Community-acquired pneumonia: Difference between revisions
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== Background == |
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* See also [[Respiratory infection in an immunocompromised person]] and [[Respiratory infection in unimmunized hosts]] |
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* Bacteria |
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=== Microbiology === |
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* Bacteria (15-30%)[[CiteRef::gadsby2022th]] |
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** Typical organisms |
** Typical organisms |
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*** |
*** [[Streptococcus pneumoniae]] (5-15%) |
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*** [[Haemophilus influenzae]] (1-7%) |
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*** [[Staphylococcus aureus]] (2-5%) |
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*** Group A |
*** [[Group A streptococcus]] |
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*** [[Moraxella catarrhalis]] |
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*** Anaerobes and aerobic gram-negative bacteria |
*** Anaerobes and aerobic gram-negative bacteria |
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**** |
**** [[Klebsiella pneumonia]] |
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**** [[Pseudomonas aeruginosa]] (1-3%) |
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**** [[Acinetobacter baumannii]] |
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** Atypical organisms |
** Atypical organisms |
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*** [[Legionella]] species (1-6%) |
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*** [[Mycoplasma pneumoniae]] (1-10%) |
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*** [[Chlamydia pneumoniae]] (1-3%) |
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*** [[Chlamydia psittaci]] |
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** Others |
** Others |
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*** [[Coxiella burnetti]] |
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*** [[Nocardia]] |
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* Viral |
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** [[ |
*** [[Mycobacteria]] |
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* Viruses (25-60%) |
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** [[Parainfluenza virus]] |
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** [[ |
** [[Rhinovirus]] (8-17%) |
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** [[ |
** [[Coronavirus]] (3-13%) |
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** [[ |
** [[Influenza virus]] (1-6%) |
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** [[Human metapneumovirus]] (1-8%) |
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** [[Middle East respiratory syndrome coronavirus]] (MERS-CoV) |
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** [[ |
** [[Parainfluenza virus]] (1-8%) |
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** [[RSV]] (1-8%) |
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| ⚫ | |||
** |
** [[Adenovirus]] (1-8%) |
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| ⚫ | |||
| ⚫ | |||
** |
** [[Pneumocystis jirovecii]] |
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** [[Cryptococcus]] species |
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** [[Coccidioides]] |
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* No cause identified (46-66%) |
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* Clinically-important but uncommon organisms |
* Clinically-important but uncommon organisms |
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** |
** [[Legionella]] species |
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** [[Influenza]] A and B, including avian influenza A H5N1 and avian influenza A H7N9 |
** [[Influenza]] A and B, including avian influenza A H5N1 and avian influenza A H7N9 |
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** [[MERS-CoV]] and [[severe acute respiratory syndrome coronavirus]] (SARS-CoV) |
** [[MERS-CoV]] and [[severe acute respiratory syndrome coronavirus]] (SARS-CoV) |
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== Investigations == |
== Investigations == |
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* Always add ''Legionella'' testing in immunocompromised, critical illness, recent travel, significant alcohol, and consider when pleural effusion is present |
* Always add ''[[Legionella]]'' testing in immunocompromised, critical illness, recent travel, significant alcohol, and consider when pleural effusion is present |
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== Management == |
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== Prognosis == |
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== Further Reading == |
== Further Reading == |
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Latest revision as of 17:30, 19 September 2024
Background
- See also Respiratory infection in an immunocompromised person and Respiratory infection in unimmunized hosts
Microbiology
- Bacteria (15-30%)1
- Typical organisms
- Streptococcus pneumoniae (5-15%)
- Haemophilus influenzae (1-7%)
- Staphylococcus aureus (2-5%)
- Group A streptococcus
- Moraxella catarrhalis
- Anaerobes and aerobic gram-negative bacteria
- Atypical organisms
- Legionella species (1-6%)
- Mycoplasma pneumoniae (1-10%)
- Chlamydia pneumoniae (1-3%)
- Chlamydia psittaci
- Others
- Typical organisms
- Viruses (25-60%)
- Rhinovirus (8-17%)
- Coronavirus (3-13%)
- Influenza virus (1-6%)
- Human metapneumovirus (1-8%)
- Parainfluenza virus (1-8%)
- RSV (1-8%)
- Adenovirus (1-8%)
- Fungi (1-3%)
- No cause identified (46-66%)
- Clinically-important but uncommon organisms
- Legionella species
- Influenza A and B, including avian influenza A H5N1 and avian influenza A H7N9
- MERS-CoV and severe acute respiratory syndrome coronavirus (SARS-CoV)
- Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA)
Clinical Manifestations
- Acute onset cough, dyspnea, and fever
- If effusion, consider Legionella
Severity
- Per IDSA guidelines2, severe CAP includes either one major criterion or three or more minor criteria
- Minor criteria
- Respiratory rate ≥ 30 breaths/min
- PaO2/FiO2 ratio ≤ 250
- Multilobar infiltrates
- Confusion/disorientation
- Uremia (blood urea nitrogen level ≥ 20 mg/dl)
- Leukopenia not due to chemotherapy (white blood cell count < 4,000 cells/μl)
- Thrombocytopenia (platelet count < 100,000/μl)
- Hypothermia (core temperature < 36°C)
- Hypotension requiring aggressive fluid resuscitation
- Major criteria
- Septic shock with need for vasopressors
- Respiratory failure requiring mechanical ventilation
Investigations
- Always add Legionella testing in immunocompromised, critical illness, recent travel, significant alcohol, and consider when pleural effusion is present
Further Reading
References
- ^ Naomi J. Gadsby, Daniel M. Musher. The Microbial Etiology of Community-Acquired Pneumonia in Adults: from Classical Bacteriology to Host Transcriptional Signatures. Clinical Microbiology Reviews. 2022;35(4). doi:10.1128/cmr.00015-22.
- ^ Joshua P. Metlay, Grant W. Waterer, Ann C. Long, Antonio Anzueto, Jan Brozek, Kristina Crothers, Laura A. Cooley, Nathan C. Dean, Michael J. Fine, Scott A. Flanders, Marie R. Griffin, Mark L. Metersky, Daniel M. Musher, Marcos I. Restrepo, Cynthia G. Whitney. Diagnosis and Treatment of Adults with Community-acquired Pneumonia. An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America. American Journal of Respiratory and Critical Care Medicine. 2019;200(7):e45-e67. doi:10.1164/rccm.201908-1581st.
