Highlights & Basics
- Aspiration pneumonia is diagnosed based on clinical signs or symptoms of pneumonia in a person with a history or risk factors for aspiration.
- Sputum or tracheal Gram stain reveals mixed flora.
- Infection usually involves the dependent lung lobe.
- Complications of disease include lung abscess and empyema.
Quick Reference
History & Exam
Key Factors
cough
dyspnea
Other Factors
fever
pleuritic chest pain
tachypnea
foul-smelling breath
crepitations
frothy or purulent sputum
history of vomiting
Diagnostics Tests
Other Tests to consider
point-of-care lung ultrasound
ABG
bronchoscopy
1st Tests to Order
O2 saturation
CXR
CBC
sputum Gram stain
sputum culture
Treatment Options
acute
all patients
antibiotic therapy
supportive care
Definition
Vignette
Common Vignette
Other Presentations
Epidemiology
Etiology
Pathophysiology
Images
Diagnostic Approach
- Consider all patients with cough, fever, or other suggestive symptoms to have COVID-19 until proven otherwise. Pneumonia due to COVID-19 is not covered in this topic.
- For patients with symptoms and signs consistent with bacterial pneumonia (not secondary to COVID-19), that start on days 1 or 2 after hospital admission, see Community-acquired pneumonia (non-Covid-19) .
Diagnostic tests
Risk Factors
History & Exam
Tests
Differential Diagnosis
Aspiration pneumonitis
Differentiating Signs/Symptoms
- Results from aspiration of sterile gastric contents (often witnessed), leading to acute lung injury from acidic and particulate gastric material.
- Occurs immediately after the precipitating event.
- Typically occurs in young people, and the main risk factor is a markedly depressed level of consciousness.[8]
- Clinically difficult to distinguish. Symptoms persist beyond the initial 24 hours. Similar pulmonary signs are seen such as coughing, wheezing, cyanosis, hypoxemia, pulmonary edema, respiratory distress, or gastric contents in oropharynx.
- Cardiac signs such as hypotension are also similar.
Differentiating Tests
- There is no good test. Clinical history can help to differentiate.[8]
Differentiating Signs/Symptoms
- Depends on the size of area of lung affected and speed at which lung collapse occurs. If a large area of the lung is affected with rapid onset, there is typically pain on the affected side, dyspnea (sudden onset), and cyanosis. Slower onset of lung collapse may be asymptomatic or cause only minor symptoms. A harsh, nonproductive cough is produced by gradual collapse of the right middle and lower lobes.
Differentiating Tests
- Lack of leukocytosis or other markers of active infection. CXR usually shows changes in posterior dependent aspects.
Differentiating Signs/Symptoms
- Presents with shortness of breath, fatigue, dyspnea on exertion, and tachypnea. History of heart disease or fluid overload can usually be elicited.
- Crackles are heard on auscultation.
Differentiating Tests
- CXR typically shows symmetric distribution of opacities, although may not be evident early on. Evaluation of left ventricular dysfunction by BNP and echo are helpful.
- Leukocytosis usually not present.
Differentiating Signs/Symptoms
- Form of aspiration pneumonia occurring acutely or chronically from aspiration of vegetable fat or mineral oil (exogenous form). There is a history of ingestion of lipid over periods of time. Acute form may present with fever and cough especially in younger patients. Chronic form may be asymptomatic.
- Can be seen resulting from propylene glycol in electronic cigarettes and other vaporizers.
Differentiating Tests
- CT can occasionally demonstrate low attenuation areas (-30HU).
Community-acquired pneumonia (CAP)
Differentiating Signs/Symptoms
- Patients typically complain of productive cough, breathlessness, chest or abdominal pain, fever, and general malaise. Older people present with atypical symptoms including confusion, lethargy, and general deterioration.
- It is possible that aspiration pneumonia is simply community-acquired pneumonia in an older patient with greater comorbidities.[4]
Differentiating Tests
- Common organisms detected on sputum culture are Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, Moraxella catarrhalis, Klebsiella pneumoniae, and other gram-negative bacilli.
- Atypical organisms may be detected with appropriate testing (e.g., serology or antigen tests).
Hospital-acquired pneumonia (HAP)
Differentiating Signs/Symptoms
- Green-yellow sputum.
- No difference in signs and symptoms. HAP refers to any pneumonia that develops after 72 hours of hospitalization. This includes all types of pneumonias, including aspiration pneumonia.
Differentiating Tests
- Sputum culture showing growth of gram-negative rods or Staphylococcus aureus is more likely.
Screening
- Clinical assessment: includes detailed pertinent history relating to swallow difficulty, detailed sensory and motor exam, and assessment of ability to swallow foods of different consistencies. Sensitivity for detection of aspiration is 80%, although ability to predict aspiration pneumonia is unclear.[12]
- Video-fluoroscopic swallow assessment (also called modified barium swallow): most commonly used instrumental measure and considered the most specific and sensitive test.
- Fiberoptic endoscopic evaluation of swallow (FEES): a more expensive test identifying aspiration, although esophageal/oral phases are not visualized and only anatomy of the pharynx/larynx can be appreciated.
Treatment Approach
- Pneumonia due to COVID-19 is not covered in this topic.
Antibiotic therapy
Treatment Options
all patients
antibiotic therapy
Comments
- For management of patients with suspected or confirmed COVID-19 pneumonia, see Coronavirus disease 2019 (COVID-19) . Pneumonia due to COVID-19 is not covered in this topic.
- Major pathogens are mixed aerobic and anaerobic mouth flora.
- Anaerobic coverage is only required for patients with anaerobic pleuropulmonary syndrome (a later presentation of cavitary pneumonia or empyema associated with prior loss of consciousness and poor dental hygiene).[7] Similarly, no additional anaerobic antimicrobial coverage is warranted for patients with dysphagia or aspiration associated with stroke.[43]
- Therapy is the same as empiric therapy for non-aspiration pneumonia, whether it is community-acquired, hospital-acquired, or ventilator-associated.
- The choice of oral or intravenous therapy is made on a case-by-case basis depending on the clinical condition of the patient and the ability of the patient to tolerate oral therapy.[7]
- Therapy is typically empiric, but should be tailored to the pathogen and its sensitivities if the pathogen is determined.
- Recommended antibiotic regimens may differ between regions and local guidance should be consulted. Discussion with an infectious diseases specialist should inform the optimal regimen.
- See Community-acquired pneumonia (non COVID-19) and Hospital-acquired pneumonia (non COVID-19) for more detailed treatment information.
supportive care
Comments
- It is important to correct any underlying problems that precipitated the aspiration.
- Empyema, if present, may need drainage. Necrotizing lung abscess, if present, may be difficult to treat, and there are no clear data on when to manage medically versus surgically.
- Other nonpharmacologic measures include oxygen, management of hypotension, and therapy for acute respiratory distress syndrome and septic shock if they ensue.
- There are no established criteria to determine hospital admission or level of care, and the decision needs to be based on clinical presentation. An intensive care unit admission is justified by patient intubation, hypotension, or altered mental status.
Emerging Tx
Angiotensin-converting enzyme (ACE) inhibitors
Cilostazol
Sensory stimuli
Other treatments
Prevention
Primary Prevention
Follow-Up Overview
Prognosis
Monitoring
Complications
Citations
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 Oct 1;200(7):e45-e67.[Abstract][Full Text]
American Society of Anesthesiologists. Practice guidelines for preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration: application to healthy patients undergoing elective procedures: an updated report by the American Society of Anesthesiologists Task Force on Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration. Anesthesiology. 2017 Mar;126(3):376-93.[Abstract][Full Text]
Kalil AC, Metersky ML, Klompas M, et al. Management of adults with hospital-acquired and ventilator-associated pneumonia: 2016 clinical practice guidelines by the Infectious Diseases Society of America and the American Thoracic Society. Clin Infect Dis. 2016 Sep 1;63(5):e61-e111.[Abstract][Full Text]
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7. 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 Oct 1;200(7):e45-e67.[Abstract][Full Text]
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20. Kalil AC, Metersky ML, Klompas M, et al. Management of adults with hospital-acquired and ventilator-associated pneumonia: 2016 clinical practice guidelines by the Infectious Diseases Society of America and the American Thoracic Society. Clin Infect Dis. 2016 Sep 1;63(5):e61-e111.[Abstract][Full Text]
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25. Mylotte JM. Will maintenance of oral hygiene in nursing home residents prevent pneumonia? J Am Geriatr Soc. 2018 Mar;66(3):590-594.[Abstract]
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32. Alkhawaja S, Martin C, Butler RJ, et al. Post-pyloric versus gastric tube feeding for preventing pneumonia and improving nutritional outcomes in critically ill adults. Cochrane Database Syst Rev. 2015;(8):CD008875.[Abstract][Full Text]
33. Horiuchi A, Nakayama Y, Sakai R, et al. Elemental diets may reduce the risk of aspiration pneumonia in bedridden gastrostomy-fed patients. Am J Gastroenterol. 2013;108:804-810.[Abstract][Full Text]
34. Takatori K, Yoshida R, Horai A, et al. Therapeutic effects of mosapride citrate and lansoprazole for prevention of aspiration pneumonia in patients receiving gastrostomy feeding. J Gastroenterol. 2013 Oct;48(10):1105-10.[Abstract]
35. El Solh AA, Saliba R. Pharmacologic prevention of aspiration pneumonia: a systematic review. Am J Geriatr Pharmacother. 2007;5:352-362.[Abstract]
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37. Puig I, Calzado S, Suárez D, et al. Meta-analysis: comparative efficacy of H2-receptor antagonists and proton pump inhibitors for reducing aspiration risk during anaesthesia depending on the administration route and schedule. Pharmacol Res. 2012;65:480-490.[Abstract]
38. Eom CS, Jeon CY, Lim JW, et al. Use of acid-suppressive drugs and risk of pneumonia: a systematic review and meta-analysis. CMAJ. 2011;183:310-319.[Abstract][Full Text]
39. Paranjothy S, Griffiths JD, Broughton HK, et al. Interventions at caesarean section for reducing the risk of aspiration pneumonitis. Cochrane Database Syst Rev. 2014;(2):CD004943.[Abstract][Full Text]
40. Niederman MS. Imaging for the management of community-acquired pneumonia: what to do if the chest radiograph Is clear. Chest. 2018 Mar;153(3):583-5.[Abstract][Full Text]
41. Qaseem A, Etxeandia-Ikobaltzeta I, Mustafa RA, et al. Appropriate use of point-of-care ultrasonography in patients with acute dyspnea in emergency department or inpatient settings: a clinical guideline from the American College of Physicians. Ann Intern Med. 2021 Jul;174(7):985-93.[Abstract][Full Text]
42. Brodsky MB, Suiter DM, González-Fernández M, et al. Screening accuracy for aspiration using bedside water swallow tests: a systematic review and meta-analysis. Chest. 2016;150:148-163.[Abstract]
43. Kishore AK, Jeans AR, Garau J, et al. Antibiotic treatment for pneumonia complicating stroke: Recommendations from the pneumonia in stroke consensus (PISCES) group. Eur Stroke J. 2019 Dec;4(4):318-328.[Abstract][Full Text]
44. Daoud E, Guzman J. Q: Are antibiotics indicated for the treatment of aspiration pneumonia? Cleve Clin J Med. 2010;77:573-576.[Abstract]
45. Shinohara Y, Origasa H. Post-stroke pneumonia prevention by angiotensin-converting enzyme inhibitors: results of a meta-analysis of five studies in Asians. Adv Ther. 2012;29:900-912.[Abstract]
46. Caldeira D, Alarcão J, Vaz-Carneiro A, et al. Risk of pneumonia associated with use of angiotensin converting enzyme inhibitors and angiotensin receptor blockers: systematic review and meta-analysis. BMJ. 2012 Jul 11;345:e4260.[Abstract][Full Text]
47. Tsunoda H, Okami Y, Honda Y, et al. Effectiveness of angiotensin converting enzyme inhibitors in preventing pneumonia: A systematic review and meta-analysis. J Gen Fam Med. 2022 Jul;23(4):217-27.[Abstract][Full Text]
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Key Articles
Referenced Articles
Guidelines
Treatment
Summary
Evidence-based clinical practice guidelines on the management of adult patients with community-acquired pneumonia. Recommendations include not routinely adding anaerobic coverage for patients with suspected aspiration pneumonia, unless empyema or lung abscess is suspected.Published by
Infectious Diseases Society of America; American Thoracic Society
Published
2019
Summary
Update of 2011 guidelines focusing on preoperative fasting recommendations for healthy patients undergoing elective procedures; includes recommendations regarding the use of pharmacologic agents to reduce the risk of pulmonary aspiration.Published by
American Society of Anesthesiologists
Published
2017
Summary
Update of the 2005 recommendations, intended for use by healthcare professionals who care for patients at risk of hospital-acquired pneumonia and ventilator-associated pneumonia.Published by
Infectious Diseases Society of America; American Thoracic Society
Published
2016