - Chest X-ray (CXR) - Gold standard. - Lobar consolidation - Bacterial pneumonia. - Patchy infiltrates - Atypical pneumonia. - Pneumatoceles - Suggests S. aureus infection. - Laboratory Tests: - CBC: Elevated WBC count with left shift. - Blood & sputum cultures. - CRP & procalcitonin: Helps distinguish pneumonia from other conditions. Treatment & Management: - Empiric antibiotics - Broad-spectrum initially, then targeted therapy. - Bronchodilators - If bronchospasm is present. - Oxygen therapy - For hypoxia. - Mucolytics & airway clearance therapy. - Hydration & rehydration therapy. Prognosis: - Depends on severity, virulence, and host factors. - Most patients recover within 2 weeks with proper treatment. Viral Pneumonia: Causative Agents: - Influenza virus (most common) - Respiratory syncytial virus (RSV) - Adenovirus - Parainfluenza virus - Rhinovirus - Coronavirus Epidemiology: - More than 100 million adult and pediatric cases per year. - Higher incidence in colder climates and winter months. - Higher mortality in the elderly and immunocompromised individuals. Signs & Symptoms: - Fever, chills - Nonproductive cough - Rhinitis (runny nose) - Muscle aches, fatigue, headache - Gradual onset compared to bacterial pneumonia Risk Factors: - Chronic pulmonary disease - Elderly individuals - Immunocompromised states - Pregnancy - Young children Diagnostic Testing: - Chest X-ray: Interstitial infiltrates - Arterial blood gas (ABG): Depends on etiology - Sinus tachycardia may be present - CBC: May be normal or show leukocytosis with lymphocytic predominance - Nasopharyngeal cultures: Standard for viral pathogen identification Treatment & Management: - Supportive care: Oxygen, fluids, symptomatic treatment. - Antivirals: Tamiflu (influenza), Ribavirin (RSV). - Antibiotics are NOT used unless secondary bacterial infection occurs. Prognosis: - Usually self-limiting but can be severe in high-risk groups (elderly, infants, immunocompromised patients). Pneumonia Classification by Anatomic Location: - Lobar Pneumonia: Involves a distinct area of the lung, often seen in community-acquired pneumonia. - Bronchopneumonia: Multifocal, involving multiple regions of one or both lungs, often seen in hospital-acquired pneumonia. - Interstitial Pneumonia: Affects lung tissue between alveoli, commonly caused by viral infections, leading to alveolar wall thickening. Key Takeaways: - Pneumonia can be bacterial, viral, or fungal. - CAP is the most common type; HAP/VAP have higher mortality. - Antibiotics for bacterial, antivirals for viral, antifungals for fungal. - Preventative measures reduce hospital-acquired pneumonia