Pneumonia

Clinical Orientation

A 78-year-old nursing home resident is admitted with fever (39.1°C), cough productive of green sputum, and SpO2 86% on room air. Chest X-ray shows right lower lobe consolidation. She is confused — her baseline is alert. This is community-acquired pneumonia. This chapter answers: What mechanism links pneumonia to bedside findings, tests, red flags, and nursing priorities?

What Goes Wrong?

Pneumonia = infection of the lung parenchyma (alveoli and interstitium).

Pathogenesis: Organisms reach the lower respiratory tract (aspiration, inhalation, hematogenous spread) → overcome host defenses (cough, mucociliary clearance, alveolar macrophages) → multiply in alveoli → trigger inflammatory response.

The inflammatory exudate: Neutrophils, bacteria, fluid, and fibrin fill the alveoli → consolidation → that segment of lung becomes airless. Blood continues to flow past these fluid-filled alveoli → intrapulmonary shunt → severe hypoxemia that is relatively resistant to supplemental O2.

Classification:

• Community-acquired (CAP): S. pneumoniae (most common), H. influenzae, atypical (Mycoplasma, Chlamydia, Legionella), viral (influenza, RSV, SARS-CoV-2).
• Hospital-acquired (HAP): Onset ≥48 hours after admission. More resistant organisms — Pseudomonas, MRSA, Enterobacteriaceae.
• Ventilator-associated (VAP): Onset ≥48 hours after intubation.
• Aspiration pneumonia: Chemical pneumonitis from gastric contents + possible bacterial infection. Anaerobes common.

What the Nurse May See

• Respiratory: Tachypnea, dyspnea, cough (productive or nonproductive). Crackles, bronchial breath sounds (consolidation), egophony, increased tactile fremitus over the affected area.
• Systemic: Fever, chills, malaise, myalgia.
• Elderly/immunocompromised: May present with confusion, weakness, falls, decreased oral intake WITHOUT fever or cough. High index of suspicion needed.
• Sepsis progression: Hypotension, tachycardia, altered mental status, rising lactate.

Tests and Monitoring

• Chest X-ray: Infiltrate/consolidation confirms pneumonia. May show lobar (one lobe), bronchopneumonia (patchy), or interstitial pattern.
• Sputum culture and Gram stain: Identify organism. Obtain BEFORE antibiotics if possible, but do NOT delay antibiotics.
• Blood cultures: For patients with severe CAP or risk of bacteremia.
• CBC: Leukocytosis (or leukopenia — ominous in sepsis).
• ABG or SpO2: Assess oxygenation. Severe pneumonia → shunt → refractory hypoxemia.
• CURB-65 or PSI score: Assess severity and need for hospitalization.

Nursing Priorities

1. Oxygenation: Target SpO2 ≥92% (or ≥88-92% in COPD). May require high-flow O2 or noninvasive/invasive ventilation.

1. Antibiotics — administer promptly: CAP: within 4-8 hours of arrival. Do NOT delay for sputum collection — obtain cultures, then give antibiotics.

1. Secretion management: Encourage cough and deep breathing. Incentive spirometry. Hydration (thins secretions). Position changes. Chest physiotherapy.

1. Monitor for sepsis: Frequent vital signs, mental status, urine output. Know the sepsis screening tools.

1. Prevention of complications: Parapneumonic effusion/empyema, lung abscess, bacteremia, respiratory failure, sepsis.

1. Infection control: Standard precautions + droplet precautions if indicated (influenza, certain pathogens). Hand hygiene.

Red Flags