Pneumonia, Adult, Emergency Medicine

Basics

Description

Epidemiology:
- 7th leading cause of death and leading cause from infectious disease in US
Highest mortality in elderly and patients with the following coexisting conditions:
- Chronic heart, lung, liver, and kidney disease
- Diabetes mellitus
- Alcoholism
- Malignancy
- Asplenia
- Immunosuppression
- Use of antimicrobials within last 3 mo
Classifications:
- Source based:
  - Community acquired (CAP)
  - Health care associated (HCAP)
  - Hospital acquired (HAP)
  - Ventilator associated (VAP)
- Symptom based:
  - Typical
  - Atypical
Complications:
- Bacteremia
- Sepsis
- Abscess
- Empyema
- Respiratory failure

Etiology

CAP (typicals):
- Streptococcus pneumoniae
- Haemophilus influenzae
- Klebsiella pneumoniae
- Moraxella catarrhalis
- Streptococcus pyogenes
- Staphylococcus aureus
CAP (atypicals):
- Mycoplasma pneumoniae
- Chlamydophila pneumoniae
- Legionella pneumophila
- Viral
HCAP/HAP/VAP:
- Gram negatives (Pseudomonas, Stenotrophomonas)
- Methicillin-resistant S. aureus (MRSA)
Immunosuppressed:
- Mycobacterium tuberculosis
- Pneumocystis jirovecii
Aspiration:
- Chemical pneumonitis ‚ ± oral and gastric anaerobes

Diagnosis

Signs and Symptoms

History

Typical:
- Acute onset
- Fever
- Chills
- Rigors
- Cough
- Purulent sputum
- Shortness of breath
- Pleuritic chest pain
Atypical:
- Subacute onset
- Viral prodrome
- Nonproductive cough
- Low-grade fever
- Headache
- Myalgias
- Malaise
- Absence of pleurisy and rigors

Physical Exam

Vital signs:
- Tachypnea
- Tachycardia
- Hypoxia
- Fever
Pulmonary exam:
- Dullness to percussion
- Tactile fremitus
- Egophony
- Rales
- Rhonchi
- Decreased breath sounds
Note that pneumonia may be present in the absence of the above signs of consolidation.

Elderly patients have higher morbidity and mortality from pneumonia.
Atypical presentations are more common.

Essential Workup

Combination of clinical and radiographic diagnosis ‚

Diagnosis Tests & Interpretation

Lab

General:
- CBC with differential
- Serum chemistry
Others:
- Blood cultures (ICU only)
- Sputum cultures and Gram stain (ICU only)
- Urine antigen tests for S. pneumoniae & Legionella
- C-reactive protein possibly helpful
- Lactate may be helpful
- Influenza viral test

Imaging
Chest radiograph: ‚

General:
- Findings are nonspecific for particular infectious etiologies.
- May be deferred in young, healthy patients receiving empiric outpatient management.
- Negative imaging should not preclude antimicrobial therapy in patients with clinical diagnosis.
Suggestive findings:
- Silhouette sign (R. heart border = RML, L. heart border = lingula, R. hemidiaphragm = RLL, L. hemidiaphragm = LLL)
- Air bronchograms
- Segmental or subsegmental consolidation
- Diffuse interstitial opacities
- Pleural effusion
- Empyema
- Abscess
- Cavitation

Diagnostic Procedures/Surgery
Thoracentesis: ‚

For large effusions, enigmatic pneumonia, and patients who fail to respond to standard therapy

Differential Diagnosis

Asthma
Bronchitis
CHF
COPD
Foreign-body aspiration
Occupational or environmental exposure
Pneumothorax
Pulmonary embolism
Tumor

Treatment

Pre-Hospital

IV access
Supplemental oxygen
Cardiac monitor
Consider inhaled bronchodilators.
Consider endotracheal intubation in cases of severe respiratory distress.

Initial Stabilization/Therapy

IV access and fluid resuscitation as needed
Supplemental oxygen
Cardiac monitor
Inhaled bronchodilators
Endotracheal intubation in cases of severe respiratory distress as indicated

Ed Treatment/Procedures

American Thoracic Society guidelines for empiric therapy:
Outpatient:
- Previously healthy, no coexisting conditions:
  - Macrolide (azithromycin) OR doxycycline
- Significant coexisting conditions (see above):
  - Combination Ž ˛-lactam (ceftriaxone, cefuroxime, cefpodoxime, high-dose amoxicillin, Augmentin) PLUS macrolide (azithromycin) OR
  - Respiratory floroquinolone (levofloxacin, moxifloxacin) alone
Inpatient:
- Noncritical care:
  - Combination Ž ˛-lactam PLUS macrolide OR
  - Respiratory floroquinolone alone
- Critical care:
  - Combination Ž ˛-lactam PLUS macrolide OR respiratory floroquinolone
  - For Pseudomonas, consider adding antipseudomonal agent (piperacillin/tazobactam, imipenem, meropenem, cefepime) PLUS antipseudomonal fluoroquinolone (high-dose levofloxacin) OR antipseudomonal agent (see above) PLUS aminoglycoside (gentamicin) PLUS macrolide (azithromycin).
  - For MRSA, consider adding vancomycin OR linezolid.
  - For aspiration, consider adding clindamycin OR metronidazole.
  - For drug-resistant S. pneumoniae, consider adding vancomycin.

Medication

Amoxicillin " “clavulanate (Augmentin): 500 mg PO q12h
Ampicillin " “sulbactam (Unasyn): 1.5 " “3 g IV q6h
Azithromycin: 500 mg PO on day 1 and 250 mg PO on days 2 " “5 OR 500 mg PO daily for 3 days OR 500 mg IV daily
Aztreonam: 1 " “2 g IV q12h
Cefepime: 2 g IV q12h
Cefotaxime: 1 " “2 g IV q8h
Cefpodoxime: 200 mg PO q12h
Ceftazidime: 2 g IV q12h
Ceftriaxone: 1 " “2 g IV daily
Cefuroxime: 0.75 and 1.5 g IV q8h
Doxycycline: 100 mg PO/IV q12h
Ertapenem: 1 g IV daily
Levofloxacin: 500 " “750 mg PO/IV daily
Linezolid: 600 mg PO/IV daily
Imipenem: 500 mg IV q6h
Meropenem: 1 g IV q8h
Moxifloxacin: 400 mg IV daily
Piperacillin " “tazobactam (Zosyn): 3.375 " “4.5 g IV q6h
Vancomycin: 1 g IV q12h

First Line

Outpatient:
- Healthy:
  - Azithromycin 500 mg PO day 1, 250 mg PO days 2 " “5 OR 500 mg PO daily for 3 days
- Comorbidities:
  - Levofloxacin 750 mg PO daily for 5 days
Inpatient:
- Non-ICU:
  - Levofloxacin 750 mg IV daily
- ICU:
  - Ceftriaxone 1 g IV daily AND levofloxacin 750 mg IV daily ‚ ± piperacillin " “tazobactam 4.5 g IV q6h ‚ ± vancomycin 1g IV q12h

Second Line
Aztreonam may be substituted for Ž ˛-lactams in confirmed penicillin-allergic patients for the above ICU regimens. ‚

Follow-Up

Disposition

Admission Criteria

Based on severity of illness, coexisting conditions, ability of home care, and follow-up
Clinical decision-making rules may aid in stratifying patients but should not supersede clinical judgment.
CURB-65 rule:
- Criteria:
  - Confusion (Abbreviated Mental Test ≤8)
  - Urea >7 mmol/L OR BUN >19
  - Respiratory rate ≥30/min
  - BP with SBP <90 mm Hg, DBP <60 mm Hg
  - Age ≥65 yr
- Interpretation:
  - 0 " “1: Outpatient treatment
  - 2: Close outpatient vs. brief inpatient
  - 3 " “5: Inpatient with ICU consideration
Pneumonia Severity Index:
- Demographics:
  - If Male: + age (yr)
  - If Female: + age (yr) " “ 10
  - If nursing home resident: +10
- Comorbid illness:
  - Neoplastic disease: +30
  - Liver disease: +20
  - Congestive heart failure: +10
  - Cerebrovascular disease: +10
  - Renal disease: +10
- Physical exam findings:
  - Altered mental status: +20
  - Pulse ≥125/min: +20
  - Respiratory rate >30/min: +20
  - SBP <90 mm Hg: +15
  - Temperature <35 ‚ °C or ≥40 ‚ °C: +10
- Lab and radiographic findings:
  - Arterial pH < 7.35: +30
  - BUN ≥30 mg/dL: +20
  - Sodium <130 mmol/L: +20
  - Glucose ≥250 mg/dL: +10
  - Hematocrit <30%: +10
  - PaO2 <60 mm Hg: +10
  - Pleural effusion: +10
- Interpretation:
  - 0: Class I (outpatient)
  - <70: Class II (outpatient vs. short observation)
  - 71 " “90: Class III (home with IV antibiotics vs. short observation)
  - 91 " “130: Class IV (inpatient)
  - >130: Class V (inpatient)
Additional considerations:
- Previous hospitalization within last year for pneumonia
- Failed outpatient therapy
- Social conditions preventing safe outpatient disposition

Discharge Criteria

Age <65 yr
No comorbid illnesses
Nontoxic appearance
Normal vital signs
Normal lab studies
Primary care follow-up within 72 hr

Issues for Referral
Follow-up with primary care within 72 hr ‚

Followup Recommendations

Primary care follow-up within 72 hr ‚

Pearls and Pitfalls

Delayed initiation of antibiotics in ill-appearing patients
Failure to recognize pneumonia in patients assumed to have exacerbations of underlying lung conditions
Failure to question patients regarding TB and HIV risk factors
Elderly and immunocompromised patients may not exhibit any classic symptoms of pneumonia when ill.

Additional Reading

Mandell ‚ LA, Wunderink ‚ RG, Anzueto ‚ A, et al. Infectious Disease Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis. 2007;44(suppl 2):S27 " “S72.
Moran ‚ GJ, Talan ‚ DA. Pneumonia. In: Marx ‚ JA, Hockberger ‚ RS, Walls ‚ RM, et al., eds. Rosens Emergency Medicine: Concepts and Clinical Practice. 7th ed. St. Louis, MO: Mosby; 2009: 927 " “938.
Moran ‚ GJ, Talan ‚ DA, Abrahamian ‚ FM. Diagnosis and management of pneumonia in the emergency department. Infect Dis Clin North Am. 2008;22(1):53 " “72.
Nazarian ‚ DJ, Eddy ‚ OL, Lukens ‚ TW, et al. Clinical policy: Critical issues in the management of adult patients presenting to the emergency department with community-acquired pneumonia. Ann Emerg Med. 2009;54:704 " “731.

Codes

ICD9

481 Pneumococcal pneumonia [Streptococcus pneumoniae pneumonia]
486 Pneumonia, organism unspecified
507.0 Pneumonitis due to inhalation of food or vomitus
997.31 Ventilator associated pneumonia
482.0 Pneumonia due to Klebsiella pneumoniae
482.2 Pneumonia due to Hemophilus influenzae [H. influenzae]
482.40 Pneumonia due to Staphylococcus, unspecified
483.0 Pneumonia due to mycoplasma pneumoniae

ICD10

J13 Pneumonia due to Streptococcus pneumoniae
J18.9 Pneumonia, unspecified organism
J69.0 Pneumonitis due to inhalation of food and vomit
J95.851 Ventilator associated pneumonia
J14 Pneumonia due to Hemophilus influenzae
J15.0 Pneumonia due to Klebsiella pneumoniae
J15.211 Pneumonia due to methicillin suscep staph
J15.7 Pneumonia due to Mycoplasma pneumoniae

SNOMED

233604007 Pneumonia (disorder)
422588002 aspiration pneumonia (disorder)
34020007 pneumonia due to Streptococcus (disorder)
429271009 ventilator-acquired pneumonia (disorder)
385093006 Community acquired pneumonia (disorder)
408679000 healthcare associated pneumonia (disorder)
441658007 pneumonia due to Staphylococcus aureus (disorder)
46970008 Pneumonia due to Mycoplasma pneumoniae (disorder)
64479007 Pneumonia due to Klebsiella pneumoniae
70036007 Haemophilus influenzae pneumonia

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