Suppurative Lung Diseases, Stages of Lung Abscess, Does a lung abscess require surgery?

by Heba Soffar · January 11, 2025

Suppurative lung diseases are characterized by chronic infection and the accumulation of pus in the lung tissue or airways, often resulting from severe or unresolved bacterial infections. These conditions can cause significant damage to the lung structure and impair respiratory function.

Suppurative Lung Diseases

Suppurative Lung Diseases include Lung abscess, bronchiectasis, and empyema with bronchopleural fistula.

Lung Abscess

Lung abscess is a localized suppurative lesion of lung parenchyma that causes a rounded cavity with an air-fluid level on chest X-ray and is not due to TB.

Early in the acute phase of the diseases, there will be an area of consolidation (pre-eruptive phase). Soon liquefactive necrosis occurs, and then there will be sudden expectoration of the pus with replacement of this pus by air, so giving an air – fluid level in the chest x-ray.

If the lesion is persistent for a long time (more than 3 months), it will be described as a chronic lung abscess.

Lung Abscess

Stages of Lung Abscess

Stage 1: Inflammatory infiltration of lung tissue.
Stage 2: Formation of a cavity filled with pus
Stage 3: Occurs obliteration of the cavity with the formation of the area of pneumosclerosis.

Lung abscess classification

Lung abscess is classified into different types

Post-pneumonic Lung Abscess: It occurs following necrotizing pneumonia e.g. staphylococcal pneumonia or klebsiella pneumonia.
Aspiration lung abscess: It occurs secondary to aspirated foreign bodies. It is important to ask the patient about disturbances in his conscious state which may predispose him to aspiration of any foreign body.
Malignant Lung abscess: Central necrosis in the tumor can result in the formation of lung abscess. The presence of central bronchial obstruction will impair the drainage of secretions and end in distal infection which leads to the formation of peripheral lung abscess.
Post-traumatic lung abscess (post-lung contusion): This can occur in an infected hematoma of the lung.
Septic emboli (IV drug addicts, Infective endocarditis, Infected DVT, septic abortions, Infective endocarditis “Tricuspid valve vegetation”).
Amoebic lung abscess: It usually spreads to the lung from an amoebic liver abscess.

Infection with pyogenic or anaerobic bacteria in any of these situations causes a lung abscess. The usual location is the superior segment of the lower lobe or the lower portion of the upper lobe most commonly in the right lung.

Pathology

Trapping of infected material by bronchial obstruction, sluggish clearing mechanism, and ischemia result in cell death (necrosis). With excess septic and cellular exudates, a progressing edge results in cavitation and liquefaction. Pus and cellular debris fill the area. Granulation in the wall is fibrosed and epithelialization by metaplastic squamous epithelial cells follows the partial evacuation of the necrotic contents in the surrounding bronchioles. A hydro aerial abscess cavity is formed.

Clinical Picture

There is a fever and the patient is very ill. Characteristically from the patient’s history, there is sudden expectoration of a big amount of sputum when the abscess communicates with a bronchus. Such sputum is usually purulent.

Clubbing may be present and clinical signs of consolidation e.g., bronchial breathing or crepitations or signs of cavity (cavernous or amphoric breathing) are found.

Weight loss, anaemia osteoarthropathy appear weeks after onset), and when the clubbing or pulmonary abscess becomes chronic (12 signs may be minimal, consolidation due to pneumonia surrounding the abscess is the most frequent finding. Inspiratory rales and pleural rub may be heard. Rupture into the pleural space produces signs of effusion or hydropneumothorax.

Differential diagnosis

1. Pulmonary cavitation: Tuberculosis bronchogenic carcinoma, mycosis, and staphylococcal pneumonia.

2. Malignant abscesses: Usually result secondary to accumulation of septic material in necrotized vacuoles in a solid tumour. The tumour is usually a solid tumour. The tumour usually has an irregular outline and scalloped interior, possibly with an uneven fluid level. Signs of local infiltration such as a punch of lymphatics toward the hilum, hilar lymphadenopathy, or pressure and invasion symptoms, e.g., eaten up rib or nerve affection are frequently detected.

3. Haematogenous lung abscesses: These usually result from septic pulmonary emboli, usually multiple, bilateral more in the lower lobes, small in size, and situated peripherally close to the pleura. Empyema is thus liable to complicate its rupture, being more frequent in children because of the thin pleural surface. Staphylococcus organisms are the dominant bacteria with other usual organisms from the respiratory flora.

Investigations

Lab investigations: CBC (increased WBC), increase in inflammatory markers (CRP, ESR).
Radiology: CXR: shows a parenchymal cavitary lesion (rounded hydro-aereal shadow with air-fluid level, which may also reveal an underlying pathology.
Chest CT: demonstrates the abscess and shows any central masses.
Microbiological assessment: Sputum or BAL for culture and antibiotic sensitivity
Bronchoscopy in cases of suspected endobronchial lesion (e.g., foreign body aspiration, endobronchial tumor, thick mucous plug) and cause bronchial obs.

Treatment

Drug treatment involves intensive antimicrobial therapy that is necessary to prevent further lung destruction. This is achieved through the identification of the organism by culture and the selection of the proper antibiotic using an antibiogram.
Acute lung abscess requires antibiotics for 6-8 weeks. Antibiotics are started empirically and then modified according to culture and antibiotic sensitivity results.
Postural and bronchoscopic drainage may be required in large abscesses.
In chronic lung abscess: surgical excision may be required Treatment of any underlying cause is important e.g., removal of an aspirated foreign body or malignant tumour causing central endobronchial obstruction by Bronchoscopy.

Types of antibiotics used:

Penicillin G in big doses is the drug of choice with which to start. Initially, two million units every six hours parenterally are given.
Metronidazole 500 mg three times daily for anaerobic organisms.
Cephalosporins with antipseudomonal activity e.g. Ceftazidime (3^rd generation) and Cefepime (4^th generation).
Quinolones with antipseudomonal activity e.g. Ciprofloxacin (2^nd generation) and Levofloxacin (3^rd generation).
Aminoglycosides with antipseudomonal activity e.g. Gentamicin, amikacin, and Tobramycin.
Carbapenems e.g. Meropenem and Imipenem.

Surgical resections may be indicated in specific chronic situations, e.g., the site of serious haemoptysis or failed medical treatment to control infection and toxaemia.