HOSPITAL-ACQUIRED PNEUMONIA

Definition

Pneumonia at least 48 hr after hospitalisation and excluding any infection that is incubating at time of admission

Symptoms and signs

• Fever, rigors
• Confusion
• Cough, dyspnoea
• Pleuritic chest pain
• Tachycardia
• Tachypnoea
• Crackles
• Bronchial breathing
• Effusion
• Purulent tracheal secretions, and new and/or persistent infiltrate on chest X-ray otherwise unexplained
• Increased oxygen requirement

Investigations

• Chest X-ray (compare with previous chest X-ray if available)
• Arterial blood gases (ABG)
• FBC, CRP, biochemical screen
• Sputum: culture and sensitivity
• Urine antigen testing (UAT) for Legionella pneumophilia and pneumococcal antigen if <4 days following admission and if severe pneumonia (see below for definition)
• 2 sets of blood cultures from separate sites. Use aseptic technique – see Collection of blood culture specimens guideline
• Diagnostic thoracentesis if patient has parapneumonic effusion, see Investigation of pleural effusion guideline

Differential diagnosis

• Congestive cardiac failure
• Pulmonary thromboembolism
• Drug reactions
• Pulmonary haemorrhage
• Adult respiratory distress syndrome
• Aspiration pneumonia

Severe hospital-acquired pneumonia

• Presence of any of the following indicates a severe illness:
• Respiratory failure (PaO₂ <8 kPa and/or PaCO₂ >4 kPa)
• Respiratory rate >25 breaths/min
• Rapid radiographic progression, multilobar pneumonia, or cavitation of lung infiltrate
• Diastolic BP <60 mmHg
• WBC low (<4 x 10⁹/L) or very high (>20 x 10⁹/L)
• Poor urine output or rising serum creatinine
• Metabolic acidosis
• Discuss with senior medical staff whether to refer to critical care

Antimicrobial therapy

• Start treatment as soon as clinical criteria for diagnosis are met, do not await microbiological confirmation. If severely ill, administer antimicrobials within 1 hr of diagnosis
• Modify initial therapy once results of respiratory tract secretions or blood cultures become available
• Route of administration depends whether patient able to swallow and absorb oral drugs, severity of illness and likely pathogens
• Many patients with severe hospital-acquired pneumonia will have some renal impairment; seek advice when selecting antimicrobial dosage. Contact pharmacy medicines information
• See current BNF for Interactions
• e.g. statins contraindicated in combination with clarithromycin

Penicillin Allergy

• True penicillin allergy is rare
• Ask the patient and record what happened when they were given penicillin
• If any doubt about whether patient is truly allergic to penicillin, seek advice from a microbiologist or consultant in infectious diseases

Infection Control alerts

• Check for IC alert
• If IC alert not available, check previous 12 months of microbiology reports
• If MRSA present, treat as tagged for MRSA. See MRSA management
• if ESBL, MGNB, CARB present, treat as tagged for ESBL. See ESBL/MGNB/CARB management

Infection starts <4 days after admission

• Treat as community-acquired pneumonia – see Community acquired pneumonia guideline if:
• <4 days after admission including patients admitted from nursing home/care home/residential home or community hospitals with pneumonia
• patients re-admitted with pneumonia after >4 days of discharge from acute hospitals

Infection starts >4 days after admission

• >4 days after admission and patients being re-admitted with pneumonia up to 4 days after discharge

Supportive therapy

• Oxygen. See Oxygen therapy in acutely hypoxaemic patient guideline
• Fluid replacement to compensate for effects of pyrexia and tachypnoea coupled with inadequate intake. See Adult fluid management guideline
• Prophylactic LMWH
• Treat any accompanying airflow obstruction or cardiac failure
• Physiotherapy only in patients with copious secretions

Analgesia for pleuritic pain

• Paracetamol alone is unlikely to be adequate
• If patient on ACE inhibitor or pregnant, avoid NSAIDs
• prefer morphine sulphate 10 mg oral 4-hrly
• If well hydrated and eGFR ≥30 mL/min, ibuprofen 400 mg oral 8-hrly
• In dehydrated patient or if eGFR <30 mL/min, to prevent renal damage, prefer morphine sulphate 10 mg oral 4-hrly
• When eGFR ≥30 mL/min, ibuprofen may be substituted once adequate fluid replacement achieved

• Pulse, BP, SpO₂ and temperature hourly until patient stable
• Repeat biochemical screen every 24–48 hr while significant abnormalities persist
• If patient not improving despite therapy, repeat chest X-ray after 72 hr
• If no improvement, refer to critical care

Duration of antimicrobials

• Transfer IV to oral as soon as clinical improvement occurs and temperature has been normal for 24 hr, providing no contraindication to oral therapy
• In uncomplicated pneumonia, continue antimicrobials for 5 days total (including IV treatment)
• In patients with severe pneumonia, staphylococcal pneumonia, or legionella pneumonia, continue antimicrobials for at least 14 days total (including IV treatment)

Failure to respond to treatment

• If proven MRSA pneumonia (usually ventilator-associated, infiltrates on CXR, sputum culture yields MRSA only) does not respond to IV vancomycin within 48 hrs, contact consultant microbiology or in infectious diseases
• Incorrect diagnosis (see Differential diagnosis)
• Re-evaluate and consider bronchoscopy to obtain protected specimens brushing and/or bronchoalveolar lavage specimens for quantitative cultures – refer to respiratory physician
• Complications: empyema, lung abscess – refer to respiratory physician and see Pleural infection and empyema guideline

• Follow up in clinic with chest X-ray about 6 weeks after discharge to ensure that resolution of radiological shadowing is occurring