5. Aspiration Pneumonia
Considered not as a distinct entity but
as a continuum that also includes
community- acquired and hospital
acquired pneumonias
5 to 15% of cases of community-
acquired pneumonia (CAP)
Figures for hospital acquired
pneumonia are unavailable
7. 50% of healthy persons aspirate during
sleep, which usually goes unrecognized,
and has no sequelae.
Determinants who gets infection?
◦ Frequency of aspiration,
◦ Volume of the aspiration,
◦ Character of the aspirated material,
◦ Host defenses
8. In healthy state, the immune tone of
airways and alveoli – calibrated by the
bacteria constituting lung microbiota
Stability of the lung microbiome is
maintained by – balance of immigration
and elimination of bacteria and by
feedback loops
Dysbiosis( change in lung microbiota ) –
impair pulmonary defenses
10. In the 1970s, anaerobes with or without
aerobes were the predominant
pathogens (e.g- Peptostreptococcus
sp., Fusobacterium sp., Bacteroides
sp.)
More recently, there has been a shift to
aerobic bacteria (usually associated
with community- and hospital-acquired
pneumonias) & the anaerobes are
recovered less frequently (STUDY)
11. The main isolates are
◦ Streptococcus pneumoniae,
◦ Staphylococcus aureus,
◦ Haemophilus influenzae, &
◦ Enterobacteriaceae in community-acquired
cases,
◦ whereas gram-negative bacilli, including
Pseudomonas aeruginosa, were found
without anaerobes in hospital-acquired
cases
◦ In cases of poor dental hygiene, the
anaerobes isolated are Porphyromonas
gingivalis, Treponema denticola, Prevotella,
12. Why such shift ?
Mostly unclear
But may be due to a shift in the
demographic characteristics of patients
And earlier sampling today than in the
past.
Prior studies often collected cultures later
in the illness, often after the development
of lung abscess or necrotising pneumonia
or empyema.
17. ASPIRATION PNEUMONIA CHEMICAL
PNEUMONITIS
ONSET OF
SYMPTOMS
HOURS TO A FEW DAYS SUDDEN
ONSET(MINUTES TO
HOURS)
SYMPTOMS FEVER, COUGH WITH
EXPECTORATION,TACHYPNEA,
SHOCK
DYSPNEA, HYPOXIA,
TACHYCARDIA, DIFFUSE
WHEEZE (NO FEVER)
CLINICALLY /
RADIOLOGIC
ALLY
DEPENDENT BRONCHOPULMONARY
SEGMENT INVOLVEMENT
( Aspirated while Supine—posterior
segment of upper lobe,usually Rt side or
superoir segments of either or both lower
lobes
Aspirated while Upright—Basal lung
B/L OPACITY ON CXR
19. Clinical history (witnessed aspiration) & findings
Risk factors
Chest X-ray (may be negative in the early
course)
CT scan of thorax
Thoracentesis
Bronchoalveolar lavage cultures
Sr. Procalcitonin isn’t helpful (STUDY)
20. •68-year-old man
•History
of cough, blood in the
sputum, and a 6.8-kg weight
loss.
•He had
extensive tooth decay and
gingival inflammation.
•Didn’t drink alcohol or abuse
illicit drugs
•But did take an
antidepressant
known to cause somnolence.
•The radiograph shows a
cavitary infiltrate in the left
lower lobe and an infiltrate
RADIOGRAPH - A
21. RADIOGRAPH - B
•84-year-old man with
small-bowel
obstruction.
•Had repeated
episodes of vomiting,
leading to
•development of
bilateral lung infiltrates,
respiratory failure & the
acute respiratory
distress syndrome.
•Initial cultures were
sterile, but 1 week later,
he continued to have
lung infiltrates
and sputum culture
showed methicillin-
resistant
22. CT Thorax -1
•56-year-old man
•Had cough after
tooth extraction
performed with
local anesthesia.
•Known alcoholic.
•Shows a cavitary
infiltrate in the right
upper lobe
posteriorly
• Bronchoscopic
cultures revealed
Klebsiella
pneumoniae
23. •79-year-old
man with
dyspnea after
upper GI
endoscopy
•Complicated by
vomiting
•Shows new
bilateral
infiltrates in
posterior,
gravity-
dependent lung
segments
CT Thorax - 2
25. As documented pathogens have shifted
from anaerobes to aerobes, treatment
regimens have also evolved.
Still anaerobes are common in patients
having severe periodontal disease & in
lung abscess, necrotising pneumonia
Studies prove that for anaerobes in
lung, clindamycin is superior to
metronidazole (STUDY)
26. Algorithmic Approach to Antibiotic
Therapy for Aspiration Pneumonia
Antibiotic selection depends on
The site of acquisition (the community, a
hospital, or a long term care facility) and
Risk factors
1. for infection with multidrug-resistant
pathogens,
2. whether treated with broad-spectrum
antibiotics in the past 90 days or
hospitalised for at least 5 days &
3. Dental health
30. Hospital acquired or long-term care acquired
Same T/T as that of CAP
But, if risk of MDR,
• Piperacillin–tazobactam,
• Cefepime
• Levofloxacin,
• Carbapenem (meropenem,imipenem)
• either Aminoglycoside or Colistin
• If MRSA, then PLUS Vancomycin or
Linezolid
31. Treatment contd..
Duration :-
Reassessment after 48 hours
5-7 days if good clinical response
Longer period for those with necrotizing
pneumonia, lung abscess, or empyema.
No role of glucocorticoids
Treatment can be modified or discontinued after
culture & sensitivity reports
No role of antibiotics and steroid in chemical
pneumonitis even with an abnormal radiograph
(exception- if the patient is severely ill, or has small bowel
obstruction or is on acid suppression therapy)
34. Stroke patients
Early mobilisation & swallowing exercises (procedure)
Soft diet with thickened liquids(nutritional
rehabilitation)
RTF in semi-recumbent position
Role of nasogastric tubes in preventing
aspiration pneumonia is uncertain (STUDY)
Post-pyloric feeding is not superior to gastric
feeding & monitoring of post-feeding residual
volume may not minimize the risk of aspiration
35. Prevention contd..
Antibiotic therapy for 24 hr in comatose
patients after emergency intubation(STUDY)
Role of ACE inhibitors and Cilostazol
(STUDY)
Role of chlorhexidine in oral hygiene
(STUDY)
36.
37. Conclusions
Diagnostic approach should be based on
clinical findings, risk factors and radioimaging
Shift of pathogens, from anaerobes to
aerobes
Clindamycin being superior to metronidazole
Treatment should be based on risk factors
and culture
No role of steroids
Preventive measures in high risk patients
38. BIBLIOGRAPHY
Mandell Lionel A. and Niederman Michael S., McMaster
University, Hamilton, Aspiration Pneumonia. N Engl J Med
2019;380:651-63.
Mandell Lionel A., Wunderink Richard, J. Larry Jameson,
Anthony S. Fauci, Kasper, Hauser, Longo, Loscalzo, Harrison’s
Principles of Internal Medicine, Volume 1, Chapter 121, Pg 908-
918, Chapter 172, Pg 1231, 20th edition
Marik Paul E. , Michael A. Grippi, Jack A. Elias, Jay A. Fishman
et al., Fishman's Pulmonary Diseases and Disorders, Chapter
69, Pg-2216-2238, 5th edition
Seaton Douglas, Anthony Seaton, A. Gordon Leitch, Crofton and
Douglas's Respiratory Diseases, Chapter 13, Pg 412-414, 5th
edition
Musher Daniel M. , Cecil, R. L. 1., Goldman, L., & Schafer A. I.,
(2012). Goldman's Cecil Medicine, Chapter 97 , Pg 618 , 25th