Synopsis
Recognise pulmonary parenchymal necrosis, identify sepsis, haemorrhage and an obstructing lesion early, and coordinate microbiology-led prolonged therapy with drainage or surgery only when source control is genuinely needed. Verify treatment against current antimicrobial, respiratory, radiology and thoracic-surgical guidance.
- A lung abscess is a localised pus-containing cavity; necrotising pneumonia is more diffuse parenchymal destruction with multiple small cavities and may progress rapidly.
- Aspiration, poor dentition, impaired consciousness, swallowing dysfunction, an obstructing tumour, immunosuppression and septic emboli are high-yield causes or contributors.
- CT with contrast usually characterises cavitation, distinguishes pleural empyema and looks for obstruction, infarction, foreign body or malignancy.
- Collect blood and good lower-respiratory samples before antibiotics where safe, but never delay sepsis treatment or stabilisation for sampling.
- Empirical therapy normally covers aerobic and anaerobic oral flora; recent healthcare exposure, influenza, resistant colonisation and immune compromise alter the spectrum.
- Clinical response is judged over days, but radiological resolution often takes weeks; total antibiotic duration is individualised to response, organism and source control.
- Persistent fever should trigger a diagnostic reset: inadequate coverage, empyema, blocked drainage, resistant organism, TB, fungus, cancer or non-infective cavitation.
- Massive haemoptysis, shock, respiratory failure or a tension-like expanding cavity requires immediate escalation and coordinated critical, respiratory, interventional and surgical care.
Key red flags
Rapid hypoxaemia, shock, high inflammatory burden, multilobar consolidation and evolving small cavities, sometimes after influenza. Escalate early because deterioration and organ failure can be abrupt.
Large-volume haemoptysis, falling haemoglobin, new pneumothorax, persistent air leak or expectoration of copious purulent material suggests vascular erosion, rupture or bronchopleural communication.
Investigation priorities
Confirm consolidation or a cavity, identify an air-fluid level and detect pneumothorax or pleural fluid rapidly.
Management branches
Hypoxaemia, shock, altered mental state, major haemoptysis or rapidly progressive cavitation.
- Use an ABCDE approach, controlled oxygen to an individual target, blood cultures and lactate, prompt sepsis antimicrobials and early critical-care review.
- Obtain urgent contrast CT when the patient can safely transfer; involve respiratory medicine, microbiology and radiology, and call thoracic surgery or interventional radiology early for haemorrhage, fistula or non-viable lung.
- Address pleural sepsis separately with ultrasound-guided drainage and protect the airway if bleeding or reduced consciousness threatens ventilation.
- Reassess within hours for organ support, antimicrobial adequacy and evolving source-control needs.