Aspiration pneumonia and pneumonitis
Background
- Difficult to predict which patients with pneumonitis will go on to develop pneumonia
- Aspiration pneumonitis
- Inflammatory chemical injury of tracheobronchial tree and pulmonary parenchyma
- Due to inhalation of regurgitated sterile gastric contents
- Must aspirate at least 20-30mL of gastric contents with pH <2.5
- Can lead to aspiration pneumonia due to pulmonary defense mechanism injury
- Aspiration pneumonia
- Alveolar space infection secondary to inhalation of pathogenic material from oropharynx
- Increased in patients with periodontal disease, chronic colonization of upper airways, or taking PPI/H2-blockers
- Accounts for up to 20% of community-acquired pneumonia in elderly, majority of nursing home-acquired pneumonia
- Microbiology
- Community acquired: Pneumococcus, staph, H flu, enterobacter
- Hospital acquired: Pseudomonas, gram-negatives
Clinical Features
- Aspiration pneumonia
- Fever
- Dyspnea
- Productive cough
- Tachypnea
- Tachycardia
- altered mental status
- Aspiration pneumonitis
- Cough
- Tachypnea
- Bloody sputum
- Respiratory distress
Differential Diagnosis
Acute dyspnea
Emergent
- Pulmonary
- Airway obstruction
- Anaphylaxis
- Angioedema
- Aspiration
- Acute respiratory distress syndrome (ARDS)
- Asthma
- Cor pulmonale
- Epiglottitis
- Inhalation exposure
- Noncardiogenic pulmonary edema
- Pneumonia
- Pneumocystis Pneumonia (PCP)
- Pulmonary embolism
- Pulmonary hypertension
- Tension pneumothorax
- Idiopathic pulmonary fibrosis acute exacerbation
- Cystic fibrosis exacerbation
- Cardiac
- Other Associated with Normal/↑ Respiratory Effort
- Other Associated with ↓ Respiratory Effort
Non-Emergent
- ALS
- Ascites
- Uncorrected ASD
- Congenital heart disease
- COPD exacerbation
- Deconditioning
- Fever
- Hyperventilation
- Interstitial lung disease
- Neoplasm
- Obesity
- Obstructive sleep apnea
- Panic attack
- Pleural effusion
- Polymyositis
- Porphyria
- Pregnancy
- Rib fracture
- Spontaneous pneumothorax
- Thyroid Disease
- URI
- Vocal cord dysfunction
Evaluation
Work-Up
- CXR
- Unilateral focal or patchy consolidations in dependent lung segments
- Right lower lobe is most common area; bilateral patterns can also be seen
- Lower lobe infiltrate when aspiration occurs in upright position
- Upper lobe infiltrate when aspiration occurs in recumbent position
- CT
- Increased sensitivity, specificity, and overall accuracy compared to CXR
- Reasonable to obtain even if CXR negative if clinical suspicion is high
Management
- Aspiration pneumonitis
- Suction upper airway if aspiration is witnessed
- Antibiotics
- Only recommended if symptoms persist >48hr
- Levo/moxifloxacin or clindamycin or amoxicillin-clavulanate
- Only recommended if symptoms persist >48hr
- Aspiration pneumonia
- Community-acquired
- Health care-associated or periodontal disease or alcoholism
- Ceftriaxone + clindamycin OR
- Piperacillin-tazobactam + clindamycin OR
- Ampicillin-sulbactam + clindamycin OR
- Cefepime + clindamycin OR
- Levofloxacin + clindamycin
Disposition
- Healthy person
- Observe for 1hr; if asymptomatic, discharge
- If mild-moderate symptoms develop and persist >48hr, treat with antibiotics
- Chronically ill or nursing home patient:
- Consider ED obs unit versus short admission for observation +/- prophylactic antibiotic
- Admit all patients with aspiration pneumonia