Pneumonia

Author: Aaron Hultgren, Assistant Professor Emergency Medicine, Ronald O. Perelman Emergency Medicine Department, NYU School of Medicine and Bellevue Hospital Center

Liliya Abrukin, Emergency Medicine Resident, Ronald O. Perelman Emergency Medicine Department, NYU School of Medicine and Bellevue Hospital Center

Editor: Rahul Patwari

Objectives

Upon finishing this module, the student will be able to describe the evaluation and management of pneumonia in the emergency department

  • Identify the common pathogens for community acquired pneumonia (CAP) and healthcare-associated pneumonia (HCAP)
  • Differentiate between community acquired pneumonia (CAP) and healthcare-associated pneumonia (HCAP).
  • Discuss the management and antibiotic treatment for community acquired pneumonia and hospital acquired pneumonia
  • Identify and discuss diagnostic considerations for evaluating pneumonia in the emergency room
  • Discuss special considerations when evaluating and treating pneumonia in regards to patients with possible tuberculosis and Legionella infections.

Introduction

Pneumonia causes significant morbidity and mortality in the United States, resulting in 5.6 million cases per year and 1.7 million hospitalizations. In the US, it is the 8th leading cause of death and the most common cause of death from infection. Emergency medicine physicians need to be able to identify and differentiate community-acquired pneumonia (CAP) from healthcare-associated pneumonia (HCAP) in order to effectively manage patients and provide the appropriate antibiotic treatment.

Pneumonia is categorized based on whether a patient is coming from the community, has significant healthcare system contact, or is hospitalized. This distinction is important because contact with the healthcare system or developing pneumonia in-hospital increases the patient’s risk of having pathogens that would be inadequately treated with the antibiotics used for patients coming from the community, especially multi-drug resistant pathogens.

Community-acquired pneumonia (CAP) occurs in a patient from the community or general population that does not have any significant contact with the healthcare system. CAP may occur due to typical pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis) or atypical pathogens (Mycoplasma pneumonia, Chlamydophila pneumonia, Legionella species, and respiratory viruses). S. pneumoniae is the single most common pathogen causing CAP and is responsible for 20-50% of infections.

Typical pathogens:

  • Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis
  • seen on gram stain
  • can be inhibited or killed using beta-lactam antibiotics

Atypical pathogens:

  • Mycoplasma pneumonia, Chlamydophila pneumonia, Legionella species, and respiratory viruses
  • cannot be visualized on gram stain and require special culture methods
  • are not killed or inhibited by penicillins or other beta-lactam antibiotics

Healthcare-associated pneumonia (HCAP) occurs in patients that have had significant exposure or contact with the healthcare system. This includes patients residing in nursing homes, patients that have been recently hospitalized, or those that receive dialysis, IV medications, or home wound care.

HCAP Criteria:

  • hospitalization for ≥2 days in the preceding 90 days
  • residence in a nursing home/facility
  • in the past 30 days:
    • attendance at a hospital or hemodialysis clinic
    • home or clinic IV therapy (antibiotics and chemotherapy)
    • home wound care

Healthcare-associated pneumonia (HCAP) may be due to pathogens such as Pseudomonas aerugunosa, Escherichia coli Klebsiella pneumonia, Acinebacter, and Staphylococcus aureus. These gram negative aerobes and gram positive cocci are not inhibited or killed by the antibiotics used to treat CAP.

Hospital-acquired pneumonia (HAP) develops in patients ≥48 hours after hospitalization and is not incubating at the time of admission, a subtype of HAP, ventilator-associated pneumonia (VAP) develops >48-72 hours after intubation. HAP patients are at an increased risk of multi-drug resistant infections, have poorer prognoses, and high mortality. Although these patients aren’t usually treated in the emergency department, it is from this patient population that the HCAP category was derived, with the goal of identifying patients at increased risk for multi-drug resistant pathogens coming from community settings.

Signs and Symptoms

Patients with pneumonia may present with signs and symptoms such as fever, chills, productive cough, pleuritic pain, chest pain, and shortness of breath or malaise.

The differential diagnosis includes other respiratory entities such as bronchitis, viral upper respiratory infections, influenza, pulmonary embolus, tuberculosis, pleural effusion, and other cardiac-pulmonary pathologies.

Initial Actions and Primary Survey

All patients should have a set of vital signs including temperature, pulse, blood pressure, pulse oximetry, and respiratory rate. The emergency physician should start with the “ABCs” approach. Acutely ill patients will need peripheral access, monitoring and supplemental oxygen. Patients in respiratory distress may require a non-rebreather for oxygenation, noninvasive ventilation, or endotracheal intubation for those with imminent respiratory failure.

ABC’s

  • Airway- Evaluate the airway for stridor, edema, or upper airway obstruction
    • Actions:
      • Reposition patient
      • Place on non-rebreather and/or nasal cannula (both for preoxygenation if preparing to intubate)
      • Airway maneuvers/adjuncts such as head tilt/chin lift, jaw thrust, or nasal trumpet insertion
  • Breathing- Assess for adequate ventilation. Look for tachypnea, increased work of breathing and signs of respiratory distress such as nasal flaring, retractions, or tripoding. Imminent or impending respiratory failure may require endotracheal intubation and potentially rapid sequence intubation (RSI).
    • Actions:
      • Supplemental oxygen (nasal cannula or non-rebreather),
      • Non-invasive (BIPAP) ventilation
      • Invasive (endotracheal intubation) ventilation
  • Circulation- Assess perfusion of vital organs and identify signs of cardiovascular compromise from pneumonia causing sepsis or septic shock
    • Actions (if concern for sepsis):
      • Place 2 large-bore peripheral IVs
      • Saline bolus of 30cc/kg
      • Early broad-spectrum antibiotics
      • Severe sepsis and septic shock patients may require central line placement and vasopressor support
  • Disability- Assess mental status. Pneumonia may cause respiratory compromise resulting in hypoxia, hypercapnea or respiratory failure leading to somnolence, confusion, and decreased mental status. Poor mentation and inadequate protection of airway may require intubation. Consider aspiration pneumonia in patients with decreased mental status or conditions that may lead to dysphagia.

Presentation

Community-acquired Pneumonia Historical features are not helpful in distinguishing typical from atypical CAP. Several prospective studies have shown that the history and physical are neither sensitive nor specific in identifying pneumonia. Classically the “typical” CAP caused by Streptococcus pneumonia is described as presenting with the sudden onset of fever or chills, productive cough, and pleuritic chest pain. Atypical CAP may have a more protracted course beginning with upper respiratory symptoms, slowly worsening cough, malaise and fatigue. Historically, these symptoms were nonresponsive to initial penicillin treatment. Although these are considered classic presentations of typical and atypical pneumonias, these classic presentations are not considered to be sensitive or specific for pneumonia.

“Classic” findings:

  • Typical Pneumonias
    • Streptococcus pneumonia – bloody or rust colored sputum
    • Haemophilus influenzae – fever, muscle pain, fatigue
  • Atypical Pneumonias
    • Mycoplasma pneumonia – “walking pneumonia;” upper respiratory symptoms, gradually worsening over weeks or even months
    • Chlamydiophila pneumonia – pharyngitis, laryngitis and sinusitis, associated with outbreaks in close-contact settings (dorms, prisons)
    • Legionella – respiratory and gastrointestinal symptoms
  • Healthcare-associated Pneumonia Staphylococcus aureus risk factors include vent-dependence, intravenous drug use, immunocompromised, recent influenza infection, and aspiration
    • Pseudomonas aeruginosa risks factors include high-dose steroid use, prolonged hospitalization or nursing home residence, and preexisting lung disease
  • Special Population-
    • Aspiration Pneumonia
      • Aspiration occurs when there is inhalation of oropharyngeal or gastric contents into the larynx or respiratory tract. It should be differentiated from aspiration pneumonitis, which is a chemical injury from inhalation of gastric contents due to regurgitation that can occur with drug overdose, seizures, cerebrovascular accident, or use of anesthesia.
      • Patients at risk for aspiration include patients with dysphagia due to neurologic disorder, nursing home residents, and patients who abuse alcohol. Aspiration of oropharyngeal secretions may result in respiratory tract pathogens that include Enterobacteriaceae, Pseudomonas aerguinosa and Staphylococcus aureus.
      • Antibiotics with activity against gram-negative organisms such as third-generation cephalosporins, fluoroquinolones and piperacillin are recommended for treatment.
    • Immunocompromised Patients
      • Immunocompromised patients represent a special subset of pneumonia given the increased susceptibility to a spectrum of potential pathogens. Patients comprising this population include those with solid organ transplants, cystic fibrosis, HIV/AIDS, hematopoietic cell transplants, pregnant women, and patients with immune defects.
      • General considerations include obtaining a thorough past medical history, as well as asking about medications such as chemotherapy, immunomodulating agents, and steroids. Leukopenia and CD4 count may guide evaluation and treatment considerations. Pneumocystis jirovecii (previously classified as Pneumocystis carinii) is typically found in immunocompromised patients with such as HIV/AIDS.
      • Symptoms include dyspnea, nonproductive cough, and fever. Chest x-ray usually shows bilateral infiltrates, but may also present with a lobar consolidation.
      • Treatment for PCP is trimethoprim-sulfamethoxazole (TMP-SMX). Tuberculosis is another important consideration in immunocompromised patients as well as patients with a history of prior tuberculosis infection, night sweats, weight loss, or exposure from shelters, prisons, or recent travel to endemic areas.

Physical exam, beyond the ABCs

A full physical exam is important to both evaluate for alternative diagnoses as well as clues related to a particular pneumonia. The physical exam starts with initial vitals and inspection of the patient for respiratory distress. Patients sitting upright or in the “tripod position” with nasal flaring, chest retractions, and abdominal breathing exhibit an increased work of breathing and may have impending respiratory failure. Review of vital signs may show tachypnea, tachycardia, hypotension, hypoxia, and fever. Examination of the chest involves a four-step process: including inspection, palpation, percussion, and auscultation of the chest. The positive predictive value of abnormal breath sounds in acute respiratory illness is 55% further illustrating the difficulty in diagnosing pneumonia with the physical exam. There are no individual or combination of clinical findings that rule in the diagnosis of pneumonia (Metlay et al. 1999).

Examiners should look for other signs of dyspnea such as congestive heart failure, pericardial effusions, pleural effusions, pulmonary embolus, and neoplasms. Lastly it is important to evaluate the head, ears and throat as many of these patients may initially had an upper respiratory infection that developed into a bacterial pneumonia and concomitant bacterial infections.

Diagnostic Testing

PA and lateral chest x-ray demonstrating a pneumonia.
Lateral chest x-ray demonstrating a pneumonia. Click for larger image.
pneumonia_hultgren_cxr_pa
PA chest x-ray demonstrating a pneumonia. Click for larger image.

The main diagnostic modality for both community and hospital acquired pneumonia is chest radiography. Some studies have shown that the absence of abnormal vital signs or abnormalities on chest examination reduces the likelihood of pneumonia and the need for further diagnostic studies (Metlay et al. 1999). Factors that predict pneumonia on chest x-ray include temperature >37.8 0C, tachycardia >100bpm, absence of asthma, rales, and locally decreased breath sounds on auscultation. Pulmonary infiltrates on chest x-ray may confirm the clinical diagnosis.

Lobar consolidation is typical of Streptococcus pneumoniae or Klebsiella pneumoniae while multi-lobar infiltrates are more consistent with Staphylococcus aureus and Pseudomonas aeruginosa. Atypical infections such as Mycoplasma pneumonia, Chlamydophila, and Legionella may reveal patchy infiltrates on radiography. Despite these patterns on chest radiography, it is important to note that typical pathogens can present with diffuse infiltrates and atypical pathogens with discrete consolidations. Radiographic evidence of pneumonia may not be evident on initial chest radiography in patients with early aspiration pneumonias or severe dehydration; however infiltrates develop on subsequent studies.

More recently, several studies have demonstrated the utility of bedside ultrasound as a reliable, noninvasive diagnostic tool for the detection of pneumonia in children, adolescents and adults, having a sensitivity of 86% and specificity of 89% and LR 7.8 (95% CI, 5.0-12.4) (Shah et al. 2013). Emergency physicians with advanced sonography skills may be able to identify consolidation; however, ultrasound is operator dependent and therefore its use in identifying pneumonia is operator dependent as well.

The gold standard for the identification of pneumonia is Computer Tomography of the chest; however, the majority of outpatient community acquired pneumonias will be diagnosed with chest x-ray. CT is more sensitive than plain films of the chest and may be used with patients with an equivocal chest x-ray, or when other etiologies for the patient’s presentation are suspected.

An EKG should be ordered on patients with pneumonia, especially those with tachycardia. Patients with congestive heart failure, cardiothoracic disease, and severe sepsis/septic shock may develop cardiac ischemia and infarction secondary to a severe pneumonia.

Prior to January 2014 blood cultures were recommended for all CAP patients admitted to the hospital, with reimbursement tied to this metric, despite a lack of evidence suggesting that obtaining blood cultures in CAP patients leads to changes in treatment that improve outcomes. In fact, multiple studies have demonstrated that in CAP, both the yield of blood cultures and how often they result in a change in management is very low. Additionally, studies have demonstrated that false positive blood cultures lead to increased length of stay, inappropriately broad antibiotic coverage, and expose patients to the risks associated with both.

As of January 2014, obtaining blood cultures in routine CAP patients admitted to the floor is no longer a reportable metric and is not required by most hospitals; however, consult your institutional guidelines and protocols. Blood cultures should be obtained in any patient ill enough to require ICU admission or mechanical ventilation, all septic patients, as well patients with CAP that are at increased risk for bacteremia and resistant organisms. These risk factors for CAP patients include:

  • cavitary lesions
  • leukopenia
  • severe liver disease
  • asplenia
  • pleural effusion
  • alcohol abuse
  • severe CAP

Of note, blood culture yield increases directly with volume.

Sputum induction for gram stain and culture should not be routinely performed in the emergency department, as it poses an infection risk to both providers and other patients and is unlikely to change ED management.

Treatment

Describe emergency department treatment options and summarize any further definitive treatment provided by subsequent services.

Antibiotics

Community Acquired Healthcare-associated Pneumonia Aspiration Special Considerations (immunocompromised)
Macrolides
Fluoroquinolones
Doxycycline
Antipseudomonal B-Lactam Plus: Piperacillin/ tazobactum
Imipenem
Meropenem
Cefepime
Ceftazidime
Anti-MRSA agent
Vancomycin
Linezolid
Ampicillin / sulbactam
Piperacillin / tazobactum
or
Clindamycin plus an aminoglycoside
Bactrim for PCP
Suspected TB avoid use of fluoroquinolones as can increase resistance

Chlamydophila
Macrolides are often the first-line treatment; tetracyclines and fluoroquinolones are also effective.

A word on HCAP antibiotic coverage:

HCAP was added as a category of pneumonia in the 2005 ATS/IDSA guidelines to identify patients at increased risk for multidrug resistant (MDR) pathogens coming from community settings- patients that would have previously been classified as CAP patients. The problem with this definition however, is that it is an overgeneralization, because not all HCAP patients are actually at increased risk for MDR infections. Studies that have looked at the difference in the microbial etiologies of pneumonia continue to demonstrate that the most commonly isolated organisms in HCAP patients are still CAP organisms such as Streptococcus pneumoniae, Haemophilus influenzae, and Klebsiella.

Thus, current HCAP antibiotic guidelines may be needlessly broad and overly aggressive for certain HCAP patients that are at low risk for MDRO infections. Very broad-spectrum antibiotic coverage not only increases the risk of MDRO colonization and infection, but also exposes patients to risks such as medication toxicities, increases in morbidity associated with broader medications, longer duration of antibiotic treatment, and longer lengths of stay.

While some HCAP patients are clearly at an increased risk for drug-resistant pathogens and require traditional HCAP antibiotic regimens, current guidelines err on the side of broader antibiotic coverage. The IDSA will be releasing new practice guidelines in the summer of 2015 and these will likely include an update on how HCAP patients are defined and treated. Refer to your institutional antimicrobial stewardship guidelines for determining antibiotic regimens.

Disposition

Clinical judgment is essential to determine the disposition of the patient with community acquired pneumonia as patients may be treated as an outpatient, placed in an observation unit or short stay unit (SSU) or treated as an inpatient. Patients with the inability to tolerate oral antibiotic treatment, hypoxia, sepsis, or respiratory distress will require admission. Patients with pneumonia with severe sepsis or septic shock will need critical care management. Risk stratification instruments may aid emergency clinicians on patient disposition for community-acquired pneumonia.

The Pneumonia Severity Index, or PSI, is a validated risk stratification instrument for CAP. The instrument may help the provider identify lower risk patients for outpatient treatment with oral antibiotics. The instrument consists of point values given for a variety of clinical and laboratory parameters that lead to a score calculation, and then patients are stratified into one of five risk classes (Fine et al. 1997). Patients with a score in class I, II, and III have low risk for death and the clinician may consider outpatient treatment for CAP. Patients with a score in class IV of V are usually hospitalized in observation status or admission status for hospital treatment of CAP.

Community-acquired pneumonia severity index (PSI) for adults
Sex
Male 0 points
Female -10 points
Demographic Factors
Age 1 point for each year
Nursing home resident 10 points
Comorbid illnesses
Neoplastic disease 30 points
Liver disease 20 points
Heart failure 10 points
Cerebrovascular disease 10 points
Renal disease 10 points
Physical examination findings
Altered mental status 20 points
Respiratory rate > 30/min 20 points
Systolic blood Pressure <90 mmHG 20 points
Temperature < 35oC of >40oC 15 points
Pulse > 125 bpm 10 points
Laboratory and radiographic findings
Arterial pH <7.35 30 points
Blood urea nitrogen > 30 mg/dL (11 mmol/L) 20 points
Sodium < 130 mEq/L 20 points
Glucose > 250 mg/dL (14mmol/L) 10 points
Hematocrit < 30 percent 10 points
Partial pressure of arterial oxygen <60mmHG or oxygen saturation <90 percent 10 points
Pleural Effusion 10 points

Pneumonia Score Interpretation

  • 0-50 Points: Class I 0.1% Mortality
  • 51-70 Points: Class II 0.6% Mortality
  • 71-90 Points: Class III 0.9% Mortality
  • 91-130 Points:Class IV 9.3% Mortality
  • 131-395 Points:Class V 27.0% Mortality

Adapted from Fine MJ, Auble TE, Yealy DM, et al. A prediction rule to identify low-risk patients with community acquired pneumonia. N Engl Med. 1997; 336: 243-250.

Another risk stratification instrument is CURB-65, which is a simple algorithm that assigns points for five clinical features (Table 1).

Table 1. CURB-65 Clinical features and point values.
Clinical Factor Point Value
C Confusion 1
U Blood urea nitrogen > or = 20 mg/dL 1
R Respiratory rate > or = 30 breaths per minute 1
B Systolic BP<90 mm Hg or Diastolic BP< or =60 mm Hg 1
65 Age > or = 65 1

Patients with a CURB-65 algorithm score of 0 or 1 (mortality 0 to 2.6%). A CURB-65 score of 2 may be able to have outpatient management with close follow-up or short admission/observation. Scores of 3 (mortality 14%) and 4 or 5 (mortality 27.8%) are higher risk and will need inpatient and potentially intensive care admission for patients with high scores. It is important to reiterate that the primary factor in determination of patient disposition is clinical judgment.

Pearls and Pitfalls

  • Management of pneumonia should start with a ABC approach and stabilization of the patient with an acute pneumonia.
  • Identify appropriate antibiotics for patients presenting with pneumonia community acquired (CAP) versus health-care associated (HCAP) pneumonia.
  • Chest radiography continues to be the mainstay for diagnosis of pneumonia; however, additional modalities such as ultrasound and CT scan may be helpful in certain situations.
  • Aspiration pneumonia as well as patients with suspected Tuberculosis and concomitant pneumonia need special consideration when choosing an appropriate antibiotic regiment.
  • Disposition of patients with pneumonia should be based on clinical judgment along with risk stratification instruments.

References

A short list of important articles with the PubMed links / ID.

  1. Corbo J, Friedman B, Bijur P, Gallagher EJ. Limited usefulness of initial blood cultures in community acquired pneumonia. Emerg Med J. 2004; Jul;21(4):446-448. PMID: 15208227
  2. Fine MJ, Auble TE, Yealy DM, et al. A prediction rule to identify low-risk patients with community acquired pneumonia. N Engl Med. 1997; 336: 243-250. PMID: 8995086
  3. Halm EA, Teirstein AS. Clinical Practice. Management of community-acquired pneumonia. N Engl J Med. 2002 Dec 19;347(25): 2039-2045. PMID: 12490686
  4. 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. PMID: 17278083
  5. Marik PE. Aspiration Pneumonitis and Aspiration Pneumonia. N Engl J Med. 2001; 344: 665-671. PMID: 11228282
  6. Metlay JP, Kappor WN, Fine MJ. Does this patient have community-acquired pneumonia? Diagnosing pneumonia by history and physical examination. JAMA 1997: 278(17): 1440-1445. PMID: 9356004
  7. Plouffe JF, Martin DR. Pneumonia in the emergency department. Emergency medicine Clinics of North America. 2008 May;26(2):389-411. PMID: 18406980
  8. Slaven EM, Santanilla JI, DeBlieux PM. Healthcare-associated pneumonia in the emergency department. Semin Respir Crit Care Med. 2009 Feb;30(1):46-51. PMID: 19199186

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