Contents

Search

pneumonia (PNA)

Infection of the pulmonary parenchyma. Etiology: 1) bacterial pneumonia a) community-acquired: Streptococcus pneumoniae - 90% of identified bacterial isolates in adults - 95% of identified isolates in preantibiotic era [22] - 10-15% of inpatient cases in the United States [22]* b) nosocomial (60% gram-negative bacilli) c) Mycobacterium tuberculosis d) rickettsiae e) common variable immunodeficiency f) other 2) viral pneumonia - > 20% of severe pneumonia with respiratory failure requiring mechanical ventilation due to viral pneumonia [29] 3) fungal pneumonia - Pneumocystis carinii (AIDS) 4) aspiration pneumonia 5) eosinophilic pneumonia 6) interstitial pneumonia 7) postobstructive pneumonia - bronchial neoplasm, foreign body, bronchial stricture 8) nosocomial pneumonia 9) community-acquired pneumonia * see etiology of pneumonia & community-acquired pneumonia * also see characteristics of etiologic agents of pneumonia * ACE inhibitors, but not ARBs may play protective role [25] Epidemiology: 1) compromised hosts are particularly vulnerable 2) pneumonia accounts for 10% of admissions to hospital wards & is still a common cause of death 3) inappropriate diagnosis of pneumonia among hospitalized adults is common - older adults with geriatric syndromes especially at risk [34] Pathology: 1) the most common mechanism for acquiring pneumonia is aspiration of organisms from the oropharynx a) aerobic gram-positive cocci & anaerobes most common b) 50% of adults aspirate during sleep c) aspiration increases with: 1] impaired consciousness 2] neurologic disorders 3] nasogastric or endotracheal tubes 2) less common mechanisms a) inhalation of infected particles b) hematogenous or contiguous spread from another infected site c) open trauma to chest 3) alterations in host defenses contribute to the pathophysiology of pneumonia a) abnormal mucociliary function b) decreased IgA allowing adherence of bacteria to airways c) compromised cellular immunity d) compromised humoral immunity 4) severity of pneumococcal pneumonia associated with bacterial load History: -> onset, duration, systemic symptoms, fever, weight loss, other medical conditions, recent antibiotic use, travel history, exposure to animals, tuberculosis history, sick contacts, alcohol/other drug use, HIV risk factors, occupational history Clinical manifestations: 1) fever 2) tachycardia 3) postural changes 4) tachypnea may be only sign in elderly [15] - may present as delirium, confusion, & falls in the elderly [32] 5) rales, pulmonary crackles 6) egophony 7) inspiratory chest expansion lag on affected side 8) splinting 9) increased fremitus 10) dullness to percussion 11) bronchial breath sounds 12) bronchophony Laboratory: 1) Sputum a) gram stain - > 5 epithelial cells per low power field suggests oral-pharyngeal rather than pulmonary secretions - > 25 neutrophils per low power field suggests lower respiratory tract infection - can lead to diagnosis in 15-45% of cases [13,14] b) culture - no anaerobic cultures because of contamination from pharyngeal anaerobes - cultures can be misleading c) fluorescent antibody studies - Legionella pneumophila d) multiplex PCR assay may become the new standard 2) Complete blood count - leukocyte count - may be low or normal in the elderly or immunocompromised - a leukocyte count < 10,000/mm3 is common in Mycoplasma pneumonia 3) blood cultures - for all hospitalized patients with pneumonia - 20-30% of patients with bacterial pneumonia have positive blood cultures 4) arterial blood gas 5) chemistry profile - electrolytes - liver function tests - renal function tests - serum glucose - serum C-reactive protein (> 30 mg/dL = high risk) + serum procalcitonin improves diagnostic accuracy [20] - serum procalcitonin > 0.1 ng/mL suggest bacterial pneumonia rather than heart failure [24] 6) serologic studies - coccidioidomycosis titers - Mycoplasma titers - HIV testing Special laboratory: 1) invasive procedures may be indicated in treatment failures or suspected non-bacterial origin of severdisease 2) transtracheal aspiration 3) transthoracic needle aspiration (thoracentesis) 4) fiberoptic bronchoscopy generally after CT a) bronchial brushings b) bronchoalveolar lavage or endotracheal aspiration c) transbronchial biopsy 5) open lung biopsy 6) induced sputum or Lukens trap Radiology: chest radiograph 1) lobar a) Streptococcus pneumonia b) Haemophilus influenza 2) interstitial a) Mycoplasma pneumonia b) viral pneumonia 3) bilateral - aspiration 4) cavitary a) Mycobacterium tuberculosis b) Klebsiella pneumonia c) Staphylococcus aureus d) Pseudomonas aeruginosa 5) radiographic resolution lags behind clinical improvement 6) follow-up chest X-rays 8 weeks after onset a) to show resolution & absence of underlying lung cancer b) may not be necessary in younger patients [19] lung ultrasound may be alternative to chest X-ray [23] CT of thorax is 'gold standard' Complications: 1) pleural (parapneumonic) effusion - thoracentesis 2) empyema - requires chest tube drainage 3) abscess formation (empyema) 4) pericarditis (purulent) 5) adult respiratory distress syndrome (ARDS) 6) sepsis with DIC 7) multi-organ failure 8) increased risk of myocardial infarction, stroke [30] - RR=5-12 for pneumococcal pneumonia, influenza Also see poor prognostic factors & criteria for severe pneumonia Management: 1) supportive measures - hydration - oxygen - noninvasive positive pressure ventilation may reduce need for endotracheal intubation 2) empiric antimicrobial therapy a) community-acquired pneumonia in adults [12] (see community-acquired pneumonia) b) nosocomial pneumonia - etiology: most frequently: - gram negative organisms - Staphylococcus - Legionella - empiric therapy: - ceftriaxone or cefotaxime plus an aminoglycoside - mezlocillin or ceftazidime plus an aminoglycoside if Pseudomonas is likely (ICU setting or immunocompromised host) - dual coverage for Pseudomonas if suspected - Cefepime, imipenem, meropenem, or Zosyn plus an aminoglycoside plus a fluoroquinolone* [5] - fluoroquinolone plus an aminoglycoside or aztreonam if Pseudomonas is suspected - dual Pseudomonas* coverage if growth from respiratory culture in past year - single agent appropriate if antibiotic sensitivity known [33] c) aspiration pneumonia - community-acquired: anaerobes & gram-positive cocci - nosocomial: gram-negative organisms & S. aureus - empiric therapy: (see aspiration pneumonia) - fluoroquinolone alone (trovafloxacin) - adding clindamycin increases risk of C difficile without benefit [6] - fluoroquinolone plus metronidazole - penicillin/beta-lactamase inhibitor + azithromycin d) pneumonia in adults with cystic fibrosis e) switching to oral therapy - patient is afebrile and stable - patients with bacteremia & other medical problems may need longer IV antibiotic therapy - for children discharged from the hospital with complicated pneumonia (pneumonia with pleural effusion), IV antibiotics offers no advantage over oral antibiotics [27] 3) oral glucocorticoids of no benefit to adults without chronic obstructive pulmonary disease [28] - also see community-acquired pneumonia 4) prevention: - immunization with PCV13 & PPSV23 - decline in pneumococcal pneumonia due to: - widespread use of pneumovax in adults - use of pneumococcal conjugate vaccine in children - decreased rates of cigarette smoking [22] - effective & consistent oral hygiene may reduce incidence of pneumonia in nursing home residents [31] * Some fluoroquinolones are not recommended for empiric antimicrobial activity in pneumonia because of unreliable activity against Streptococcus pneumoniae. Fluoroquinolones with enhanced activity against Streptococcus pneumonia include: 1) levofloxacin 2) sparfloxacin 3) trovafloxacin 4) grepafloxacin 5) moxifloxacin 6) gatifloxacin 7) gemifloxacin Antimicrobial therapy for pneumonia caused by specific organisms (select or see specific organism) Response to therapy 1) most patients will show clinical improvement within 48-72 hours 2) fever & leukocytosis generally resolves by day 4 3) consider empyema if response to therapy poor 4) chest X-ray often lags behind clinical improvement 5) follow-up chest X-ray to show resolution (8-12 weeks after onset) [17] 6) weeks to months may be necessary for complete resolution of symptoms [7] Duration of therapy: (bacterial pneumonia) 1) 2 to 3 weeks [6] 2) 8 days equivalent to 15 days for ventilator-associated pneumonia [11] Also see treatment failure Notes: - readmissions are more common with: - comorbidities, including diabetes mellitus, COPD, malignancies, & immunosuppression - healthcare-associated pneumonia rather than community-acquired pneumonia - predictors of readmission: - admission from a nursing home or long-term care facility - immunosuppression - prior antibiotic therapy - hospitalization during the past 90 days

Interactions

disease interactions

Related

characteristics of etiologic agents of pneumonia etiology of pneumonia poor prognostic factors & criteria for severe pneumonia pulmonary infiltrate in immunocompromised host treatment failure, pneumonia

Specific

aspiration pneumonia bacterial pneumonia chronic pneumonia community-acquired pneumonia (CAP) eosinophilic pneumonia; Andrews syndrome; pulmonary eosinophilia interstitial pneumonia nosocomial pneumonia; hospital-acquired pneumonia; health care-associated pneumonia nursing home associated pneumonia postobstructive pneumonia recurrent pneumonia viral pneumonia

General

lung disease pulmonary infection

References

  1. Manual of Medical Therapeutics, 28th edition, Ewald & McKenzie (eds) Little, Brown & Co, 1995, pg 299-302
  2. Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook, Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 421
  3. Contributions from Linda Kuribayashi MD, Dept of Medicine, UCSF Fresno
  4. Bartlett JG et al Community-acquired pneumonia in adults: guidelines for management. The Infectious Diseases Society of America. Clinical Infectious Diseases 26:811-38, 1998 PMID: 9564457
  5. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 796-99
  6. Medical Knowledge Self Assessment Program (MKSAP) 11, 19. American College of Physicians, Philadelphia 1998, 2019
  7. Journal Watch 21(3):22, 2001 Marrie TJ et al Predictors of symptom resolution in patients with community-acquired pneumonia. Clin Infect Dis 31:1362, 2000 PMID: 11096003
  8. Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 1146
  9. Bartlett JG et al Community-acquired pneumonia in adults: guidelines for management. The Infectious Diseases Society of America. Clin Infect Dis 26:811, 1998 PMID: 9564457
  10. Geriatrics Review Syllabus, American Geriatrics Society, 5th edition, 2002-2004
  11. Journal Watch 24(2):10, 2004 Chastre J et al Comparison of 8 vs 15 days of antibiotic therapy for ventilator-associated pneumonia in adults: a randomized trial. JAMA 290:2588, 2003 PMID: 14625336
  12. Selected Treatment Issues in the Updated Guidelines for Community-Acquired Pneumonia in Immunocompetent Adults and Bacterial Sinusitis Prescriber's Letter 11(2):12 2004 Detail-Document#: 200209 (subscription needed) http://www.prescribersletter.com
  13. Journal Watch 24(20):151, 2004 Garcia-Vazquez E, Marcos MA, Mensa J, de Roux A, Puig J, Font C, Francisco G, Torres A. Assessment of the usefulness of sputum culture for diagnosis of community-acquired pneumonia using the PORT predictive scoring system. Arch Intern Med. 2004 Sep 13;164(16):1807-11. PMID: 15364677
  14. Musher DM, Montoya R, Wanahita A. Diagnostic value of microscopic examination of gram-stained sputum and sputum cultures in patients with bacteremic pneumococcal pneumonia. Clin Infect Dis. 2004 Jul 15;39(2):165-9. Epub 2004 Jul 01. PMID: 15307023
  15. Internal Medicine World Report 2006; 21(2)
  16. The Canadian Critical Care Trials Group. A randomized trial of diagnostic techniques for ventilator-associated pneumonia. N Engl J Med 2006, 355:2619 PMID: 17182987
  17. Bruns AH, Oosterheert JJ, Prokop M, Lammers JW, Hak E, Hoepelman AI. Patterns of resolution of chest radiograph abnormalities in adults hospitalized with severe community-acquired pneumonia. Clin Infect Dis. 2007 Oct 15;45(8):983-91. Epub 2007 Sep 12. PMID: 17879912
  18. Rello J et al. Severity of pneumococcal pneumonia associated with genomic bacterial load. Chest 2009 Sep; 136:832. PMID: 19433527
  19. Tang KL et al. Incidence, correlates, and chest radiographic yield of new lung cancer diagnosis in 3398 patients with pneumonia. Arch Intern Med 2011 Jul 11; 171:1193 PMID: 21518934
  20. van Vugt SF et al. Use of serum C reactive protein and procalcitonin concentrations in addition to symptoms and signs to predict pneumonia in patients presenting to primary care with acute cough: Diagnostic study. BMJ 2013 Apr 30; 346:f2450. PMID: 23633005
  21. Shorr AF et al. Readmission following hospitalization for pneumonia: The impact of pneumonia type and its implication for hospitals. Clin Infect Dis 2013 Aug 1; 57:362. PMID: 23677872 http://cid.oxfordjournals.org/content/57/3/362?ijkey=31280879cc468ec733f0825bcd5d6d5263813a89&keytype2=tf_ipsecsha - Sexton DJ. "Excess readmissions" for pneumonia: A dilemma with a penalty. Clin Infect Dis 2013 Aug 1; 57:368. PMID: 23677873 http://cid.oxfordjournals.org/content/57/3/368?ijkey=62dd7bc29b45c07a960c0c8ff7196bdde491c406&keytype2=tf_ipsecsha
  22. Musher DM, Thorner AR Community-Acquired Pneumonia. N Engl J Med 2014; 371:1619-1628October 23, 2014 PMID: 25337751 http://www.nejm.org/doi/full/10.1056/NEJMra1312885
  23. Nazerian P et al. Accuracy of lung ultrasound for the diagnosis of consolidations when compared to chest computed tomography. Am J Emerg Med 2015 May; 33:620 PMID: 25758182
  24. Alba GA, Truong QA, Gaggin HK et al Diagnostic and Prognostic Utility of Procalcitonin in Patients Presenting to the Emergency Department with Dyspnea. Am J Med. 2016 Jan;129(1):96-104.e7 PMID: 26169892
  25. Caldeira D, Alarcao J, Vaz-Carneiro A, Costa J. Risk of pneumonia associated with use of angiotensin converting enzyme inhibitors and angiotensin receptor blockers: systematic review and meta-analysis. BMJ. 2012 Jul 11;345:e4260. Review. PMID: 22786934 Free PMC Article
  26. Eom CS, Jeon CY, Lim JW, Cho EG, Park SM, Lee KS. Use of acid-suppressive drugs and risk of pneumonia: a systematic review and meta-analysis. CMAJ. 2011 Feb 22;183(3):310-9. Review. PMID: 21173070 Free PMC Article
  27. Shah SS, Srivastava R, Wu S et al Intravenous Versus Oral Antibiotics for Postdischarge Treatment of Complicated Pneumonia Pediatrics Nov 2016, e20161692 PMID: 27940695
  28. Hay AD, Little P, Harnden A et al Effect of Oral Prednisolone on Symptom Duration and Severity in Nonasthmatic Adults With Acute Lower Respiratory Tract Infection. A Randomized Clinical Trial. PMID: 28829884 http://jamanetwork.com/journals/jama/article-abstract/2649201
  29. Shorr AF, Fisher K, Micek ST, Kollef MH. The burden of viruses in pneumonia associated with acute respiratory failure: An underappreciated issue. Chest. 2017 Dec 21. pii: S0012-3692(17)33236-1 PMID: 29274318
  30. Warren-Gash C et al. Laboratory-confirmed respiratory infections as triggers for acute myocardial infarction and stroke: A self-controlled case series analysis of national linked datasets from Scotland. Eur Respir J 2018 Mar; 51:1701794 PMID: 29563170 Free full text http://erj.ersjournals.com/content/51/3/1701794
  31. Zimmerman S, Sloane PD, Ward K et al Effectiveness of a Mouth Care Program Provided by Nursing Home Staff vs Standard Care on Reducing Pneumonia IncidenceA Cluster Randomized Trial. JAMA Netw Open. 2020;3(6):e20432 PMID: 32558913 Free PMC article. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2767357
  32. Musgrave T, Verghese A. Clinical features of pneumonia in the elderly. Semin Respir Infect. 1990 Dec;5(4):269-75. PMID: 2093972 Review.
  33. NEJM Knowledge+
  34. Gupta AB et al. Inappropriate diagnosis of pneumonia among hospitalized adults. JAMA Intern Med 2024 May; 184:548 PMID: 38526476 PMCID: PMC10964165 Free PMC article https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2816759
  35. National Heart, Lung, and Blood Institute (NHLBI) Pneumonia https://www.nhlbi.nih.gov/health-topics/pneumonia