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Pneumonia
Aka: Pneumonia, Bacterial Pneumonia, Atypical Pneumonia, Community-Acquired Pneumonia, Community Acquired Pneumonia
- See Also
- Viral Pneumonia
- Pneumonia in Children
- Pneumonia in the Elderly (includes Pneumonia in the Nursing Home)
- Pneumonia Accelerated Diagnostic Protocol
- Hospital Acquired Pneumonia
- Ventilator Associated Pneumonia
- Definitions
- Community Acquired Pneumonia (CAP)
- Lower respiratory tract infection
- Develops in non-hospitalized patient
- May be Bacterial, viral, fungal or parasitic
- May be present despite normal Chest XRay
- Epidemiology: Community Acquired Pneumonia
- Incidence: 9.2 to 33 per 1000 person-years in U.S.
- Adult mortality: 60,000 deaths per year from Pneumonia or Influenza (8th leading cause of death)
- Most severe cases in very young and very old
- U.S. cost/year for Community Acquired Pneumonia: $10-17 billion (90% of cost is inpatient care)
- Causes: Community Acquired Pneumonia
- See Pneumonia Causes
- Bacteria: Typical
- Streptococcus Pneumoniae
- Staphylococcus aureus
- HaemophilusInfluenzae
- Moraxella catarrhalis
- Bacteria: Atypical (named for their failure to be identified on Gram Stain)
- Mycoplasma pneumoniae
- Legionella pneumonia
- Chlamydia Pneumonia
- Q Fever
- Psittacosis
- Virus
- Adenovirus
- Influenza A and B
- Parainfluenza
- Respiratory Syncytial Virus
- Fungus
- Blastomycosis
- Coccidioidomycosis
- Histoplasmosis
- Risk Factors
- Age over 65 years
- Recent antibiotics
- Immune compromised (e.g. HIV Infection)
- Respiratory illness (COPD, Asthma)
- Vascular disease (CHF, CVA)
- Diabetes Mellitus
- Chronic Liver Disease
- Chronic Kidney Disease
- Cancer
- Findings: Signs and Symptoms
- Bacterial Pneumonia
- Cough
- Productive of Purulent Sputum with typical Bacteria
- Non-productive in atypical cases
- Sudden onset
- Fever and Chills
- Fatigue
- Ill appearing patient
- Pleuritic Chest Pain
- Dyspnea
- Tachypnea
- Tachycardia
- Viral Pneumonia
- Non-productive cough
- Gradual Onset with prodrome (malaise and Headache)
- Chest XRay more impressive than exam
- Onset in fall or winter
- Wheezing more common in viral causes
- Low grade Temperature (<101.3 F)
- Mycoplasma pneumonia
- Constant, harsh, non-productive cough
- Wheezing may occur in Mycoplasma pneumonia
- Fever typically lasts longer than 3 days
- More common in age over 3 years
- Legionella
- Onset with myalgias and Headache
- Fever to 104 F for first few days
- Gastrointestinal symptoms predominate in up to 40%
- Cough is late onset, mild, often non-productive
- Signs
- General findings
- Fever
- Positive Likelihood Ratio: 2.1
- Negative Likelihood Ratio: 0.71
- Ill appearing patient
- Dyspnea
- Tachypnea
- Tachycardia
- Hypoxia (check Oxygen Saturation)
- Localized findings at involved lung region
- Egophony
- Positive Likelihood Ratio: 8.6
- Negative Likelihood Ratio: 0.96
- Dullness to percussion
- Positive Likelihood Ratio: 4.3
- Negative Likelihood Ratio: 0.79
- Rales
- Diminished breath sounds
- Bronchial breath sounds
- Tactile fremitus
- References
- Metlay (1997) JAMA 278(17): 1440-5 [PubMed]
- Diagnosis: General
- See Diehr Rule to Diagnose Pneumonia
- Normal Vital Signs and Lung Exam in primary care reduces likelihood of Pneumonia to <0.4%
- Criteria: Normal Body Temperature, Respiratory Rate, Heart Rate and Lung Exam
- Community Acquired Pneumonia Likelihood reduced to<0.4% if criteria met
- Marchello (2019) J Am Board Fam Med 32(2): 234-47 [PubMed]
- Findings with highest Test Sensitivity for Pneumonia
- Fever and chills
- Pleuritic Chest Pain
- Cough productive of mucopurulent Sputum
- Dyspnea
- Tachypnea (especially in over age 65 years)
- Findings with highest Specificity
- Asymmetric breath sounds
- Pleural rubs
- Egophony
- Increased tactile fremitus
- Diagnosis: IDSA Pneumonia Criteria
- Major Criteria
- Septic Shock and need for Vasopressors
- Respiratory Failure requiring Mechanical Ventilation
- Leukopenia (WBC <4000 cells/ul) without other known cause
- Fore example, not due to Chemotherapy or underlying condition
- Minor Criteria
- Respiratory Rate >30 breaths per minute
- PaO2/FIO2 Ratio <250
- Multilobar infiltrates
- Confusion or Disorientation
- Blood Urea Nitrogen or BUN > 20 mg/dl (Uremia)
- Thrombocytopenia (Platelet Count <1000,000 cells/ul)
- Hypothermia (core Temperature <36.8 C)
- Hypotension (requiring aggressive fluid Resuscitation)
- Interpretation
- Pneumonia diagnosis positive if 1 major criteria or 3 minor criteria
- Labs
- General
- Consider specific testing based on risks
- See Pneumonia Causes (as well as indications below)
- Lab Indications
- Moderate or severe Community Acquired Pneumonia
- Patient with comorbid conditions
- Efficacy of Labs
- No value in non-severe Community Acquired Pneumonia
- Theerthakarai (2001) Chest 119:181-4 [PubMed]
- Sputum Gram Stain and Culture
- See Sputum Culture
- Adequacy
- Good quality sample: <25 epithelial cells/LPF and contains Neutrophils
- Indications (IDSA/ATA 2007)
- ICU Admission (consider endotracheal aspirate if intubated)
- Failed outpatient antibiotic therapy
- Cavitary infiltrates (obtain specific fungal and Tuberculosis cultures)
- Active Alcohol Abuse
- Severe COPD
- Pleural Effusion (also perform Thoracentesis for Pleural Fluid culture and analysis)
- Positive Legionella urine Antigen (Legionella culture requires special media)
- Positive Pneumococcal urine Antigen
- Efficacy
- Sputum has low diagnostic yield in Community Acquired Pneumonia
- Not recommended in outpatient Community Acquired Pneumonia
- Ewig (2002) Chest 121:1486-92 [PubMed]
- Blood Culture
- Indications (IDSA/ATA 2007)
- Not indicated unless severe disease (highest yield in severe Pneumonia)
- Consider in hospitalized Community Acquired Pneumonia (especially if possible ICU patient)
- Intensive Care unit admission
- Cavitary infiltrates
- Leukopenia
- Active Alcohol Abuse
- Chronic severe liver disease
- Asplenia
- Pleural Effusion
- Positive Pneumococcal urine Antigen
- Efficacy
- Low sensitivity: Positive in only 5-10% of cases
- Does not predict severity or outcome
- References
- Campbell (2003) Chest 123:1142-50 [PubMed]
- Specific Testing with reasonable efficacy
- Influenza
- Rapid Influenza Test (Influenza DFA)
- Obtain in all Community Acquired Pneumonia cases during Influenza season
- Treat positive Influenza cases regardless of duration (i.e. even if >48-72 hours)
- Legionella pneumophila
- Rapid PCR of Sputum (80% Test Sensitivity)
- Urinary Antigen
- Test Sensitivity 70-90% (for serogroup 1, responsible for >80% of cases)
- Test Specificity 99%
- Indications (Legionella UAT per IDSA/ATS 2007)
- Severe Community Acquired Pneumonia including Intensive Care unit admission
- Failed outpatient antibiotic therapy
- Active Alcohol Abuse
- Travel within prior 2 weeks
- Pleural Effusion
- Legionella outbreak
- Mycoplasma pneumoniae
- Rapid PCR of Sputum (>30% Test Sensitivity)
- Chlamydia Pneumonia
- Rapid PCR (>30% Test Sensitivity)
- Streptococcus Pneumoniae (Pneumococcus)
- Pneumococcal Urine Antigen Test (UAT)
- Test Sensitivity 60-80%
- Test Specificity >90%
- Indications (Pneumococcal UAT per IDSA/ATS 2007)
- Intensive Care unit admission
- Failed outpatient antibiotic therapy
- Active Alcohol Abuse
- Chronic severe liver disease
- Leukopenia
- Asplenia
- Pleural Effusion
- Other Testing
- Low Procalcitonin does not exclude Pneumonia
- Antibiotics should not be witheld based on low Procalcitonin alone
- Thoracentesis with fluid analysis
- Indicated for Pleural Effusion >5 cm
- Send for Gram Stain, aerobic and anaerobic culture
- Fungal and TB Culture
- Cavitary lesions
- Foreign travel or immigration
- References
- Mandell (2007) Clin Infect Dis 44:S27–72 [PubMed]
- Imaging: Chest XRay
- Precautions: Underlying malignancy
- Confirm infiltrate resolution at 6 weeks after management (especially in smokers, or those over age 50)
- Precautions: Low Test Sensitivity in Pneumonia (esp. in early presentation)
- Chest XRay Test Sensitivity 43% (Test Specificity 93%) for pulmonary opacities consistent with Pneumonia (compared with CT)
- False Negatives are more common in early presentation
- Serial Chest XRays may be needed, or consider bedside Lung Ultrasound or CT
- Chest XRay does not exclude Pneumonia in severe illness
- Positive in only 40% of acute pneumococcal Community Acquired Pneumonia (CAP)
- Indications: All cases of suspected Community Acquired Pneumonia
- Any patient with at least 1 of the following
- Temperature >100 F (37.8 C)
- Heart Rate >100 beats/min
- Respiratory Rate >20 breaths/min
- Any patient with at least 2 of the following
- Decreased breath sounds
- Rales or crackles
- No Asthma history to explain findings
- Other indications (not included in Ebell protocol)
- Hypoxemia
- Confusion
- Known structural lung disease
- Age > 60 years old
- Systemic illness signs
- Ebell (2007) Am Fam Physician 76(4): 560-2 [PubMed]
- Causes: False Positives - alternative causes of infiltrates
- Atelectasis
- Acute Respiratory Distress Syndrome (ARDS)
- Lung Neoplasm
- Diffuse Alveolar Hemorrhage (e.g. immune disorder)
- Pulmonary Embolism with Lung Infarction
- Right-sided endocarditis with septic emboli
- Tuberculosis
- Interstitial Lung Disease (e.g. acute Chlorine gas inhalation, Farmer's Lung)
- Causes: Pneumonia with effusion (and other non-infectious effusions)
- Pneumococcal Pneumonia (most common)
- Staphylococcal Pneumonia
- Haemophilus Influenzae Pneumonia
- Legionella
- Tuberculosis (especially consider in comorbid HIV Infection)
- Predominately left-sided effusions (e.g. Aortic Dissection, Esophageal Rupture)
- Predominately right-sided effusions (e.g. CHF, Pancreatitis, hepatitis)
- Causes: Lung Cavitary Lesions
- Lung Abscess caused by Anaerobic Bacteria (most common)
- Staphylococcal Pneumonia
- Pseudomonas Pneumonia
- Tuberculosis
- Interpretation
- Lobar infiltrate suggests typical Bacterial Community Acquired Pneumonia (CAP)
- Diffuse, bilateral infiltrates suggests atypical Community Acquired Pneumonia (CAP)
- References
- Swadron (2019) Pulmonary 1, CCME Emergency Board Review, accessed 5/29/2019
- Imaging: Advanced
- CT Chest
- CT Chest is considered gold standard and frequently identifies Pneumonia not seen on Chest XRay
- CT Chest identifies more than twice as my Pneumonia cases not visualized on Chest XRay
- CT Chest excludes Pneumonia in False Positive Pneumonia cases based on Chest XRay
- Self (2013) Am J Emerg Med 31(2): 401–405. [PubMed]
- Lung Ultrasound
- May be more accurate than Chest XRay in the diagnosis of Pneumonia
- Findings consistent with Pneumonia
- Localized B-Line artifacts (Interstitial Edema)
- Localized liver-like appearance of lung (consolidation)
- Also defines other respiratory conditions at the bedside (e.g. Pneumothorax, Pleural Effusion)
- Test Sensitivity: 94 to 95%
- Test Specificity: 90 to 96%
- Chavez (2014) Respir Res 15:50 [PubMed]
- Ye (2015) PLoS One 10(6): e0130066 [PubMed]
- Differential Diagnosis
- See Pneumonia Causes
- See Cough Causes
- Acute Respiratory Distress Syndrome
- Severe Acute Respiratory Syndrome
- Churg-Strauss Syndrome
- Congestive Heart Failure
- Inflammatory Lung Disease
- Idiopathic Pulmonary Fibrosis
- Interstitial pneumonitis
- Pulmonary Embolism
- Lung Cancer
- Sarcoidosis
- Granulomatosis with Polyangiitis (previously known as Wegener's Granulomatosis)
- Bronchiolitis Obliterans with Organizing Pneumonia
- Bioterrorism Agents
- Anthrax
- Plague
- Tularemia
- Q Fever
- Brucellosis
- Management
- See Pneumonia Management
- See Pneumonia in the Elderly
- See Pneumonia Accelerated Diagnostic Protocol
- See Community Acquired Pneumonia Refractory to Standard Management
- Convert to oral antibiotic within 72 hours if possible
- See Pneumonia Hospitalization Criteria
- See Pneumonia Hospitalization Criteria in the Elderly
- See Severe Community Acquired Pneumonia Criteria
- See Mortality Prediction Tool for Patients with Community Acquired Pneumonia (CURB-65)
- See Pneumonia IRVS Prediction Tool (SMART-COP)
- Complications
- Pulmonary
- Parapneumonic Effusion or empyema
- Pneumothorax
- Lung Abscess
- Bronchopleural Fistula
- Necrotizing Pneumonia
- Acute Respiratory Failure
- Metastatic spread
- Meningitis or CNS Abscess
- Pericarditis or endocarditis
- Osteomyelitis or Septic Arthritis
- Systemic
- Sepsis or SIRS
- Hemolytic Uremic Syndrome
- References
- Bradley (2011) Clin Infect Dis 53(7): e1-52 [PubMed]
- Prognosis: Predictors of increased mortality
- See Pneumonia Prognostic Factors in Older Patients
- See Mortality Prediction Tool for Patients with Community Acquired Pneumonia (CURB-65)
- See Pneumonia Severity Index
- Comorbid neurologic disease
- Renal disease
- Congestive Heart Failure
- Hypotension
- Tachypnea
- Hypothermia
- Hypoglycemia (Serum Glucose <70mg/dl on presentation)
- Prevention
- See Pneumonia Prevention in the Elderly
- See Influenza Vaccine
- See Pneumococcal Vaccine
- References
- Bernstein (1999) Chest 115:9S-13S [PubMed]
- Cunha (2001) Med Clin North Am 85(1):43-77 [PubMed]
- Fine (1997) N Engl J Med 336:243-50 [PubMed]
- Fine (1990) Am J Med 89:713-21 [PubMed]
- Gleason (1997) JAMA 278:32-9 [PubMed]
- Kaysin (2016) Am Fam Physician 94(9); 698-706 [PubMed]
- Lim (2009) Thorax 64(suppl 3):1-55 [PubMed]
- Lutfiyya (2006) Am Fam Physician 73:442-50 [PubMed]
- Marrie (2000) Clin Infect Dis 31(4):1066-78 [PubMed]
- Metlay (2019) Am J Respir Crit Care Med 200(7):e45-67 +PMID:P 31573350 [PubMed]
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6812437/
- Metlay (2003) Ann Intern Med 138:109-18 [PubMed]
- Watkins (2011) Am Fam Physician 83(11): 1299-306 [PubMed]