Dr. Sunil Kumar Sharma provides an overview of aspiration pneumonia. There are two main types: chemical pneumonitis caused by inhalation of large volumes of gastric contents, and aspiration pneumonia caused by bacteria normally residing in the oral cavity. Aspiration pneumonia is more common in individuals with impaired airway protection mechanisms. Common predisposing conditions include altered consciousness, neurological impairment, and dysphagia. Clinical presentation varies from mild to critical illness depending on the volume and pathogens involved. Diagnosis involves assessing risk factors and radiographic evidence of lung infiltrates.

1. Dr. Sunil Kumar Sharma
(Senior Resident)
Moderator
Dr. Dilip Maheshwari(DM)
Asso. Prof.
Dept. of Neurology
GMC Kota

2. Overview
 Aspiration pneumonitis results from inhalation of
stomach contents , food material or secretions of the
oropharynx leading to lower respiratory tract infection
 Clinical manifestation depends upon
-the quantity and nature of the aspirated material,
-the frequency of aspiration,
-the host factors

3. Types of aspiration syndromes
 Mainly two types-
1-Chemical pneumonitis or Mendelson's
syndrome.
2-Aspiration pneumonia.

4.  Aspiration pneumonia is caused by bacteria that
normally reside in the oral and nasal pharynx.
 Historically, aspiration pneumonia caused primarily by
oropharyngeal anaerobes, less virulent bacteria.
 It is now recognized that the most common
pathogens causing aspiration pneumonia are from
the oral cavity or nasopharynx ,such as Streptococcus
pneumoniae,Haemophilus influenza, Staphylococcus
aureus, and Gram negative bacteria, and are relatively
virulent.

5. Predisposing Conditions for
Aspiration Pneumonia
 Altered or reduced consciousness
 Impaired gag reflex
 Inability to maintain an airway
 Periodontal disease

6. Predisposing Conditions for
Aspiration Pneumonia…
 Alcoholism
 Drug overdose
 Head trauma
 General anesthesia
 Intracranial mass lesion

7. Predisposing Conditions for
Aspiration Pneumonia…
 Dysphagia: Oropharyngeal dysphagia has been found in
the majority of elderly patients .
 Esophageal strictures
 Esophageal neoplasm
 Esophageal diverticula
 Tracheoesophageal fistula

8. Predisposing Conditions for Aspiration
Pneumonia(Neurological)…
 Stroke
 Seizure
 GBS
 Multiple sclerosis
 Dementia
 Parkinson's disease
 Myasthenia gravis
 Pseudobulbar/bulbar palsy

9. Predisposing Conditions for Aspiration
Pneumonia…
 Protracted vomiting
 Prolonged recumbency
 Chronic debilitating illnesses
 Critical illness

10. Pathophysiology
 Infiltrate develops in a patient at increased risk of
oropharyngeal aspiration of material that is colonized
by upper airway flora.
 Risk is indirectly related to the level of consciousness
of the patient(GCS)
 Aspiration of small amounts of material from the
buccal cavity, particularly during sleep, is not an
uncommon event.

11. Determinants of the extent and
severity of aspiration pneumonia
 The nature of the aspirated material,
 Volume of the aspirated material,
 State of the host defenses.

12. Chemical pneumonitis
 Also known as Mendelson syndrome, is due to the
parenchymal inflammatory reaction caused by a large
volume of gastric contents independent of infection.
 Can produce acute respiratory distress within one
hour.
 Occurs in people with altered levels of consciousness
resulting from seizures, CVA, ICSOL, drug intoxication
or overdose, and head trauma

13. Chemical pneumonitis…
 The acidity of gastric contents results in chemical
burns to the tracheobronchial tree.
 Initial chemical burn is followed by an inflammatory
cellular reaction fueled by the release of potent
cytokines, particularly tumor necrosis factor (TNF)–
alpha and interleukin (IL)–8.

14. Aspiration pneumonia
 Occurs most commonly in individuals with chronically
impaired airway defense mechanisms, such as
-Gag reflex,
-Coughing,
-Ciliary movement,
-Immune mechanisms.
 All of these helps in removing infectious material from
the lower airways

15. Aspiration pneumonia….
 Aspiration pneumonia can occur in the community or
in a hospital or health care facility (ie, nosocomial).
 In both situations, anaerobic organisms alone or in
combination with aerobic and/or microaerophilic
organisms play a role in the infection
 In anaerobic pneumonia, the pathogenesis is related to
the large volume of aspirated anaerobes and to host
factors (eg, as in alcoholism)

16. Aspiration pneumonia….
 Nosocomial aspiration pneumonia caused by hospital
acquired florae through oropharyngeal colonization(eg,
enteric Gram negative bacteria, staphylococci).
 Colonization of gram negative organisms in the
oropharynx, sedation, and intubation of the patient‘s
airways are important pathogenetic factors in nosocomial
pneumonia.

17. Aspiration pneumonia….
 Normal gastric contents is relatively sterile
 Bacteria do not play an important role in the early stages of
the gastric content aspiration unless there is ,
-Gastroparesis
-Small bowel obstruction or
-Using antacids (PPIs & histamine receptor antagonists)
 Bacterial superinfection may occur after the initial
chemical injury.

18. Causative microorganisms

19. Evidence for Anaerobes – El-Solh et al
(2003)
 95 patients admitted to an ICU for suspected severe
pneumonia were prospectively studied.
 The study only required risk factors for oropharyngeal
aspiration (eg, dysphagia) — witnessed or strongly
suspected aspiration was not required.

20. Evidence for Anaerobes – El-Solh et al
(2003)
 The study collected bronchoalveolar lavage (BAL)
samples on all patients.
 Of the 95 patients, 54 (57%) had a positive BAL result.
 Gram negative enteric bacilli were most common
(49%), followed by anaerobes (16%) and S. aureus
(12%). 22% of positive cultures were polymicrobial.

21.  Initial bacteriologic studies - anaerobic bacteria were
the predominant pathogens .
 Subsequent studies revealed that Streptococcus
pneumoniae, Staphylococcus aureus, Haemophilus
influenzae, and Enterobacteriaceae are the most
common organisms.
 Hospital acquired aspiration pneumonia is often
caused by Gram negative organisms including
Pseudomonas aeruginosa, particularly in intubated
patients(Croce MA et al. )

22.  MRSA was more common in those with HCAP versus
community acquired aspiration pneumonia (4.2% vs
1.4%) .
 These studies demonstrated a limited role of
anaerobic pathogens in both the community and
nosocomial variants of the disease.

23. Epidemiology
 Several studies suggest that 5-15% of the community
acquired pneumonia (CAP) result from aspiration
pneumonia.
 A retrospective review found that the 30 day mortality
rate from aspiration pneumonia is 21% & slightly
higher in HCAP pneumonia (29.7%).

24. Epidemiology
 Nosocomial bacterial pneumonia is the second most
likely cause of nosocomial infections, and it is the leading
cause of death from hospital acquired infections.
 Nosocomial bacterial pneumonia caused by aspiration is
much more frequent in adults than in children, and M>F.
 Predisposing factors are more common among elderly
people.

25. Clinical Presentation

26. Clinical Presentation
 Ranges from mildly ill and ambulating to critically ill,
with signs and symptoms of septic shock and/or
respiratory failure.
 Host factors and chronic conditions that result in a
decreased ability to protect one‘s airway include
-Previous CVA,
-History of esophageal diseases including achalasia
or esophageal web,
-Being a nursing home patient,
-Being chronically fed by feeding tube.

27. Physical examination findings
 Fever or hypothermia
 Tachypnea
 Tachycardia
 Decreased breath sounds
 Dullness to percussion over areas of consolidation
 Rales

28. Physical examination findings…
 Egophony and pectoriloquy
 Decreased breath sounds
 Pleural friction rub
 Altered mental status
 Hypoxemia
 Hypotension (in septic shock)

29. Chemical pneumonitis
 Acute /abrupt onset within a few minutes to two hours
of the aspiration event, as well as respiratory distress
and rapid breathing, audible wheezing, and cough
with pink or frothy sputum.
 Findings on physical examination may include
tachypnea, tachycardia, fever, rales, wheezing, and
possibly cyanosis.

30. Bacterial aspiration pneumonia
 The onset of illness may be subacute or insidious, with
the symptoms manifesting in days to weeks when
anaerobic organisms are the pathogens
 Cough with purulent sputum
 Fever or chills
 Malaise, myalgias

31. Bacterial aspiration pneumonia
 Rigors +/_
 Shortness of breath, dyspnea
 Pleuritic chest pain
 Putrid expectoration (a clue to anaerobic bacterial
pneumonia)
 headache, nausea/vomiting, anorexia, and weight loss

32. Bacterial aspiration pneumonia
 In hospital acquired aspiration pneumonia, the symptoms
of cough and shortness of breath of may be more acute in
onset than in CAP when aerobic organisms are the
pathogens.
 Patients brought in after witnessed large volume vomitus
and subsequent aspiration pneumonitis may have a history
consistent with an acute change in mental status, d/t
-seizure,
-alcohol abuse,
-drug overdose
-head trauma

33. Bacterial aspiration pneumonia
 On physical examination, findings may include
- Periodontal disease (primarily noted as gingivitis),
- Bad breath,
- Fever,
- Bronchial breath sounds and rales .

34. Diagnosis
 Risk factors and radiographic evidence of an infiltrate
suggestive of aspiration pneumonia.
Differentials:-
- Necrotizing pneumonia,
- Bronchopleural fistula,
- Lung carcinoma,
- Lung abscess, mycoses, and hypersensitivity
pneumonitis.

35. In children,
-Bronchiolitis,
-Croup or laryngotracheobronchitis,
-Epiglottitis,
-Asthma,
-Respiratory distress syndrome, and
- Foreign bodies should be considered

36. …
In addition, assess for the following conditions:
 Acute respiratory distress syndrome
 Tuberculosis
 Bronchitis
 Chronic obstructive pulmonary disease and emphysema
 Adult epiglottitis

37. …
 Pneumonia, empyema and abscess
 Pneumonia, Immunocompromised
 Mycoplasma pneumonia
 Viral pneumonia
 Septic shock

38. Arterial Blood Gas Analysis
 Arterial blood gas (ABG) analysis is used to assess
oxygenation and pH status.
 ABG analysis adds information that may guide oxygen
supplementation.
 The results of ABG analysis typically demonstrate acute
hypoxemia in patients with chemical pneumonitis and
normal to low partial pressure of carbon dioxide.
 A lactate level can be used as an early marker of severe
sepsis or septic shock.

39.  Serum electrolyte,
 Blood urea nitrogen (BUN), and
 Creatinine levels
 CBC With Differential
 Sputum Gram Stain, Microscopy, and Culture
 Blood Cultures

40. Chest Radiography
 Radiographic evidence of aspiration pneumonia
depends on the position of the patient when the
aspiration occurred
 The right lower lung lobe is the most common site of
infiltrate formation .
 while standing- B/L lower lung lobe infiltrates.

41. Chest Radiography
 Patients lying in the lateral decubitus position are
more likely to have ipsilateral infiltrates .
 The right upper lobe may be involved particularly in
alcoholics who aspirate while in the prone position.

43. Chemical pneumonitis
 CXR Characterized by the presence of infiltrates,
predominantly the alveolar type, in one or both lower
lobes, or diffuse simulation of the appearance of
pulmonary edema.
 Volume loss in any lobar area suggests obstruction
(eg, by aspirated food particles or other foreign bodies)
in the bronchus.

44. Bacterial pneumonia
 Chest radiographic findings in patients with anaerobic
bacterial pneumonia typically demonstrate an
infiltrate with or without cavitation in one of the
dependent segments of the lungs (ie, posterior
segments of the upper lobes, superior segments of the
lower lobes).
 Lucency within the infiltrate suggests a necrotizing
pneumonia.

45. Bacterial pneumonia…
 Air-fluid levels within a circumscribed infiltrate indicate a
lung abscess.
 Costophrenic angle blunting is a signs of a parapneumonic
pleural effusion.

48. Ultrasonography:- For confirming and locating pleural
effusions.
CT Scanning:-
-For characterizing pleural effusions and empyema
-For detecting necrosis within infiltrates and cavitary lesions.
Bronchoscopy:-
 Bronchoscopy is indicated in patients with chemical
pneumonia only when aspiration of a foreign body or food
material is suspected.

49. Pulmonary Artery Catheterization:-
 Pulmonary artery catheter placement may be helpful to
differentiate cardiac from noncardiac pulmonary edema in
the setting of chemical pneumonitis.
Thoracentesis & pleural fluid analysis
Mechanical Ventilation:-
 Required in acute respiratory distress syndrome (ARDS)
and in respiratory insufficiency due to aspiration
pneumonia

50. Chest Tube Placement(ICD)
 May be employed to drain a complicated pleural
effusion or an empyema.

51. Treatment

52. Prehospital Management of Aspiration
Pneumonia
 Should focus on stabilizing the patient's A.B.C.
 Suctioning of the upper airway
 ET Intubation.
 Oxygen supplementation
 Cardiac monitoring and pulse oximetry
 Intravenous (IV) catheter placement and IV fluids, as
indicated

53. Inpatient Management
Patients with aspiration pneumonia, need inpatient care
for several reasons:-
-Acuity of illness,
-Host factors
-The uncertain course
-Prognosis of aspiration pneumonia.

54. ICU care
 Patients with severe hemodynamic compromise
and/or persistent respiratory distress.
 Intubated and ventilated patients
 Patients with severe sepsis or septic shock

55. Complications
 Acute respiratory failure,
 Acute respiratory distress syndrome (ARDS),
 Sec. Bacterial infection in chemical pneumonitis.
 Parapneumonic effusion,
 Empyema,

56. Complications…
 Lung abscess
 Superinfection
 Bronchopleural fistula
 Respiratory failure.

57. Antimicrobial Therapy
 Antibiotics are indicated for aspiration pneumonia.
 prophylactic AB are not recommended

58. Antimicrobial Therapy…
 Administer antibiotics if the pneumonitis fails to
resolve within 48 hours.
 Patients with small bowel obstruction, particularly of
the lower region, should receive antibiotics.
 Antibiotics should be considered for patients on
antacids due to the potential for gastric colonization
with microorganisms.

59. Antimicrobial Therapy…
 For patients without a toxic appearance, the antibiotic
chosen should cover typical community acquired
pathogens.
-Ceftriaxone plus azithromycin, levofloxacin, or
moxifloxacin are appropriate choices

60. Antimicrobial Therapy…
 For patients with a toxic appearance or who were
recently hospitalized, Gram negative bacteria
including Pseudomonas aeruginosa and Klebsiella
pneumoniae as well as MRSA must be covered.
 Piperacillin/tazobactam or imipenem/cilastatin plus
vancomycin .

61. Antimicrobial Therapy…
 Features S/O anaerobic infection:-
-The presence of chronic aspiration risks,
-Putrid discharge,
-Indolent hospital course,
-Necrotizing pneumonia
 Add clindamycin to the antibiotic regimen

62. Antimicrobial Therapy…
 Choosing antibiotics based on organisms cultured
from sputum, tracheal aspirates, rather than
empirically is more appropriate.
 It is recommended that each hospital generate
antibiograms to guide healthcare professionals with
respect to the optimal choice of antibiotics.

63. What Should be the Antibiotic Therapy
in ICU Setting?(ICS/NCCP)
 The recommended regimen is a β-lactam (cefotaxime,
ceftriaxone or amoxicillin-clavulanic acid) plus a
macrolide for patients without risk factors for
Pseudomonas aeruginosa (2A).
 If P. aeruginosa is an aetiological consideration, an
anti-pneumococcal, antibiotic (e.g., cefepime,
ceftazidime, cefoperazone, piperacillin-tazobactam,
cefoperazone-sulbactam, imipenem or meropenem)
should be given (2A).

64.  Combination therapy may be considered with the
addition of aminoglycosides/antipseudomonal
fluoroquinolones (e.g., ciprofloxacin) (3A).
 Fluoroquinolones may be used if TB is not a diagnostic
consideration at admission (1A).
 Patients should also undergo sputum testing for AFB
simultaneously if fluoroquinolones are being used.
 Antimicrobial therapy should be changed according to
specific pathogen(s) isolated (2A).

65.  Diagnostic/therapeutic interventions should be done for
complications, e.g., thoracentesis, chest tube drainage,
etc., as required (1A).
 If a patient does not respond to treatment within 48-72
hours, he/she should be evaluated for the cause of non-
response, including development of complications,
presence of atypical pathogens, drug resistance, etc (3A).
 Switch to oral from intravenous therapy is safe after
clinical improvement in moderate to severe CAP (2A).

66. Corticosteroid Management
 corticosteroids have been used in the past for
aspiration pneumonitis, but RCTs demonstrate d no
benefit of using high dose corticosteroids.
 Low dose corticosteroids can be given in patients
with septic shock that requires vasoactive substances
to maintain blood pressure and in those on longterm
corticosteroid treatment.

67. Prevention of Aspiration Pneumonia
 Position patients with altered consciousness in a
semirecumbent position with the head of the bed at a
30-45° angle.
 Soft diet, reducing the bite size, keeping the chin
tucked and the head turned, and repeated swallowing.
 But their efficacy has not been proven in controlled
trials.

68. Prevention of Aspiration Pneumonia
 Feeding through a nasogastric or gastric tube .
 A recent study found that treatment of patients with
gastrostomy tubes with Mosapride citrate was
associated with a lower risk of aspiration pneumonia
in comparison to both placebo and proton pump
inhibitor treatment.

69. Prevention of Aspiration Pneumonia
 Gastric acid suppression and consequent loss of the acid
barrier to bacteria is associated with a higher rate of
pneumonia.
 Before initiating enteral tube feeding, the tip location
should be confirmed radiographically.
 Residual gastric volume regularly monitored.
 For those on bolus tube, feeding residual should not
exceed 150 mL before the next bolus feed.
 Avoid oversedating patients

70. Prognosis of Aspiration Pneumonia
Depends on-
 Underlying diseases,
 Complications,
 The patient's health status.
 A retrospective study found the 30 day mortality rate
in aspiration pneumonia to be 21% overall and 29.7%
in hospital associated aspiration pneumonia.

71. References.
 Aspiration Pneumonitis and Pneumonia: Anand
Swaminathan, MD, MPH; Chief Editor: Ryland P Byrd, Jr,
MD(2016)
 Guidelines for Diagnosis and Management of Community
and Hospital Acquired Pneumonia in Adults: Joint ICS/
NCCP (I) Recommendations-2012, Dheeraj Gupta et al.
 Management of Adults With Hospital-acquired and
Ventilator-associated Pneumonia: 2016; Clinical Practice
Guidelines by the Infectious Diseases Society of America
and the American Thoracic Society

72. References…
 Wei C, Cheng Z, Zhang L, Yang J. Microbiology and
prognostic factors of hospital and community acquired
aspiration pneumonia in respiratory intensive care unit.
Am J Infect Control. 2013 Mar 22.
 Lanspa MJ, Jones BE, Brown SM, Dean NC. Mortality,
morbidity, and disease severity of patients with aspiration
pneumonia. J Hosp Med. 2013 Feb. 8(2):8390
 Loeb MB, Becker M, Eady A, WalkerDilks C.
Interventions to prevent aspiration pneumonia in older
adults: a systematic review. J Am Geriatr Soc. 2003
Jul.51(7):101822

73. Thank you