|Fever - Pyrexia of unknown origin
Poor prognosis with old age, severe comorbidities, immunosuppression, bronchial obstruction, and neoplasms.
- Presence of a pus-filled cavity within the lung parenchyma.
- Elderly, immunocompromised, aspiration (right lower lobe)
- Alcoholics, IV drug users
- Primary: patients who are prone to aspiration or in otherwise healthy individuals
- Secondary lung abscesses associated with a stenosing lung neoplasm or a systemic disease that compromises immune defences, such as AIDS, or after organ transplantation
- Aspiration Pneumonia reflect the resident flora of the oropharynx.
- Anaerobic bacteria (Prevotella, Bacteroides, Fusobacterium, Peptostreptococcus) or streptococci
- Alcoholics with poor oral hygiene: Staphylococcus aureus, Streptococcus pyogenes and Actinomyces.
- Staphylococcal aureus post Influenza
- Klebsiella pneumoniae, Pseudomonas
- Mycobacterium tuberculosis, Legionella
- Gram negatives, Fungi, Parasites
- Bronchial obstruction e.g. tumour or inhaled foreign body
- Cough with foul sputum and halitosis
- Fever, cachexia, weight loss, Finger clubbing
- Night sweats, anaemia, dyspnoea
- Amoebic abscess - brown sputum
- Squamous Carcinoma with cavitation
- Granulomatosis with polyangiitis (WG)
- Pulmonary infarction
- FBC:elevated WCC and CRP, U&E, LFT, CRP
- CXR: There is consolidation +/- cavitation with an air-fluid level in a thin-walled cavity
- HRCT chest will define anatomy and destruction and help to direct drainage
- Specimens (preferably before antibiotic treatment is commenced)
- Blood cultures
- Respiratory secretions e.g. sputum, bronchial washings for culture (including AFB)
- CT or USS-guided transthoracic percutaneous needle aspiration. Risk of bleeding, PTX and seeding of the infection to the pleural space, if abscess is not adjacent to the pleura.
Management: Take early expert advice
- Postural drainage and physiotherapy to aid the production of purulent sputum.
- Check oral and gum/dental hygiene as sources of bacteria
- Antibiotics should be based on culture results. IV therapy maybe required until the patient shows signs of improvement (1 week) and Prolonged treatment over several weeks is typically required. Oral antibiotics are often required. Treatment should continue until the cavity has resolved. Choices may include
- Co-amoxiclav 1.2 g TDS
- Clindamycin 600 mg QDS + Ciprofloxacin 750 mg BD
- IV Levofloxacin 500 mg BD and Metronidazole 500 mg TDS
- Referral criteria for specialist Respiratory input
- Fever and other symptoms persist after 10-14 days of treatment
- Chest x-rays indicate that the abscess is not shrinking.
- Referral for surgery. Very rarely required if appropriate antibiotics are given. May be needed if
- Failure to respond after at least 6 weeks of treatment
- Very large abscess (>6cm diameter)
- Resistant organisms
- Recurrent disease
- Drainage by Needle aspiration or Thoracotomy may be needed
- Bronchoscopy and removal of foreign body where needed
- Treatment failure - Consider the following explanations:
- Incorrect diagnosis
- Resistant or unusual organism (e.g. Mycobacterium tuberculosis, Nocardia, fungi)
- Antibiotic hypersensitivity reaction
- Complication e.g. empyema
- Underlying lung disease e.g. lung cancer
- Immunosuppression (known or unexpected)
- Large cavity (>6cm) may require drainage
- Non-bacterial cause e.g. Wegener's granulomatosis