Overview
Aspiration Pneumonia
Topic Overview
Summary
Aspiration pneumonia is lung infection following inhalation of oropharyngeal or gastric contents. It occurs in patients with impaired swallowing or reduced consciousness. Risk factors include stroke, dementia, alcoholism, anaesthesia, and nasogastric feeding. It is typically polymicrobial, including anaerobes. Treatment is antibiotics covering gram-negatives, gram-positives, and anaerobes, plus management of underlying swallowing dysfunction. Prevention through swallow assessment and aspiration precautions is critical.
Key Facts
- Cause: Aspiration of oropharyngeal/gastric contents into lungs
- Risk factors: Dysphagia, reduced GCS, stroke, dementia, anaesthesia
- Location: Often right lower lobe (anatomy of bronchi)
- Organisms: Polymicrobial; anaerobes, gram-negatives, Strep
- Treatment: Broad-spectrum antibiotics; address swallowing
Clinical Pearls
Aspiration pneumonitis (chemical) vs aspiration pneumonia (infectious) — both may overlap
Right lower lobe most common (right main bronchus more vertical)
Recurrent aspiration pneumonia = investigate swallowing and consider goals of care
Why This Matters Clinically
Aspiration pneumonia is common in elderly and frail patients. Prevention is key. Recurrent episodes often indicate poor prognosis and warrant goals of care discussions.
Visual Summary
Visual assets to be added:
- Aspiration anatomy diagram
- CXR showing aspiration pneumonia
- Risk factor checklist
- Management algorithm
Epidemiology
Incidence
- 5-15% of community-acquired pneumonia
- Up to 30% in nursing home residents
Demographics
- Elderly
- Nursing home residents
- Post-stroke patients
- ICU patients
Risk Factors
| Factor | Notes |
|---|---|
| Dysphagia | Stroke, Parkinson's, dementia, motor neurone disease |
| Reduced consciousness | Alcohol, drugs, anaesthesia, seizures |
| GORD/vomiting | Gastric aspiration |
| Mechanical | NG tube, tracheostomy |
| Poor oral hygiene | Increases bacterial load |
| Frailty/debility |
Pathophysiology
Types
| Type | Mechanism |
|---|---|
| Aspiration pneumonitis | Chemical injury from gastric acid; sterile initially |
| Aspiration pneumonia | Bacterial infection from oropharyngeal flora |
Mechanism
- Aspiration of material into lower respiratory tract
- Failure of protective reflexes (cough, gag)
- Bacterial colonisation and infection
- Inflammatory response → pneumonia
Organisms
| Source | Organisms |
|---|---|
| Oropharyngeal | Strep pneumoniae, H. influenzae, S. aureus, anaerobes |
| Gastric | May be sterile initially; secondary infection |
| Hospital-acquired | Gram-negatives (Pseudomonas, Klebsiella), MRSA |
Location
- Right lower lobe (most common — anatomy)
- Right middle lobe
- Posterior segments of upper lobes (if supine)
Clinical Presentation
Acute Presentation
Insidious Presentation (Elderly/Frail)
Signs
Red Flags
| Finding | Significance |
|---|---|
| Witnessed aspiration | Immediate assessment |
| Respiratory failure | May need NIV/ITU |
| Recurrent episodes | Goals of care discussion |
| Cavitation/abscess | Prolonged antibiotics; consider drainage |
Cough (may be weak)
Common presentation.
Fever
Common presentation.
Dyspnoea
Common presentation.
Hypoxia
Common presentation.
Productive sputum (often foul-smelling if anaerobes)
Common presentation.
Clinical Examination
Vital Signs
- Fever
- Tachycardia
- Tachypnoea
- Hypoxia
Respiratory
- Reduced breath sounds
- Crackles (right lower zone typical)
- Bronchial breathing (consolidation)
Swallowing Assessment
- Wet/gurgly voice
- Coughing on swallowing
- Drooling
- Food residue in mouth
Investigations
Blood Tests
| Test | Finding |
|---|---|
| WCC | Elevated |
| CRP | Elevated |
| U&E | Renal function; dehydration |
| ABG | Hypoxia, respiratory failure |
Microbiology
| Sample | Notes |
|---|---|
| Sputum culture | Often difficult to obtain |
| Blood cultures | If septic |
Imaging
| Modality | Findings |
|---|---|
| CXR | Consolidation, typically right lower lobe; cavitation if abscess |
| CT chest | If complicated (abscess, empyema) |
Swallow Assessment
- Bedside swallow screen
- SALT assessment if safe
- Videofluoroscopy or FEES if needed
Classification & Staging
By Type
| Type | Features |
|---|---|
| Aspiration pneumonitis | Chemical injury; rapid onset; may not need antibiotics initially |
| Aspiration pneumonia | Bacterial infection; requires antibiotics |
By Setting
- Community-acquired
- Hospital-acquired (HAP)
- Nursing home-acquired
Management
Immediate
| Action | Details |
|---|---|
| Oxygen | Target SpO2 94-98% (88-92% if COPD) |
| NBM | Until swallow assessed |
| IV fluids | If dehydrated |
| Analgesia | For pleuritic pain |
Antibiotics
Community-Acquired:
| Regimen | Notes |
|---|---|
| Co-amoxiclav | Covers anaerobes |
| Or amoxicillin + metronidazole | Alternative |
| Duration | 5-7 days (longer if complicated) |
Hospital-Acquired/Severe:
| Regimen | Notes |
|---|---|
| Piperacillin-tazobactam | Broad-spectrum including Pseudomonas |
| + metronidazole | If anaerobic cover needed |
| Or meropenem | If ESBL risk |
Aspiration Pneumonitis Only
- May not need antibiotics if no infection develops
- Observe for 48-72 hours
- Start antibiotics if clinical deterioration
Swallowing Management
| Action | Notes |
|---|---|
| NBM initially | Until safe swallow confirmed |
| SALT assessment | As soon as possible |
| Modified diet | Thickened fluids, soft diet if needed |
| NG feeding | If prolonged dysphagia |
| PEG | Consider if long-term feeding needed |
Prevention
| Measure | Notes |
|---|---|
| Head of bed elevation | 30-45 degrees |
| Oral hygiene | Reduces bacterial load |
| Swallow assessment | Before oral intake |
| Aspiration precautions | Supervision, positioning |
| Review medications | Sedatives may worsen |
Goals of Care
- Recurrent aspiration in frail/end-stage patients
- Discuss prognosis and treatment goals
- May be appropriate to focus on comfort
Complications
Pulmonary
- Lung abscess
- Empyema
- ARDS
- Respiratory failure
Systemic
- Sepsis
- Death
Prognosis & Outcomes
Prognosis
- Mortality 20-30% in hospitalised patients
- Higher in frail, elderly, recurrent aspiration
Recurrence
- High recurrence rate without addressing underlying cause
- Poor prognosis with recurrent episodes
Evidence & Guidelines
Key Guidelines
- NICE NG138: Pneumonia (Community-Acquired)
- BTS Guidelines on CAP
Key Evidence
- Aspiration precautions reduce recurrence
- SALT assessment improves outcomes in stroke patients
Patient & Family Information
What is Aspiration Pneumonia?
Aspiration pneumonia is a lung infection caused by food, drink, or saliva going down the wrong way into the lungs.
Who is at Risk?
- People who have difficulty swallowing (e.g., after a stroke)
- People who are confused or drowsy
- Elderly or frail people
Treatment
- Antibiotics
- Assessment of swallowing
- Modified diet or tube feeding if needed
Prevention
- Sit upright when eating
- Take small sips and bites
- Follow speech therapist advice
Resources
References
Primary Guidelines
- NICE. Pneumonia (Community-Acquired): Antimicrobial Prescribing (NG138). 2019.
- Lim WS, et al. BTS guidelines for the management of community-acquired pneumonia in adults. Thorax. 2009;64(Suppl 3):iii1-55. PMID: 19783532
Key Reviews
- Mandell LA, Niederman MS. Aspiration pneumonia. N Engl J Med. 2019;380(7):651-663. PMID: 30763196