Last updated on: February 1st, 2021

Pneumonia, hospital acquired

Clinicals - History


Hospital-acquired pneumonia (HAP) is a nosocomial lung infection that occurs 48 hours after hospital admission.

Common causative organisms include aerobic gram-negative bacilli (e.g., Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Enterobacter, Acinetobacter, Legionella pneumophila) and gram-positive cocci (such as Staphylococcus aureus, and Streptococcus spp.).


Cough is a common complaint in patients with pneumonia. Cough occurs reflexively in response to the presence of secretions caused by the infection and resulting inflammatory process.

Shortness of breath

Patients usually have a history of shortness of breath. This is caused by the presence of secretions in the alveoli, which leads to ineffective gaseous exchange.

Pleuritic chest pain

Patients with pneumonia may complain of chest pain. This is often described as stabbing, intense, and worsened by deep breathing, coughing, and sneezing. While the visceral pleura does not contain pain receptors, involvement of the somatic nerves in the parietal pleura leads to pleuritic chest pain.


Patients with pneumonia typically present with fever and night sweats. This is due to cytokine release following the initial inflammatory reaction.


Patients with pneumonia may complain of headache. This is caused by the action of cytokines, prostaglandins, and other immune mediators.


Patients with pneumonia can present with confusion due to disturbances in the frontal cortex and reticular activating system. Elderly patients are more likely to present with altered mental status.


Patients with HAP may present with sputum production. This is due to the exudative inflammatory infiltrate.

Risk of multidrug resistant pathogens

Risk factors for infection by a multidrug resistant (MDR) pathogen include: intravenous antibiotic use in last 90 days, use of mechanical ventilation, presence of structural lung disease, alcoholism, septic shock, and immunocompromised states.

Risk factors

Risk factors include: old age, malnutrition, pre-existing lung diseases, thoracic and abdominal surgery and immunocompromised states.

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