Aspiration pneumonia overview: Difference between revisions
No edit summary |
|||
| Line 35: | Line 35: | ||
===History and Symptoms=== | ===History and Symptoms=== | ||
Patients with aspiration pneumonia may have a positive history of predisposing condition or altered level of [[consciousness]]. The most common symptoms of aspiration pneumonia include [[chest pain]], [[cough]], [[fever]], and [[Perspiration|sweating]]. Less common symptoms of aspiration pneumonia include [[fatigue]], [[nausea and vomiting]], [[diarrhea]], and [[dyspnea]]. | |||
===Physical Examination=== | ===Physical Examination=== | ||
Patients with aspiration might appear normal or toxic. Physical examination of patients with aspiration pneumonia is usually remarkable for: [[fever]], [[tachypnea]], [[hypotension]], [[Rales|crackles]], decreased [[breath sounds]], and increased [[tactile fremitus]]. | |||
===Laboratory Findings=== | ===Laboratory Findings=== | ||
Revision as of 20:47, 3 April 2018
|
Aspiration pneumonia Microchapters | |
|
Diagnosis | |
|---|---|
|
Treatment | |
|
Aspiration pneumonia overview On the Web | |
|
American Roentgen Ray Society Images of Aspiration pneumonia overview | |
|
Risk calculators and risk factors for Aspiration pneumonia overview | |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sunny Kumar MD [2]
Overview
Historical Perspective
The literature on aspiration pneumonia came into knowledge of medical society along with the discovery of pneumonia. During 1893, Veillon was first to write about the role of anaerobic bacteria in aspiration pneumonia. The major breakthrough came when x-ray was invented by Roentgen in 1896.
Classification
Aspiration pneumonia is a part of aspiration syndrome which is consist of four classes depending on nature of aspirated substance including foreign body aspiration, chemical pneumonitis, bacterial infection, and lipid pneumonia. Aspiration pneumonia depends on the duration of systems might be classified into two groups of acute and chronic.
Pathophysiology
Aspiration pneumonia is a common pneumonia among patients with risk factors including neurologic diseases. Microaspiration and macroaspiration of different materials are the main cause of aspiration pneumonia. The mechanism behind damage of lung due to aspiration of depends on the content of aspirate and the response of lung tissue to the content. Host factors including mucociliary clearance, cough reflex, and immune system might be probably impaired. Chemical pneumonitis usually occurs following aspiration of materials that are toxic to pulmonary tissue. There might be no bacterial or viral organisms involved. It is mostly associated with aspiration of gastric acid. In case of oropharyngeal secretions the damage is due to bacteria infecting and inducing inflammation in lung tissues. Foreign body aspiration might present acutely with mechanical obstruction or chemical pneumonitis. Lipoid pneumonia is caused by aspiration of mineral oil when used for constipation treatment. Following oil aspiration there is an inflammatory response with regional edema and acute cough, fever, and dyspnea. Patients with genetic syndromes and paralysis of lower cranial nerves might be prone to aspiration pneumonia. On gross pathology, different aspirated particles might be seen. On microscopic histopathological analysis, aspirated material fragments, inflammation, fibrosis, and skeletal muscle fibers might be seen.
Causes
Aspiration pneumonia is caused by aspiration of different particles including secretions, gastric contents or any foreign material which reaches lung parenchyma and damages lung tissue by inflammation. Microorganisms that are responsible for aspiration pneumonia include S. aureus, S. pneumoniae, Enteric bacilli, Hemophilus species, Neisseria species, M. catarrhalis, P. aeruginosa.
Differentiating Xyz from Other Diseases
Aspiration pneumonia must be differentiated from other diseases that cause productive cough, fever, and dyspnea.
Epidemiology and Demographics
The incidence and prevalence of aspiration pneumonia are underestimated. It is mostly because of similarities between pneumonias from different causes and lack of specific marker to distinguish pneumonias from each other. The incidence of aspiration pneumonia is approximately 300,000 to 600,000 individuals annually in the United States. The prevalence of aspiration pneumonia is approximately 5,000 to 15,000 per 100,000 individuals admitted in the hospital due to community acquired pneumonia. The mortality rateof aspiration pneumonia is approximately 10.6-21%. The incidence of aspiration pneumonia increases with age; the median age at diagnosis is 70-80 years. Males are more commonly affected by aspiration pneumonia than females. There is no racial predilection to aspiration pneumonia.
Risk Factors
Common risk factors in the development of aspiration pneumonia include dysphagia, swallowing dysfunction, altered mental status, COPD, and hospitalization. Less common risk factors in the development of aspiration pneumonia include medications, esophageal motility disorders, vomiting, enteral feeding, oropharyngeal colonization, male sex, and smoking.
Screening
There is insufficient evidence to recommend routine screening for aspiration pneumonia.
Natural History, Complications, and Prognosis
Aspiration pneumonia occurs following aspiration of different materials and particles. Natural history, complications, and prognosis are different for each category. Chemical pneumonitis usually develop after aspiration of gastric acid and might present acutely within two hours. Rapid clinical recovery or worsening of respiratory distress and hypoxemia might happen. Bacterial infection following aspiration is slower that other community-acquired pneumonia and might be acute, subacute, or chronic. Foreign bodyaspiration might present acutely with mechanical obstruction or chemical pneumonitis. Patients might present acutely with inflammation and cough, fever, and dyspnea. However, they might be asymptomatic and present with an incidental mass on radiographs. Complications of aspiration pneumonia include segmental or lobar pneumonia, bronchopneumonia, bronchiectasis, lung abscess, empyema, respiratory failure, bacteremia, and shock.
Diagnosis
Diagnostic Study of Choice
History and Symptoms
Patients with aspiration pneumonia may have a positive history of predisposing condition or altered level of consciousness. The most common symptoms of aspiration pneumonia include chest pain, cough, fever, and sweating. Less common symptoms of aspiration pneumonia include fatigue, nausea and vomiting, diarrhea, and dyspnea.
Physical Examination
Patients with aspiration might appear normal or toxic. Physical examination of patients with aspiration pneumonia is usually remarkable for: fever, tachypnea, hypotension, crackles, decreased breath sounds, and increased tactile fremitus.