Also known as : Necrotizing Pneumonia or Lung Gangreene .
What is it ?
Lung abscess is a localised area of necrosis of lung tissues with development of fluid filled cavities .
Microorganisms commonly isolated from lesions of lung abscess are Streptococci , Staphylococci , anaerobic organisms like Bacterioids and a host of gram negetive organisms .
They are introduced into the lungs by the following mechanisms -
a) Aspiration of infected material ( commonest cause ) : like food , decaying teeth ,gastric contents , necrotic tissue from lesions in the mouth , upper respiratory tract , nasopharynx .
b) Preceding bacterial infection - like S.aureus , Pseudomonus aerugenosa , K.pneumonie or infective conditions like tuberculosis ,bronchiectasis .
c) Bronchial obstruction .
d) Septic embolism - from thrombophlebitis , pyaemia or vegetative bacterial endocarditis .
e) Neoplasia .
f) Miscellaneous - trauma to lungs ; infection spreading from neighbouring organs ; infections due to pyogenic organisms .
Clinical course :
- Patients show symptoms like fever ,cough with foul smelling & bad testing sputum , chest pain , weight loss .
- There may be decreased breath sounds , course crackling sounds during inspiration , dulness to percussion & contralateral shift of mediastinum .
- Clubbing of fingers and toes may appear within a few weeks after the onset of abscess .
Laboratory investigations :
a) TLC & DC reveals leukocytosis .
b) Sputum for Gram staining , Acid-fast staining , culture obtained .
c) Blood culture may be done .
d) Imaging studies - Chest X-ray , CT scan & USG imaging may be done .
e) Tissue biopsy and histological investigations to be done .
What are the treatments available ?
Antibiotic therapy lasting for 4-6 weeks are usually perscribed .
The commonly used antibiotics are :-
- Penicilin G
- Ampicillin + Sulbalactum + Cephalosporin( occationally )
If conventional therapy fails lung abscesss drainage or surgical resection is considered .
How to privent this disorder ?
a) Early intubation .
b) Positioning patient at 30 degree reclined angle .
c) Oral hygine & dental care decreases risk .
What are the complications arising in this disorder ?
b) Fibrosis of pleura
c) Pleural cutaneous fistula
e) Brain abscess or meningitis from septic emboli .
f) Secondary amyloidosis ( rarely )
The prognosis of lung abscess following antibiotic therapy is generally favourable with about 90% being cured due to medication alone , unless caused by bronchial obstruction secondary to carcinoma .
Article written by : A . Biswas, MBBS(std)