Pneumonia (main)

For pediatrics see pediatric pneumonia

Background
  • Definition: infection of lung parenchyma
  • Empirically classified based upon location/risk factors

Hospital-acquired pneumonia (HAP)
  • HCAP no longer entity in ISDA/American Thoracic Society guidelines[1]
  • ISDA recommends only covering empirically for MRSA or pseudomonas in adults with CAP if "locally validated" risk factors for either pathogen and then, continuing empiric coverage while obtaining culture data to justify extended coverage
  • Commonly accepted risk factors for resistant pathogens (e.g. MRSA, pseudomonas) historically include:
    • Hospitalized for 2 or more days within past 90 days
    • Nursing home/long-term care residents
    • Receiving home IV antibiotics
    • Dialysis
    • Receiving chronic wound care
    • Receiving chemotherapy
    • Immunocompromised

Pseudomonas risk factors
  • Alcoholism
  • Immunosuppression (including steroids)
  • Structural lung disease
  • Malnutrition
  • Recent antibiotics
  • Recent hospital stay

Causes of Pneumonia

Bacteria

Viral

Fungal

Parasitic

Commonly Encountered Pathogens by Risk Factor
Risk Factor Associated Organism
Alcoholism
COPD and/or Smoking
Nursing Home
Exposure to bird droppingsHistoplasma capsulatum
Exposure to birdsChlamydophila psittaci
Exposure to rabbitsFrancisella tularensis
Exposure to farm animalsCoxiella burnetii (Q fever)
Exposure to southwestern USCoccidiomycosis (Valley fever)
Early HIV
Late HIV (as above, plus:)
AspirationAnaerobes
Structural Lung Disease (CF, bronchiectasis)
Injection drug use
Influenza
Ventilator Associated Pneumonia

Clinical Features

Differential Diagnosis

Acute dyspnea

Emergent

Pediatric-specific

Non-Emergent

Evaluation
CXR showing prominent wedge-shape area of airspace consolidation in the right lung, characteristic of bacterial pneumonia.
CT chest showing right sided pneumonia
  • CXR
    • Immunocompromised patients may not manifest radiographic evidence of pneumonia despite suggestive clinical findings
    • Clinical and radiographic findings do not necessarily correspond: the patient may be improving cliniclly despite having a worsening appearance on the CXR
  • CBC
  • Chemistry

If patient will be admitted:

  • Blood Cultures are ONLY indicated for CAP patients with:
    • ICU (required)
    • Multi-lobar
    • Pleural effusion
    • Cavitary lesions
    • Leukopenia
    • Prosthetic valves
    • IV drug users
    • Parenteral antibiotics in the last 90 days
    • Consider for higher-risk patients admitted with CAP
      • Liver disease
      • Immunocompromised
      • Significant comorbidities
      • Other risk factors
  • Sputum staining
    • If concern for particular organism

Chest X-Ray Mimics
  • Legionella urine antigen test
    • ICU patients
    • Alcoholics
    • Outbreaks
    • Recent (within 2 weeks) travel history

Management

Outpatient

Coverage targeted at S. pneumoniae, H. influenzae. M. pneumoniae, C. pneumoniae, and Legionella

Healthy[2]

No comorbidities (chronic heart, lung, liver, or renal disease; diabetes mellitus; alcoholism; malignancy; or asplenia) and no or risk factors for MRSA or Pseudomonas aeruginosa (include prior respiratory isolation of MRSA or P. aeruginosa or recent hospitalization AND receipt of parenteral antibiotics (in the last 90 d))

  • Amoxicillin 1 g three times daily (strong recommendation, moderate quality of evidence), OR
  • Doxycycline 100 mg twice daily (conditional recommendation, low quality of evidence), OR
  • Macrolide in areas with pneumococcal resistance to macrolides <25% (conditional recommendation, moderate quality of evidence).
  • Duration of therapy 5 days minimum

Unhealthy[3]

If patient has comorbidities or risk factors for MRSA or Pseudomonas aeruginosa

  • Combination therapy:
    • Amoxicillin/Clavulanate
      • 500 mg/125 mg TID OR amox/clav 875 mg/125 mg BID OR 2,000 mg/125 mg BID. Duration is for a minimum of 5 days and varies based on disease severity and response to therapy; patients should be afebrile for ≥48 hours and clinically stable before therapy is discontinued[4]
    • OR cephalosporin
    • AND macrolide
      • Azithromycin 500 mg on first day then 250 mg daily
      • OR clarithromycin 500 mg BID OR clarithromycin ER 1,000 mg daily]) (strong recommendation, moderate quality of evidence for combination therapy)
    • OR doxycycline 100 mg BID (conditional recommendation, low quality of evidence for combination therapy)
  • Monotherapy: respiratory fluoroquinolone (strong recommendation, moderate quality of evidence):

Inpatient
  • Monotherapy or combination therapy is acceptable
  • Combination therapy includes a cephalosporin and macrolide targeting atypicals and Strep Pneumonia [5]
  • The use of adjunctive corticosteroids (methylprednisolone 0.5 mg/kg IV BID x 5d) in CAP of moderate-high severity (PSI Score IV or V; CURB-65 ≥ 2) is associated with:[6]
    • ↓ mortality (3%)
    • ↓ need for mechanical ventilation (5%)
    • ↓ length of hospital stay (1d)

Community Acquired (Non-ICU)

Coverage against community acquired organisms plus M. catarrhalis, Klebsiella, S. aureus

Hospital Acquired or Ventilator Associated Pneumonia

Ventilator Associated Pneumnoia
  • High Risk of MRSA: Use 3-Drug Regimen. Several options are available, but recommendation is to include an antibiotic from each of these categories:[7]

ICU, low risk of pseudomonas

ICU, risk of pseudomonas

Disposition

IDSA 2019 guidelines recommend clinical judgement plus PSI over CURB-65. [8]

Pneumonia severity index (Port Score)

Risk Factors

Points
Demographic Factors
Age for men
 Age
Age for women
 Age -10
Nursing home resident
 +10
Coexisting Illnesses

Neoplastic disease (active)
 +30
Chronic liver disease
 +20
Heart Failure
 +10
Cerebrovascular disease
 +10
Chronic renal disease
 +10
Physical Exam

AMS
 +20
RR > 30/min
 +20
Sys BP < 90
 +20
Temp <35 or >40
 +15
Pulse > 125
 +10
Lab and xray findings
Arterial pH < 7.35
 +30
BUN > 30
 +20
Na <130
 +20
Glucose > 250
 +10
Hematocrit <30%
 +10
PaO2 < 60 or SpO2 < 90%
 +10
Pleural effusion
 +10

Classification

Class
Points
Mortality
I
 <51 0.1%
II
 51-70 0.6%
III
 71-90
 0.9%
IV
 91-130
 9.3%
V
 >130
 27%

Disposition Pathway
  • Classes I and II: consider discharge
  • Class III: discharge verus admit based on clinical judgment
  • Classes IV and V: consider admission

CURB-65
  1. Confusion
  2. bUn > 19 mg/dl
  3. RR > 30
  4. BP < 90 SBP, or < 60 DBP
  5. Age > 65
  • Approximate 30-day mortalities and Tx considerations
    • +1 --> 3%, outpt tx
    • +2 -->7%, inpt, possible outpt
    • +3 --> 14% inpt, possible ICU
    • +4-5 --> 30% ICU

Prognosis
  • Half of patients are still symptomatic at 30 days, with a significant minority of patients experiencing chest pain, malaise or mild dyspnea even 2 to 3 months after treatment
  • In adults with CAP whose symptoms have resolved within 5-7 days, it is not recommended to routinely obtain follow-up chest imaging

See Also

References
  1. Diagnosis and Treatment of Adults with Community-acquired Pneumonia. An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America Am J Respir Crit Care Med. 2019 Oct 1;200(7):e45-e67
  2. Diagnosis and Treatment of Adults with Community-acquired Pneumonia. An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America Am J Respir Crit Care Med. 2019 Oct 1;200(7):e45-e67
  3. Diagnosis and Treatment of Adults with Community-acquired Pneumonia. An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America Am J Respir Crit Care Med. 2019 Oct 1;200(7):e45-e67
  4. IDSA. Mandell 2007
  5. Chokshi R, Restrepo MI, Weeratunge N, Frei CR, Anzueto A, Mortensen EM. Monotherapy versus combination antibiotic therapy for patients with bacteremic Streptococcus pneumoniae community-acquired pneumonia. Eur J Clin Microbiol Infect Dis. Jul 2007;26(7):447-51
  6. Siemieniuk RA, Meade MO, Alonso-Coello P, Briel M, Evaniew N, Prasad M, Alexander PE, Fei Y, Vandvik PO, Loeb M, Guyatt GH. Corticosteroid Therapy for Patients Hospitalized With Community-Acquired Pneumonia: A Systematic Review and Meta-analysis. Ann Intern Med. Aug 11, 2015
  7. 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 Sep 1;63(5):e61-e111.
  8. Diagnosis and Treatment of Adults with Community-acquired Pneumonia. An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America AJRCCM Vol. 200, No. 7, Oct 01, 2019
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