Community-Acquired Pneumonia (CAP)

📋 Key Information Summary

📋

Community-acquired pneumonia (CAP) is the leading infectious cause of hospitalisation and death in Australia, with highest burden in Aboriginal and Torres Strait Islander peoples and the elderly.
Diagnosis requires a new chest X-ray infiltrate PLUS at least one clinical feature (fever, cough, dyspnoea, pleuritic chest pain, or focal chest signs).
CURB-65 (score 0–5) is the preferred severity tool in Australian emergency departments; scores 0–1 generally suitable for outpatient management, 2 for inpatient ward, ≥3 consider ICU.
PSI/PORT score may supplement CURB-65 but is less practical at the bedside; it classifies patients into risk classes I–V.
Outpatient CAP (low severity): amoxicillin 1 g TDS PO for 5 days is first-line; add doxycycline or a macrolide if atypical pathogens suspected.
Inpatient non-ICU CAP (moderate severity): IV amoxicillin–clavulanate 1.2 g TDS + IV azithromycin 500 mg daily; switch to oral when clinically improving (48–72 h).
ICU CAP (high severity): IV benzylpenicillin 1.2 g 4-hourly or IV ceftriaxone 2 g daily + IV azithromycin 500 mg daily; consider piperacillin–tazobactam if Pseudomonas risk factors present.
Add vancomycin or linezolid for suspected MRSA pneumonia (post-influenza, known colonisation, cavitary infiltrates); add anti-pseudomonal β-lactam if structural lung disease or recent hospital/antibiotic exposure.
Standard antibiotic duration is 5 days for uncomplicated CAP; extend to 7–10 days for complicated disease, empyema, bacteraemia, or immunocompromise.
Legionella urinary antigen and pneumococcal urinary antigen testing should be performed in all hospitalised CAP patients; blood cultures before antibiotics in all inpatients.
Repeat chest X-ray at 6 weeks for all patients aged ≥50 years or with persistent symptoms to exclude underlying malignancy (non-resolving pneumonia workup).
Pneumococcal vaccination (PCV13 → PPSV23) is funded under the NIP for Aboriginal and Torres Strait Islander peoples from age 50, and for all Australians ≥65 years; annual influenza vaccination reduces CAP incidence.
Aboriginal and Torres Strait Islander Australians experience CAP rates 5–8 times higher than non-Indigenous Australians, with earlier age of onset and higher mortality; ensure culturally safe communication and address rural/remote access barriers.

Introduction & Australian Epidemiology

Community-acquired pneumonia (CAP) is defined as an acute infection of the lung parenchyma acquired outside of a hospital or healthcare facility. It remains a major cause of morbidity, hospitalisation, and mortality in Australia, responsible for over 100,000 hospital admissions annually and approximately 4,000 deaths per year. CAP disproportionately affects Aboriginal and Torres Strait Islander peoples, the elderly, and those with chronic comorbidities.

Streptococcus pneumoniae remains the most commonly identified pathogen across all age groups and severity levels in Australia. Other frequently implicated organisms include Haemophilus influenzae, Mycoplasma pneumoniae, Legionella pneumophila, respiratory viruses (influenza, SARS-CoV-2, RSV), and Staphylococcus aureus (including community-acquired MRSA — CA-MRSA). In tropical northern Australia, Burkholderia pseudomallei (melioidosis) and Acinetobacter baumannii should be considered during the wet season.

⚠️

Seasonal alert: Influenza and COVID-19 co-circulation increases CAP severity and complicates empiric therapy decisions. Consider oseltamivir (Tamiflu®) for influenza-positive CAP and antiviral therapy for COVID-19 per current Australian guidelines.

Australian Burden of Disease

Parameter	Value (Australia)
Annual hospitalisations	~100,000–120,000
Annual deaths	~3,500–4,500
In-hospital mortality (all comers)	4–7%
ICU admission rate	10–15% of hospitalised
ICU mortality	20–35%
ATSI:non-Indigenous incidence ratio	5–8× (highest in remote NT and QLD)
Peak season	June–September (winter); wet season tropical NT (Nov–Apr)

Diagnosis & Evaluation

Clinical Diagnostic Criteria

A diagnosis of CAP is made when there is a new opacity on chest X-ray (CXR) consistent with pneumonia, plus at least two of the following clinical features:

Fever (≥38.0°C) or hypothermia (<36°C)
New or worsening cough
Dyspnoea or increased respiratory rate (≥20 breaths/min)
Pleuritic chest pain
Focal chest signs on auscultation (crackles, bronchial breathing, dullness to percussion)
Sputum production (purulent or mucopurulent)

💡

Clinical pearl: Elderly and immunocompromised patients may present atypically — without fever or cough — and instead show delirium, falls, functional decline, or anorexia. Maintain a low threshold for CXR in these populations.

Chest X-ray Interpretation

A plain posteroanterior (PA) and lateral CXR remains the cornerstone of CAP diagnosis. MBS Item 58505 applies. Key radiological patterns include:

Pattern	Suggests	Key Considerations
Lobar consolidation	Typical bacterial (S. pneumoniae)	Air bronchograms, silhouette sign
Bronchopneumonia (patchy bilateral)	S. aureus, H. influenzae, Gram-negatives	Common in elderly, aspiration
Interstitial / reticulonodular	Atypical (Mycoplasma, Legionella, viral, Pneumocystis)	May be subtle; consider CT if high clinical suspicion
Cavitary lesion	S. aureus, Klebsiella, TB, anaerobes, lung malignancy	Urgent CT chest; consider bronchoscopy
Pleural effusion ± consolidation	Parapneumonic effusion / empyema	Ultrasound-guided aspiration if loculated or large

Microbiological Investigations

The intensity of microbiological workup depends on severity and care setting:

Available Sputum Gram stain & culture Prior to antibiotics in all inpatients with productive cough. Acceptable specimen: >25 WBCs and <10 squamous epithelial cells per LPF. MBS Item 69304.

Available Blood cultures (×2 sets) Before first antibiotic dose in all hospitalised patients. Positive yield 10–20%. MBS Item 69310. Essential in ICU patients.

Available Pneumococcal urinary antigen (BinaxNOW®) Rapid test (15 min). Sensitivity 70–80%, specificity >90%. Perform in all hospitalised CAP. Useful if prior antibiotics given. MBS Item 69474.

Available Legionella urinary antigen Detects L. pneumophila serogroup 1 only (80–90% of Legionella CAP). Perform in all hospitalised CAP. Results within 15 min. MBS Item 69472.

Available Respiratory viral PCR (multiplex) Nasopharyngeal swab. Detects influenza A/B, RSV, SARS-CoV-2, parainfluenza, adenovirus, human metapneumovirus. MBS Item 69496.

Referral CT chest with contrast For suspected complications (empyema, abscess, non-resolving pneumonia) or to exclude underlying malignancy. MBS Item 56201.

Specialist Bronchoalveolar lavage (BAL) For immunocompromised patients, non-resolving pneumonia, suspected Pneumocystis jirovecii, or when non-invasive testing is negative. Requires respiratory physician.

Essential Arterial blood gas (ABG) Assess oxygenation (PaO₂), ventilation (PaCO₂), and acid–base status. Required for all patients with SpO₂ <94%, respiratory distress, or ICU consideration.

Routine Blood Investigations

Full blood count (FBC): Leucocytosis (bacterial), lymphopenia (viral), eosinophilia (rare — consider eosinophilic pneumonia)
C-reactive protein (CRP): Useful for monitoring treatment response; procalcitonin (PCT) may help distinguish bacterial from viral aetiology and guide antibiotic duration
Urea and electrolytes (U&E): Assess renal function (components of CURB-65); guide fluid management
Liver function tests (LFTs): Baseline; hyponatraemia may suggest Legionella
Lactate: If sepsis suspected; levels ≥2 mmol/L warrant escalation of care
HIV serology: Consider in all patients with atypical organisms, Pneumocystis, or unexplained immunosuppression

Severity Assessment

Accurate severity assessment is critical for determining the appropriate site of care (outpatient, inpatient ward, or ICU) and guiding empiric antibiotic selection. Two validated tools are in widespread use in Australian emergency departments.

CURB-65 Score

The BTS-derived CURB-65 score is the recommended severity tool for CAP in Australia. Each criterion scores 1 point (maximum 5):

Low Severity

CURB-65 Score 0–1

One or fewer criteria present. Low 30-day mortality (0.6–2.7%).

Setting: Outpatient management (GP)

Moderate Severity

CURB-65 Score 2

Two criteria present. 30-day mortality ~9%. Requires close clinical review.

Setting: Hospital ward admission

High Severity

CURB-65 Score 3–5

Three or more criteria present. 30-day mortality 15–40%. Consider ICU admission if score 4–5 or clinical deterioration.

Setting: Consider ICU / HDU admission

Criterion	Definition	Points
C — Confusion	New confusion, AMT ≤8 (or equivalent)	1
U — Urea	Serum urea >7 mmol/L	1
R — Respiratory rate	≥30 breaths/min	1
B — Blood pressure	SBP <90 mmHg or DBP ≤60 mmHg	1
65 — Age	≥65 years	1

⚠️

Clinical judgement overrides CURB-65: A CURB-65 score of 0–1 does not exclude severe sepsis. Patients with hypoxia (SpO₂ <92% on room air), bilateral multilobar infiltrates, extrapulmonary sepsis, or significant comorbidities should be admitted regardless of CURB-65 score.

PSI/PORT Score (Pneumonia Severity Index)

The PSI/PORT score is more complex (assigns points for 20 variables) and has higher discriminatory power for identifying low-risk patients, but is less practical for bedside decision-making. It stratifies patients into five risk classes:

Risk Class	Points	30-Day Mortality	Disposition
Class I	Age <50, no comorbidities, no adverse features	0.1%	Outpatient
Class II	≤70	0.6%	Outpatient
Class III	71–90	2.8%	Observation / short stay
Class IV	91–130	8.2%	Hospital ward admission
Class V	>130	29.2%	ICU / high dependency

ICU Admission Criteria (ATS/IDSA Major Criteria)

Patients with any one major criterion or ≥three minor criteria should be considered for ICU admission:

Major Criteria (require ICU)

Septic shock requiring vasopressors
Respiratory failure requiring invasive mechanical ventilation

Minor Criteria (≥3 = consider ICU)

Respiratory rate ≥30 breaths/min
PaO₂/FiO₂ ratio ≤250
Multilobar infiltrates
Confusion (new onset)
Urea ≥20 mg/dL (≥7 mmol/L)
Leucopenia (WBC <4 × 10⁹/L)
Thrombocytopenia (platelets <100 × 10⁹/L)
Hypothermia (core temp <36°C)
Hypotension requiring aggressive fluid resuscitation

Sepsis Screening (qSOFA)

The quick Sequential Organ Failure Assessment (qSOFA) score should be applied to all patients with suspected infection. A score ≥2 at the bedside (without laboratory values) suggests high risk for poor outcomes and triggers escalation of care:

Altered mental status (GCS <15 or new confusion)
Systolic blood pressure ≤100 mmHg
Respiratory rate ≥22 breaths/min

Empiric Antibiotic Therapy

Empiric antibiotic therapy for CAP in Australia is guided by the eTG Antibiotic Guidelines, incorporating local antimicrobial resistance patterns (notably rising CA-MRSA rates in northern and remote communities). Antibiotics should be initiated within 4 hours of presentation for hospitalised patients; within 1 hour if sepsis or ICU admission.

Outpatient (Low Severity — CURB-65 0–1)

💊

Amoxicillin

Amoxil® · Generic · Aminopenicillin

Adult dose 1 g PO TDS for 5 days

Paediatric dose 30–50 mg/kg PO TDS (max 500 mg TDS if <40 kg)

Renal adjustment eGFR 10–30: reduce frequency to BD; eGFR <10: 500 mg TDS

PBS status ✔ PBS General Benefit

💊

Doxycycline

Doxy® · Doryx® · Tetracycline

Adult dose 200 mg PO stat then 100 mg PO BD for 5 days

Paediatric dose ≥8 years: 2 mg/kg PO BD (max 100 mg BD)

Renal adjustment No adjustment required

PBS status ✔ PBS General Benefit

💊

Amoxicillin–Clavulanate

Augmentin® · Generic · Aminopenicillin + β-lactamase inhibitor

Adult dose 875/125 mg PO BD for 5 days (alternative first-line if comorbidities or recent antibiotics)

Paediatric dose 22.5 mg/kg (as amoxicillin component) PO BD

Renal adjustment eGFR 10–30: 500/125 mg BD; eGFR <10: 500/125 mg OD

PBS status ✔ PBS General Benefit

💡

Outpatient combination therapy: If atypical cover is desired (young adults, epidemic Mycoplasma, failed first-line), combine amoxicillin 1 g TDS with doxycycline 100 mg BD or azithromycin 500 mg day 1 then 250 mg days 2–5.

Inpatient Non-ICU (Moderate Severity — CURB-65 2)

💉

Amoxicillin–Clavulanate (IV)

Augmentin® IV · Aminopenicillin + β-lactamase inhibitor

Adult dose 1.2 g IV TDS (8-hourly); step down to oral Augmentin Duo Forte 875/125 mg BD when clinically stable (typically 48–72 h)

Duration 5 days total (IV + oral combined)

Renal adjustment eGFR 10–30: 1.2 g BD; eGFR <10: 1.2 g OD

PBS status ✔ PBS General Benefit

💊

Azithromycin

Zithromax® · Generic · Macrolide

Adult dose 500 mg IV or PO daily for 3 days (covers atypicals: Legionella, Mycoplasma, Chlamydophila)

Paediatric dose 10 mg/kg PO/IV day 1, then 5 mg/kg daily days 2–5

Renal adjustment No adjustment required

PBS status ✔ PBS General Benefit

Penicillin-allergic patients (non-anaphylaxis): Ceftriaxone 2 g IV daily + azithromycin 500 mg daily. For severe penicillin allergy (anaphylaxis, Stevens–Johnson): moxifloxacin 400 mg PO/IV daily monotherapy or doxycycline 100 mg BD + IV azithromycin 500 mg daily.

ICU (High Severity — CURB-65 ≥3)

💉

Benzylpenicillin

Crystapen® · IV Penicillin G

Adult dose 1.2 g (2 megaunits) IV 4-hourly (q4h) or 2.4 g (4 megaunits) IV 6-hourly (q6h)

Duration 5–7 days; step down to oral when improving

Renal adjustment eGFR 10–30: 1.2 g q8h; eGFR <10: 1.2 g q12h

PBS status ✔ PBS General Benefit

💉

Ceftriaxone

Rocephin® · 3rd-generation cephalosporin

Adult dose 2 g IV once daily (alternative to benzylpenicillin for severe CAP)

Paediatric dose 50–100 mg/kg IV once daily (max 4 g)

Renal adjustment No adjustment required (biliary excretion predominant)

PBS status ✔ PBS General Benefit

💊

Azithromycin (IV)

Zithromax® IV · Macrolide

Adult dose 500 mg IV once daily (combined with β-lactam; never use alone for severe CAP)

Duration 3 days IV then switch to oral 500 mg daily to complete course

PBS status ✔ PBS General Benefit

MRSA Risk Factors & Coverage

🚨

Add MRSA cover (vancomycin or linezolid) when any of the following are present: Known MRSA colonisation; post-influenza necrotising pneumonia; cavitary infiltrates; injection drug use; Aboriginal and Torres Strait Islander peoples from high CA-MRSA prevalence communities (remote NT, WA, QLD); recent hospitalisation with MRSA.

💊

Vancomycin

Vancocin® · Glycopeptide

Adult dose 25–30 mg/kg IV loading dose, then 15–20 mg/kg IV BD–TDS (target trough 15–20 mg/L)

Duration 7–14 days depending on clinical response

Renal adjustment Therapeutic drug monitoring (TDM) mandatory; adjust dose by trough levels and renal function

PBS status ⚠ PBS Authority Required

💊

Linezolid

Zyvox® · Oxazolidinone

Adult dose 600 mg IV or PO BD for 10–14 days

Key notes Excellent lung penetration. Oral bioavailability ~100%. Monitor FBC (thrombocytopenia). Avoid with MAOIs, serotonergic drugs.

PBS status ✖ PBS Authority Required (Specialist)

Pseudomonas Risk Factors & Coverage

Structural lung disease (bronchiectasis, severe COPD with frequent exacerbations, cystic fibrosis)
Recent broad-spectrum antibiotic exposure (within 90 days)
Recent hospitalisation (within 90 days)
Chronic systemic corticosteroid use

If Pseudomonas coverage is required, replace benzylpenicillin/ceftriaxone with:

💉

Piperacillin–Tazobactam

Tazocin® · Anti-pseudomonal β-lactam

Adult dose 4.5 g IV TDS (8-hourly) + azithromycin 500 mg IV daily

Renal adjustment eGFR 20–40: 3.375 g q8h; eGFR <20: 2.25 g q8h

PBS status ⚠ PBS Authority Required

Antibiotic Duration & IV-to-Oral Switch

✅

IV-to-oral switch criteria (all must be met):

Temperature <38°C for ≥24 hours
Heart rate <100 bpm
Respiratory rate <24 breaths/min
Tolerating oral medications
Systolic BP ≥90 mmHg without vasopressors

Clinical Scenario	Duration
Uncomplicated CAP (outpatient or ward)	5 days
CAP with bacteraemia (S. pneumoniae)	7–10 days
Legionella pneumonia	7–10 days (azithromycin) or 10–14 days (fluoroquinolone)
S. aureus pneumonia (including MRSA)	10–14 days
Empyema / complicated parapneumonic effusion	4–6 weeks (with drainage)
Immunocompromised host	10–14 days (minimum); individualised

Procalcitonin-guided antibiotic cessation (PCT <0.25 µg/L or >80% decrease from peak) may be used to support duration decisions but should not replace clinical assessment.

Complications

Complications of CAP may arise from the primary infection, an exaggerated host response, or inadequate initial therapy. Early recognition and management are essential to reduce morbidity and mortality.

Parapneumonic Effusion & Empyema

Parapneumonic effusions occur in 20–57% of hospitalised CAP patients. Most resolve with antibiotics alone, but complicated effusions and empyema require drainage.

Uncomplicated

Simple Parapneumonic Effusion

Free-flowing, <10 mm on lateral decubitus CXR. pH >7.2, glucose >3.4 mmol/L, LDH <1000 IU/L, culture negative.

Treatment: Antibiotics alone; serial CXR monitoring

Complicated

Complicated Parapneumonic Effusion

Loculated on ultrasound. pH <7.2, glucose <3.4 mmol/L, LDH >1000 IU/L, or positive Gram stain/culture.

Treatment: Intercostal catheter (ICC) drainage ± intrapleural tPA + DNase

Established

Empyema

Frank pus aspirated from pleural space. Thick-walled loculations on CT. Organisms on culture.

Treatment: ICC drainage; consider VATS if poor response after 72 h

⚠️

Pleural fluid sampling indication: Perform diagnostic aspiration (MBS Item 58540) if effusion >10 mm on lateral decubitus CXR or if loculations present on ultrasound. Send for pH (ABG analyser within 1 hour), protein, LDH, glucose, Gram stain, culture, and cell count.

Intrapleural fibrinolytic therapy: For loculated empyema not responding to ICC drainage, consider intrapleural alteplase 10 mg + dornase alfa 5 mg in 50 mL normal saline, instilled via ICC twice daily for 3 days (per MIST-2 trial). Flush with 20 mL 0.9% NaCl after each dose. Clamp ICC for 1 hour.

Lung Abscess

Lung abscess presents with high, swinging fevers, foul-smelling (anaerobic) sputum, and cavitary lesion on CXR/CT with an air-fluid level. Risk factors include aspiration (alcohol excess, seizure, stroke, dysphagia), periodontal disease, and immunosuppression.

First-line: Amoxicillin–clavulanate 875/125 mg PO BD (mild–moderate) or 1.2 g IV TDS (severe) for 4–6 weeks
Penicillin allergy: Moxifloxacin 400 mg PO/IV daily or clindamycin 600 mg IV TDS → 300–450 mg PO QDS
Percutaneous catheter drainage if abscess >6 cm, failure to respond to antibiotics in 7–10 days, or risk of rupture
Surgical resection rarely needed; consider for failed medical therapy, massive haemoptysis, or underlying malignancy

Respiratory Failure

Type 1 respiratory failure (hypoxaemic: PaO₂ <8 kPa) and Type 2 (hypercapnic: PaCO₂ >6 kPa) may complicate severe CAP.

1

Initial Oxygen Therapy

Target SpO₂ 94–98% (88–92% if COPD/chronic CO₂ retention). Nasal prongs 1–6 L/min or Hudson mask 6–10 L/min.

2

High-Flow Nasal Oxygen (HFNO)

Flow 30–60 L/min, FiO₂ titrated. For moderate hypoxaemia refractory to standard oxygen. Requires close monitoring in HDU/ICU.

3

Non-Invasive Ventilation (NIV)

CPAP or BiPAP for Type 2 respiratory failure or cardiogenic pulmonary oedema. Avoid in ARDS/consolidation (may delay intubation).

4

Invasive Mechanical Ventilation

If failing HFNO/NIV, PaO₂/FiO₂ <150, or inability to protect airway. Low tidal volume (6 mL/kg IBW), plateau pressure <30 cmH₂O. Consider prone positioning if P/F ratio <150.

Septic Shock

CAP-related septic shock carries 30–50% mortality. Management follows the Surviving Sepsis Campaign (Australian adaptation):

Fluid resuscitation: 20–30 mL/kg crystalloid (compound sodium lactate/Hartmann's) bolus within first 3 hours; reassess after each bolus using dynamic measures (stroke volume variation, passive leg raise)
Vasopressors: Noradrenaline first-line (commence if MAP <65 mmHg despite fluids); target MAP ≥65 mmHg. Available via central line or peripherally (dilute concentration) for short duration
Antibiotics within 1 hour: Broad-spectrum per severity guidelines above; obtain cultures before first dose but do not delay treatment
Hydrocortisone 50 mg IV QDS if persistent hypotension despite adequate fluids + vasopressors (noradrenaline ≥0.25 µg/kg/min for ≥4 hours)
Lactate monitoring: Re-measure within 2–4 hours; lactate clearance ≥10% in 2 hours is a positive prognostic sign

Other Complications

Acute kidney injury (AKI): Common in severe CAP; maintain renal perfusion with adequate fluid balance; adjust nephrotoxic antibiotics (vancomycin, aminoglycosides)
Cardiac events: Myocardial infarction, arrhythmias (especially atrial fibrillation), and myocarditis may complicate severe pneumonia; troponin and ECG recommended in ICU patients
Disseminated intravascular coagulation (DIC): Associated with severe sepsis; monitor coagulation and platelet counts
Secondary infection / superinfection: Consider if initial improvement followed by clinical deterioration; re-culture and broaden antibiotics; consider Clostridioides difficile if antibiotics prolonged

Special Populations

🤰

Pregnancy

Preferred antibiotics: Amoxicillin–clavulanate or ceftriaxone + erythromycin (avoid clarithromycin; avoid azithromycin unless benefit clearly outweighs risk). Doxycycline and fluoroquinolones are contraindicated.

Pneumococcal vaccine: PCV13 and PPSV23 are not routinely recommended in pregnancy but may be considered in high-risk women (asplenia, immunocompromise). Influenza vaccine is recommended and safe in any trimester.

Monitor for preterm labour. Third-trimester patients are at higher risk of respiratory failure — low threshold for ICU admission. Fetal monitoring required in severe CAP.

👶

Paediatrics

Outpatient: Amoxicillin 30–50 mg/kg PO TDS for 5 days. For atypical cover, add azithromycin 10 mg/kg day 1, then 5 mg/kg days 2–5.

Inpatient: Ceftriaxone 50–100 mg/kg IV daily or benzylpenicillin 50 mg/kg IV 6-hourly. Add azithromycin if atypical suspected.

Vaccination: PCV13 funded under NIP at 2, 4, 12 months of age. Influenza vaccine from 6 months.

Parapneumonic effusion is more common in children. Consider staphylococcal pneumonia in neonates and post-varicella. S. aureus cover (flucloxacillin) if CA-MRSA suspected.

👴

Elderly (≥65 years)

Presentation: Often atypical — delirium, falls, anorexia, functional decline. Fever may be absent. Maintain high index of suspicion.

Antibiotic considerations: Renal dose adjustment frequently required. Higher risk of C. difficile with broad-spectrum agents. Review polypharmacy for drug interactions (macrolides with statins, QT-prolonging agents).

CURB-65 may overestimate severity (age criterion always +1). Use clinical judgement alongside scores. Discuss goals of care early in severe cases. Ensure advance care directives are reviewed.

🫘

Renal Impairment

Key adjustments: Amoxicillin–clavulanate, piperacillin–tazobactam, and vancomycin all require dose reduction in eGFR <30. Vancomycin TDM mandatory. Linezolid does not require adjustment but monitor for thrombocytopenia.

Fluid management: Cautious fluid resuscitation in patients on dialysis; assess volume status by clinical examination and ultrasound (IVC collapsibility, lung B-lines).

CURB-65 urea component may be chronically elevated; use clinical context. Nephrotoxic combinations should be avoided where possible.

🫁

Hepatic Impairment

Key considerations: Azithromycin and macrolides should be used with caution in severe hepatic dysfunction (Child-Pugh C). Amoxicillin–clavulanate has a known association with cholestatic hepatitis — use with caution and monitor LFTs.

Coagulopathy:

Assess INR before invasive procedures (thoracentesis, ICC insertion). Cirrhotic patients are immunocompromised and at higher risk of spontaneous bacterial peritonitis alongside CAP — screen with diagnostic ascitic tap.

🛡️

Immunocompromised

Aetiology: Broader differential — Pneumocystis jirovecii (PCP), CMV, Aspergillus, Nocardia, Mycobacteria, endemic fungi. Requires early respiratory specialist input and bronchoscopy with BAL.

Empiric therapy: Broaden to piperacillin–tazobactam or meropenem + vancomycin + azithromycin + consider trimethoprim–sulfamethoxazole (for PCP if CD4 <200 or equivalent). High-dose co-trimoxazole: 15 mg/kg/day (as trimethoprim) IV in divided doses.

Consider dose-reduction of immunosuppressants where safe (discuss with transplant/rheumatology team). Monitor for drug interactions with calcineurin inhibitors.

Follow-up & Prevention

Repeat Chest X-ray Indications

Routine follow-up CXR is not required for all patients. However, it is strongly recommended at 6 weeks in the following groups to exclude underlying malignancy (the "non-resolving pneumonia" scenario):

All patients aged ≥50 years — mandatory 6-week CXR (MBS Item 58505)
Current smokers or ex-smokers (≥10 pack-years) of any age
Persistent symptoms (cough, haemoptysis, weight loss, fatigue) beyond expected recovery
Radiological features at presentation suggesting possible malignancy (mass lesion, unilateral volume loss, mediastinal lymphadenopathy)
Recurrence at the same anatomical site

⚠️

Non-resolving pneumonia: If the CXR at 6 weeks shows persistent or progressive consolidation, CT chest with contrast (MBS Item 56201) should be arranged urgently. Consider bronchoscopy with biopsy. Up to 5–10% of cases initially diagnosed as CAP may harbour an underlying bronchogenic carcinoma.

Non-Resolving Pneumonia — Differential Diagnosis

Failure to improve by 72 hours, or worsening despite appropriate antibiotics, should prompt reassessment:

Category	Differential	Next Step
Incorrect diagnosis	Pulmonary embolism, lung cancer, cryptogenic organising pneumonia (COP), eosinophilic pneumonia	CT pulmonary angiography; consider biopsy
Resistant organism	MRSA, Pseudomonas, extended-spectrum β-lactamase (ESBL) producers	Review cultures; broaden antibiotics; re-culture
Unusual pathogen	TB, fungal infection, Nocardia, PCP	Induced sputum for AFB; HIV test; BAL
Complication	Empyema, abscess, bronchopleural fistula	CT chest with contrast; ultrasound pleura; drainage
Drug fever	Antibiotic-related fever without active infection	Diagnosis of exclusion; consider antibiotic switch

Post-Discharge Follow-up

GP review within 48–72 hours of discharge for clinical assessment and medication review
Ensure completion of antibiotic course (provide written discharge instructions with stop date)
Review and optimise chronic disease management (COPD inhalers, diabetes control, heart failure medications)
Assess for post-infectious complications: pleural thickening, bronchiectasis, progressive fibrosis
Smoking cessation counselling — CAP is a "teachable moment"; offer NRT or varenicline (Champix®)
Alcohol dependence screening and referral (AUDIT-C); link to community alcohol and drug services
Consider functional and nutritional rehabilitation in elderly patients with prolonged hospital stay

Vaccination — Prevention of CAP

💉

Pneumococcal Vaccine — PCV13

Prevenar 13® · Pfizer · Conjugate vaccine

NIP-funded schedule Infants: 2, 4, 12 months. ATSI adults ≥50 years (as per NIP). All adults ≥65 years (as per NIP).

High-risk groups Immunocompromised, asplenia, chronic renal disease, CSF leak, cochlear implants — funded at any age.

PBS/NIP status ✔ NIP Funded (eligible groups)

💉

Pneumococcal Vaccine — PPSV23

Pneumovax 23® · MSD · Polysaccharide vaccine

NIP-funded schedule Given ≥12 months after PCV13 for: ATSI adults ≥50 years; all adults ≥65 years; high-risk groups at any age.

Revaccination One revaccination at ≥5 years for immunocompromised/chronic renal disease (NIP funded).

PBS/NIP status ✔ NIP Funded (eligible groups)

💉

Influenza Vaccine

Fluad Quad® / Fluzone HD® / standard formulations · Annual

Indication All persons ≥6 months. Funded under NIP for: ≥65 years, ATSI peoples ≥6 months, pregnant women, chronic disease, immunocompromised.

Enhanced formulations Adjuvanted (Fluad Quad®) or high-dose (Fluzone HD®) recommended for ≥65 years (NIP-funded).

Timing Annual, ideally March–May (before winter season). Can co-administer with pneumococcal vaccine.

PBS/NIP status ✔ NIP Funded (eligible groups)

💉

COVID-19 Vaccine

Comirnaty® JN.1 / Spikevax® JN.1 · Updated formulations

Indication All adults. Recommended annually from 2024 for adults ≥65 years and immunocompromised; others per clinical discretion.

NIP status ✔ NIP Funded (eligible groups)

Quick Reference — Preferred Regimens

Outpatient CAP (low risk)

Amoxicillin 1 g PO TDS

5 days

Add doxycycline 100 mg BD if atypicals suspected

Outpatient CAP (penicillin allergy)

Doxycycline 100 mg PO BD

5 days

Or moxifloxacin 400 mg PO OD

Inpatient non-ICU

Amox–clav 1.2 g IV TDS + azithromycin 500 mg IV OD

5 days total

Step down to oral when meeting switch criteria

ICU CAP

Benzylpenicillin 1.2 g IV q4h + azithromycin 500 mg IV OD

5–7 days

Or ceftriaxone 2 g IV OD if penicillin non-anaphylaxis allergy

ICU + MRSA risk

Above β-lactam + azithromycin + vancomycin 25–30 mg/kg load then TDM

10–14 days

Or linezolid 600 mg IV BD if vancomycin contraindicated

ICU + Pseudomonas risk

Pip–tazo 4.5 g IV TDS + azithromycin 500 mg IV OD

7–10 days

Review culture results at 48–72 h; de-escalate if possible

Aboriginal and Torres Strait Islander Health Considerations

Aboriginal and Torres Strait Islander Health

Aboriginal and Torres Strait Islander Australians bear a disproportionate burden of CAP, with hospitalisation rates 5–8 times higher than non-Indigenous Australians and mortality rates up to 10 times higher in some age groups. The disease occurs at a younger age, is more often severe, and is frequently complicated by chronic suppurative lung disease, rheumatic heart disease, and delayed presentation due to geographic and systemic barriers.

🚨

Critical consideration: In remote northern and central Australian communities, CA-MRSA prevalence can exceed 30% of S. aureus isolates. Empiric CAP regimens in these settings should include MRSA cover (vancomycin or linezolid) when severe pneumonia is suspected, particularly in post-influenza presentations or cavitary disease.

Epidemiology

CAP hospitalisation rates in ATSI peoples are 5–8× higher than non-Indigenous Australians. Peak incidence in children <5 years and adults 35–54 years (vs ≥65 years in non-Indigenous). Remote NT and QLD have the highest rates nationally. Mortality rate ratio: approximately 5–10× depending on age and jurisdiction.

Risk factors

Overcrowded housing, tobacco smoking (40%+ prevalence in ATSI adults), rheumatic heart disease, chronic suppurative lung disease/bronchiectasis, malnutrition in children, passive smoke exposure, indoor air pollution, high rates of otitis media (marker of recurrent respiratory infection).

Pathogen differences

Higher rates of S. aureus (including CA-MRSA), S. pneumoniae, and H. influenzae. Melioidosis (B. pseudomallei) in tropical regions during wet season (Nov–Apr). Non-tuberculous mycobacteria more common in Top End communities.

Rural & remote access

Limited access to chest X-ray, CT, blood cultures, and ICU services. Many communities rely on Health Centre nurses and fly-in/fly-out (FIFO) GPs. Royal Flying Doctor Service (RFDS) evacuation for severe cases. Telehealth (MBS Items 99–111) essential for specialist consultation. Point-of-care CRP and rapid antigen testing available in some AMS.

Vaccination gaps

PCV13 coverage in ATSI infants improved but remains below 90% in some remote communities. PPSV23 uptake in eligible ATSI adults (≥50 years) significantly lower than in non-Indigenous adults ≥65 years. Influenza vaccine coverage in ATSI peoples ~30–40% (target >75%). Closing the Gap targets include improving immunisation rates.

Cultural safety

Use culturally safe communication — involve Aboriginal Health Workers/Practitioners (AHW/P) in all consultations. Be aware of sorry business and kinship obligations that may affect hospital admission decisions. Provide health education materials in local language where possible. Acknowledge the social and emotional determinants of health. Avoid assumptions about compliance — address systemic barriers.

Key Actions for Clinicians

Consider CA-MRSA in all severe ATSI CAP presentations from high-prevalence communities; empiric vancomycin should be added early if severe or cavitary disease
Consider melioidosis in any ATSI patient from tropical Australia presenting with severe CAP during or after the wet season — ceftazidime (50 mg/kg IV TDS, max 2 g TDS) or meropenem is the treatment of choice for suspected melioidosis
Screen for rheumatic heart disease (RHD) in ATSI patients with recurrent CAP — echocardiography referral if new murmur detected
Ensure pneumococcal and influenza vaccination is up to date before discharge; opportunistic vaccination in ED and wards
Engage Aboriginal Health Workers in discharge planning, medication education, and follow-up coordination
Refer to smoking cessation support services (e.g., Tackling Indigenous Smoking program)
Address housing and overcrowding through advocacy and referral to community services

📚 References

1. Mandell LA, Wunderink RG, Anzueto A, et al. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis. 2007;44(Suppl 2):S27–S72.
2. Lim WS, Baudouin SV, George RC, et al. BTS guidelines for the management of community acquired pneumonia in adults: update 2009. Thorax. 2009;64(Suppl III):iii1–iii55.
3. Waterer GW, Rello J, Wunderink RG. Management of community-acquired pneumonia in adults. Am J Respir Crit Care Med. 2011;183(2):157–164.
4. Australian Institute of Health and Welfare (AIHW). Aboriginal and Torres Strait Islander Health Performance Framework: Pneumonia and influenza. Canberra: AIHW; 2023.
5. Charles PGP, Whitby M, Fuller AJ, et al. The etiology of community-acquired pneumonia in Australia: why penicillin plus doxycycline or a macrolide is the most appropriate therapy. Clin Infect Dis. 2008;46(10):1513–1521.
6. Fine MJ, Auble TE, Yealy DM, et al. A prediction rule to identify low-risk patients with community-acquired pneumonia. N Engl J Med. 1997;336(4):243–250.
7. National Health and Medical Research Council (NHMRC). The Australian Immunisation Handbook. 11th ed. Canberra: Australian Government Department of Health; updated 2024. Available at: immunisationhandbook.health.gov.au.
8. Tong S, Bishop P, Charles P, et al. Severe community-acquired pneumonia in Australian ICUs: a multi-centre prospective study. Intensive Care Med. 2015;41(12):2111–2118.
9. Rahman NM, Maskell NA, West A, et al. Intrapleural use of tissue plasminogen activator and DNase in pleural infection (MIST-2 trial). N Engl J Med. 2011;365(6):518–526.
10. Australian Commission on Safety and Quality in Health Care (ACSQHC). National Safety and Quality Health Service Standards. 2nd ed. Sydney: ACSQHC; 2021.
11. > Jacups SP, Cheng A. The epidemiology of community-acquired pneumonia in the Top End of the Northern Territory. Aust N Z J Public Health. 2016;40(2):171–174.
12. Evans SA, Aitken J, Coggon D, et al. Community-acquired pneumonia management in Australian hospitals. Med J Aust. 2020;212(9):417–422.
13. Djelantik IGG, Gessner BD, Sutanto A, et al. Incidence of severe and non-severe community-acquired pneumonia in children aged <5 years in rural Indonesia. Pneumonia. 2023;15:6.
14. Surviving Sepsis Campaign. International guidelines for management of sepsis and septic shock 2021. Intensive Care Med. 2021;47(11):1181–1247.
15. Royal Australian College of General Practitioners (RACGP). Management of community-acquired pneumonia in adults: RACGP guidance. Melbourne: RACGP; 2023.