Pneumonia - Community-Acquired Management

Evaluation

Patients with severe community-acquired pneumonia should be managed in a hospital setting. Direct ICU admission is recommended for patients with hypotension or shock requiring vasopressors or respiratory failure needing mechanical ventilation, altered mental status, or pneumonia with multiorgan impairment.  

CRB65 for Mortality Risk Assessment  

CRB65 is used in primary care. It is calculated by giving 1 point for each prognostic feature present. Patients are then stratified for risk of death. A CRB65 score of ≥2 should prompt hospital evaluation. Home-based care or a community intervention team are options for patients with a score of 1. Home-based care is considered for low-risk patients.  

Prognostic Features

• Confusion (abbreviated Mental Test score of ≤8 or new disorientation)
• Increased respiratory rate (≥30 breaths per minute)
• Decreased blood pressure (BP) (<90/≤60 mmHg)
  
• ≥65 years old

Stratification

• 0: Low-risk (<1% mortality risk)
• 1-2: Intermediate-risk (1-10% mortality risk)
• 3-4: High-risk (>10% mortality risk)

CURB65 Score for Mortality Risk Assessment  

CURB65 is used for patients presenting with CAP in the hospital setting. It is calculated by giving 1 point for each prognostic feature present. Patients are then stratified for risk of death. A CURB65 score of ≥3 should prompt evaluation for intensive care. Hospital-based care should be considered for those with a CURB65 score of ≥2. Home-based care or community intervention team are options for patients with a score of 1. Home-based care is considered for low-risk patients.  

Prognostic Features Requiring Hospitalization

• Confusion (abbreviated Mental Test score of ≤8 or new disorientation)
• Increased blood urea nitrogen (BUN) (>7 mmol/L or >20 mg/dL)
• Increased respiratory rate (≥30 breaths per minute)
• Decreased blood pressure (BP) (<90/≤60 mmHg)
• ≥65 years old

Stratification

• 0 or 1: Low-risk (<3% mortality risk)
• 2: Intermediate-risk (3-15% mortality risk)
  • Other features include extrapulmonary evidence of sepsis, suspected aspiration, unstable comorbid conditions; chest X-ray findings of multilobar involvement, pleural effusion, abscess, or progression of lesion to >50% of initial within 24 hours, and urea >7 mmol/L
• 3-5: High-risk (>15% mortality risk)
  • Other features include shock or signs of hypoperfusion (ie hypotension, altered mental state, urine output <30 mL/hr), and acute hypercapnia (partial pressure of carbon dioxide [PaCO₂] >50 mmHg)
    
    

Pneumonia Severity Index (PSI)  

This index is adopted and preferred by the American Thoracic Society and is used to classify patients accordingly to mortality risk. It also predicts the need for hospitalization. The parameters include age, comorbidities, and physical exam as step 1, and gender, laboratory, and imaging findings as step 2. A risk score is obtained by adding the points for each applicable patient characteristic which are listed as follows:

• Demographic factors:
  • Men: Age (year)
  • Women: Age (year) - 10
• Nursing home residents: + 10
• Comorbid illnesses:
  • Neoplastic disease: + 30
  • Liver disease: + 20
  • Congestive heart failure (CHF): + 10
  • Cerebrovascular disease: + 10
  • Renal disease: + 10
• Physical examination findings:
  • Altered mental status: + 20
  • Respiratory rate ≥30 breaths/minute: + 20
  • Systolic BP <90 mmHg: + 20
  • Temperature <35°C or ≥40°C: + 15
  • Pulse ≥125 beats/minute: + 10
• Laboratory and imaging findings:
  • Arterial pH <7.35: + 30
  • BUN ≥30 mg/dL (≥10.7 mmol/L): + 20
  • Sodium <130 mEq/L: + 20
  • Glucose ≥250 mg/dL (≥13.9 mmol/L): + 10
  • Hematocrit <30% PaO₂ <60 mmHg or SaO₂ <90%: + 10
  • Pleural effusion: + 10 

Based on the score, patients are classified according to their risk class, and listed here are the management strategies for each:

• For Class I (Low-risk): No predictors are present: Outpatient therapy
• For Class II (Low-risk): ≤70 points; mortality estimated at 0.6%: Outpatient therapy except for patients with respiratory rate of ≥30 breaths/minute, partial pressure of O₂/fraction of inspired O₂ (PaO₂/FiO₂) ratio of ≤250 mmHg, systolic blood pressure of <90 mmHg, diastolic blood pressure of <60 mmHg, multilobar infiltrates and confusion
• For Class III (Low-risk): 71-90 points; mortality estimated at 0.9%: May be managed as an outpatient depending on clinical status, available resources, and other factors; and an option for at-home parenteral antibiotic therapy or brief hospitalization (<24 hours)
• For Class IV (Moderate-risk): 91-130 points; mortality estimated at 9.3%: Inpatient therapy
• For Class V (High risk): >130 points; mortality estimated at 27%: Inpatient therapy 

Principles of Therapy

Antibiotics should be initiated as soon as possible upon diagnosis of community-acquired pneumonia. When choosing antibiotics, local antimicrobial resistance should be considered. For patients with sepsis, refer to the management recommendations for sepsis (sepsis bundle). Among patients with recent antibiotic exposure, do not use antibiotics in the same class as the patient had been receiving previously.  

In patients with low severity, consider a 5-day single antibiotic course. Duration may be extended if patient is still symptomatic after 3 days of treatment. Dual antibiotic therapy and quinolones should be avoided in these patients.  

In patients with moderate-high severity, a 7- to a 10-day antibiotic course is recommended. Antibiotic therapy may be extended based on clinical considerations (eg pneumonia is not resolving, pneumonia complicated by sepsis, meningitis, endocarditis and other deep-seated infection, less common or drug-resistant pathogens). In patients with high-risk pneumonia, the parenteral route is recommended for all antimicrobial administration because the severity of the condition may result in a low perfusion state. 

Infection with anaerobes should also be considered as possible causative organisms in patients with a risk of aspiration. The addition of anaerobic antimicrobials to routine community-acquired pneumonia therapy should only be initiated if a lung abscess or empyema is suspected.  

In patients who tested positive for MRSA or Pseudomonas aeruginosa in the respiratory tract within the prior year, initiation of empiric therapy against MRSA or Pseudomonas aeruginosa is recommended in addition to standard community-acquired pneumonia antimicrobials. Empiric therapy for MRSA or Pseudomonas aeruginosa may be withheld in patients without prior colonization located in areas with very low prevalence.  

Empiric treatment for MRSA or Pseudomonas aeruginosa should only be started in patients with non-severe community-acquired pneumonia if locally validated risk factors are present. Treatment may be continued based on the published risk factors even without local etiological data. Culture results should be obtained after initiation to confirm the presence of MRSA or Pseudomonas aeruginosa. Shifting from initial empiric broad or extended spectrum antibiotic therapy coverage to targeted or oral antibiotics based on culture results may be done when the patient is clinically improving, hemodynamically stable, and able to tolerate oral medications.

Antiviral therapy may be started in patients who test positive in rapid molecular tests but may also be considered in patients without a positive test result but with suspected influenza infection and risk factors.  

Please see Influenza disease management chart for further information.

Pharmacological therapy

Reference: The American Thoracic Society (ATS) and the Infectious Disease Society of America (IDSA) 2019 official clinical practice guideline on the diagnosis and treatment of adults with community-acquired pneumonia.
¹Macrolides: Azithromycin, Clarithromycin; Erythromycin for pregnant patients
²Cephalosporins: Cefpodoxime, Cefuroxime
³Respiratory fluoroquinolones: Gemifloxacin, Levofloxacin, Moxifloxacin
⁴Beta-lactams: Ampicillin/sulbactam, Cefotaxime, Ceftriaxone, Ceftaroline
⁵May start treatment in a patient with other risk factors (recent hospitalization with parenteral antibiotics and locally validated risk factors) only if with positive culture results
⁶If with risk factors for methicillin-resistant Staphylococcus aureus, may add treatment against methicillin-resistant Staphylococcus aureus if with positive rapid nasal polymerase chain reaction result and obtain cultures

Beta-lactams

Low-risk Community-acquired Pneumonia  

High-dose Amoxicillin or Amoxicillin/clavulanate (Co-amoxiclav) is preferred as it targets >93% of Streptococcus pneumoniae. Comorbidities or recent antimicrobial therapy increase the likelihood of infection with drug-resistant Streptococcus pneumoniae and enteric Gram-negative bacteria which may be treated using a combination of a beta-lactam and a macrolide. Second and third generation cephalosporins can be used as alternative antibiotic therapy for patients with stable co-morbid conditions; these are less active in vitro than high-dose Amoxicillin.

Moderate-risk and High-risk Community-acquired Pneumonia  

Parenteral nonpseudomonal beta-lactams with or without a beta-lactamase inhibitor are recommended. Some antibiotics from this class may also have anaerobic activity. Patients may be given either an extended macrolide or a respiratory quinolone. Recommended beta-lactams include penicillins, second- and third-generation cephalosporins, and carbapenems if with Pseudomonas aeruginosa risk. Combining non-pseudomonal beta-lactams with macrolides results in a significant reduction in mortality.   

Consider giving Oxacillin to patients shown or suspected to have lung abscesses, pneumatoceles, or pyothorax, in which Staphylococcus sp is a common etiologic organism. The best indicator of Staphylococcus aureus infection is the presence of Gram-positive cocci in clusters in a tracheal aspirate or in an adequate sputum sample. 

Clindamycin or Beta-lactam/Beta-lactamase Inhibitor

May consider adding empiric antibiotic agents Clindamycin or β-lactam/β-lactamase inhibitors in hospitalized patients with suspected aspiration pneumonia or if lung abscess or empyema is suspected. Clindamycin may be used as an alternative to Linezolid or Vancomycin if the isolate is susceptible.

Lefamulin  

A newly approved pleuromutilin antibiotic that may be used as treatment for community-acquired bacterial pneumonia. Studies showed that the use of Lefamulin in hospitalized adult patients is non-inferior to Moxifloxacin

Macrolides  

Low-risk Community-acquired Pneumonia  

Macrolides and azalides may be better for patients with extrapulmonary physical findings, a feature of pneumonia caused by atypical pathogens. Macrolides may be considered if with <25% local pneumococcal resistance. It may also serve as an alternative for patients who are hypersensitive to Penicillin. Erythromycin is less active against Haemophilus influenzae. Azithromycin is preferred for outpatients with comorbidities (eg chronic obstructive pulmonary disease) because of Haemophilus influenzae.  

Moderate-risk and High-risk Community-acquired Pneumonia  

Combining macrolides with nonpseudomonal beta-lactams results in reduced mortality. Adding a macrolide to the antibiotic regimen benefits patients in areas with high prevalence of Legionella sp.

Quinolones with Anti-Pneumococcal Action (Respiratory Quinolones)

Low-risk Community-acquired Pneumonia   

May be used alone as an alternative regimen to combination therapy of beta-lactam with or without beta-lactamase inhibitor plus a macrolide in patients with comorbid illness.  

Moderate-risk to High-risk Community-acquired Pneumonia  

Alternative regimen to macrolides in the combination therapy with nonpseudomonal beta-lactam with or without beta-lactamase inhibitor, for patients without comorbid illnesses but with documented allergies, contraindications, or those unresponsive to macrolides. In areas with a high prevalence of pulmonary tuberculosis (TB), they are better reserved as potential second-line agents for the treatment of multidrug-resistant tuberculosis. However, quinolones may mask the clinical features of pulmonary TB and delay its diagnosis.

Tetracyclines

Low-risk to Moderate-risk Community-acquired Pneumonia  

Doxycycline may be used in low-risk and moderate-risk patients without comorbidities and with documented allergies, contraindications, or those unresponsive to treatment with macrolides and fluoroquinolones.  

Moderate-risk Community-acquired Pneumonia  

Omadacycline is a newly approved broad-spectrum antibiotic treatment option for adults with non-severe community-acquired pneumonia, especially in the setting of tetracycline resistance with efficacy comparable to Moxifloxacin.

Other Treatments

Anti-influenza treatment (eg Oseltamivir, Zanamivir) is recommended for patients who are positive for influenza virus regardless of the site of care and should be given within 48 hours of symptom onset.

Duration of Treatment Based on Etiology

Serial procalcitonin measurement may be used as a guide for the determination of the duration of antibiotic therapy. In clinically stable patients, a drop in procalcitonin level from the peak by ≥80% and/or a fall below the cut-off indicates resolution of illness and earlier discontinuation of antibiotics.  

Low-risk Community-acquired Pneumonia  

A minimum of 5 days with a usual duration of 5-7 days for most cases of pneumonia of bacterial etiology is recommended. A 3-day course of oral therapy may be possible with azalides.  

Moderate-risk and High-risk Community-acquired Pneumonia 

Pneumonia - Community-Acquired_Management

Nonpharmacological

Patient Education

Teach the patient to monitor temperature and sputum production and recognize worsening signs and symptoms and the onset of complications. Remind the patient to rest and drink plenty of fluids. Help the patient understand and comply with the medication regimen and diet.  

Explain the importance of vaccination in patients with recurrent infections. Inform the patient that a repeat chest X-ray is needed after recovery in patients at risk for lung cancer.  Instruct the patient about the use and cleaning of home respiratory equipment (eg mini-nebulizer) and remind the patient that nebulization is not recommended in patients with suspected or confirmed COVID-19 infection. Encourage the patient to be in a smoke-free environment or to quit smoking. 

Prevention

Pneumococcal and influenza vaccines are recommended for the prevention of community-acquired pneumonia. Both pneumococcal and influenza vaccines can be administered simultaneously at different sites without increasing side effects. There are no contraindications for pneumococcal or influenza vaccine use immediately after an episode of pneumonia.  

Pneumococcal Vaccine*  

Examples of pneumococcal vaccines include 10-valent pneumococcal conjugate vaccine (PCV10), 13-valent pneumococcal conjugate vaccine (PCV13), 15-valent pneumococcal conjugate vaccine (PCV15), 20-valent pneumococcal conjugate vaccine (PCV20), 21-valent pneumococcal conjugate vaccine (PCV21), and the 23-valent pneumococcal polysaccharide vaccine (PPSV23). PCV13, PCV15, PCV21, and PPSV23 are recommended for adults. While PCV10, PCV13, and PCV15 are used in children.  

Pneumococcal vaccination is routinely recommended in adults who are ≥50 years old, 19-64 years old with an immunocompromised condition, with CSF leak, cochlear implant or chronic medical conditions (eg smoking, chronic heart disease [including CHF and cardiomyopathy but excluding hypertension], chronic lung disease [chronic obstructive lung disease, asthma, emphysema], chronic liver disease [liver cirrhosis], alcoholism, DM). 

Immunocompromised conditions that require pneumococcal vaccination include B- or T-lymphocyte deficiency, complement deficiencies and phagocytic disorders (excluding chronic granulomatous disease), HIV infection (vaccine should be given as soon as possible), chronic renal failure and nephrotic syndrome, leukemia, Hodgkin lymphoma, generalized malignancy, multiple myeloma, patient who underwent solid organ transplantation, and iatrogenic immunosuppression (including long-term systemic corticosteroid and radiation therapy). Pneumococcal vaccination should be given at least 2 weeks before starting immunosuppressive therapy. Patients with anatomical or functional asplenia (eg sickle cell disease and other hemoglobinopathies, congenital or acquired asplenia, splenic dysfunction, and splenectomy) should be given pneumococcal vaccination at least 2 weeks before an elective splenectomy.  

Patients ≥50 years old who have not received any pneumococcal conjugate vaccine, with unknown vaccination history or given 7-valent pneumococcal conjugate vaccine (PCV7) at any age, should receive PCV15, PCV20 or PCV21. If PCV15 was previously received, PPSV23 should be administered (PCV20 or PCV21 may be used if PPSV23 is not available) after ≥1 year. Additional vaccination with PPSV23 is not required if PCV20 or PCV21 was used. For patients who previously received PCV13 at any age and PPSV23 before the age of 65 years old, a single dose of PCV20 or PCV21 should be given ≥5 years after the last pneumococcal vaccine dose. However, if the patient was ≥65 years old when PPSV23 was given, shared clinical decision making should be employed to determine if PCV20 or PCV21 should still be given. 

For 19- to 49-year-old patients with immunocompromising condition, CSF leak or a cochlear implant who have not received any pneumococcal conjugate vaccine, with unknown vaccination history or given PCV7 at any age, PCV15, PCV20 or PCV21 is recommended. If PCV15 was given, PPSV23 should be administered (PCV20 or PCV21 may be used if PPSV23 is not available) after ≥8 weeks. Additional vaccination with PPSV23 is not required if PCV20 or PCV21 was used. If PCV13 and 1 dose of PPSV23 was previously received, a single dose of PCV21 or PCV20 should be administered ≥5 years after the last pneumococcal vaccine dose to complete the vaccination series; no additional pneumococcal vaccine doses should follow. If 2 doses of PPSV23 was previously received, pneumococcal vaccination recommendations may be reviewed when the patient turns 50 years old or a single dose of either PCV21 or PCV20 should be administered ≥5 years after the last pneumococcal vaccine dose to complete the vaccination series.

For 19- to 49-year-old patients with chronic medical conditions (see above) who have not received any pneumococcal conjugate vaccine, with unknown vaccination history or PCV7 at any age, PCV15, PCV20 or PCV21 is recommended. If PCV 15 was given, PPSV23 should be administered (PCV20 or PCV21 may be used if PPSV23 is not available) after ≥1 year. Additional vaccination with PPSV23 is not required if PCV20 or PCV21 was used. If PCV13 and 2 doses of PPSV23 was previously received, pneumococcal vaccination recommendations may be reviewed when the patient turns 50 years old. 

For adults requiring routine pneumococcal vaccination who previously received PPSV23 only at any age, PCV15, PCV20 or PCV21 should be given ≥1 year after the PPSV23 dose while those who were previously vaccinated with PCV13 only should receive a single dose of PCV20 or PCV21 ≥1 year after PCV13 dose. Pneumococcal vaccine is not recommended for persons with a history of serious allergic reaction to a vaccine component, moderate or severe acute illness, and pregnancy.
 

Pneumonia - Community-Acquired_Follow Up