From: Subject: Best Dx/Best Rx: Community-Acquired Pneumonia Date: Wed, 3 Jun 2009 21:11:20 -0700 MIME-Version: 1.0 Content-Type: multipart/related; type="text/html"; boundary="----=_NextPart_000_0134_01C9E48F.D7B9BCE0" X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_0134_01C9E48F.D7B9BCE0 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Content-Location: http://www.acpmedicine.com/acp/newrxdx/rxdx/dxrx0720.htm Best Dx/Best Rx: Community-Acquired Pneumonia



Community-Acquired=20 Pneumonia

Harvey B. Simon, M.D., = F.A.C.P.
Massachusetts General=20 Hospital

Defin= ition/Key=20 Clinical Features
Diffe= rential=20 Diagnosis
Best = Tests
Best = Therapy
Best = References

Definition/Key Clinical=20 Features

  • Cough (with or without sputum), fever (with or = without=20 chills), chest pain (usually pleuritic), dyspnea, hypoxia=20
  • High fever, tachypnea, confusion, hypoxia, and = hypotension indicate more severe illness=20
  • Physical exam often nonspecific but may reveal = rales,=20 rhonchi, bronchial breath sounds, percussion dullness=20
  • Respiratory rate often > 20/min=20
  • Chest x-ray reveals infiltrates=20
  • Bacterial: abrupt onset of illness, copious = sputum=20 production, high temps, chills, signs of consolidation or at least = localized=20 rales and rhonchi; patients generally appear sicker than they would = with viral=20 pneumonia=20
  • Atypical (Mycoplasma pneumoniae, Chlamydia=20 pneumoniae, Legionella pneumophila, various viruses): little or no = sputum=20
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Differential = Diagnosis

  • Asthmatic bronchitis=20
  • Hypersensitivity pneumonia=20
  • COPD=20
  • Atelectasis=20
  • Pulmonary embolism=20
  • Pulmonary edema=20
  • Tuberculosis=20
  • Hypersensitivity reaction=20
  • Congestive heart failure=20
  • Aspiration=20
  • Lung abscess
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Best=20 Tests

  • Chest x-ray=97necessary for diagnosis=20
  • Sputum exam for leukocytes and bacteria =
  • Sputum culture=20
  • Bronchoscopy with bronchoalveolar lavage: = consider for=20 immunosuppressed patients and extremely ill patients=20
  • Tracheal aspirate is rarely necessary=20
  • Molecular diagnosis may be helpful to diagnose = Legionella, Mycloplasma, or Chlamydia pneumonia=20
  • CT extremely helpful in complex = infections=20


Clinical Pearls

  • Consider Legionnaires disease with segmental, = lobar, or=20 interstitial pneumonia with no etiologic agent evident on Gram = stain=20
  • Nonbacterial infection: scant quantities of = thin sputum=20 with scant cellular response and few bacteria=20
  • True interstitial infiltrate suggests = nonbacterial=20 pneumonia
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Best=20 Therapy

  • Clinical and lab data identify patients who = require=20 hospitalization and aggressive therapy and are at greatest risk for=20 death=20
  • Initiate treatment based on clinical setting, = chest=20 x-ray, and sputum Gram stain, and then tailor to culture and = sensitivity=20 results, clinical response, side effects=20
  • Treat with antibiotics for 7=9614 days for=20 Streptococcus pneumoniae and 10=9621 days for M. pneumoniae, = C.=20 pneumoniae, and Legionella

General Principles

  • Adequate hydration/humidification=20
  • Expectorants are ineffective=20
  • Oxygen for hypoxia=20
  • Avoid cough suppressants in bacterial=20 infection

Antibiotics


Initial Antibiotic Therapy for = Community-Acquired=20 Pneumonia in Outpatients

  • Fluoroquinolones: excellent first-line = drugs=20
    • Levofloxacin=20
      • Dose: 500 mg p.o., q. 24 hr for 10 = days=20
      • Cost/mo: $108
    • Moxifloxacin=20
      • Dose: 400 mg p.o., q. 24 hr
      • Cost/mo: $300
    • Gemifloxacin=20
      • Dose: 320 mg p.o., q. 24 hr=20
      • Cost/mo: N/A
  • Macrolides: cost-effective alternative, but GI = intolerance is common with erythromycin=20
    • Erythromycin: inexpensive but GI intolerance = common=20
      • Dose: 250=96500 mg p.o., q. 6 hr
      • Cost/mo: $27 or $40, depending on = formulation=20 used
    • Clarithromycin: better GI tolerance and = activity=20 against Haemophilus and Moraxella; good first-line = drug=20
      • Dose: 250=96500 mg p.o., q. 12 hr=20
      • Cost/mo: $297 or $260, depending on = formulation=20 used
    • Azithromycin: better GI tolerance and = activity against=20 Haemophilus and Moraxella=20
      • Dose: 500 mg p.o. day 1, then 250 mg p.o. = days=20 2=965=20
      • Cost/mo: $276
    • Doxycycline: cost-effective = alternative=20
      • Dose: 100 mg p.o., q. 12 hr=20
      • Cost/mo: $42 =

 

Initial Antibiotic Therapy for = Community-Acquired=20 Pneumonia in Hospitalized Patients

  • Cephalosporins: first-line treatment for = severely ill=20 patients when combined with a second agent=20
    • Cefotaxime or ceftriaxone + a macrolide or a = fluoroquinolone=20
      • Dose: cefotaxime, 1=962 g I.V. q. 4 hr; = ceftriaxone,=20 1=962 g I.V. q. 12=9624 hr
  • Fluoroquinolones: first-line treatment, either = alone or=20 with a third-generation cephalosporin=20
    • Levofloxacin=20
      • Dose: 500 mg p.o. or I.V. q. 24 hr = Cost/mo: $310
    • Moxifloxacin=20
      • Dose: 400 mg p.o. or I.V. q. 24 hr=20
      • Cost/mo: $300
  • Vancomycin + a macrolide or a fluoroquinolone: = alternative for severely ill patients who are allergic to = β-lactams=20
    • Dose: vancomycin, 1 g I.V. q. 12 hr =
  • Linezolid + a macrolide or a fluoroquinolone: = for=20 severely ill patients who cannot tolerate β-lactams or = vancomycin=20
    • Dose: Linezolid, 600 mg p.o. or I.V. q. 12 = hr=20
    • Cost/mo: $3,648

Antibiotic Therapy for Aspiration=20 Pneumonia

  • Clindamycin: may be superior to = penicillin=20
    • Dose: 150=96300 mg p.o., q. 6 hr to 600 mg = I.V. q. 8 hr,=20 depending on severity of infection=20
    • Cost/mo: $312 or $601, depending on = formulation=20 used
  • Penicillin: traditional drug of choice=20
    • Dose: 500 mg p.o., q. 6 hr to 1=962 million = units I.V.=20 q. 4 hr, depending on severity of infection=20
    • Cost/mo: $12
  • Metronidazole: excellent alternative=20
    • Dose: 500 mg p.o., q. 8 hr to 500 mg I.V. q. = 6 hr,=20 depending on severity of infection=20
    • Cost/mo: $28
  • Amoxicillin-clavulanate: alternative for oral=20 therapy=20
    • Dose: 500 mg p.o., q. 8 hr or 875 mg p.o., = q. 12=20 hr=20
    • Cost/mo: $391
  • Ampicillin-sulbactam: alternative useful in = hospitalized=20 patients=20
    • Dose: 1=962 g ampicillin + 0.5=961 g = sulbactam I.V. q. 6=20 hr
  • Imipenem: alternative useful in hospitalized=20 patients=20
    • Dose: 0.5=961 g. I.V. q. 6=968 hr =
  • Meropenem: alternative useful in hospitalized=20 patients=20
    • Dose: 1 g I.V. q. 8 hr
  • Fluoroquinolones: excellent for = community-acquired=20 pneumonias but less active against oral anaerobes than penicillin,=20 clindamycin, and metronidazole=20
    • Moxifloxacin=20
      • Dose: 400 mg p.o., q. 24 hr=20
      • Cost/mo: $300
    • Levofloxacin=20
      • Dose: 500 mg p.o. or I.V. q. 24 hr=20
      • Cost/mo: $310

     

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Best References

Castro-Guardiola A, et al: Am J Med 111:367, 2001 = [PMID=20 11583639]

Cunha BA: Chest 125:1913, 2004 [PMID = 15136407]

Dunbar LM, et al: Clin Infect Dis 37:752, 2003 = [PMID=20 12955634]

Mandell LA, et al: Clin Infect Dis 37:1405, 2003 = [PMID=20 14614663]

August=20 2006

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