Management Of Aspiration Pneumonia In Stroke Patients
Management Of Aspiration Pneumonitis In Neurological Patients
Dr. Sunil Kumar Sharma(Senior Resident)
ModeratorDr. Dilip Maheshwari(DM)Asso. Prof.Dept. of NeurologyGMC Kota
OverviewAspiration pneumonitisresults 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
Types of aspiration syndromesMainly two types-
1-Chemical pneumonitis or Mendelson's syndrome.
2-Aspiration pneumonia.
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.
Predisposing Conditions for Aspiration Pneumonia
Altered or reduced consciousness
Impaired gag reflex
Inability to maintain an airway
Periodontal disease
Predisposing Conditions for Aspiration PneumoniaAlcoholism
Drug overdose
Head trauma
General anesthesia
Intracranial mass lesion
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
Predisposing Conditions for Aspiration Pneumonia(Neurological)
StrokeSeizureGBSMultiple sclerosisDementiaParkinson's diseaseMyasthenia gravisPseudobulbar/bulbar palsy
Predisposing Conditions for Aspiration Pneumonia
Protracted vomiting
Prolonged recumbency
Chronic debilitating illnesses
Critical illness
PathophysiologyInfiltrate 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.
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.
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
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.
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
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)
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 patients airways are important pathogenetic factors in nosocomial pneumonia.
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.
Causative microorganisms
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.
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.
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. )
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.
EpidemiologySeveral 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%).
EpidemiologyNosocomial 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.
Clinical Presentation
Clinical PresentationRanges 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 ones airway include -Previous CVA, -History of esophageal diseases including achalasia or esophageal web, -Being a nursing home patient, -Being chronically fed by feeding tube.
Physical examination findingsFever or hypothermia
Tachypnea
Tachycardia
Decreased breath sounds
Dullness to percussion over areas of consolidation
Rales
Physical examination findings
Egophony and pectoriloquy
Decreased breath sounds
Pleural friction rub
Altered mental status
Hypoxemia
Hypotension (in septic shock)
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.
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
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
Bacterial aspiration pneumoniaIn 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
Bacterial aspiration pneumonia
On physical examination, findings may include- Periodontal disease (primarily noted as gingivitis),Bad breath, Fever,Bronchial breath sounds and rales .
DiagnosisRisk factors and radiographic evidence of an infiltrate suggestive of aspiration pneumonia.
Differentials:-Necrotizing pneumonia,Bronchopleural fistula, Lung carcinoma, Lung abscess, mycoses, and hypersensitivity pneumonitis.
In children,-Bronchiolitis,
-Croup or laryngotracheobronchitis,
-Epiglottitis,
-Asthma,
-Respiratory distress syndrome, and
- Foreign bodies should be considered
In addition, assess for the following conditions:
Acute respiratory distress syndrome
Tuberculosis
Bronchitis
Chronic obstructive pulmonary disease and emphysema
Adult epiglottitis
Pneumonia, empyema and abscess
Pneumonia, Immunocompromised
Mycoplasma pneumonia
Viral pneumonia
Septic shock
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.
Serum electrolyte,
Blood urea nitrogen (BUN), and
Creatinine levels
CBC With Differential
Sputum Gram Stain, Microscopy, and Culture
Blood Cultures
Chest RadiographyRadiographic 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.
Chest RadiographyPatients 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.
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.
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.
Bacterial pneumoniaAir-fluid levels within a circumscribed infiltrate indicate a lung abscess.
Costophrenic angle blunting is a signs of a parapneumonic pleural effusion.
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.
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
Chest Tube Placement(ICD)
May be employed to drain a complicated pleural effusion or an empyema.
Treatment
Prehospital Management of Aspiration PneumoniaShould 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
Inpatient Management
Patients with aspiration pneumonia, need inpatient carefor several reasons:- -Acuity of illness,
-Host factors
-The uncertain course
-Prognosis of aspiration pneumonia.
ICU care
Patients with severe hemodynamic compromise and/or persistent respiratory distress.
Intubated and ventilated patients
Patients with severe sepsis or septic shock
Complications
Acute respiratory failure,
Acute respiratory distress syndrome (ARDS),
Sec. Bacterial infection in chemical pneumonitis.
Parapneumonic effusion,
Empyema,
ComplicationsLung abscess
Superinfection
Bronchopleural fistula
Respiratory failure.
Antimicrobial Therapy
Antibiotics are indicated for aspiration pneumonia.
prophylactic AB are not recommended
Antimicrobial TherapyAdminister 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.
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
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 .
Antimicrobial TherapyFeatures S/O anaerobic infection:--The presence of chronic aspiration risks,-Putrid discharge, -Indolent hospital course, -Necrotizing pneumonia
Add clindamycin to the antibiotic regimen
Antimicrobial TherapyChoosing 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.
What Should be the Antibiotic Therapy in ICU Setting?(ICS/NCCP)The recommended regimen is a -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).
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).
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).
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.
Prevention of Aspiration PneumoniaPosition 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.
Prevention of Aspiration PneumoniaFeeding 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.
Prevention of Aspiration PneumoniaGastric 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
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.
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
ReferencesWei 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
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