Sandbox:Aditya: Difference between revisions

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*It is the treatment of choice for patients who have failed to respond to antibiotic therapy .<ref name="pmid1987590">{{cite journal |vauthors=vanSonnenberg E, D'Agostino HB, Casola G, Wittich GR, Varney RR, Harker C |title=Lung abscess: CT-guided drainage |journal=Radiology |volume=178 |issue=2 |pages=347–51 |year=1991 |pmid=1987590 |doi=10.1148/radiology.178.2.1987590 |url=}}</ref>  
*It is the treatment of choice for patients who have failed to respond to antibiotic therapy .<ref name="pmid1987590">{{cite journal |vauthors=vanSonnenberg E, D'Agostino HB, Casola G, Wittich GR, Varney RR, Harker C |title=Lung abscess: CT-guided drainage |journal=Radiology |volume=178 |issue=2 |pages=347–51 |year=1991 |pmid=1987590 |doi=10.1148/radiology.178.2.1987590 |url=}}</ref>  
*Patients who have an impaired cough reflex


*Patients who are unsuitable for surgical intervention (e.g. due to severe immunodeficiency or mechanical ventilation).
*Patients who are unsuitable for surgical intervention (e.g. due to severe immunodeficiency or mechanical ventilation).


*lung abscesses with diameters greater than 4-8 cm
*Lung abscesses with diameters greater than 4-8 cm
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*Performed under fluoroscopic, ultrasound or computed tomography guidance.(CT is generally preferred due to additional information provided about location, content and wall-thickness of the abscess.)
*Performed under fluoroscopic, ultrasound or computed tomography guidance.(CT is generally preferred due to additional information provided about location, content and wall-thickness of the abscess.)

Revision as of 21:16, 1 February 2017

Historical perspective

  • In 1904 Guillemot first put weight to the theory that aspirated oropharyngeal organisms were responsible for cause of lung abscess
  • In 1938 first cutaneous drain of lung abscess was performed.
  • In 1942 Brock added evidence in stating that aspirated contents gravitated to the dependents part of the lungs
  • In early 19th century arsenicals and physiotherapy were the mainstay of treatment of lung abscess

Pathophysiology

Pathogenesis

  • Aspiration of anerobic bacteria from the oro-pharnynx, due to altered level of consciousness, absent gag reflex or inability to swallow is the inciting event for the development of primary lung abscess.[1]
  • In healthy individuals, defense mechanisms cope up with the small amounts of aspirates with no effects, however, in conditions like alcoholism, DM, and immunocompromised state these defense mechanisms can be compromised leading to decreased activity of alveolar macrophages and mobility of leucocytes. [2].
  • In secondary lung abscess, abscess formation depends on the underlying lung disease and predisposing factors,for example, bronchial obstruction from benign or malignant intrabronchial lesions or extrinsic compression of bronchus as in middle lobe syndrome results in distal abscess formation due to decrease oropharyngeal clearance due to decreased clearance meachanisms and favouring abscess formation.
  • Once the aspirate is localized it results in pneumonitis [3]
  • Inflammatory mediators are released along with various bacterial toxins, leading to disrupture of small blood vessels and release of various proteolytic enzymes from the neutrophils resulting in the formation of colliquative necrosis [4]

Location of abscess

  • The right lung is more commonly affected than the left lung because is of it more angulation than the left bronchi.
  • The most common location is the posterior segment of the right apical lobe or apical segments of lower lobes of both the lungs.[5]
  • Lateral part of the posterior segment of upper lobe of the right lung is more commonly involved in alcoholics.

Genetics

  • Congenital diseases such as cystic fibrosis, vasculitis, pulmonary sequestration and bronchial cysts are associated with increased the risk of lung abscess in children.[6]

Gross Morphology

  • In acute lung abscess, the lesions are well circumscribed filled with necrotic debris and do not demonstrate well-defined borders with the surrounding lung parenchyma.[7]
  • In chronic long standing abscess, the lesions are irregular and filled with grayish thick debris.

Microscopic Findings

  • In acute lung abscess, neutrophilic granulocytes are demonstrated with dilated blood vessels and inflammatory edema.[7]
  • In chronic lung abscess, biopsy specimen demonstrates lymphocytes, plasma cells, and histiocytes around a layer of pyogenic membrane surounding the abscess cavity which is filled with pus.

Classification

  • Lung abscess can be classified into three types based on duration of symptoms, etiology and mode of spread as follows:

Based on duration of symptoms

  • Acute: If the duration of symptoms is less than 4-6 weeks before presenting to medical care.[8]
  • Chronic: If the symptoms persists for more than 6 weeks.

Based on Etiology

  • Primary: when the abscess develops after lung infection in previously healthy persons or in patients prone to aspiration [9]
  • Secondary: Abscess formation in patients due to complications of a co-existing lung disease such as post obstructive process (bronchial obstruction due to tumor , foreign body or enlarged lymphnodes) and systemic process resulting in decreased immune response likeHIV, and patients onimmunosuppressantss and corticosteroids.

Based on mode of spread

Bronchiogenic: Abscess formation is due to aspiration and inhalation.[8]

  • Aspiration of oropharyngeal secretions
  • Bronchial obstruction by tumor
  • Foreign body, congenital malformations, and enlarged lymph nodes

Hematogenic: Abscess formation due to dissemination of causative agents from other infected sites

  • Infective endocarditis
  • Abdominal sepsis
  • Septic thromboembolism

Risk Factors

  • Numerous risk factors that result in altered level of consciousness and decreased immune response play a key role in the development of lung abscess :

Common Risk Factors

  • Alcoholism[10]
  • Seizure disorder
  • Artificial ventilation
  • Coma
  • Neuromuscular disorders with bulbar dysfunction
  • Nocturnal aspiration
  • Bronchial obstruction
  • Gingivo-dental sepsis
  • Diabetes mellitus
  • Immunosuppression

Less Common Risk factors

  • Drug abuse
  • Malnutrition
  • Mental retardation
  • Gastroesophageal reflux disease

Causes

Lung abscess is caused by one or more of the following reasons:

  • Necrotizing infection of lung parenchyma
  • Necrosis of an infarcted lung tissue
  • Cavitation in the necrotic tissue by malignant lesions

Microbiology

  • About 90% of the lung abscess is caused by polymicrobial infection.[11] [12]
  • Anaerobes are the predominant pathogens involved in primary lung abscess, followed by Streptococcus pneumoniae.
  • Klebsiella pneumoniae is the more common in alcoholics.[13]
  • Staphylococcus aureus is the most common pathogen responsible for lung abscess in children with cystic fibrosis.[14]

The following table elaborates the most common etiological pathogens responsible for lung abscess [15]

 
 
 
 
 
 
 
 
 
 
 
 
 
 
Polymicrobial
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Bacterial
 
 
 
 
 
 
 
 
 
 
Fungal
 
 
 
Parasites
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Anerobic
 
 
 
 
 
 
 
 
 
Aerobic
 
 
 
 
Histoplasma
Blastomyces
Coccidoides
Aspergillus
Cryptococcus
 
 
 
Entamoeba histolytica
Paragominus Westermani
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Gram Negative
 
 
 
Gram Positive
 
 
 
Gram Positive
 
 
 
Gram Negative
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Bacteroides fragilis
Fusobacterum capsulatum
Fusobacterum necrophorum
 
 
 
Peptostreptococcus
Microerophilic streptococci
Actinomyces
 
 
 
Staphyloccocus areus(including MRSA)
Streptococcous Pneumonia
Streptococcus Pyogens
Nocardia
 
 
 
Klebsiella pneumoniae
Heamophillus influenza type B
Pseudomonas aeurongiosa
Escherichia coli
Legionella Pneumophilia
Acinetobacter spp

Natural History, Prognosis and Complications

Natural History

  • Lung abscess is most commonly seen in the fourth decade of life in patients with risk factors or underlying other lung disorders.[16]
  • Clinical manifestations include fever, productive cough, pleuritic chest pain and occasional episodes of hemoptysis, typically developing 8-14 days after aspiration.
  • The progression of the abscess is dependent on two important factors: immune status of the patient and antibiotic therapy.
  • In immunocompetent patients with complete treatment abscess resolves forming a granulation tissue scar, without treatment the abscess progressively worsens and can result in septicemia, hemorrhage, and death.

Prognosis

The prognosis of lung abscess is good with appropriate antibiotic treatment with a high success rate. The outcomes depend on the other associated conditions underlying lung abscess. The mortality rate of lung abscess is as high as 75% in patients with underlying immunocompromised state and bronchial obstruction favoring poor prognosis The following factors are considered to be associated with poor prognosis among patients.[17]

  • Large size cavities(>6cms)
  • Old age
  • Necrotizing pneumonia
  • Prolonged symptoms
  • Abscess due to aerobic bacteria and hospital acquired
  • Bronchial obstruction due to tumors or foreign body (secondary abscess)
  • Immunocompromised individuals

Complications

Without treatment, lung abscess can result in the following complications:

  • Hemorrhage [18]
  • Pyopneumothorax
  • Pleural empyema[19]
  • Fibrosis and calcification of lung tissue
  • Mediastinal, pleural and cutaneous fistulas
  • Sepsis

Diagnosis

History and symptoms

  • The distinction of a lung abscess from pneumonia on history or clinical findings is possible.Common symptoms and signs reported with lung abscess are described below, Fever and cough consistently predominate but are not universal.

More common symptoms

  • Fever with chills,
  • Cough (at the beginning cough is non-productive, but when communication with bronchus appears, productive cough is produced which is a typical symptom )[20] [21]
  • Pleuritic chest pain
  • Putrid lung abscesses with discolored phlegm and foul-tasting or foul-smelling sputum is seen in if the infection is by anaerobic pathogens.
  • Rapid fever with rapid progression of symtoms is seen with aerobic bacteria and indulent and gradual progression in other causative agents.

Less common symptoms

  • Dyspnea
  • Weight Loss
  • Anemia and fatigue is more commonly seen in anaerobic infections
  • Clubbing of fingers.

Physical examination

Physical examination findings of Lung abscess largely depends on the other underlying conditions, and organisms involved and severity of the disease and other comorbidities

HEENT

  • Poor oral hygiene with gingivitis, dental erosions or poor dentition

Extremities

Digital clubbing is seen in chronic cases of lung abscess

Lungs

  • Tachypnea
  • Localised Crepetations
  • Decreased breath sounds on the side of lung abscess
  • Dullness to percussion
  • Bronchial breath sounds on auscultation
  • Inspiratory crackles
  • Contralateral shift of mediastinum if effusion is present
  • Absent of breath sounds over the effusion

General appearance

  • Fever with chills

Laboratory findings

Microbial testing

  • The most important component of the evaluation of a lung abscess is to define the etiologic agent in order to select appropriate antibiotic therapy and to detect associated conditions, such as malignancy. Most patients with "primary lung abscess" do not have a pathogen defined. It is important to exclude an underlying lesion such as a neoplasm.
  • When patients present with typical symptoms of fever with chills, cough with purulent sputum for more than 2 weeks and with risk factors of aspiration it is appropriate to suspect anaerobes as a possible pathogen.[22]
  • Cultures of the sputum for anaerobic bacteria is not recommended because of its contamination by the normal flora in the oral cavity.the only cultures that can give a positive result for anaerobes is empyema
  • It is often difficult to get uncontaminated sputum specimens as both upper respiratory tract and lower respiratory tract along oral cavity is contaminated with various flora.
  • The only methods available for obtaining uncontaminated specimens are trans-tracheal aspirates (TTA), transthoracic needle aspirates (TTNA), culture of pleural fluid, or blood cultures are recommended before administration of empiric antibiotics
  • Sputum analysis and culture is recommended for finding out aerobic and other causative agents of lung abscess.The conatmination of the sputum sample can be minimized by
    • Obtaining the sptum sample prior to antibiotic treatment.[23]
    • Rinsing the mouth prior to expectoration
    • NPO for one to two hours prior to expectoration
    • Inoculation of the culture media immediately after the specimen is obtained


 
 
 
 
 
 
 
 
Sputum Analysis
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Acid Fast Stain
 
Culture on Sabourad's medium
 
Direct Microscopic Examination for sulphur granules
 
Gentain Voilet Stain
 
Aerobic Culture
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Tuberculosis
 
Yeast and Fungi
 
Actinomyces and other mycelia of Fungi
 
Fusiform Bacteria and Spirochetes
 
Pyogenic organsims
  • Interpretation of sputum cultures in these cases must take into account the clinical features of the patient, concentrations of the different organisms found in the culture and Gram stain, and the antibiotics the patient has received.

Chest Xray

  • The diagnosis of lung abscess is made on the chest radiograph, supported by more definitive imaging initiated as part of interventional therapy. The use of CT scanning may facilitate the distinction between a lung abscess and necrotizing pneumonia, as well as being part of the interventional procedure to guide the interventional radiologist as he or she drains the abscess.14
  • An irregularly shaped cavity with an air-fluid level is typically seen for lung abscess on chest xray.
    Lung abscess
    Lung abscess
    [24]
  • Lung abscesses as a result of aspiration most frequently occur in the posterior segments of the upper lobes or the superior segments of the lower lobes. [25]
  • The wall thickness of a lung abscess progresses from thick to thin and from ill-defined to well-circumscribed as the surrounding lung infection resolves. The cavity wall can be smooth or ragged but is less commonly nodular, which raises the possibility of cavitating carcinoma. [26]
  • The extent of the air-fluid level within a lung abscess is often the same in posteroanterior or lateral views. The abscess may extend to the pleural surface, in which case it forms acute angles with the pleural surface.
  • Anaerobic infection may be suggested by cavitation within a dense segmental consolidation in the dependent lung zones. Lung infection with a virulent organism results in more widespread tissue necrosis, which facilitates progression of underlying infection to pulmonary gangrene.
  • Up to one-third of lung abscesses may be accompanied by an empyema.[27]
  • Repeat chest radiographs must be obtained to determine the response of antimicrobial therapy.

CT Scan

  • On CT scan lung abscess is visualized as a rounded radiolucent lesion with a thick wall and ill-defined irregular margins, and is located within the parenchyma compared with loculated empyema, which may be difficult to distinguish on chest radiographs. [28]
  • Computed tomography (CT) lung is considered as the gold standard not only for the diagnosis of lung abscess but also for guiding therapeutic procedures such as trans-thoracic drainage of localized lung abscess .[29]
  • CT scan helps in differentiating the cavitation of abscess that cannot be clearly delineated on the chest radiograph from empyema.[27]
  • CT scan is very helpful in excluding endobronchial obstruction due to malignancy or foreign body and provides additional information about size and location of the abscess,when the abscess is peripheral it forms acute angles with the pleural surface chest wall

Ultrasound

  • Ultrasound has a minimal role in diagnosing lung abscess .
  • Lung abscess appears as a rounded hypoechoic lesion with an outer margin on ultrsound.
  • Lung abscesses which are peripheral and with pleural contact or included inside a lung consolidation are detectable using bedside lung ultrasonography.

Medical treatment

  • The mainstay of management for lung abscess is : hospital admission and systemic antibiotics, which adequately treat 90% of patients of all ages.
  • Empiric treatment should be commenced as soon as possible after culture samples are obtained.
  • The choice of empiric antibiotics should be determined on the basis of the possible risk of multi-drug resistant causative bacteria, and culture results.
  • Clindamycin (600 mg i.v. every 8 hours followed by 150-300 mg every 6 hours p.o.) is considered the first-line drug of choice for anaerobic lung infections.[30] [31]
  • With the emergence of resistance of anaerobic bacteria and microaerophilic Streptococci mostly to penicillin G and more rarely to clindamycin, due to β-lactamase production, β-lactam/β-lactamase inhibitor combinations (amoxicillin/clavulanate, ampicillin/sulbactam) presented as highly effective agents for community-acquired lung abscesses.[32] [33]
    • This antimicrobial regimen provides adequate coverage against gram (+), gram (-) Enterobacteriaceae (e.g. Klebsiella pneumonia, Enterobacter) and anaerobic bacteria.[34]
  • A possible therapeutic alternative is the combination of a 2nd (cefuroxime, cefoxitin) or 3rd generation cephalosporin (ceftriaxone) with clindamycin or metronidazole.
  • Monotherapy with metronidazole should be avoided due to inadequate coverage for aerobic and microaerophilic Streptococci, such as Streptococcus milleri.[35]
  • Linezolid (initial i.v.administration 600 mg twice daily and subsequent oral administration after clinical improvement) is preferred in cases of lung abscess caused by MRSA.[36]
  • An alternative choice is vancomycin (15 mg/kg x2 i.v., with dose adapted according to optimal serum levels (15-20 mcg/ml) and renal function). Low daptomycin concentrations achieved in lung tissue renders daptomycin inadequate for lower respiratory infections.[37]
  • Clinical improvement is reflected in the subsidence of fever (within the first 3-4 days) and complete defervescence within 7-10 days.Persistent fever can be explained by treatment failure due to uncommon pathogens (multidrug resistant common bacteria, mycobacteria, fungi)or by the presence of an alternative diagnosis (e.g. endobronchial obstruction, vasculitis) that requires further diagnostic workup (e.g. bronchoscopy, transdermal or surgical lung biopsy).[38]
  • The duration of treatment with antibiotics is not well defined, according to many experts, the optimal duration of antimicrobial therapy is 3-6 weeks, whereas others take the timing of radiological response into consideration. [38]
  • In that case, the length of antibiotic treatment depends on complete radiological resolution or stabilization to a small residual lesion.
  • Treatment interval may then be prolonged to several months (more than 2),6 especially when the initial lesion is of large size (maximum diameter more than 6cm).


Medical Therapy for the management of Lung Abscess
Empiric Therapy
  • Clindamycin
  • Penicillin with betalactamase inhibitor
Non responsive to initial therapy and based on culture reports
  • MRSA: Linezolid or Vancomycin
  • Cephalosporin with clindamycin or metronidazole

Surgical Therapy

Indications

  • When an abscess is greater than 6 cm in diameter
  • If symptoms last more than 12 weeks with appropriate therapy, which have little chances for only conservative healing

Surgical Options

  • Options for surgery includes: Chest tube drainage and surgical resection of the lung abscess with the surrounding lung tissue

Chest tube drainage

  • The concept of CT-guided drainage and the insertion of a pigtail catheter when medical therapy has failed or for rapid diagnostic and therapeutic benefit has emerged in the late 1980's.9,27 with a significant reduction in mortality and hospital stay.
  • Percutaneous and endoscopic drainage techniques are considered as a first-line management, especially for patients who are not candidates for surgery [39]

Percutaneous drainage

Type of chest drain Indications Procedure Complications
Percutaneous thoracocentesis
  • It is the treatment of choice for patients who have failed to respond to antibiotic therapy .[40]
  • Patients who are unsuitable for surgical intervention (e.g. due to severe immunodeficiency or mechanical ventilation).
  • Lung abscesses with diameters greater than 4-8 cm
  • Performed under fluoroscopic, ultrasound or computed tomography guidance.(CT is generally preferred due to additional information provided about location, content and wall-thickness of the abscess.)
  • Two techniques of insertion of chest tube employed: Seldinger, and Trochar
  • Seldinger technique of insertion the tube is considered as it is  safer and it permits greater control in the positioning of the drainage tube and  is accompanied by fewer complications[41]
  • Chest tube drainage with trocar is highly effective surgical procedure and is recommended for thoracic surgeons
  • Drainage duration varies but a minimum of 4-5 weeks are required and is done according to radiographic findings.Chest tubes should not be flushed in order to avoid bronchogenic spread of the pus.[39]
  • The usage of intra-cavitary fibrinolytic agents (streptokinase, urokinaze) is not recommended, due to possibility of bronchopulmonary or bronchopleural fistula can occur.[42]
      
  • Technique related includes :advancing of the guidewire through the thicked-wall abscess may cause bending or rupture of the guidewire or the catheter.[43]
  • Hemothorax, hemoptysis, pyopneumothorax and fistula formation between the pleural cavity and the abscess resulting in empyema.
  • Less significant complications are those related to bending or leaking of the drainage catheter.
Endoscopic thoracic drainage
  • Pateints with poor general condition,
  • Coagulopathies
  • For the abscesses with central locations in lungs.
  • A guidewire is inserted into the cavity through the working channel of a flexible bronchoscope.Once guidewire location has been ascertained by fluoroscopy, a 7 French pigtail catheter is advanced.
  • If infusion of contrast medium via the catheter confirms its proper positioning, the guidewire and bronchoscope are withdrawn and the catheter tip is stabilized at the nasal wall. *Bronchography may be selectively performed to identify the airway that leads into the abscess, thus permitting the insertion of the guidewire via the catheter used for the bronchography. Subsequently, the cavity is flushed daily with normal saline solution through the catheter, while antibiotic infusions (e.g. gentamicin or amphotericin in confirmed fungal infections) may also be administered.[44]
  • The catheter remains open for the rest of the day, thus ensuring the drainage of the abscess.
  • In a small number of patients with recurrent lung abscesses, endoscopic drainage was performed with the help of laser.[45]
  • The catheter is inserted through a bronchoscope and laser is used in order to perforate the wall of the abscess through the airway and to lead the catheter inside the cavity. The catheter is removed after 4-6 days with immediate improvement of clinical status and radiological imaging within the first 24 hours
  • Spillage of necrotic detritus in other parts of the lungs
  • These techniques demonstrated benefits even in patients without contraindications to surgery. More specifically, cases of primary lung abscess that were treated by Yellin A et al during a 5-year period (1978-1982) underwent successful percutaneous drainage, without any complications or relapse after 2-5 years of monitoring.[46]
  • Percutaneous drainage failure and indication for surgery may arise when the abscess is multiloculated, organized and/or thick-walled.
  • Percutaneous drainage of lung abscesses is characterized by high therapeutic effectiveness and preservation of functional lung tissue, it is a minimally invasive method with fewer complications and lower mortality rates (approximately 4%) in comparison to surgical management.[47]
  • In case of pleural space obliteration, with peripheral localization of lung abscess, it is possible to perform pneumostomy or cavernostomy-open drainage of abscess(Monaldi procedure) but it is limited due to it invasiveness.

Surgical Intervention

  • Surgery is considered in about 10% of the patients when medical therapy and drain failed

Indications

    • Hemoptysis,
    • Prolonged sepsis and febricity,[48]
    • Bronchopleural fistula,
    • Rupture of abscess in the pleural cavity with pyopneumothorax/empyema.
    • Unsuccessfully treated lung abscess more than 6 weeks,
    • Suspicion of cancer,
    • Cavitary lesion larger than 6 cm,
    • Leukocytosis despite the use of antibiotics.

Surgical resection

  • The surgical approach is thoracotomy and the extent of surgical resection depends on the size of the underlying lesion. [48]
  • Lobectomy is the most common type of surgical resection. Segmentectomies are performed in smaller abscesses (<2 cm), whereas a pneumonectomy should be performed in the presence of multiple abscesses or gangrene. [49],[50]
  • Surgical debridement followed by immediate filling of the cavity with a flap of highly vascular soft tissue, or debridement and cavity fistulization into the pleural space followed by drainage by means of a chest tube are proposed when conservative measures fail to control sepsis and poor performance status prohibits more extensive surgery (lobectomy or pneumonectomy), provided that a limited thoracotomy is feasible.
  • When the chronic inflammatory process of pulmonary infection causes incomplete re-expansion of the remaining lobes, it is quite possible that a portion of the pleural space will remain empty. Some thoracic surgeons recommend filling that space with a large pedicled ipsilateral latissimus dorsi muscle flap or omentum.
  • In addition, bronchial stump reinforcement with a pedicled intercostal muscle flap or other highly vascular tissue may prevent the formation of a bronchopleural fistula.
  • When thoracotomy is contraindicated, open surgical drainage may be required either by creating a cavernostomy52 or a pouch-like cavity communicating with the thoracic wall through limited rib resection.
  • Cross-contamination of contralateral lung is the main complication to be feared of during surgery. Placement of a double-lumen endotracheal tube, prone positioning of the patient and artificial obstruction of the main bronchus before removing the abscess are the usual measures for preventing cross-contamination.
  • Recently, a thoracoscopic technique (Video assisted thoracoscopic surgery: VATS) for abscess debridement and drainage has been effectively implemented in a small number of patients.53

Differential diagnosis

Non-infectious

causes of lung cavities

Clinical presentation Radiographic findings Diagnosis

confirmation

  • Malignancy (Primary lung cancer)[51]
  • Elderly male or female [51]
  • H/o of smoking
  • Cough, hemoptysis
  • Bronchial obstruction, wheezing
  • Weight loss,fatigue,
  • A coin-shaped lesion with thick wall(>15mm) is seen on X-ray.[52]
  • Cavitation in malignancy is indicator of poor prognosis
  • Small cell carcinomas are commonly associated with cavitations.[53]
  • Biopsy of the lesion
  • Classified into two types
    • Small cell carcinoma
    • Non-small cell carcinoma
  • Granulomatosis with polyangiitis (Wegener's)[54]
  • Upper respiratory tract: perforation of nasal septum,chronic sinusitis, otitis media,mastoditis.[55]
  • Lower respiratory tract: hemoptysis, cough,dyspnea.
  • Renal: hematuria, red cell casts
  • Pulmunory nodules with cavities and infiltrates are a frequent manifestation on CXR.
  • Positive for P-ANCA
  • Biopsy of the tissue involved [54]
    • Triad:
      • Focal necrotizing vasculitis
      • Necrotizing granulomas in the lung and upper airway
      • Necrotizing glomerulonephritis
  • Sarcoidosis
  • Immune-mediated,[56]
  • More common in African-American females.
  • Often asymptomatic except for enlarged lymph nodes.
  • Associated with restrictive lung disease (interstitial fibrosis),
  • Erythema nodosum,
  • Lupus pernio (skin lesions on face resembling lupus),
  • Bell palsy,
  • Epithelioid granulomas containing microscopic Schaumann and asteroid bodies,
  • Uveitis,
  • Hypercalcemia
  • On chest Xray bilateral adenopathy and coarse reticular opacities are seen.
  • CT of the chest demonstrates extensive hilar and mediastinal adenopathy
  • Additional findings on CT include fibrosis (honeycomb, linear, or associated with bronchial distortion), pleural thickening, and ground-glass opacities.[57]
  • Non-caseating granuloma on lung biopsy
  • Bronchiolitis obliterans (Cryptogenic organizing pneumonia)[58][59]
  • It is a pathological diagnosis
  • And is triggered by drug or toxin exposure, autoimmune diseases,viral infections, or radiation injury but is most often idiopathic
  • Presents with fever, cough, weight loss, and dyspnea over weeks to months, similar to many infectious diseases[60]
  • Common appearance on CT is patchy consolidation,often accompanied by ground-glass opacities and nodules.[61]
  • Langerhan'scell histiocytosis[62]
  • Exclusively afflicts smokers, with a peak age of onset of between 20 and 40 years.
  • Clinical presentation varies, but symptoms generally include months of drycough, fever, night sweats, and weight loss.
  • Thin-walled cystic cavities are the usual radiographic manifestation, observed in over 50% of patients by either plain chest radiography or computed tomography scans.[63]
  • Biopsy of the lung
Infectious agent Patient characteristics, comorbidities,

and/or risk factorsa

Epidemiology Radiological findings

Bacteria

  • Actinomyces spp.[64]
  • Male predominance,
  • Poor oral hygiene
  • Alcohloics
  • Normal inhabitant of oral cavity,
  • Gastrointesinal tract, and female reproductive tract
  • Commonly involves infection of neck,thoracic region and abdomen pelvis.[65]
  • Infection of lungs is commonly resulted from the aspiration of actinomyces load from neck infection
  • Pleural mass with wavy perisoteal reaction involving ribs is seen at the site of involvement on Xray
  • Cavitary lesions are only appreciated on CT scan .[66]
  • Klebsiella spp.
  • Alcoholism, corticosteroid use,
  • Hematologic malignancy,
  • Male predominance
  • Nosocomial and community acquisition
  • Bulging interlobar fissures, unilateral/bilateral infiltrates, abscess, cavitation
  • Nocardia spp.
  • Chronic obstructive pulmonary disease,
  • Corticosteroid use,
  • HIV/AIDS (rare),
  • Malignancy,posttransplant
  • Soil organism
  • Lobar consolidation, nodular infiltrate, solitary mass, cavitation
  • Staphylococcus aureus
  • Debilitated hospitalized patients,
  • Immunocompetent patients with extrapulmonary staphylococcal infection (e.g., skin infection with community-acquired MRSA)
  • Community acquired or nosocomial
  • Consolidation, pneumatocele, cavity
  • Mycobacterium tuberculosis
  • Birth or prolonged residence in area of endemicity (developing world),
  • Diabetes mellitus,
  • Head and neck cancer,
  • Hematologic malignancy,
  • HIV/AIDS,
  • Immunosuppressive therapy,tumor necrosis factor alpha antagonist use
  • Spread from person to person through inhalation of droplet nuclei;
  • More prevalent in developing countries
  • Upper lobe infiltrates, cavity,miliary pattern, tuberculoma, hilar lymphadenopathy

Fungus

  • Aspergillus spp.
  • Hematologic malignancy,
  • HIV/AIDS, immunosuppressive therapy, malnutrition,
  • Neutropenia posttransplant,
  • Underlying pulmonary disease (asthma, cystic fibrosis)
  • For invasive aspergillosis; alcoholism, chronic obstructive pulmonary disease, collagen vascular disease, diabetes mellitus, low-dose corticosteroid use, malnutrition, pnemoconiosis for semi-invasive; and prior tuberculosis or other cavity causing disease for aspergilloma
  • Saprophytic fungi that grow on organic debris;
  • Potential environmental exposure for hospitalized high-risk patients
  • Invasive aspergillosis: macronodules, consolidation,halo sign, air-crescent sign,cavitation.
  • Semi-invasive aspergillosis: progressive or chronic infiltrate, cavity with or without air-crescent sign,
  • Aspergilloma:fungus ball in preexisting cavity
  • Blastomyces dermatitides
  • black race, diabetes mellitus,
  • Male gender, outdoor activity,
  • Prior history of pneumonia
  • Endemic to Mississippi and Ohio River valleys, Great Lakes, and St. Lawrence River region;
  • Also found in parts of Mexico, Central and South America, Africa, and the Middle East
  • Acute: Patchy alveolar opacities nodular densities;
  • Chronic: Fibronodular upper lobe disease,smooth-walled cavities, solitary mass lesion, volume loss, calcification, fibrosis, miliary pattern
  • Coccidioides immitis
  • Corticosteroid use,
  • Diabetes mellitus,
  • HIV/AIDS, malignancy,
  • Black or Filipino race/ethnicity,
  • Organ transplant
  • Endemic to the southwestern United States and Mexico;
  • Also be associated with occupational exposure (construction, archeological excavation) or extreme weather conditions in an area(i.e., duststorm)
  • Acute: patchy opacities, multilobar consolidation, thick-walled cavities, pleural effusion, hilar lymphadenopathy;
  • Chronic: thinwalled cavities, pleural effusion, pneumothorax, single or multiple nodules
  • Cryptococcus spp.
  • Corticosteroid use,
  • Diabetes mellitus,
  • HIV/AIDS,hematologic malignancy,
  • Organ transplant,
  • Sarcoidosis
  • Isolated from soil contaminated by pigeon and chicken excreta
  • solitary or multiple nodules, alveolar consolidation,interstitial pattern, cavitation,lymphadenopathy, pleural effusion
  • Histoplasma capsulatum
  • Heavy equipment operators,
  • Poultry breeders
  • Chronic obstructive pulmonary disease,
  • Middle-aged men
  • Endemic to the Ohio and Mississippi River valleys,Virginia, and Maryland;
  • Grows well in soil that has been enriched by bird excreta
  • Acute: scattered patchy or diffuse interstitial opacities, solitary pulmonary nodule, miliary pattern, hilar or mediastinal lymphadenopathy;
  • Chronic:cavitation
  • Pneumocystis jirovecii
  • Autoimmune disorders,
  • Corticosteroid use,
  • Hematologic malignancy,
  • HIV/AIDS,
  • Posttransplantation
  • Ubiquitous fungi
  • Bilateral alveolar/interstitial infiltrates, solitary or multiple nodules, pneumothorax, cavity,

Parasites

  • Echinococcus granulosus
  • Endemic to Mediterranean region, Middle East, Africa, Latin America, southwest United States, southern Europe,
  • Largely in livestockrearing areas; dogs are the definitive host
  • Spherical homogenous masses with smooth borders surrounded by normal lung tissue, bullae,calcifications, cavity
  • Paragonimus westermani
  • Zoonosis that is endemic to Japan, the Korean peninsula, the Philippines, and parts of China;
  • May be acquired through eating freshwater crabs and raw boar meat
  • Nodules, mediastinal lymphadenopathy, pleural effusion

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