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# Aspiration pneumonia and pneumonitis

Lung injury from inhaling food, saliva or [stomach](https://durgical.com/en/anatomy/stomach/) contents. Pneumonitis is chemical irritation; pneumonia is the infection that may follow.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Right lower lobe](https://durgical.com/en/anatomy/inferior-lobe-of-right-lung/)
- [Main bronchi](https://durgical.com/en/anatomy/right-main-bronchus/)
- [Epiglottis](https://durgical.com/en/anatomy/epiglottis/)
- [Pharynx](https://durgical.com/en/anatomy/pharynx/)
- [Vocal folds](https://durgical.com/en/anatomy/vocal-fold/)
- [Esophagus](https://durgical.com/en/anatomy/esophagus-abdominal-part/)
- [Trachea](https://durgical.com/en/anatomy/trachea/)
- [Right middle lobe](https://durgical.com/en/anatomy/middle-lobe-of-right-lung/)

## In embryology

- [Esophageal atresia and tracheoesophageal fistula](https://durgical.com/en/embryology/esophageal-atresia-and-tracheoesophageal-fistula/)
- [Congenital pulmonary airway malformation, sequestration and bronchogenic cyst](https://durgical.com/en/embryology/congenital-pulmonary-airway-malformation-sequestration-and-bronchogenic-cyst/)

## In the clinical exam

- [Consolidation syndrome](https://durgical.com/en/clinical-exam/consolidation-syndrome/)
- [Cavitation syndrome](https://durgical.com/en/clinical-exam/cavitation-syndrome/)

## Why it happens

- [Chemical (toxic) cell injury: direct and after metabolism](https://durgical.com/en/general-pathology/chemical-cell-injury-direct-and-after-metabolism/)
- [Patterns of acute inflammation: serous, fibrinous, purulent, abscess, ulcer](https://durgical.com/en/general-pathology/patterns-of-acute-inflammation-serous-fibrinous-purulent-abscess-ulcer/)
- [Airway defenses, cough and mucociliary clearance](https://durgical.com/en/physiology/airway-defenses-cough-and-mucociliary-clearance/)
- [Swallowing and esophageal motility](https://durgical.com/en/physiology/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](https://durgical.com/en/anatomy/epiglottis/) and [vocal folds](https://durgical.com/en/anatomy/vocal-fold/) fail, material passes into the [trachea](https://durgical.com/en/anatomy/trachea/). The [right main bronchus](https://durgical.com/en/anatomy/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

## Red flags

- Rapidly worsening hypoxaemia or respiratory distress
- Signs of sepsis or shock
- Airway obstruction by a food bolus or foreign body (choking)
- Cavity on imaging (abscess) or a large effusion (possible empyema)

## 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](https://durgical.com/en/anatomy/region/chest/) X-ray showing infiltrates in dependent segments, more often the [right lower lobe](https://durgical.com/en/anatomy/inferior-lobe-of-right-lung/); 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.

[Add to my cards (5)](https://durgical.app/estudiar/?add=/en/conditions/aspiration-pneumonia-and-pneumonitis/)

## Related conditions

- [Community-acquired pneumonia](https://durgical.com/en/conditions/community-acquired-pneumonia/)
- [Hospital-acquired and ventilator-associated pneumonia](https://durgical.com/en/conditions/hospital-acquired-and-ventilator-associated-pneumonia/)
- [Acute respiratory failure (hypoxaemic and hypercapnic)](https://durgical.com/en/conditions/acute-respiratory-failure/)
- [Acute respiratory distress syndrome (ARDS)](https://durgical.com/en/conditions/acute-respiratory-distress-syndrome/)
- [Ischaemic stroke](https://durgical.com/en/conditions/ischaemic-stroke/)
- [Parkinson disease](https://durgical.com/en/conditions/parkinson-disease/)
- [Alzheimer disease](https://durgical.com/en/conditions/alzheimer-disease/)
- [Epilepsy and seizures](https://durgical.com/en/conditions/epilepsy-and-seizures/)
- [Gastro-oesophageal reflux disease (GERD)](https://durgical.com/en/conditions/gastro-oesophageal-reflux-disease/)
- [Achalasia](https://durgical.com/en/conditions/achalasia/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Aspiration pneumonia: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/000121.htm) (MedlinePlus (U.S. National Library of Medicine), 2024).

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Source: https://durgical.com/en/conditions/aspiration-pneumonia-and-pneumonitis/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/aspiration-pneumonia-and-pneumonitis/