COMMUNITY-ACQUIRED PNEUMONIA

• if patient has symptoms and signs below plus new unexplained Chest X-ray shadowing, and the illness is the primary clinical problem, treat as pneumonia

Symptoms

• Malaise, fever, rigors
• Vomiting, diarrhoea
• Confusion (especially in the elderly)
• Dyspnoea, cough
• Sputum (may be blood-stained, viscid and difficult to expectorate)
• Pleuritic pain

Social history

• Enquire about
• pet birds (psittacosis, chlamydial infection)
• recent hotel residence away from home (legionellosis)

Signs

• High fever (often absent in the elderly, where hypothermia may be seen)
• Tachycardia
• Tachypnoea
• Localised crackles
• Bronchial breathing (in about one third of hospital admissions)
• Chest signs may be absent or masked by other respiratory signs (e.g. COPD, CCF)

Investigations

• Chest X-ray
• Oximetry
• if SpO₂ <94% or features of severe pneumonia (see severity assessment below), measure ABG
• FBC, U&E, LFT, CRP
• Microbiology:
• include full clinical history on request
• sputum – culture and sensitivity
• blood cultures in all patients requiring IV antibiotics, irrespective of temperature – see Blood culture guideline
• in the seriously ill, nose and throat swab in viral transport media for atypical organisms (influenza A and B, Chlamydia psittaci, Coxiella burnetii, Mycoplasma pneumoniae, Legionella pneumophila). Indicate date of onset clearly on request form
• in the seriously ill, send urine for legionella antigen and pneumococcal antigen

Differential diagnosis

• Pulmonary thromboembolism
• Lung cancer
• Left ventricular failure

Severity

• Management is based on the CURB 65 assessment of severity

CURB 65 assessment

Acute necrotising pneumonia

• If a previously healthy young adult presents with acute necrotising pneumonia with rapid lung cavitation, suspect Panton-Valentine Leukocidin (PVL) toxin-producing Staphylococcus aureus
• isolate in single room and contact microbiologist, infectious disease, or respiratory consultant

Admission

• Admit to a respiratory ward
• if patient meets the frail elderly criteria and has pneumonia as well as other diagnoses, consider admission to elderly care ward

Supportive therapy

• Oxygen. See Hypoxaemia guideline
• Fluid replacement to compensate for effects of pyrexia and tachypnoea coupled with inadequate intake. See 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
• if eGFR ≥30 mL/min, ibuprofen may be substituted once adequate fluid replacement achieved

Antimicrobial therapy

• Start as soon as diagnosis made – give first dose within 1 hr of presentation to hospital and before leaving assessment area
• therapy should always cover Streptococcus pneumoniae
• Route of administration depends whether patient able to swallow and absorb oral drugs, severity of illness and likely pathogens
• 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 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

Choice of Antimicrobials

Select one of:

• In severe pneumonia, clinical assessment (including mental state) 12-hrly, until improving
• Pulse, BP, temperature, respiratory rate and SpO₂ with FiO₂ 4-hrly until stable
• aim for SpO₂ ≥92%
• if type 2 respiratory failure – see Respiratory failure guideline
• Biochemical screen – repeat every 24–48 hr while significant abnormalities persist
• If patient not improving after 48 hr despite adequate therapy, repeat chest X-ray and CRP
• if CRP not falling, consider possibility of empyema, abscess or inappropriate antimicrobial regimen

• Nutritional support in prolonged illness
• If risk factors for HIV are present or recurrent pneumonia, test for HIV – seeHIV infection testing guideline

Duration of antimicrobials

• If IV route used on admission, change to oral when clinical improvement occurs and temperature normal for 24 hr
• use oral antimicrobial to which microbe sensitive
• If sensitivity not known, give co-amoxiclav 625 mg oral 8-hrly plus clarithromycin 500 mg oral 12-hrly. If allergic to penicillin, clarithromycin 500 mg oral 12-hrly
• In uncomplicated pneumonia non-severe, give 5–7 days treatment including IV treatment
• In patients with severe pneumonia, necrotising pneumonia, staphylococcal pneumonia, or legionella pneumonia, continue antimicrobials for at least 2 weeks including IV treatment

Failure to respond to therapy

• Request review by specialist in respiratory medicine/infectious disease and consider:
• incorrect diagnosis (e.g. pulmonary embolism, pulmonary oedema, pulmonary eosinophilia, Wegener's granulomatosis)
• resistant organism (e.g. amoxicillin-resistant/penicillin-resistant Strep. pneumoniae, haemophilus, mycoplasma, psittacosis, Q fever or staphylococcal pneumonia) – discuss with microbiologist
• unrecognised pulmonary tuberculosis
• unrecognised immunodeficiency (e.g. HIV infection leading to pneumocystis pneumonia)
• Complications:
• parapneumonia effusion or empyema – aspirate, culture and drain, and refer to respiratory physician – see Pleural infection and empyema guideline
• lung abscess – refer to respiratory physician
• bronchial obstruction – refer to respiratory physician
• pulmonary embolism – see Pulmonary embolism guidelines
• fever related to drug therapy – omit therapy for 48 hr

• Check within 24 hr of planned discharge that patient does not have more than one of the following:
• temperature >37.8°C
• heart rate >100/min
• respiratory rate >24/min
• systolic blood pressure <90 mmHg
• oxygen saturation <90%
• inability to maintain oral intake
• abnormal mental status
• Clinical review by GP or in hospital clinic after approximately 6 weeks
• request follow-up Chest X-ray before patient discharged for all patients who have persistent symptoms or are at high risk of underlying malignancy (especially smokers and those aged >50 yr) whether or not they have been admitted
• convalescent serology can be obtained at this visit