Hospital-acquired pneumonia (HAP) is typically caused by bacteria, especially aerobic gram-negative bacilli, such as Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and Acinetobacter species.
Patients with hospital-acquired pneumonia usually present with a combination of fever (or hypothermia), leukocytosis (or leukopenia), increased tracheal secretions, and poor oxygenation. Alveolar shadowing on chest x-ray or computed tomography scan supports the diagnosis.
A lower respiratory culture should be obtained before initiating antibiotics; result of the culture should be used to de-escalate antibiotics and focus on the offending pathogen.
Broad-spectrum antimicrobials should be used initially for patients with risk factors for multidrug-resistant pathogens.
HAP is an acute lower respiratory tract infection that is by definition acquired at least 48 hours after admission to the hospital and is not incubating at the time of admission. The spectrum of HAP is now distinct from ventilator-associated pneumonia (VAP), which is defined as pneumonia occurring more than 48 hours after endotracheal intubation. Healthcare-associated pneumonia is no longer considered a clinical entity in the most recent guidelines for HAP and VAP by the Infectious Diseases Society and the American Thoracic Society.
This topic focuses on the diagnosis and management of HAP/VAP in adults; it does not cover pneumonia due to COVID-19. See Coronavirus disease 2019 (COVID-19).
History and exam
Key diagnostic factors
- productive cough
Other diagnostic factors
- chest pain
- asymmetric expansion of the chest
- diminished resonance
- whisper pectoriloquy
- crackles or rhonchi
- poor infection control/hand hygiene
- intubation and mechanical ventilation; endotracheal cuff pressure <20 cm H₂O
- elevated head of bed
- poor oral hygiene
- sedation/no interruption in sedation
1st investigations to order
- chest x-ray
- WBC count with differential
- pulse oximetry
- culture of lower respiratory tract sample
Investigations to consider
- diagnostic thoracentesis
- CT chest
- lung ultrasound
- MRSA nasal swab
before culture results: without risk factors for multidrug-resistant (MDR) pathogen
before culture results: with risk factors for multidrug-resistant (MDR) pathogen, including Pseudomonas and MRSA
after culture results: due to gram-negative pathogen
after culture results: due to gram-positive pathogen
- Coronavirus disease 2019 (COVID-19)
- Cardiogenic pulmonary edema
- Acute respiratory distress syndrome
- Pneumonia in adults: diagnosis and management
- Strategies to prevent ventilator-associated pneumonia, ventilator-associated events, and nonventilator hospital-acquired pneumonia in acute-care hospitals
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