Pneumonia

1. In a patient who presents without the classic respiratory signs and symptoms (e.g., deterioration, delirium, abdominal pain), include pneumonia in the differential diagnosis.

2. In a patient with signs and symptoms of pneumonia, do not rule out the diagnosis on the basis of a normal chest X-ray film (e.g., consider dehydration, neutropenia, human immunodeficiency virus [HIV] infection).

3. In a patient with a diagnosis of pneumonia, assess the risks for unusual pathogens (e.g., a history of tuberculosis, exposure to birds, travel, HIV infection, aspiration).

4. In patients with pre-existing medical problems (e.g., asthma, diabetes, congestive heart failure) and a new diagnosis of pneumonia:

   1. Treat both problems concurrently (e.g., with prednisone plus antibiotics).

   2. Adjust the treatment plan for pneumonia, taking into account the concomitant medical problems (e.g., be aware of any drug interactions, such as that between warfarin [Coumadin] and antibiotics).

5. Identify patients, through history-taking, physical examination, and testing, who are at high risk for a complicated course of pneumonia and would benefit from hospitalization, even though clinically they may appear stable.

6. In the patient with pneumonia and early signs of respiratory distress, assess, and reassess periodically, the need for respiratory support (bilevel positive airway pressure, continuous positive airway pressure, intubation) (i.e., look for the need before decompensation occurs).

7. For a patient with a confirmed diagnosis of pneumonia, make rational antibiotic choices (e.g., outpatient + healthy = first-line antibiotics; avoid the routine use of “big guns”).

8. In a patient who is receiving treatment for pneumonia and is not responding:

   1. Revise the diagnosis (e.g., identify other or contributing causes, such as cancer, chronic obstructive pulmonary disease, or bronchospasm), consider atypical pathogens (e.g., Pneumocystis carinii, TB) and diagnose complications (e.g., empyema, pneumothorax).

   2. Modify the therapy appropriately (e.g., change antibiotics).

9. Identify patients (e.g., the elderly, nursing home residents, debilitated patients) who would benefit from immunization or other treatments (e.g., flu vaccine, Pneumovax, ribavarine) to reduce the incidence of pneumonia.

10. In patients with a diagnosis of pneumonia, ensure appropriate follow-up care (e.g., patient education, repeat chest X-ray examination, instructions to return if the condition worsens).

11. In patients with a confirmed diagnosis of pneumonia, arrange contact tracing when appropriate (e.g., in those with TB, nursing home residents, those with legionnaires’ disease).

General Overview

• Pathogens

  • Typical: Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis

  • Atypical: Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella spp

  • Aspiration: Bacteroides (anaerobes)

• Community-Acquired

  • No hospitalization within 14d of onset OR <4d prior to onset

• Diagnosis

  • Two symptoms (fever, rigors, cough change, pleuritic chest pain, SOB), AND auscultatory findings (localized crackles, bronchial breath sounds), AND X-ray opacity

History

• Symptoms

  • Fever/chills

  • New or change in cough

  • Pleuritic chest pain

  • N/V

  • Urine/Stools

  • Fatigue, Myalgias

• Risk Factors

  • Smoker, comorbid

  • Antibiotics or hospitalization in past 3 months

• Note: The only significant findings for a bacterial pneumonia is acute onset (LR+3.6, LR-0.31) and age >65 (LR+2.7, LR-0.43)

  • Chills, pleuritic chest pain, purulent sputum, signs of consolidation on auscultation were not helpful in making the diagnosis

• Note: Adults with an acute respiratory infection and normal vital signs/pulmonary exam are unlikely (~0.4%) to have pneumonia

Investigations

• Chest X-ray (PA and lateral) required for diagnosis according to IDSA

  • Highly suggested in children as well according to CPS

• Labs

  • CRP was the most accurate lab test

    • CRP < 10 mg/L; LR- = 0.27

    • CRP > 20 mg/L; LR+ = 2.08

    • CRP > 50 mg/L; LR+ = 3.68

    • CRP > 100 mg/L; LR+ = 5.79

  • Procalcitonin had a good LR+, but a minimally useful LR-

    • Procalcitonin > 0.25 mcg/L and 0.50 mcg/L; LR+ = 5.43 and 8.25

  • Leukocytosis was only modestly, if at all, accurate (> 9.5 - 10.5; LR+ = 3.15)

• Consider if severe

  • Urine legionella/pneumococcal Ag

    • Positive even after days of antibiotic therapy

  • Sputum gram stain and culture (r/o MRSA, P. aeruginosa)

    • Legionella Culture

  • Nasopharyngeal swab viral PCR (influenza, coronavirus, etc...)

  • If not improving can monitor CRP / Procalcitonin

• Pneumonia Severity Index (PSI) more evidence than CURB-65 to determine outpatient vs inpatient treatment

Treatment

Supportive

• Oxygen

• Drain large pleural effusions or if suspect empyema

Antibiotics

• If no antibiotics in past three months

  • Clarithromycin 500mg PO BID x7d or Azithromycin 500mg PO daily x1 day then 250mg PO daily x 4 days or Doxycycline 100mg PO BID x 7 days

    • Promote less resistance to macrolides by using clarithromycin

  • Amoxicillin 1g PO TID x7d (less emphasis on covering atypicals)

    • Pediatrics - Amoxicillin 90 mg/kg/d PO divided TID x7-10d (consider atypical coverage in children ≥5 years old)

      • May consider shorter courses in children with community-acquired pneumonia (3d or 5d) as per recent studies CAP-IT, SAFER, SCOUT-CAP.

• If comorbidities or recent antibiotics

  • Amoxicillin with atypical coverage (Clarithromycin or Azithromycin or Doxycycline)

  • If non-anaphylactic penicillin allergy

    • Cefuroxime or Cefadroxil + atypical coverage (consider monitor in office 1-2h)

  • Anaphylactic penicillin allergy

    • Levofloxacin or Moxifloxacin as below

• Second-line (after failed 72-96h)

  • Levofloxacin 750mg PO daily x 5 days or Moxifloxacin 400mg PO daily x 7d

• If hospitalized and intensive care

  • Cefotaxime 1-2g IV q8h or Ceftriaxone 1-2g IV q12-24h AND Levofloxacin or Moxifloxacin or Azithromycin

    • Note: Ceftriaxone superior to Pip/Tazo (as 15% Strep pneumo resistant to Pip/Tazo in community-acquired pneumonia)

• Consider covering for legionella if risk factors

  • Elderly, immunosuppression, smoker, lung disease

  • T>39ºC

  • Neurological (Confusion/Weakness/Gen det)

  • GI (diarrhea)

  • Electrolytes (Hyponatremia. hypophosphatemia, renal/hepatic dysfunction, thrombocytopenia, leukococytosis)

  • Hematuria

  • Hotel, cruise ships, residence (water reservoir contamination)

Follow-up

• Return if no improvements after 72h of treatment (fever should not return after 3d)

• IDSA recommends not routinely obtaining follow-up imaging if symptoms resolve within 7 days (low quality evidence)

• Repeat CXR in 6w (r/o underlying disease) if

  • >50yo or immunosuppressed, lung disease, alcohol, smoker, >5% weight loss in past month

  • Extensive/necrotizing pneumonia

Prevention

• Smoking cessation

• Hygiene (handwashing)

• Vaccination

  • Influenza

  • Pneumococcal >65yo or comorbidity

    • Prevents invasive pneumococcal disease (bacteremia)