Pathology of lung abscess

2021-01-28 12:00 AM

Chest scans may reveal a round or oval blur, which is more common in the base of the right lung.


A pulmonary abscess is a purulent, master-necrotic condition of the lung tissue following an acute inflammatory process, mainly caused by purulent, parasitic bacteria.

It is divided into two categories:

Primary purulent lung: is the acute burning of pus in the lung without old lesions.

Secondary purulent foci: Pus calcination occurs over an existing lung lesion such as tuberculosis, lung cyst, necrotic lung cancer, bronchiectasis.

The disease has been known for a long time, but the diagnosis is clearer since the X-rays are present.


There are many conferences and materials about lung abscesses because bouncing disease used to be quite high. But since there are means to help diagnose the cause and especially new and specific antibiotics, this rate has decreased significantly. Lung carcinoma accounts for 4.8% of lung diseases (Chu Van Y 1991), or 3% of inpatient lung diseases in tuberculosis hospital and lung disease (Nguyen Viet Co 1987).

The disease is common in all ages, but the middle age has a higher rate, the disease occurs more in people with depressed, immunosuppressed, alcoholics, tobacco, diabetes, and chronic lung diseases. count. The course of the disease depends on early diagnosis, correct treatment and adequate treatment.


The pathogen

Anaerobic bacteria: These are the most common bacteria, accounting for about 60% (Cameron 1980), or 89% (Barlett 1982), easy to detect because the breath and phlegm are very bad, they can cause so the abscesses spread, subacute and often combined with other bacteria such as streptococcus, pneumococcus ... Common anaerobic bacteria are Bacteroide melanogenic, Fusobacterium nucleotum, Bacteroide fragilis Peptococus, Pepto streptococcus .. .

Staphylococcus aureus: Common in the youngest children is breastfed, clinical symptoms such as high fever, digestive disorders (vomiting, bloating ...) weight loss. Clinical condition both lung and pleura (pneumothorax, pleural fluid) cause respiratory failure, serious infections.

Klebsiella Pneumoniae (Friedlander): It spreads rapidly, becomes hemostatic, very severe illness and high risk of death.

Other bacteria: such as pneumococcus, streptococcus, group A or haemolytic, Gram (-) bacteria like Pseudomonas aeruginosa, Hemophilus influenzae, Legionella pneumophila.

Parasitology: The most common is amoeba, which can be primary but mostly secondary to liver and intestinal Aaip. The most common lesions are the basal of the lungs, close to the diaphragm and often with damage to the pleura. The sputum is chocolate in colour, but more commonly, fresh blood. Perhaps less common is the fungus.

Favourable factors

Lung, bronchial tumours cause obstruction, multiple or necrotic (cancer).

Bronchiectasis: Both a cause and a consequence of a lung abscess.

On available lung lesions: cavernous tuberculosis, congenital lung cocoon.

Open thoracic injuries, intubation.

Bad sites: Diabetes, immunodeficiency, severe malnutrition, drug addiction.

Mechanism of pathogenesis

Most lung abscesses are primary, the bacteria that cause lung abscesses by the following entry routes:

Airway - bronchus

Due to inhalation from the air, nasopharyngeal infection products, teeth - gums, amygdala, ENT surgeries, molar facials, airway foreign objects, during coma, intubation, gastric effusion ... Because the patient has a disorder of swallowing reflex, cannot cough and cough up sputum, paralysis of the respiratory muscles, diaphragm, obstruction of the airway causing stasis ...

Blood sugar

Due to phlebitis, endocarditis, embolism, infarction, and calcification, or from a distant focal point (sepsis) often causes small abscesses of both lungs. (often caused by staphylococcus aureus)

Adjacent road

Sub-diaphragmatic abscess, amoebic liver abscess, biliary tract abscess, mediastinal abscess, oesophageal abscess, exponential pleurisy, pericarditis ... or the lymphatic tract

Some cases of secondary lung abscess on a previous lung cavity such as tuberculosis, lung cocoon or some pre-existing diseases such as bronchiectasis, lung cancer necrosis or bronchial obstruction ...


Initially, in the inflamed lung parenchyma one or more foci of purulent inflammation, the lung parenchyma is frozen, if treated at this stage, the damage can be completely restored. Otherwise, these inflammatory foci will spread necrosis and combine to form a large, necrotic and purulent colony. This is the stage of acute purulent heating and lung abscess has formed, with a thin shell. Then damage to the neighbouring bronchi and the patient will spit out pus, and necrotic tissues.

After a while (about 6-8 weeks), fibromyalgia begins to surround the abscess forming multiple septum, or the pus will spread through the vicinity causing new lesions.

After about 12 weeks, the fibrous shell thickens and becomes a chronic lung abscess, inside there is granulomatous and epidermal tissue from neighbouring bronchial branches, the parenchyma is infused with fibrin and many lymphocytes. damage to blood vessels causes coughing up blood, if the bronchial wall is destroyed a lot, it will lead to bronchiectasis.


For any reason, the abscess also progresses through 3 stages.

Closed latex period

Function: This stage only has a dry cough or sometimes spit out a little sputum. Symptoms are dull chest pain, pain deeply and increase with coughing or deep breathing, less difficulty breathing unless lung damage is widespread or due to severe infectious poisoning.

Body: High fever, chills, fatigue, loss of appetite, weight loss, emaciated expression, low urine, dark colour.

Entity: Usually very poor, sometimes resembling an atypical pulmonary coagulation syndrome.


Blood tests showed that leukocytes increased, leukocytes increased, blood deposited was high.

Chest scans may reveal a round or oval blur, which is more common in the base of the right lung.

Conceptual stage

After a period of burning for about 5-7 days depending on the type of bacteria, the patient has increased chest pain, cough a lot, depression, bad breath, there may be blood clots first and then chest pain and cough a lot and then vomiting exuding a lot of pus, often very stench, the quantity is sometimes 300-400 ml. In some cases, it only coughs up a little pus, the thick pus is like a coin and a long bamboo. After the discharge of pus, the person feels more comfortable, the fever subsides, and the chest pain subsides.

Open latex stage

After 3-5 days, the infection gradually decreases, the potential mark decreases with good treatment. But usually the syndrome of prolonged infection, the state of deterioration is much due to the fact that pus has not been flushed out, causing prolonged inflammation and sometimes further expansion, due to improper treatment or bad resistance. Expressed with chronic respiratory failure, finger drumstick.

Examination of the lungs at this stage showed massive humid cavernous syndrome, cavernous lung sound and the body could hear a murmur of chest. Taking a chest film, there was a round cave, thick bank, with water vapor level. The most important is a sputum test to find the cause of the disease without antibiotics.


Implementing the quadrants

The closed period of latex is often difficult because the symptoms are poor, atypical, and if possible, rely solely on X-rays and ultrasound.

During the purulent phase, diagnosis is relatively easier. In general, the diagnosis is based on:

Acute infection syndrome.

Excessive pus concept (or coin-shaped phlegm), stench.

The cavernous syndrome, more importantly, is a chest radiograph with water-vapor levels.

Finger shaped drumstick.

Diagnose the cause

Mainly transplanting sputum, making antibiotics (when antibiotic is not used), if looking for amoeba, it is necessary to take bloody sputum and test immediately.

Note asking the history, to find the favourable factors that cause the disease.

Differential diagnosis

Closed latex period:

Pneumonia: Pneumonia can progress completely or may be abscesses.

Lung tumours: Can be benign or malignant, infectious syndrome is absent, congenital, clinical, radiology and bronchoscopy ... help with differential diagnosis.

Open latex stage:

Bronchial cancer - lung necrosis, or may also be the cause of lung abscess. In this case, inside the tumour is irregular necrosis, no vapor-vapor level, endoscopy, biopsy and look for foreign cells in the sputum to confirm.

Superinfection bronchiectasis: In the history of a history of prolonged expectoration, a contrasted bronchoscope helps to diagnose. Note that lung abscess is often a complication of bronchiectasis.

Superinfected tuberculosis cave: Usually the cave is located at the top of the lung, bank, coughing up blood.

Liver abscess rupture into the lungs: Pathological process is symptomatic of the liver first, then the lungs. Ultrasound, x-ray helps diagnose.

Progression and complications

Must continuously monitor the disease in terms of temperature, clinical symptoms, quantity and nature of pus spit, blood count, blood sedimentation rate. Lung film must be taken weekly, then 1 month, 3 months, 6 months ... until completely cured.


Before antibiotics, lung abscess was very serious disease, high mortality rate, especially in children and the elderly.

Today, thanks to good, specific antibiotics, adequate medical treatment can completely cure the disease. Usually, the temperature decreases gradually after pus settles, the amount of pus gradually decreases and can go away after 7-10 days of treatment, but the sedimentation test and especially x-ray is much slower, sometimes 3-6. next week, with fibrosis left or no sequelae on the lung film.

Leaving left caves: Lasts for a long time and can be considered as healing if during the X-ray monitoring, nothing changes (thin shell, no translation ...)

Chronic lung abscess: After 3 months of active treatment of regressive disease, all acute infection syndrome, pus cessation, but the disease does not heal completely and there have been episodes of purulent return, lesions on film persist or tend direction of diffusion or one more abscess, with clear drumstick finger mark.


Severe haemoptysis: It can be caused by an abscess feeding into large blood vessels.

Fibrous fluid or pleural effusion leaves sequelae thick pleural stick, causing chronic respiratory failure.

Bronchiectasis, pulmonary fibrosis.


Chronic lung abscess.

Death: Due to serious illness, or complications, in a case of death immediately after purulent discharge due to bronchial shutdown and bronchospasm reflexes (pulmonary shock)


The principles of treatment

Treatment of lung abscess must adhere to the following principles:

Timely, aggressive, and persistent medical treatment.

If it is possible to select an antibiotic according to the results of the antibiotic, the lung abscess will resolve quickly.

Indicated for surgery early before there are serious complications such as severe haemoptysis, purulent inflammation of the pleura.

Specific treatment

Internally medical treatment.

Supportive treatment:

Diet: Many Protide, providing adequate energy, can pass fresh or dry plasma or lipofundin or amine acide solutions such as Alvesine, Cavaplasmal ... in combination with vitamin B group as Becozyme for injection.

Postural drainage: To allow the patient to cough up mucus and pus easily.

Bronchoscopy: With a flexible straw placed into the abscess to remove pus and other mucus, this is a better method of drainage.

Adjust water and electrolyte disorders: if there is often dehydration due to high fever, or electrolyte disturbance and acidosis due to acute respiratory failure, seen in severe cases.

Oxygen: In case of acute respiratory failure, with nasal inhalation, high volume is about 6 liters / min. If there is chronic respiratory failure, breathe oxygen with low volume of about 2 liters / min.

Treatment with antibiotics:

Anaerobic bacteria:

Penicillin G high dose about 20 million units / day, intramuscular or intravenous in 3-4 divided doses or intravenous infusion in 5% Glucose; can be combined with Metronidazole 250 mg, 4-6 tablets / day, in 4 divided doses or Tinidazole 500mg, 3 tablets / day, in 3 divided doses, or Metronidazole, bottle, 500 mg content, dosage 20-30 mg / kg / day, given intravenously 12 hours apart, is highly effective on Bacteroide fragillis and Fusobacterium. People often combine with an aminoxide such as Gentamicin, ampoules, 40 mg and 80 mg, dose 1-1.5 mg / kg / 8 hours, intramuscular or slow IV or Amikacins (Amiklin), bottle, 250 mg content, dose of 15 mg / kg / day can be used 1, 2 or 3 times by intramuscular injection or slow IV.

Clindamycin (Dalacine), capsules, 75 mg and 150 mg, 15 mg / kg / day, or 1 150 mg tablet for 10 kg body weight / day or 1 75 mg tablet for 5 kg body weight / day, is highly effective on Bacteroide fragillis and Fusobacterium.

Cefoxitin (Mefoxin), bottles, content of 1 g and 2 g, dose of 1-2 g / 8 hours, intramuscularly or slow intravenous injection, can be IV, highly effective on Bacteroide fragillis and bacteria Other anaerobic.

Klebsiella pneumoniae:

This is a highly toxic bacteria, causing a very serious infection, so it must be treated quickly and actively.

People often coordinate Cephalosporin generation 3 as Cefotaxime (Claforan), water bottle, content 1 g; powder bottle, content 500 mg; or Ceftriaxone (Rocephin) bottle of water, content of 2 g; powder bottle, content 1 g; Average dose 50-60 mg / kg / day, in severe cases can be increased to 200 mg / kg / day, divided into 3 times, intramuscularly or intravenously, can be passed intravenously. Combined with aminoxide such as Gentamicin or Amikacins, dosage as described above.

Staphylococcus aureus:

Staphylococcus aureus outside of the hospital: bacteria sensitive to Methicillin (MS), people use Cefazoline, bottle, 500 mg and 1 g, dosage 25-50 mg / kg / day, divided into 2 or 4 times. , intramuscularly, intravenous direct or intravenous. Also, can use Cefadroxil (Oracefal), capsules, 500 mg content, dose 50 mg / kg / day, in 3 divided doses. Can be combined with Clindamycin (Dalacine), tube, 600 mg content, dose 15-40 mg / kg / day, intramuscularly or mixed with physiological sodium chlorure or 5% glucose by slow IV

Staphylococcus aureus in the hospital: Methicillin resistant bacteria (MS), people use Vancomycin (Vacocime), powdered bottle, content of 125 mg, 250 mg, 500 mg, dose 30 mg / kg / day, injection intravenously or intravenously for 60 minutes, divided 2-4 times; or 3rd generation Cephalosporine (Cefotaxime: Claforan; Ceftriaxone: Rocephine) content and dosage as mentioned above; Combined with Gentamicin or Amikacine. Also, can be used in combination with Ofloxacin, tablets, 200 mg content, dose of 2 tablets / day, in 2 divided doses.

Pseudomonas aeruginosa:

Often used in combination with a Betalactamine such as Carboxypenicillin (Carbenicillin), dose 70 mg / kg / 4 hours intramuscularly or slow IV; or Ureidopenicillin (Mezlocillin), dose of 35 mg / kg / 4 hours intramuscularly or slowly intravenously or a 3rd generation Cephalosporine in combination with an Aminoxide.

In the event that bacteria cannot be isolated, coordinate:

A 3rd generation Cephalosporine combined with an Aminoxide and Metronidazole.

Penicillin G combined with an Aminoxide and Metronidazole.

3rd generation cephalosporine combined with an Aminoxide or with vancomycin. The duration of treatment depends on the condition of the disease, on average 4-6 weeks.


Combination of Metronidazole 250 mg, 4-6 tablets, in 4 divided doses, or Tinidazole 500 mg, 3 tablets / day, in 3 divided doses or Metronidazole, 500 mg bottle, dose 20-30 mg / kg / day, intravenously 12 hours together, coordinate with Dehydroemetine, ampoules, content of 20 mg, dose 1 mg / kg / day for 10 days.

Surgical treatment

Surgery to remove the abscessed lung is indicated in case of a chronic lung abscess, meaning no results are found after 3 months of medical treatment.

In addition, emergency surgery in case the patient coughs up blood repeatedly, about 200 ml each time.