Aspiration pneumonia and pneumonitis !
Lung injury from inhaling food, saliva or stomach contents. Pneumonitis is chemical irritation; pneumonia is the infection that may follow.
Updated 2026-11-01
Structures involved
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In embryology
- Esophageal atresia and tracheoesophageal fistula
- Congenital pulmonary airway malformation, sequestration and bronchogenic cyst
In the clinical exam
Why it happens
- Chemical (toxic) cell injury: direct and after metabolism
- Patterns of acute inflammation: serous, fibrinous, purulent, abscess, ulcer
- Airway defenses, cough and mucociliary clearance
- Swallowing and esophageal motility
What it is
Aspiration pneumonitis is acute chemical lung injury after inhaling sterile gastric contents. Aspiration pneumonia is a lung infection caused by inhaling oropharyngeal secretions colonised by bacteria, usually in people with impaired swallowing or consciousness.
Who gets it
Common in older adults, in people with stroke, dementia or Parkinson disease, and in nursing homes and hospitals; it accounts for a significant share of pneumonias in these groups. Stroke-related dysphagia is a frequent cause in Colombian hospitals.
Causes
- Oropharyngeal bacteria (streptococci, Staphylococcus aureus, gram-negative bacilli, and anaerobes with poor dental hygiene)
- Acidic gastric contents (pneumonitis, Mendelson syndrome)
- Food, liquids or a foreign body entering the airway
Risk factors
- Dysphagia after stroke, or in Parkinson disease, dementia or neuromuscular disease
- Reduced consciousness: alcohol or drug intoxication, seizures, sedation, general anaesthesia
- Vomiting, gastro-oesophageal reflux, achalasia or oesophageal obstruction
- Nasogastric or feeding tubes and lying flat during feeding
- Poor oral hygiene and older age
Pathophysiology
When the cough and the closure of the epiglottis and vocal folds fail, material passes into the trachea. The right main bronchus is wider, shorter and more vertical, so aspirated material usually reaches the right lung. Supine, it lands in the posterior segments of the upper lobes and superior segments of the lower lobes; upright, in the basal segments of the lower lobes. Acid causes immediate chemical injury, while colonised secretions cause infection over days.
Classification
- Aspiration pneumonitis: chemical injury from gastric contents, often witnessed, after reduced consciousness
- Aspiration pneumonia: bacterial infection from colonised secretions, more gradual
- Complicated forms: lung abscess, necrotising pneumonia, empyema
Symptoms and signs
- Cough, often during or after eating or drinking
- Fever and purulent or foul-smelling sputum (anaerobes)
- Shortness of breath and wheeze
- Chest pain
- Sudden hypoxaemia within hours after witnessed vomiting and aspiration (pneumonitis)
- Wet or gurgling voice after swallowing as a sign of dysphagia
Diagnosis
- Clinical
- Suspected from risk factors (dysphagia, reduced consciousness, vomiting) plus respiratory symptoms. A bedside swallow screen is done before any oral intake after a stroke, a key nursing safety step.
- Tests
- Blood count, blood cultures and sputum culture when possible, blood gases. Formal swallowing assessment by a speech therapist (videofluoroscopy or endoscopic evaluation) to find the cause.
- Imaging
- Chest X-ray showing infiltrates in dependent segments, more often the right lower lobe; CT for abscess, empyema or an unclear picture. Bronchoscopy to remove a foreign body.
Differential diagnosis
- Community-acquired pneumonia
- Hospital-acquired pneumonia
- Cardiogenic pulmonary oedema
- ARDS from another cause
- Retained foreign body
- Pulmonary tuberculosis (if cavitation)
Goal of treatment
Clear and protect the airway, support oxygenation, treat infection when present and correct the swallowing or consciousness problem that caused the aspiration.
Treatment
- Acute
- Suction of the oropharynx and airway, positioning on the side or upright, supplemental oxygen and ventilatory support if needed; bronchoscopy for solid particles.
- Medical
- Antibiotics for aspiration pneumonia (e.g. a beta-lactam with beta-lactamase inhibitor, wider cover for hospital-onset cases); pure chemical pneumonitis does not routinely need antibiotics unless it does not improve within about 48 hours.
- Conservative
- Nil by mouth until the swallow is assessed, then texture-modified diet and thickened liquids; feeding upright and staying upright 30 minutes after meals; oral care.
- Rehabilitation
- Swallowing therapy by a speech and language therapist, with compensatory techniques such as chin tuck.
Complications
- Lung abscess and necrotising pneumonia
- Empyema
- ARDS and acute respiratory failure
- Sepsis
- Recurrent aspiration and malnutrition
Prognosis
Pneumonitis often improves within a few days if there is no infection. Aspiration pneumonia has a higher mortality than ordinary community-acquired pneumonia because it affects frail people, and it tends to recur while dysphagia persists.
Prevention
- Swallow screening before oral intake after stroke
- Head of bed elevation and upright feeding, especially with feeding tubes
- Fasting before anaesthesia and careful airway management
- Good oral hygiene in older adults and nursing home residents
- Limiting sedatives in people at risk
Test yourself
Think of the answer, then tap the question to see it.
Why does aspirated material usually go to the right lung?
The right main bronchus is wider, shorter and more vertical than the left.
Which lung segments are affected when a person aspirates while lying supine?
The posterior segments of the upper lobes and the superior segments of the lower lobes.
How does aspiration pneumonitis differ from aspiration pneumonia?
Pneumonitis is chemical injury from sterile gastric acid, appearing within hours; pneumonia is a bacterial infection from colonised oropharyngeal secretions, developing over days.
What should be done before giving food or drink to a patient after a stroke?
A swallow screen; the patient stays nil by mouth until it is passed or a formal assessment is done.
Which complication is suggested by foul-smelling sputum and a cavity with an air-fluid level?
A lung abscess, usually from anaerobic bacteria after aspiration.
Related conditions
- Community-acquired pneumonia
- Hospital-acquired and ventilator-associated pneumonia
- Acute respiratory failure (hypoxaemic and hypercapnic)
- Acute respiratory distress syndrome (ARDS)
- Ischaemic stroke
- Parkinson disease
- Alzheimer disease
- Epilepsy and seizures
- Gastro-oesophageal reflux disease (GERD)
- Achalasia
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Aspiration pneumonia: MedlinePlus Medical Encyclopedia (MedlinePlus (U.S. National Library of Medicine), 2024).
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