Category Archives: SYNDROMES

CAP vs. HCAP vs. HAP vs. VAP

This post is written by a guest writer, Jeff Pearson, PharmD. 

In 2016, the Infectious Diseases Society of America (IDSA) published updated guidelines for the treatment of hospital-acquired pneumonia (HAP) & ventilator-associated pneumonia (VAP).

The plan was to release new community-acquired pneumonia (CAP) guidelines shortly thereafter.

Those CAP guidelines have now been pushed back to be tentatively published in summer 2018.

This post is meant to cover some common misconceptions about the treatment of pneumonia and clinical pearls while we patiently await the release of the new guidelines.

Let’s start with the basics:

HCAP & CAP – those presenting to the hospital with pneumonia
HAP & VAP – those that developed pneumonia >48 hours after admission to the hospital or mechanical ventilation, respectively.

CAP vs HCAP vs HAP vs VAP

But I thought the term HCAP was gone…

While the 2016 guidelines no longer address HCAP, HCAP as an entity has not disappeared (despite what some may tell you). It will likely be discussed in the as-of-yet unreleased CAP guidelines. But in the meantime, feel free to use the algorithm presented above for guidance.

Previous guidelines from 2005 grouped HCAP in with HAP and VAP in terms of treatment. But since then, it’s been determined that not all HCAP patients require MRSA and Pseudomonas coverage. Many can be treated as typical CAP patients.

High-risk HCAP patients =

  • multiple risk factors for multi-drug resistant organisms (see green-box above)
  • require ICU admission to justify broad spectrum antibiotic treatment.

Treatment:

CAP/low risk HCAP
—–NO MRSA or Pseudomonas coverage
—–YES atypical pneumonia pathogens coverage (i.e. mycoplasma, legionella, chlamydia spp.)
Ex. Levofloxacin; ceftriaxone + azithromycin*

High-risk HCAP
—–YES MRSA and Pseudomonas coverage
—–YES atypical pneumonia pathogens coverage (i.e. mycoplasma, legionella, chlamydia spp.)
Ex. Vancomycin + cefepime + azithromycin*

HAP
—–YES MRSA and Pseudomonas coverage
—–Consider double pseudomonal coverage if patient is hemodynamically unstable
—–NO atypical pneumonia pathogen coverage
Ex. Vancomycin + cefepime*

VAP
—–YES MRSA and Pseudomonas coverage
—–Consider double pseudomonal coverage if patient is hemodynamically unstable
—–NO atypical pneumonia pathogen coverage
Ex. Vancomycin + cefepime + tobramycin*

*These are example regimens. Please reference your own institution’s pneumonia guidelines for additional information.

 

Duration of Treatment = 7 days!!!

* This can likely be even shorter in cases of CAP.
** From the IDSA: “There exist situations in which a shorter or longer duration of antibiotics may be indicated, depending upon the rate of improvement of clinical, radiologic, and laboratory parameters.” 2

TAKE-HOME POINTS:

  • HCAP is still an entity – but it has been separated from HAP
  • CAP and HCAP – pneumonia <48 hours into a hospital stay
    HAP and VAP – pneumonia >48 hours into a hospital stay
  • CAP and low risk HCAPNO need for MRSA and Pseudomonas coverage
    High risk HCAP, HAP, and VAPDO need MRSA and Pseudomonas coverage
  • Duration of treatment = 7 days

 

References:

  1. Mandell LA, Wunderink RG, Anzueto A, et al. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis. 2007; 44:S27-S72
  2. Kalil AC, Metersky ML, Klompas M, 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. Clin Infect Dis. 2016; 63(5):e61-e111
  3. Dinh A, Ropers J, Davido B, et al. Effectiveness of three days of beta-lactam antibiotics for hospitalized community-acquired pneumonia: a randomized non-inferiority double-blind trial [abstract]. ECCMID Madrid, Spain, April 22, 2018.

Guest author: Jeff Pearson is currently a PGY-2 infectious diseases pharmacy resident at Beth Israel Deaconess Medical Center in Boston, Massachusetts. He also serves as an adjunct faculty member at MCPHS University, lecturing and facilitating in various courses. He received his Doctor of Pharmacy from Northeastern University in 2014. His main area of interest is antimicrobial stewardship and he will be a senior pharmacist in infectious diseases at Brigham and Women’s Hospital after completing his residency year in August 2018.

 

Peer-reviewed by Milana Bogorodskaya, MD

Aspiration pneumonia vs. Aspiration pneumonitis

Why this matters:

Let me briefly tell you a story that was published in JAMA:  A patient was admitted to the hospital for seizures and intubated for airway protection. CXR showed infiltrates so patient was started on antibiotics and despite rapid improvement in 24 hours, received a 7 day course of antibiotics ‘just in case’. He was re-admitted to the hospital a week later with severe C.diff infection that did not improve despite adequate treatment and died in the hospital.

 

Antibiotics can cause harm. Sometimes they can be life-saving but risks and benefits need to be weighed each time.

 

Did that patient have aspiration pneumonia or aspiration pneumonitis?

 

Aspiration pneumonia = clinical evidence of pneumonia due to a bacterial infection

Aspiration pneumonitis = chemical lung injury due to gastric acid in the lower airways

– 13-26% can progress to develop bacterial pulmonary superinfections

 

Aspiration pneumonitis Aspiration pneumonia
Fever Low grade only/- +/-
Cough/SOB ++ ++
Hypoxia ++ ++
CXR infiltrate Resolves w/in 48-72 hrs Takes weeks to resolve
Sputum culture negative Positive/negative; purulent
Time to sx resolution Quick (48-72 hrs) Slow (>72 hrs)
Bronchoscopy Bronchial erythema Bronchial purulence

 

Risk factors for aspiration pneumonia:

  1. Risk of aspiration
  • altered mental status
  • esophageal disorders (inc. GERD)
  • neurological disorders that promote dysphagia (i.e. ALS, stroke, etc.)
  • seizures
  • vomiting
  • heavy alcohol use
  • recent intubation, bronchoscopy, upper endoscopy, or NG tube (any mechanical disruption of the natural mechanisms that prevent aspiration)
  1. Risk of aspirating increased inoculum of bacteria
  • poor dental hygiene
  • acid-suppressive medications (H2-blockers, PPIs) – loss of gastric acidity allows more pathogens to survive in the stomach ⇒ higher inoculum is present when aspiration occurs

Prevention of aspiration:

  • aspiration is pretty common in small amounts
  • it becomes pathogenic when a patient has chronic, recurrent aspiration or when the inoculum of bacteria in the aspirate increases to reach the threshold for causing chemical lung injury +/- bacterial infection.
  • there are not enough data to suggest that any interventions help to prevent recurrent aspiration

 

Microbiology:

  1. Flora – oral cavity and stomach (strep spp., H.flu, anaerobes, aerobic GNR)
  2. Community: strep spp., haemophilus influenza > anaerobes
  3. Hospital/long term care facilities:
    staphylococcus aureus, aerobic gram-neg bacilli >> anaerobes
    – these pathogens colonize the oral cavity
    Staph and aerobic GNR are more likely to be the infectious cause in these patients due to their intrinsic higher pathogenicity
  4. Anaerobespeptostreptococcus, fusobacterium nucleatum, Prevotella, Bacteroides spp.
  5. Most of these infections are polymicrobial

 

Diagnosis:

– usually a clinical diagnosis

sputum culture may help to isolate aerobic gram-neg bacilli or staph aureus to alter antimicrobial therapy

– “anaerobic bacteria are virtually never detected in pulmonary infections due to lack of access to specimens that are uncontaminated with the normal flora of the upper airways” (UpToDate) and we also do not culture sputum anaerobically so obligate anaerobes would not be able to grow in a typical sputum culture.

CXR should be ordered to assess for evidence of an infiltrate

  • Imaging: does location of infiltrate matter? YES.
    • aspiration in sitting position: lower lobes
    • aspiration in lying position: lower lobes OR posterior segment of upper lobes

 

Workup:

  • consider repeat CXR to evaluate for resolution of pulmonary infiltrate if patient has clinically improved within 48 hours ⇒ if CXR infiltrate resolved and symptoms resolved, likely pneumonitis and can discontinue the antibiotics.

So far, no trials looking at the utility of pro-calcitonin in differentiating aspiration pneumonitis vs. pneumonia that I know of, although would be a great study to do!

 

When to suspect anaerobic involvement
in pneumonia:

  • indolent course
  • risk factors for aspiration
  • absence of rigors
  • no main isolated pathogen on sputum cultures
  • putrid odor sputum
  • evidence of periodontal disease
  • imaging shows cavitation/necrosis or empyema

 

Treatment:

1. To treat or not to treat

  • It seems difficult to imagine coming into a patient’s room who is in respiratory distress with a leukocytosis and possible fever, and deciding to withhold antibiotics. At that time, everyone will likely start antibiotics.
  • Consider clinically re-evaluation at 48 hours – if CXR infiltrates and symptoms have resolved, it’s likely aspiration pneumonitis and you can probably stop antibiotics

2. Anaerobes: to treat or not to treat

  • community-acquired: always treat for anaerobes in addition to other common pathogens (see above)
  • hospital-acquired: consider treating if patient has poor dentition (that predisposes them to pathogenic anaerobic infections)

3. Antibiotic regimens (with anaerobic coverage)

  1. Community-acquired
    a) Amoxicillin-clavulanate or Ampicillin-sulbactam
    b) Ceftriaxone + metronidazole
    c) Clindamycin (if penicillin/cephalosporin allergic, not ideal regimen due to high resistance rates to certain pathogens)
    d) Moxifloxacin
  2. Hospital-acquired or recent history of antibiotics – cover for drug-resistant pathogens as well
    a) Vancomycin + Piperacillin-tazobactam
    b) Vancomycin + Carbapenem (if history of MDR pathogens)
  3. Duration – 7 days for uncomplicated pneumonia
    *For complicated pneumonia, duration of antibiotics will depend on the complication as well as patient’s clinical status and rate of recovery

 

Complications:

  1. ARDS (can happen both in pneumonitis and pneumonia)
  2. Lung abscess
  3. Empyema

 

Take-home points:

  • Aspiration pneumonitis ≠ Aspiration pneumonia
  • Re-evaluate patient in 48 hours and decide whether patient needs to continue antibiotics
  • Anaerobes are less likely to play a pathogenic role in hospital-acquired pneumonia (consider treatment for anaerobes if patient has poor dentition)

 

References:

1. Bartlett, J. G. 2017. Aspiration pneumonia in adults. Uptodate.
2. Finegold, S.M. 1991. Aspiration Pneumonia. CID. 13(9), S737-S742. DOI: 10.1093/clinids/13.Supplement_9.S737
3. Mandell, L. A. et al. 2007. IDSA guidelines for CAP. Section on aspiration pneumonia. 2007. CID. 44(S2): S27-72. DOI: 10.1086/511159
4. Dragan, V. et al. 2018. Prophylactic antimicrobial therapy for acute aspiration pneumonitis. CID. DOI: 10.1093/cid/ciy120
5. Loeb, M.B. et al. 2003. Interventions to prevent aspiration pneumonia in older adults: a systematic review. Journal of American Geriatric Society. 51(7):1018.
DOI: 10.1046/j.1365-2389.2003.51318.x
6.
Joundi, R.A. et al. 2015. Antibiotics “Just-In-Case” in a Patient with aspiration pneumonitis. JAMA Internal Medicine: Teachable moment – Less is more. 175(4); 489-490. DOI:10.1001/jamainternmed.2014.8030