Abscess of the lung

Abscess of the lung - nonspecific inflammation of the lung tissue, accompanied by its melting in the form of a limited focus and the formation of one or more purulent-necrotic cavities.

Lung abscess is a necrotizing infection characterized by a localized accumulation of pus. An abscess is almost always caused by aspiration of the secretion of the oral cavity by patients with impaired consciousness. Symptoms of lung abscess are persistent cough, fever, sweating, and weight loss. Diagnosis of lung abscess is based on anamnesis, physical examination and chest X-ray. Treatment of lung abscess is usually performed with clindamycin or a combination of beta-lactam antibiotics with beta-lactamase inhibitors.

In 10-15% of patients, the process can transition to a chronic abscess, which can be talked about not earlier than 2 months. From the onset of the disease.

[1], [2], [3],

What causes an abscess of the lung?

Most lung abscesses develop after aspiration of oral cavity secretion by patients with gingivitis or poor oral hygiene, who are unconscious or in a state of dull consciousness as a result of taking alcohol, illegal drugs, anesthesia, sedatives or opioids. Older patients and patients unable to provide oral cavity removal, often due to nervous system damage, are at risk. Lung abscess less often complicates necrotizing pneumonia, which can develop as a consequence of hematogenic semen collection with septic emboli with intravenous drug use or purulent thromboembolism. Unlike aspiration, these conditions usually cause multiple rather than single abscesses of the lung.

The most frequent pathogens are anaerobic bacteria, but about half of all cases are caused by a mixture of anaerobic and aerobic microorganisms. The most frequent aerobic pathogens are streptococci. Immunodeficient patients with a lung abscess are more likely to have an infection caused by Nocardia, mycobacteria or fungi. Residents of developing countries are at risk of abscess due to mycobacterium tuberculosis, amoebic invasion (Entamoeba histolytica), paragonimiasis or Burkholderia pseudomallei.

The introduction of these pathogens into the lungs initially leads to the development of inflammation, which leads to tissue necrosis and then to the formation of an abscess. Most often, abscesses break through into the bronchus, and their contents cough, leaving a cavity filled with air and liquid. In about a third of cases, direct or indirect spread (through bronchopleural fistula) into the pleural cavity leads to empyema. Pulmonary cavity lesions are not always abscesses.

Causes of cavities in the lungs

Anaerobic bacteria

• Gram-negative bacilli
  • Fusobacterium sp.
  • Prevotella sp.
  • Bacteroides sp.
  • Gram-positive cocci
  • Peptostreptococcus sp.
• Gram-positive bacilli
  • Clostridium sp.
  • Actinomycetes

Aerobic bacteria

• Gram-positive cocci
  • Streptococcus milleri and other streptococci
  • Staphylococcus aureus
• Gram-negative bacilli
  • Klebsiella pneumoniae
  • Pseudomonas aeruginosa
  • Burkholderia pseudomallei
• Gram-positive bacilli
  • Nocardia
  • Mycobacteria
  • Mycobacterium tuberculosis
  • Mycobacterium avium-cellulare
  • Mycobacterium kansasii
• Mushrooms
  • Histoplasmosis
  • Aspergillosis
  • Blastomycosis
  • Coccidiomycosis
  • Cryptococcal infection
  • Mucormycosis
  • Sporotrichosis
  • Infection with Pneumocystis jiroveci (formerly P. Carinii)
• Parasites
  • Paragonimaz
  • Echinococcosis
  • Amebiasis
  • Bronchiectases

Non-infectious causes

• Lung cancer
• Bulla with liquid level
• Pulmonary sequestration
• Pulmonary embolism
• Wegener's granulomatosis
• Nodular node silicosis with central necrosis

[4], [5], [6], [7], [8], [9]

Symptoms of lung abscess

Before the breakdown of pus in the bronchi are characterized by: high body temperature, chills, heavy sweats, dry cough with pain in the chest on the side of the lesion, shortness of breath or shortness of breath due to the impossibility of deep inspiration or early respiratory failure. With percussion of the lungs - intensive shortening of sound over the lesion, auscultatory - breathing weakened with a harsh tone, sometimes bronchial. Characteristic symptoms of lung abscess are found in typical cases during examination. Pale skin is noted, sometimes a cyanotic blush on the face, more pronounced on the side of the lesion. The patient takes a forced position (often on the "sick" side). The pulse is rapid, sometimes arrhythmic. Arterial pressure often tends to decrease, with extremely severe course, the development of bacteriemic shock with a sharp drop in blood pressure is possible. The heart sounds are muffled.

After a breakthrough in the bronchus: an attack of cough with the release of a large amount of sputum (100-500 ml), purulent, often fetid. With good drainage of the abscess, the well-being improves, the body temperature decreases, with percussion of the lungs - the sound is truncated over the lesion, less often - the tampanic shade due to air in the cavity, auscultatory - small bubbling rales; within 6-8 weeks. Symptoms of lung abscess disappear. With poor drainage, body temperature remains high, chills, sweats, cough with poor separation of fetid sputum, shortness of breath, symptoms of intoxication, loss of appetite, thickening of terminal phalanges in the form of "drumsticks" and nails in the form of "watch glass".

The course of a lung abscess

With a favorable variant of the flow after the spontaneous breakthrough of the abscess in the bronchi, the infectious process quickly stops, and recovery comes. In unfavorable course, there is no tendency to purify the inflammatory necrotic focus, and there are various complications: pyopneumothorax, pleural empyema, respiratory distress syndrome (symptomatology is described in the relevant chapters), bacterial (infectious-toxic) shock, sepsis, pulmonary hemorrhage.

Bleeding is a frequent complication of lung abscess. It is arterial and is caused by damage (arrosia) of the bronchial arteries. Pulmonary haemorrhage is the secretion of more than 50 ml of blood per day (more than 50 ml of blood is considered hemopoiesis). The blood loss in the amount of 50 to 100 ml per day is regarded as small; from 100 to 500 ml - as an average and over 500 ml - as heavy or heavy.

Clinically, pulmonary hemorrhage is manifested by expectoration of phlegm with an admixture of frothy scarlet blood. In some cases, blood can be released from the mouth with almost no coughing. With significant blood loss, characteristic symptoms develop: pallor, frequent pulse of weak filling, arterial hypotension. Aspiration of blood can lead to severe respiratory failure. Severe pulmonary hemorrhage can cause death.

Diagnosis of lung abscess

Lung abscess is suspected on the basis of anamnesis, physical examination and chest X-ray. In anaerobic infection due to aspiration, chest X-ray classically reveals consolidation with a single cavity containing an air bubble and fluid level in the lungs affected by the patient's lying position (for example, the posterior segment of the upper lobe or the upper segment of the lower lobe). These signs help distinguish anaerobic abscess from other causes of cavitary lung lesions, for example, diffuse or embolic lung lesions that can cause multiple cavities, or tuberculosis in the upper limbs of the lungs. CT is usually not required, but it can be useful when X-rays suggest cavitation damage or when there is a suspected volume formation in the lungs that compress the draining segmental bronchus. Anaerobic bacteria are rarely recognized in culture, as it is difficult to obtain non-contaminated samples, and also because most laboratories do not carry out analyzes for anaerobic flora on an ongoing basis. If the sputum is putrefactive, the cause of the pathology is most likely an anaerobic infection. Sometimes bronchoscopy is prescribed to exclude malignant neoplasm.

When anaerobic infection is less likely, aerobic, fungal or mycobacterial infection is suspected and attempts are made to identify the pathogen. To do this, examine sputum, bronchoscopic aspirates or both.

[10], [11]

Laboratory diagnosis of lung abscess

1. General blood test: leukocytosis, stab shift, toxic granulocyte neutrophil, significant increase in ESR. After a breakthrough in the bronchus with good drainage - a gradual decrease in changes. With chronic abscess flow - signs of anemia, increased ESR.
2. General urine analysis: moderate albuminuria, cylindruria, microhematuria.
3. Biochemical analysis of blood: an increase in the content of sialic acids, seromucoid, fibrin, haptoglobin, a2- and y-globulins, in the chronic course of the abscess - a decrease in the level of albumins.
4. General clinical analysis of sputum: purulent sputum with an unpleasant odor, when standing, is divided into two layers, with microscopy - leukocytes in large quantities, elastic fibers, crystals of hematoidin, fatty acids.

Instrumental diagnosis of lung abscess

X-ray examination: before breakthrough of abscess in bronchus - infiltration of pulmonary tissue, more often in segments II, VI, X of right lung, after breakthrough in bronchus - bleaching with horizontal liquid level.

Program of examination for suspected abscess of the lung

1. General analysis of blood, urine, feces.
2. Clinical examination of sputum for elastic fibers, atypical cells, BC, hematoid, fatty acids.
3. Bacterioscopy and sputum culture on elective media for culture of the pathogen.
4. Biochemical blood test: total protein, protein fractions, sialic acids, seromucoid, fibrin, haptoglobin, aminotransferase.
5. ECG.
6. X-ray and radiography of the lungs.
7. Spirography.
8. Fibrobronchoscopy.

Examples of the formulation of the diagnosis

1. Postpneumonia abscess of the middle lobe of the right lung, moderate severity, complicated by pulmonary hemorrhage.
2. Aspiration abscess of the lower lobe of the left lung (severe course complicated by a limited pleural empyema, acute respiratory failure of the third degree.
3. Acute staphylococcal abscess of the right lung with a lesion of the lower lobe, severe course, empyema of the pleura.

[12], [13], [14], [15], [16], [17], [18], [19]

Treatment of lung abscess

Treatment of lung abscess is carried out with antibiotics. Clindamycin 600 mg intravenously every 6-8 hours is the drug of choice, taking into account its excellent anti-anaerobic and anti-streptococcal activity. A possible alternative is a combination of beta-lactam antibiotics with beta-lactamase inhibitors (for example, ampicillin-sulbactam, 1-2 g intravenously every 6 hours, ticarcillin-clavulanate 3-6 g intravenously every 6 hours, piperacillitazobactam 3 g intravenously every 6 hours). You can use metronidazole 500 mg every 8 hours, but it must be combined with penicillin (ampicillin) 2 million units every 6 hours intravenously or intravenously with cephalosporins of the third generation (ceftriaxone 2.0 g 2 times a day or cefotaxime 1.0- 2.0 g 3 times a day). In a less severe course of the disease, the patient can be given oral antibiotics such as clindamycin 300 mg every 6 hours or amoxicillin-clavulanate 875 mg / 125 mg orally every 12 hours. Intravenous antibiotics can be replaced with oral antibiotics when the patient begins to recover.

The optimal duration of treatment is unknown, but standard practice requires the use of drugs for 3-6 weeks, if the chest X-ray does not reveal a complete cure earlier. In general, the greater the abscess of the lung, the longer it will persist on the x-ray. Large abscesses therefore usually require several weeks or months of treatment.

Most authors do not recommend physiotherapy on the chest and postural drainage, as they can cause a breakthrough in other bronchi with infection or the development of acute obstruction. If the patient is weak or paralyzed or has respiratory failure, tracheostomy and suction of secretion may be required. In rare cases, bronchoscopic sanitation helps to drain. Concomitant empyema should be drained; liquid is a good medium for anaerobic infection. Percutaneous or surgical drainage of lung abscesses is needed in approximately 10% of patients who do not respond to antibiotics. Resistance to antibiotic therapy occurs in large cavities and infections that complicate obstruction.

If surgical treatment is necessary, lobectomy is most often performed; if the lung abscess small can be sufficiently segmental resection. Pulmonectomy may be necessary for multiple abscesses or gangrene of the lung, resistant to drug therapy.