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Monitoring

• Outpatients
  • Follow up by telephone within 48 h.
    • Most patients feel better by this time.
    • ~10% are unchanged.
    • ~5% feel worse and should be reassessed by a physician.
    • Patients should receive written information about warning signs of pneumonia exacerbation, including:
      
      • Shortness of breath while walking on level ground (assuming no underlying lung disease)
      • Temperature of > 38.5°C (101.3°F) after 72 h of antibiotic therapy
      • New onset of confusion or pleuritic chest pain
      • Hemoptysis
• Inpatients
  • Monitor temperature curve and WBC count for resolution.
    • Follow up on culture results and adjust therapy accordingly.
    • Watch for superinfection with S. aureus.
    • Monitor comorbid conditions (e.g., COPD, renal disease)
• Follow up to ensure radiographic clearance of pneumonia.
  • All patients > 40 years old and all tobacco smokers should have a follow-up chest radiograph to document pneumonia resolution, which may lag behind clinical improvement for several weeks.
    • Nonsmokers < 50 years old who lack underlying lung disease: 6 weeks
    • Elderly patients with COPD: 8–12 weeks
  • Up to 2% of patients hospitalized with CAP have cancer in the lung (with pneumonia distal to an obstructed bronchus)
    • 50% of these cancers are evident on the initial chest film.
    • 50% manifest as failure of pneumonia resolution and are diagnosed at bronchoscopic evaluation for unresolving pneumonia.
• Considerations when pneumonia fails to improve despite treatment
  • Reconsider the diagnosis.
    • Is another illness presenting as pneumonia?
      • For example, collagen vascular diseases involving the lung often are initially diagnosed as pneumonia.
    • Are you treating the wrong pathogen?
      • For example, if you are treating conventional bacterial causes of pneumonia, is this case actually due to M. tuberculosis or to Pneumocystis or another fungus?
    • Are you treating the right pathogen with the wrong drug?
      • For example, if you are using nafcillin or cloxacillin to treat S. aureus and your patient is infected with MRSA, you should be using vancomycin or linezolid.
  • Is there a mechanical reason for the patient’s failure to improve (e.g., an obstructed bronchus due to carcinoma or sequestration of a segment of the lung)?
  • Have you overlooked an undrained or metastatic pyogenic focus (e.g., empyema, brain abscess, endocarditis, splenic abscess, osteomyelitis)?
  • Does the patient have drug-associated fever?
• Workup when pneumonia fails to improve
  • Careful physical examination
  • Blood, urine, and sputum cultures
  • Repeat chest film
  • Chest CT
  • Bronchoalveolar lavage to obtain fluid for microbiologic studies and cytology
    

Complications

General complications

• Since most patients hospitalized with pneumonia are elderly and have multiple comorbid conditions, complications during the hospital stay are not uncommon.
• The most common complications are:
  • Respiratory failure
  • Congestive heart failure
  • Shock
  • Atrial dysrhythmias
  • Myocardial infarction
  • Gastrointestinal bleeding
  • Renal insufficiency
• Only ~30% of patients hospitalized for the treatment of pneumonia have no complications.
• The major systemic complication is bacteremia.
  • Can lead to metastatic infection, including septic arthritis or meningitis
    

Complicated pleural effusion

• Pleural effusion is seen in ~40% of patients hospitalized for CAP.
• All patients with a pleural effusion should have a lateral decubitus chest radiograph with the affected side down.
• If the effusion is > 1 cm, the fluid should be aspirated.
• If the fluid has a pH of < 7, a glucose level of < 2.2 mmol/L, and an LDH content of > 1000 units and is positive on Gram’s staining or culture, it should be drained.
• If frank pus is aspirated, insertion of a large-bore chest tube is recommended.
  • Loculated collections may be manageable with multiple chest tubes placed into loculated compartments.
  • The utility of treatment with intrapleural lytic agents is controversial.
• The goal is eradication of the collection.
  • Follow-up with postdrainage imaging is required to confirm adequate catheter placement and complete pleural fluid drainage.
• Thoracotomy and decortication may be necessary.
• All patients with a complicated pleural effusion, as defined above, should have a consultation with a thoracic surgeon.

Lung abscess

• Incidence
  • Uncommon; 4–5 cases/10,000 hospital admissions
• Risk factors
  • Conditions associated with impaired cough reflex and/or aspiration, such as alcoholism, anesthesia, drug abuse, epilepsy, and stroke
  • Dental caries
  • Bronchiectasis
  • Bronchial carcinoma
  • Pulmonary infarction
• Etiology
  • Most aspiration-associated lung abscesses are due to a combination of aerobic and anaerobic bacteria.
  • On average, 6 or 7 bacterial species are identified in an individual case.
  • Anaerobic bacteria include:
    • Bacteroides fragilis group
    • Bacteroides gracilis
    • Prevotella spp. (intermedia, denticola, melaninogenicus, oralis)
    • Fusobacterium nucleatum
    • Peptostreptococcus spp. (micros, anaerobius, magnus)
  • Aerobic pathogens include:
    • Streptococcus milleri (one of the principal pathogens)
    • S. aureus
    • S. pneumoniae
    • H. influenzae
    • P. aeruginosa
    • E. coli
    • Klebsiella pneumoniae
  • Rarely, S. pneumoniae alone (usually capsular type 3) can cause a lung abscess.
  • In HIV-infected patients, lung abscesses can be due to Pneumocystis, Rhodococcus equi, and Cryptococcus neoformans as well as the bacteria noted above.
• See Lung Abscesses and Empyema for further details, including treatment.

Recurrent pneumonia

• Of patients hospitalized for the treatment of CAP, 10–15% have another episode within 2 years.
• If the recurrence affects the same anatomical location as the previous episode, the most likely cause is an obstructed bronchus due to either a tumor or a foreign body.
• COPD and repeated macroaspiration are the most common causes of recurrent pneumonia.
• Persons without COPD, with pneumonia in a different location from the previous episode, and with no risk factors for aspiration should undergo evaluation for immunodeficiency (including HIV testing), immunoglobulin determination, protein electrophoresis, and enumeration of T and B cells.
• CT of the chest often detects pulmonary anatomical defects (e.g., bronchiectasis) that might be the cause of the recurrence.

Prognosis

• Outpatients
  
  • Young, otherwise healthy adults
    • Those treated as outpatients usually feel well enough to return to work in 4 or 5 days; almost all recover in 2 weeks.
    • Those with relatively severe symptoms may require longer to recover.
  • ~2–4% of those treated as outpatients experience a progression of symptoms and require hospital admission.
• Inpatients
  
  • Patients generally stabilize within 3–7 days.
  • The in-hospital mortality rate from pneumonia is ~8%.
    • The most common immediate causes of death are respiratory failure, heart disease, and sepsis.
    • ~50% of deaths are related to pneumonia and ~50% to comorbid illnesses.
    • Pneumonia-related deaths are much more likely to occur during the first week of hospitalization.
    • Increasing age and evidence of aspiration independently predict both pneumonia-related and comorbidity-related mortality.
  • Factors independently associated with pneumonia-unrelated mortality include:
    • Dementia
    • Immunosuppression
    • Active cancer
    • Systolic hypotension
    • Male gender
    • Multilobar pulmonary infiltrates
  • Mortality associated with PORT score (see Treatment Approach)
    
  • Class I: 0–0.5%
  • Class II: 0.4–0.9%
  • Class III: 0–1.25%
  • Class IV: 9.0–12.5%
  • Class V: 27.1%
• Mortality is related to the specific etiology.
  • Rates are highest (>50%) for P. aeruginosa, followed by Klebsiella spp., E. coli, S. aureus, and Acinetobacter spp. (all 30–35%).
  • Pneumococcal capsular serotype 3 is associated with a much higher mortality rate than serotype 1, as are group A streptococcal M serotypes 1 and 3 (compared with other serotypes).
• Early, appropriate antibiotic therapy is associated with decreased mortality rates.
  

Prevention

• Influenza and pneumococcal vaccination status should be ascertained and vaccines offered when appropriate.
• All patients with pneumonia who are tobacco smokers should be encouraged to join smoking cessation programs.
• When a patient is prone to aspiration, preventive measures should be taken, including attention to oral hygiene.
• Only sterile water should be used in humidifiers in long-term-care facilities.
• Antimicrobial prophylaxis should be given in special situations—for example:
  
  • Latent tuberculosis prophylaxis (see Tuberculosis)
  • Pneumocystis prophylaxis for selected immunocompromised patients (see Pneumocystis Infections)
    

The Harrison's Practice Preview allows you to view 5 FREE complete topics or conduct a search that delivers abstracts for more than 450 medical topics. For full access, please subscribe today!