Aspiration pneumonia in older people
David J Stott
David Cargill Professor of Geriatric
Medicine
Aspiration pneumonia in older people
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Epidemiology
Causes of aspiration pneumonia
– Oropharyngeal dysphagia
• Cerebrovascular and degenerative neurological disease
– Oropharyngeal bacterial colonisation / poor oral health
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Issues of older age
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‘Physiology’ of ageing
Multimorbidity
Undernutrition
Reduced functional and cognitive reserve
Non-specific presentation of disease
Prevention
Management
Conflict of interest
Research funding from pharmaceutical industry –
Trials of statins, antithrombotics, nutritional
supplements
Consultancy – Nestle Nutrition, Pfizer, Astra Zeneca
Epidemiology
• Incidence of pneumonia increases with
aging and frailty
– RR=6 if age > 75 compared to < 60 years
– hospitalisations per year for pneumonia
1.1 / 1000 community-dwelling elderly adults
33 / 1,000 nursing home residents per year
• Morbidity and mortality from pneumonia
increases with aging
Marik, Chest 2003
Definitions and mechanisms
• Aspiration is the misdirection of oropharyngeal or
gastric contents into the larynx and lower
respiratory tract
• Aspiration pneumonia develops after aspiration of
bacterially colonized oropharyngeal contents
• Aspiration of bacteria from oropharynx is the
primary pathway by which bacteria gain entrance
to the lungs
Bacterial cause of communityacquired pneumonia (CAP)
• Diagnosis of the bacterial cause of CAP is made in <50%
– Particular problem in frail elderly patients, often unable to produce
adequate sputum specimens
• Higher prevalence of Gram-negative pathogens and Staph
aureus in elderly patients with CAP
– Presumably due to oropharyngeal colonization with subsequent
aspiration
• Strep pneumoniae remains the single most common
implicated pathogen in elderly patients
– Unclear if patients with dysphagia are at risk of acquiring
pneumococcal pneumonia
Health-care associated pneumonia
Risk factors - pneumonia in older people
• Community dwelling
– ‘Silent’ aspiration in 71% of patients with CAP
compared to 10% in controls
• Residents of long-term care facilities
– Difficulty swallowing food (OR 2.0) and
medication (OR 8.3)
– Witnessed aspiration
– Sedative medicines
Protection against aspiration
• Preserved swallow or cough reflex are important defenses
against oropharyngeal aspiration
• Impaired swallow / cough increase risk of aspiration
pneumonia
• Approximately half of all healthy adults aspirate small
amounts of oropharyngeal secretions during sleep, most
have no sequelae
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low bacterial burden of normal pharyngeal secretions
coughing
active ciliary transport
normal humoral and cellular immune mechanisms
Functional neuroanatomy of voluntary
swallowing – regional CBF / PET
• Increase in rCBF over
large-scale distributed
neural network
– L+R inferior pre-central
gyrus
– R anterior insula
– L cerebellum
– Putamen, thalamus,
several cortical areas
Zald, Ann Neurol 1999;46:281
Dementia prevalence (%) by age (yrs)
Nosocomial pneumonia occurs in up
to 40% of acute stroke patients
Dysphagia after stroke
• Difficulty with / inability to swallow
• 50% of acute stroke patients have clinical
dysphagia
• Most (80%) resolve in the first 7-10 days
• Associates with big strokes, aphasia
• Increased risk of pneumonia
Mann et al, Stroke 1999; 30:744
Poor oral health + oropharyngeal bacterial
colonisation after stroke
Can’t do oral hygiene!
• Reduced conscious level
• Impaired hand / arm function
Can’t ask for oral hygiene!
• Communication barriers
• Dysphasia
• Delirium
• Dementia
Increased oral vulnerability
• Dysphagia
• Xerostomia
• Nil by mouth
• Drugs
• Nutritional supplements
Poor oral health in older people is
often associated with other problems
Associated problems
• Poor oral health
• Chronic physical
disability
• Cognitive decline and
dementia
• Sensory impairment
– Hearing, vision
• Acute illness
Mechanisms
• Common risk factors
– Cigarettes, alcohol,
socio-economic status,
low education
• Two-way relationship
– Poor oral health →
systemic illness
– Systemic illness →
poor oral health
The mouth after acute stroke
Dentures (%)
53%
No teeth or dentures (%)
15%
Oral cavity score
10 (8, 13)
(median + IQR)
Xerostomia (%)
61%
(<1uL/min salivary flow)
Sellars, Stott et al, Stroke 2007;
38:2284
Oral bacterial and fungal flora
70
% acute
stroke
patients
60
50
40
Candida Albicans
Candida Glabrata
Gram Positive
Gram Negative
30
20
10
0
No Salivary
Flow
1-120uL/min
>120uL/min
Kerr, Sweeney, Bagg, Stott et al,
Cerebrovascular Diseases; 2010
Predictors of post-stroke pneumonia
Univariate predictors not
significant on multivariate
analysis
• Poor oral health
• Oral bacterial colonisation
• COPD
Independent predictors
(Binary logistic regression)
• Age > 65 years
• Dysarthria or aphasia
• Severe disability
– modified Rankin > 4
• Cognitive impairment
– Abbreviated Mental Test < 8
• Failed water swallow test
Sellars, Stott et al, Stroke 2007; 38:
2284
Swallowing assessment and
investigation after stroke
Routine assessment
• Look in the mouth!
No impaired consciousness
• Water swallow test
• Bedside swallow
assessment
Selected patients
• Nasendoscopy
• Modified Barium swallow
(video-fluoroscopy)
Key concepts in illness in later life
• Reduced homeostatic reserve with ageing
• Multiple diseases
– Frailty
– Undernutrition
– Iatrogenesis, adverse drug reactions
• Non-specific presentation of disease
– Geriatric giants
• Multiple problems, requiring complex
solutions
FVC and FEV1 and ageing
Knudson, Am Rev Resp Dis 1976
Healthy ageing and the swallow
• Older people swallow more slowly
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Laryngeal vestibule closure delayed
Maximal hyolaryngeal excursion delayed
Upper esophageal sphincter opening delayed
Oral bolus transport time prolonged
• Safety of oropharyngeal swallowing is not
compromised
– No increase in the frequency of aspiration in
radiographic studies that compare older to younger
adults
– However reduced physiological reserve
Cough reflex –respiratory defence
• No apparent effect of healthy ageing on the
cough reflex
• The cough threshold concentration for
inhaled citric acid
– 2.6 ± 4.0 mg/mL in control subjects
– 37.1 ± 16.7 mg/mL in patients with dementia
– > 360 mg/mL in survivors of aspiration
pneumonia
Geriatric Giants – non-specific
presentation of disease
• Intellectual impairment
– Delirium and dementia
• Immobility
– ‘Off feet’
• Instability
– Falls
• Incontinence
• Loss of swallow
Fernandez-Sabe et al Medicine
2003; 82:159
• 1,474 patients hospitalized with CAP
– nursing home residents excluded
• 305 (21%) over 80 years versus under 80s
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pleuritic chest pain reduced (37 versus 45%)
headache (7 versus 21%)
myalgias (8% versus 23%)
absence of fever (32% versus 22%)
‘altered mental status’ (21 versus 11%)
Cumulative incidence of delirium
in hospitalised patients
Age > 65 years
15-20%
‘Frail’ elderly
40-60%
Prior chronic
cognitive
impairment
30-45%
Cochrane Database of Systematic
Reviews
Causes of delirium
D istu r b a n c e
% o f c a se s
In fe c tio n
35
C a rd io -re sp ira to ry
32
F lu id / e le c tro ly te
30
M e ta b o lic
13
In tra c ra n ia l
12
D ru g
to x ic ity /w ith d ra w a l
20
O'Keefe & Lavan, Age Ageing
1999;28: 115
Outcome of delirium
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Prolonged hospital stay
Increased mortality
Increased costs of health care
Residual cognitive impairment
Increased risk of progression to dementia
Management strategies to reduce the
risk of aspiration pneumonia
• Assistance with regular oral hygiene
• Screening / investigation for dysphagia
– High risk subgroups e.g. stroke, dementia, pneumonia, witnessed
aspiration
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Nil-by-mouth during high risk periods
Postural interventions / swallowing manoeuvres for dysphagia
Hand-feeding
Small amounts frequently
Modified diet / thickened fluids / food supplements
Conclusions
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Aspiration is the main cause of pneumonia in later life
Oropharyngeal dysphagia plus bacterial colonisation
Frailty, cognitive impairment and multi-morbidity
Non-specific presentation
Potential for prevention
– multi-modal / multi-disciplinary strategies
Acknowledgements
Collaborators
• Petrina Sweeney
• Jeremy Bagg
• Gillian Kerr
• Marian Brady
• Cameron Sellars
• Lindsay Bowie
• Peter Langhorne
Funders
• CSO Scottish Executive
• Chest Heart and Stroke
Scotland