View source for Aspiration pneumonia and pneumonitis

==Background==
*Difficult to predict which patients with pneumonitis will go on to develop pneumonia, aspiration alone does not cause pneumonia
*Witnessed aspiration key to distinguishing between the two
*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
**Usually resolves after 24-48 hrs with supportive care only
**Can lead to aspiration pneumonia due to pulmonary defense mechanism injury
*Aspiration pneumonia
**Alveolar space infection secondary to inhalation of pathogenic material from oropharynx
**Result of a complex interplay of the aspirated material, aspirated volume, pH, patient physiology and pulmonary defense mechanisms
**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
***Anaerobes not believed to play significant role in pathogenesis
***Community acquired: [[Pneumococcus]], [[staph]], [[H flu]], [[enterobacter]]
***Hospital acquired: [[Pseudomonas]], [[gram-negative]]s

==Risk factors==
*Advanced age
*Altered level of consciousness
*Anatomic abnormality of upper airway
*[[Dementia]]
*Esophageal disorders
*Gastroesophageal reflux
*Neuromuscular disease
*Poor oral hygiene
*Prior history of aspiration
*Prolonged supine position
*Retained gastric material
*Tube feedings

==Clinical Features==
*Aspiration pneumonia
**[[Fever]]
**[[Dyspnea]]
**Productive [[cough]]
**[[Tachypnea]]
**[[Tachycardia]]
**[[Altered mental status]]
*Aspiration pneumonitis
**[[Cough]]
**Bronchospasm
**[[Tachypnea]]
**Bloody sputum
**Low-grade fever
**[[Respiratory distress]]

==Differential Diagnosis==
{{SOB DDX}}

==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
**Aspiration is a risk factor for pulmonary abscess formation

==Management==
===Aspiration pneumonitis===
*Suction upper airway if aspiration is witnessed
*Caused by aspiration of gastric contents. Usually resolves in 24-48 hrs w/o treatment
*Antibiotics '''only''' recommended if symptoms persist >48hr
**Same as those for community-acquired aspiration pneumonia below

===Aspiration pneumonia===
*Treat same as [[community acquired pneumonia]] (see below)
**Routinely adding anaerobic coverage beyond the standard empiric treatment for community-acquired aspiration pneumonia is no longer recommended unless lung abscess, [[empyema]], healthcare-associated, periodontal disease, or [[SBO]]<ref>Metlay JP, Waterer GW, Long AC, et al. Diagnosis and treatment of adults with community-acquired pneumonia. An official clinical practice guideline of the American Thoracic Society and Infectious Diseases Society of America. Am J Respir Crit Care Med. 2019;200(7):e45–e67.</ref>

{{Pneumonia Antibiotics}}

==Disposition==
*Generally admit all patients with aspiration pneumonia
*For aspiration pneumonitis, consider discharge if:
**Otherwise healthy and non-toxic
**Give outpatient antibiotics if symptomatic for >48hrs
*For aspiration pneumonitis, consider admission for:
**Chronically ill or immunocompromised
**Nursing home patient

==See Also==
*[[Pneumonia (Main)]]

==References==
<References/>

[[Category:ID]]
[[Category:Pulmonary]]