Hospital-acquired pneumonia

Disease Description (Causes and Symptoms)

• Definition: Hospital-acquired pneumonia (HAP) is pneumonia that develops 48 hours or more after hospital admission and was not already incubating before admission. When it occurs in a patient using mechanical ventilation, it is a specific subgroup called ventilator-associated pneumonia (VAP).
• Causes (pathogenesis): Pathogenic microorganisms acquired in the hospital environment or the patient’s own endogenous microorganisms enter the airways and cause inflammation in the lower respiratory tract. Major risk factors include mechanical ventilation/endotracheal intubation, immunosuppression, general debility, prolonged hospitalization, recent intravenous antibiotic use, contamination of respiratory treatment equipment, and aspiration risk (altered consciousness, dysphagia), among others.
• Common pathogens: Pseudomonas aeruginosa, Staphylococcus aureus (including MRSA), Enterobacterales (e.g., Klebsiella, Enterobacter), and other Gram-negative bacilli. The distribution varies according to regional antimicrobial susceptibility (antibiotic resistance rates).
• Main symptoms: Sudden fever, chills, cough (dry or with purulent sputum), increased sputum production, chest pain (pleuritic pain), shortness of breath, muscle aches, and general weakness. In severe cases, hypoxemia and signs of sepsis may occur.

Treatment Methods

• Initial diagnostic measures
  • When HAP is suspected, obtain blood cultures (2 sets) and sputum (or endotracheal secretions) for culture, identification, and antibiotic susceptibility testing before administering antibiotics whenever possible.
  • Assess respiratory status with a chest X-ray (chest CT if necessary) and oxygen saturation/arterial blood gas testing.
• Empiric antibiotic therapy (initial)
  • Antibiotic selection is based on individual patient risk factors (recent IV antibiotic use, long-term care facility history, local prevalence of MRSA/Pseudomonas, etc.) and hospital antibiotic susceptibility data (local antibiogram).
  • If there is a risk of MRSA (e.g., high local MRSA prevalence, previous MRSA identification, IV antibiotic use within the past 90 days, etc.) → add vancomycin or linezolid.
  • If there is a risk of Pseudomonas and other multidrug-resistant Gram-negative bacteria → use an antipseudomonal beta-lactam (e.g., piperacillin-tazobactam, cefepime, ceftazidime, imipenem/meropenem, etc.); if necessary, consider combination therapy with two agents (e.g., a beta-lactam + an aminoglycoside/fluoroquinolone).
  • In patients with low risk factors, narrow-spectrum antibiotic monotherapy may be possible according to local guidelines.
• Treatment duration and adjustment
  • If the clinical response is good and a specific organism is identified by culture, narrow the antibiotic therapy according to susceptibility results (de-escalation).
  • In general, when there is clinical improvement, a treatment duration of approximately 7 days is recommended (longer for nonfermenting bacilli such as Pseudomonas or in cases with complications).
• Supportive care
  • Oxygen therapy, fluid and electrolyte correction, pain and fever management, promotion of sputum clearance (physical therapy), and appropriate ventilatory management for patients on mechanical ventilation.
  • Severe cases (respiratory failure, sepsis, etc.) require intensive care and mechanical ventilation.
• Prevention and management (during hospitalization)
  • Infection control: Hand hygiene, disinfection and management of medical equipment, and adherence to sterilization/single-use guidelines for respiratory equipment.
  • Patients on mechanical ventilation: VAP prevention bundle (head elevation, dental and oral hygiene, removal of airway secretions, minimizing sedation, etc.).
  • Vaccines: Influenza and pneumococcal vaccines are recommended for eligible individuals.

Checklist Before an Outpatient Visit (Including Sample Questions)

• Items to prepare and information to confirm
  • A list of current medications (including prescription drugs, nonprescription drugs, and supplements), medication allergies, and previous antibiotic use (within the past 90 days).
  • Recent history of hospitalization, residence in a long-term care facility, and whether mechanical ventilation or a tracheostomy was used.
  • When symptoms began (how many hours/days after admission), the presence of fever, cough, and sputum, the color and amount of sputum, whether shortness of breath is present, and whether chest pain is present.
  • If available, bring recent test results (chest X-ray, blood tests, oxygen saturation, etc.) or culture results whenever possible.
  • Information about underlying conditions (chronic obstructive pulmonary disease, heart failure, diabetes, immunosuppression, etc.).
• Items to submit or report when visiting the doctor
  • Changes in symptoms during the day (fever pattern, changes in sputum color), whether shortness of breath worsens with exercise, and changes in symptoms after taking medication.

General Sample Questions to Ask the Doctor

• "What are the target organisms and expected side effects of the antibiotic I need to take?"
• "How long will the treatment last, and when will I be reevaluated (and my medication adjusted)?"
• "If my shortness of breath worsens, when should I go to the emergency room?"
• "What care should I receive at home to prevent recurrence?"

Sample Questions Tailored to This Disease

• "I have a history of antibiotic use (or hospitalization) within the past 90 days. How does this affect the choice of initial antibiotics?"
• "How will my antibiotic treatment plan be adjusted based on the antibiotic susceptibility test results used at the hospital (or the hospital’s prevalence of MRSA/Pseudomonas)?"

If you need additional information, please let us know about any recent chest imaging or culture results (if available), and we will provide more specific explanations and guidance on preparing for your medical visit.