Pneumonia
Acute inflammation of the lung parenchyma caused by microbial organisms.
Ethology of pneumonia
- Airway distal to larynx normally sterile; defence mechanisms active.
- Pneumonia occurs when these defence mechanisms are unable to function normally; when overwhelmed by infectious agent.
- Organisms into lungs in three ways;
Aspiration, inhalation, or via hematogenous spread (infection spread from another part of the body via the bloodstream to the lungs).
What are the two types of oenumonia
- Community acquired (CAP)
- Hospital acquired (HAP)
Community acquired pneumonia (CAP)
-onset within community or onset within two days of hospitalization
- increased incidence in winter
- risk factors: COPD, aspiration risk, smoking, and recent antibiotic use.
- causative agent identified 50% of the time
Hospital acquired pneumonia (HAP)
Onset over >48HR after hospital admission and no signs/symptoms at admission; 2nd most common hospital (25% of ICU infections); different microbes than CAP; risk factors are immunosuppression, intubation and chronic illness
Aspiration pneumonia
- abnormal entry of microbes into airway from secretions or substances; often from mouth or stomach into trachea or lungs
- patient often has a history of decreased LOC; seizures EtOH use, head injury, stroke, anesthesia (decreased gag reflex)
Three types of aspiration pneumonia?
- Chemical pneumonitis: aspiration of gastric contents
- Bacterial aspiration pneumonia: results from the inhalation of oral or pharyngeal secretions containing bacteria.
- Aspiration of foreign material: inhalation of non infectious solids or liquids (food;liquids) that obstructs the airway cussing blockage or inflammation
Pneumonia: opportunistic infections
- occur in people with altered immunity
- change in B & T lymphocyte function, and decreased bone marrow function; decreased neutrophil and macrophage activation.
- at risk populations include immunodeficient, transplant recipients, immunosuppressant drugs, corticosteroid use, protein-calorie malnutrition.
- more at risk for atypical infections
- P. Jiroveci more common in patients with AIDS and HMs (long term prophylaxis required)
Pathophysiology
- Congestion
- Red hepatization
- Grey hepatization
- Resolution
Clinical manifestations of pneumonia
Sudden onset of fever; chills; productive cough (sputum purlins); pleuritic chest pain; vital signs changes (increased BP, decreased SpO2); older adult confusion.
Atypical onset: gradual onset of symptoms, extrapulmonary symptoms (fever, malaise, sore throat, vomiting, nausea).
Pneumonia assessment findings:
- Dyspnea (SOB), fatigue, cough (productive with frothy pink sputum), use of accessory muscles when breathing, decreased chest expansion on affected side, tachypnea, crackles or wheezing on auscultation, or decreased breath sounds
Diagnostic testing for Pneumonia
Health history; physical exam; chest X-ray; sputum culture and sensitivity; gram stain, pulse oximetry & ABG, CBC, and blood cultures
Complication due to pneumonia
Often none; however, pleurisy, pleural effusions, atelectasis, delayed resolution, lung abscess, empyema, pericarditis, meningitis, endocarditis, bacteremia.
