OVERVIEW

What is a lung abscess?

A lung abscess is an inflammatory necrosis of lung tissue caused by pyogenic bacterial infection, forming a cavity containing pus and necrotic debris. It often occurs secondary to pneumonia. When a lung abscess develops, patients typically experience symptoms such as coughing and expectorating large amounts of purulent sputum.

SYMPTOMS

How does purulent sputum form when a lung abscess occurs?

Initially, bacteria reach the bronchioles (the distal airways deep in the lungs), multiply, and irritate the surrounding tissues, causing inflammatory thrombosis in small blood vessels. At this stage, the lung tissue undergoes suppurative inflammation and necrosis, eventually forming a lung abscess. The necrotic tissue liquefies and ruptures into the bronchi, and the pus is expelled through coughing.

What are the symptoms of a lung abscess?

Typical symptoms include: high fever (above 39°C), cough, purulent sputum, and sticky sputum (sometimes with a foul odor).

Many patients show no obvious symptoms in the early stages. After 1 to 2 weeks, tissue necrosis (a process similar to the spoilage of meat) leads to abscess formation in the lungs, followed by cavity formation. Patients may cough up foul-smelling purulent sputum and sometimes experience hemoptysis (which may be related to the rupture of small blood vessels in the lungs).

What are the systemic toxic symptoms of a lung abscess?

These usually refer to chills and high fever caused by infection, with temperatures often reaching 39°C, accompanied by sweating, headaches, and in severe cases, impaired consciousness.

What are the classifications of lung abscess?

Based on the speed of onset, lung abscesses are divided into two types:

• Acute lung abscess: More common in young adults, with a higher incidence in males than females, and frequently occurring in winter and spring. Symptoms often include sudden high fever, cough with large amounts of purulent sputum, etc.
• Chronic lung abscess: Usually develops from an acute lung abscess, often due to inadequate early treatment, weakened immune function, or bacterial resistance.

What complications can lung abscess patients develop?

• Empyema: Caused by the abscess rupturing through the visceral pleura into the pleural cavity.
• Bronchopleural fistula: A passage forms between the bronchus connected to the abscess cavity and the pleural cavity.
• Others, such as distant abscesses or systemic infections.

Why do lung abscess patients experience chest pain?

Chest pain occurs when the abscess involves the pleura, worsening with deep breathing. It is usually caused by the abscess rupturing into the pleural cavity, leading to sudden chest pain accompanied by rapid breathing.

CAUSES

What causes lung abscess?

Most lung abscesses are caused by the normal flora of the oral cavity, such as the small amount of oropharyngeal bacteria we often inhale during sleep, which are usually quickly cleared by the body's defense mechanisms.

When a larger amount is inhaled and the body's normal defense mechanisms cannot clear it in time, a lung abscess may develop.

The vast majority of lung abscess patients are often infected with anaerobic bacteria (a type of bacteria that grows and reproduces rapidly in oxygen-deprived environments), and are also commonly mixed with the following bacteria: Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, etc.

Who is more prone to lung abscess?

People with the following underlying conditions are more likely to develop lung abscess:

• Infectious diseases, such as chronic bronchitis, chronic obstructive pulmonary disease, bronchiectasis, liver abscess, etc.;
• Diabetes;
• Secondary immunodeficiency, such as HIV-infected individuals or those using immunosuppressants (commonly seen in patients with kidney or bone marrow diseases).

Is lung abscess contagious?

No. Lung abscess is usually a purulent infection caused by common bacteria, and its pathogens are not among the legally notifiable infectious diseases.

However, special populations should avoid contact with lung abscess patients, such as children (whose immune systems are not fully developed), those using immunosuppressants (e.g., organ transplant recipients), or immunocompromised individuals (e.g., HIV-infected persons).

DIAGNOSIS

What tests are generally required for the diagnosis of lung abscess?

• Complete blood count: Peripheral blood white blood cells and neutrophils are significantly elevated.
• Chest imaging: Typical imaging findings of lung abscess can further assist in diagnosis.
• Sputum culture: Sputum culture can identify sensitive antibiotics for more targeted treatment.
• Pus culture: Pus is obtained via bronchoscopy (a flexible, tube-shaped device inserted through the nose or mouth into the trachea and bronchi for direct visualization). This method avoids contamination of bacteria in the abscess cavity by oropharyngeal bacteria, providing more accurate identification of bacterial types at the lesion site.

TREATMENT

How to treat lung abscess?

Early empirical antibiotic therapy is administered initially, followed by selecting appropriate antibiotics based on drug sensitivity test results from pus culture. Concurrently, the patient's immune function is improved. Generally, after 4 to 6 weeks of anti-infective treatment, most patients show improvement.

How is bronchoalveolar lavage performed under bronchoscopy for lung abscess patients?

With advancements in medical technology, the most critical aspects of lung abscess treatment are effective antibiotic use and drainage. Bronchoalveolar lavage under bronchoscopy can better drain purulent sputum. During lung abscess formation, inflammatory stimulation, varying degrees of bronchial opening stenosis, and pus plugs obstructing the bronchi hinder the drainage of large amounts of purulent secretions, resulting in poor pus expulsion. Bronchoscopic intervention can improve this condition.

The basic procedure involves: using a bronchoscope to aspirate pus from the abscess, rinsing with saline, and then injecting gentamicin or corticosteroids to reduce swelling and inflammation.

What are the benefits of bronchoalveolar lavage under bronchoscopy for lung abscess patients?

• Improves deep bronchial drainage and enhances sputum expulsion.
• Dilutes purulent sputum and stimulates coughing to promote expectoration.
• Provides high local antibiotic concentration and strong bactericidal effect, with elevated drug levels in the abscess cavity.
• Promotes necrotic tissue shedding and reduces toxin absorption.
• Within 1 to 3 days after lavage, sputum volume significantly increases, symptoms improve, and treatment duration is shortened.

Which lung abscess patients are unsuitable for bronchoscopy?

Main contraindications include:

• Active major bleeding or coagulation disorders;
• Severe cardiopulmonary dysfunction;
• Severe arrhythmias;
• Recent myocardial infarction;
• Severe pulmonary hypertension, as bronchoscopy may cause significant bleeding.

What complications may occur after bronchoscopy in lung abscess patients, and how to prevent them?

• Aspiration: Fasting for 2 hours before the procedure prevents aspiration.
• Laryngeal or tracheobronchial spasm: Prompt use of antispasmodics can relieve symptoms.
• Induced arrhythmias.
• Secondary lung infection: Strict aseptic techniques during the procedure and postoperative antibiotics prevent worsening infections.
• Respiratory depression and hypotension due to sedatives.
• Hemoptysis or pneumothorax from improper operation: Ensuring normal coagulation before the procedure minimizes bleeding risks.

What precautions should lung abscess patients take before bronchoscopy?

• Fast for 2 hours before the procedure for safety.
• Hemostatic agents may be used post-procedure if bleeding occurs.
• Due to local anesthesia, avoid eating/drinking for 2 hours afterward. Start with small sips of water to check for choking before resuming normal intake.
• Report symptoms like hemoptysis, chest tightness, or difficulty breathing promptly after returning to the ward.

Which lung abscess patients require surgical treatment?

• Abscess duration >3 months with no cavity reduction after medical therapy, or cavities >6 cm;
• Life-threatening hemoptysis unresponsive to medical treatment;
• No improvement in sputum volume, characteristics, or imaging after 1 week, suggesting obstruction, drug resistance, or malignancy. Surgical intervention may be considered if physically feasible.

How is traditional surgical treatment for lung abscess performed?

Traditional surgery involves lobectomy, with a reported success rate of 90%.

Drawbacks include severe vascular adhesion around the abscess, making dissection difficult, significant trauma, and intraoperative bleeding. Postoperative complications are common, and patients with poor physical condition may not tolerate the procedure.

What are the advantages of thoracoscopic surgery for lung abscess?

Compared to traditional surgery, thoracoscopy offers minimal trauma and shorter hospitalization.

Procedure: Based on CT localization, small incisions are made for thoracoscopic abscess drainage. Pus and necrotic tissue are removed, followed by irrigation with 0.1% iodophor solution. The cavity walls are cauterized for hemostasis and sterilization.

The cavity is left open with drainage tubes placed for postoperative irrigation until clear fluid is observed.

Even elderly patients with poor cardiopulmonary function can tolerate this minimally invasive approach.

What is lung abscess drainage?

For patients unresponsive to medication but unsuitable for surgery, percutaneous catheter drainage is performed under local anesthesia with ultrasound/CT guidance. A small incision is made, and a catheter is inserted to drain pus.

Which lung abscess patients are suitable for drainage?

• Tension abscesses compressing surrounding structures;
• Progressive abscesses with contralateral infection or increasing fluid;
• Persistent fever and purulent sputum after 3 days of antibiotics;
• Abscess diameter >4 cm;
• Mechanical ventilation dependence.

Should lung abscess patients consult internal medicine or surgery?

Early symptoms (fever, cough, purulent sputum) warrant a respiratory medicine visit.

After evaluation, if CT shows a large abscess risking bronchial rupture, pulmonary artery invasion, massive hemoptysis, or asphyxia, surgical intervention (thoracic surgery) is advised.

Patients with no improvement after 3 months should also consider surgery.

Can lung abscess be cured? Will it recur?

Acute cases often resolve with antibiotics and rarely recur.

Chronic cases with comorbidities (e.g., diabetes) may recur post-surgery due to factors like poor glycemic control.

DIET & LIFESTYLE

What should patients with lung abscess pay attention to after surgical treatment?

Patients whose symptoms of lung abscess do not improve significantly after conservative medical treatment may opt for surgical intervention. Depending on the specific condition, the affected lung tissue may need to be removed.

• Actively and effectively cough after surgery to promote lung expansion and expel secretions such as phlegm from the lungs in a timely manner, preventing postoperative lung infections.
• Pay attention to nutrition post-surgery, consuming easily digestible, high-protein foods such as eggs, fish, fresh vegetables, and fruits.
• A follow-up chest X-ray can be performed 2–3 weeks after discharge to assess recovery progress.

What should patients with lung abscess pay attention to after recovery?

Focus on nutrition and rest, avoid upper respiratory infections, and strengthen immunity. Seek medical attention promptly if discomfort occurs shortly after discharge.

PREVENTION

How to Prevent Lung Abscess?

• Pay attention to the treatment of oral diseases (such as dental caries, suppurative tonsillitis, gingival abscess, etc.) in daily life.
• Maintain oral hygiene after oral surgeries (such as tooth extraction, teeth cleaning, or fillings).
• After thoracic or abdominal surgery, promptly clear oral secretions, encourage patients to cough actively, and ensure respiratory tract drainage remains unobstructed.
• Maintain oral hygiene for comatose patients.

How to Prevent Recurrence of Lung Abscess?

Recurrence of lung abscess often occurs in individuals with weakened immunity or underlying diseases. To prevent recurrence, it is essential to eliminate lung infections, eradicate primary lesions, and ensure thorough abscess drainage during treatment. Additionally, managing chronic conditions is crucial (e.g., diabetic patients should control blood sugar levels, and immunocompromised individuals should avoid crowded places).