traction bronchiectasis is a finding of abnormal airway dilation due to lung fibrosis. It istypically seen on high resolution computed tomography (CT) scan.It is classically seen in idiopathic pulmonary fibrosis.Bronchiectasis is a disease state defined by localized, irreversible dilation of part of thebronchial tree. It is classified as an obstructive lung disease, along with bronchitis andcystic fibrosis. Involved bronchi are dilated, inflamed, and easily collapsible, resulting inairflow obstruction and impaired clearance of secretions. Bronchiectasis is associatedwith a wide range of disorders, but it usually results from necrotizing bacterial infections,such as infections caused by the Staphylococcus or Klebsiella species or Bordetellapertussis.CausesThere are both congenital and acquired causes of bronchiectasis. Kartagener syndrome,which affects the mobility of cilia in the lungs, aids in the development of the disease.Another common genetic cause is cystic fibrosis, in which a small number of patientsdevelop severe localized bronchiectasis. Youngs syndrome, which is clinically similarto cystic fibrosis, is thought to significantly contribute to the development ofbronchiectasis. This is due to the occurrence of chronic, sinopulmonary infections.Patients with alpha 1-antitrypsin deficiency have been found to be particularlysusceptible to bronchiectasis, for unknown reasons. Other less-common congenitalcauses include primary immunodeficiencies, due to the weakened or nonexistent immunesystem response to severe, recurrent infections that commonly affect the lung.Acquired bronchiectasis occurs more frequently, with one of the biggest causes beingtuberculosis. Endobronchial tuberculosis commonly leads to bronchiectasis, either frombronchial stenosis or secondary traction from fibrosis. An especially common cause ofthe disease in children is acquired immune deficiency syndrome, stemming from thehuman immunodeficiency virus. This disease predisposes patients to a variety ofpulmonary ailments, such as pneumonia and other opportunistic infections..Bronchiectasis can sometimes be an unusual complication of inflammatory boweldisease, especially ulcerative colitis. It can occur in Crohns disease as well, but does soless frequently. Bronchiectasis in this situation usually stems from various allergicresponses to inhaled fungus spores. Recent evidence has shown an increased risk ofbronchiectasis in patients with rheumatoid arthritis who smoke. One study stated atenfold increased prevalence of the disease in this cohort. Still, it is unclear as towhether or not cigarette smoke is a specific primary cause of bronchiectasis.Other acquired causes of bronchiectasis involving environmental exposures includerespiratory infections, obstructions, inhalation and aspiration of ammonia and other toxicgases, pulmonary aspiration, alcoholism, heroin (drug use), and various allergies. Diagnosis
The diagnosis of bronchiectasis is based on the review of clinical history andcharacteristic patterns in high-resolution CT scan findings. Such patterns include "tree-in-bud" abnormalities and cysts with definable borders. In one small study, CT findings ofbronchiectasis and multiple small nodules were reported to have a sensitivity of 80%,specificity of 87%, and accuracy of 80% for the detection of bronchiectasis.Bronchiectasis may also be diagnosed without CT scan confirmation if clinical historyclearly demonstrates frequent, respiratory infections, as well confirmation of anunderlying problem via blood work and sputum culture samples. TreatmentTreatment of bronchiectasis is aimed at controlling infections and bronchial secretions,relieving airway obstruction, and preventing complications. This includes the prolongedusage of antibiotics to prevent detrimental infections, as well as eliminatingaccumulated fluid with postural drainage and chest physiotherapy. Surgery may also beused to treat localized bronchiectasis, removing obstructions that could cause progressionof the disease.Inhaled steroid therapy that is consistently adhered to can reduce sputum production anddecrease airway constriction over a period of time, and help prevent progression ofbronchiectasis. One commonly used therapy is beclometasone dipropionate, which is alsoused in asthma treatment. Use of inhalers such as albuterol (salbutamol), fluticasone(Flovent/Flixotide) and ipratropium (Atrovent) may help reduce likelihood of infectionby clearing the airways and decreasing inflammation.Although not approved for use in any country, Mannitol dry inhalation powder, under thename Bronchitol, has been granted orphan drug status by the FDA for use in patients withbronchiectasis and with cystic fibrosis.Combination therapies, long acting bronchodilators and inhaled corticosteroids such asSymbicort and Advair Diskus are also commonly used inhaled medicines which has inmany cases been effective in clearing the airways, reducing sputum and reducinginflammation. PreventionIn order to prevent future development of bronchiectasis, an x-ray of the chest should betaken after any severe attack of measles, whooping cough or other acute respiratoryinfection in childhood. While smoking has not been found to be a direct cause ofbronchiectasis, it is certainly an irritant that all patients should avoid in order to preventthe development of infections (such as bronchitis) and further complications.A healthy body mass index, vaccination (especially against pneumonia and influenza)and regular doctor visits may have beneficial effects on the prevention of progressing
bronchiectasis. The presence of hypoxemia, hypercapnia, dyspnea level and radiographicextent can greatly affect the mortality rate from this disease.Bronchiectasis is an abnormal destruction and dilation (permanent or abnormal widening)of the large airways. This injury is the beginning of a cycle in which your airways slowlylose their ability to clear out mucus. The mucus builds up and creates an environment inwhich bacteria can grow. This leads to repeated serious lung infections.Bronchiectasis is many a times caused by recurrent inflammation or infection of theairways. It may be present at birth, but most often begins in childhood as a complicationfrom infection or inhaling a foreign object. Prior to the widespread use of immunizations,bronchiectasis was often the result of a serious infection with either measles orwhooping cough. Now, viruses that cause influenza (flu) or influenza-like syndromes,may lead to development of bronchiectasis.Some other Causes of Bronchiectasis may be: • Respiratory syncytial virus can cause bronchiectasis in some childs. • Some inherited conditions. For example, a condition called primary ciliary dyskinesia affects the cilia so they do not beat correctly to clear the mucus. Cystic fibrosis is another condition that affects the lungs and causes bronchiectatic airways. • Inhaled objects, such as peanuts, can become stuck and block an airway. This may lead to local damage to that airway. Acid from the stomach that is regurgitated and inhaled can also damage airways. Inhaling poisonous gases may also cause damage. • Some rare immune problems can also cause lung infections and damage to airways thereby causing bronchiectasis. • Severe lung infections such as tuberculosis (TB), whooping cough, pneumonia or measles can damage the airways at the time of infection. Ongoing bronchiectasis may then develop. • Less commonly, bronchiectasis may be caused by cystic fibrosis, an inhaled foreign body such as a peanut, following tuberculosis, or lung infection in Aids. • Other causes include inhalation of damaging gases, dust or smoke. The condition is worsened by smoking. • It is also seen in later life after severe lung infections such as pneumonia in childhood, and it is sometimes present from birth if the babys lungs have not developed properly in the womb.Symptoms of BronchiectasisBronchiectasis can develop at any age and to any person. But, is most commonly seen inearly childhood. Symptom severity varies widely from patient to patient and sometimesthe patient may be even asymptomatic. In other people, symptoms begin gradually,usually after a respiratory infection, and tend to worsen over the years. The classicsymptom, however, is a chronic cough that produces foul-smelling, mucopurulentsecretions in amounts ranging from less than 10 ml/day to more than 150 ml/day. Thisfinding is observed in more than 90% of bronchiectasis patients. There may be coughing
spells - these are most common in the early morning and late in the day. Othercharacteristic findings include coarse crackles during inspiration over involved lobes orsegments, dyspnea, sinusitis, anemia, malaise, clubbing, and other signs of infection.Some other Symptoms of Bronchiectasis may be: • Cough worsened by lying on one side • Shortness of breath worsened by exercise • Weight loss. • Coughing up of blood is also common. • Fatigue. • Wheezing. • recurrent fever, chills, • Skin discoloration, bluish. • Paleness. • Abnormal chest sounds. • Breath odor. • There may be frequent bouts of pneumonia or hemoptysis.Treatment for BronchiectasisTreatment of bronchiectasis is aimed at controlling infections and bronchial secretions,relieving airway obstruction, and preventing complications. Some of the Treatmentoptions are given below: • Antibiotics may be given to the patient - orally or intravenously, for at least 7 - 10 days or until sputum production decreases. Long term antibiotic therapy is not appropriate because it may predispose the patient to serious Gram- negative infections. • Bronchodilators, combined with postural drainage and chest percussion, help remove secretions if the patient has bronchospasm and thick, tenacious sputum. • Bronchoscopy may be used to help mobilize secretions. • Hypoxia requires oxygen therapy; severe hemoptysis commonly requires lobectomy, segmental resection, or bronchial artery embolization if pulmonary function is poor.Lung abscess is necrosis of the pulmonary tissue and formation of cavities (more than 2cm) containing necrotic debris or fluid caused by microbial infection.This pus-filled cavity is often caused by aspiration, which may occur during alteredconsciousness. Alcoholism is the most common condition predisposing to lung abscesses.Lung Abscess is considered primary(60%) when it results from existing lungparenchymal process and is termed secondary when it complicates another process e.g.vascular emboli or follows rupture of extrapulmonary abscess into lung.Conditions contributing to lung abscess • Aspiration of oropharyngeal or gastric secretion • Septic emboli • Necrotizing pneumonia
• Vasculitis: Wegeners granulomatosis • Necrotizing tumors: 8% to 18% are due to neoplasms across all age groups, higher in older people; primary squamous carcinoma of the lung is the commonest.OrganismsIn the post-antibiotic era pattern of frequency is changing. In older studies anaerobeswere found in up to 90% cases but they are much less frequent now. • Anaerobic bacteria: Peptostreptococcus, Bacteroides, Fusobacterium species, • Microaerophilic streptococcus : Streptococcus milleri • Aerobic bacteria: Staphylococcus, Klebsiella, Haemophilus, Pseudomonas,Nocardia, Escherichia coli, Streptococcus, Mycobacteria • Fungi: Candida, Aspergillus • Parasites: Entamoeba histolytica, Signs and SymptomsOnset of symptoms is often gradual, but in necrotizing staphylococcal or gram-negativebacillary pneumonias patients can be acutely ill. Cough, fever with shivering and nightsweats are often present. Cough can be productive with foul smelling purulent sputum(≈70%) or less frequently with blood (i.e. hemoptysis in one third cases) . Affectedindividuals may also complain of chest pain, shortness of breath, lethargy and otherfeatures of chronic illness.Patients are generally cachectic at presentation. Finger clubbing is present in one third ofpatients. Dental decay is common especially in alcoholics and children. On examinationof chest there will be features of consolidation such as localised dullness on percussion,bronchial breath sound etc. DiagnosisChest Xray and other imaging studiesAbscess is often unilateral and single involving posterior segments of the upper lobes andthe apical segments of the lower lobes as these areas are gravity dependent when lyingdown. Presence of air-fluid levels implies rupture into the bronchial tree or rarely growthof gas forming organism.Laboratory studiesRaised inflammatory markers (high ESR, CRP) are usual but not specific. Examination ofsputum is important in any pulmonary infections and here often reveals mixed flora.Transtracheal of Transbronchial (via bronchoscopy) aspirates can also be cultured. Fibre
optic bronchoscopy is often performed to exclude obstructive lesion; it also helps inbronchial drainage of pus. ManagementBroadspectrum antibiotic to cover mixed flora is the mainstay of treatment. Pulmonaryphysiotherapy and postural drainage are also important. Surgical procedures are requiredin selective patients for drainage or pulmonary resection. ComplicationsRare nowadays but include spread of infection to other lung segments, bronchiectasis,empyema, and bacteraemia with metastatic infection such as brain abscess. PrognosisMost cases respond to antibiotic and prognosis is usually excellent unless there is adebilitating underlying condition. Mortality from lung abscess alone is around 5% and isimprovingLung abscess is defined as necrosis of the pulmonary tissue and formation of cavities containingnecrotic debris or fluid caused by microbial infection. The formation of multiple small (<2 cm)abscesses is occasionally referred to as necrotizing pneumonia or lung gangrene. Both lung abscessand necrotizing pneumonia are manifestations of a similar pathologic process. Failure to recognizeand treat lung abscess is associated with poor clinical outcome.Lung abscesses can be classified based on the duration and the likely etiology. Acute abscesses areless than 4-6 weeks old, whereas chronic abscesses are of longer duration. Primary abscess isinfectious in origin, caused by aspiration or pneumonia in the healthy host; secondary abscess iscaused by a preexisting condition (eg, obstruction), spread from an extrapulmonary site,bronchiectasis, and/or an immunocompromised state. Lung abscesses can be further characterized bythe responsible pathogen, such as Staphylococcus lung abscess and anaerobic or Aspergillus lungabscess.Most frequently, the lung abscess arises as a complication of aspiration pneumonia caused by mouthanaerobes. The patients who develop lung abscess are predisposed to aspiration and commonly haveperiodontal disease. A bacterial inoculum from the gingival crevice reaches the lower airways, andinfection is initiated because the bacteria are not cleared by the patients host defense mechanism.This results in aspiration pneumonitis and progression to tissue necrosis 7-14 days later, resulting information of lung abscess.Other mechanisms for lung abscess formation include bacteremia or tricuspid valve endocarditis,causing septic emboli (usually multiple) to the lung. Lemierre syndrome, an acute oropharyngealinfection followed by septic thrombophlebitis of the internal jugular vein, is a rare cause of lungabscesses. The oral anaerobe F necrophorum is the most common pathogen.MicrobiologyBecause of the difficulty obtaining material uncontaminated by nonpathogenic bacteria colonizing theupper airway, lung abscesses rarely have a microbiologic diagnosis. The most common anaerobes arePeptostreptococcus species, Bacteroides species, Fusobacterium species, and microaerophilicstreptococci.
Aerobic bacteria that may infrequently cause lung abscess include Staphylococcus aureus,Streptococcus pyogenes, Streptococcus pneumoniae (rarely), Klebsiella pneumoniae, Haemophilusinfluenzae, Actinomyces species, Nocardia species, and gram-negative bacilli.Nonbacterial and atypical bacterial pathogens may also cause lung abscesses, usually in theimmunocompromised host. These microorganisms include parasites (eg, Paragonimus andEntamoeba species), fungi (eg, Aspergillus, Cryptococcus, Histoplasma, Blastomyces, andCoccidioides species), and Mycobacterium species.Mortality/MorbidityMost patients with primary lung abscess improve with antibiotics, with cure rates documented at90-95%.Host factors associated with a poor prognosis include advanced age, debilitation, malnutrition, humanimmunodeficiency virus infection or other forms of immunosuppression, malignancy, and duration ofsymptoms greater than 8 weeks.3 The mortality rate for patients with underlying immunocompromisedstatus or bronchial obstruction who develop lung abscess may be as high as 75%.4Aerobic organisms, frequently hospital acquired, are associated with poor outcomesLung abscesses likely occur more commonly in elderly patients because of the increased incidence ofperiodontal disease and the increased prevalence of dysphagia and aspirationThe bacterial infection may reach the lungs in several ways. The most common is aspiration oforopharyngeal contents. • Patients at the highest risk for developing lung abscess have the following risk factors: o Periodontal disease o Seizure disorder o Alcohol abuse o Dysphagia • Other patients at high risk for developing lung abscess include individuals with an inability to protect their airways from massive aspiration because of a diminished gag or cough reflex, caused by a state of impaired consciousness (eg, from alcohol or other CNS depressants, general anesthesia, or encephalopathy). • An abscess may develop as an infectious complication of a preexisting bulla or lung cyst. • An abscess may develop secondary to carcinoma of the bronchus; the bronchial obstruction causes postobstructive pneumonia, which may lead to abscess formation.ClinicalHistorySymptoms depend on whether the abscess is caused by anaerobic or other bacterial infection. • Anaerobic infection in lung abscess o Patients often present with indolent symptoms that evolve over a period of weeks to months. o The usual symptoms are fever, cough with sputum production, night sweats, anorexia, and weight loss. o The expectorated sputum characteristically is foul smelling and bad tasting. o Patients may develop hemoptysis or pleurisy • Other pathogens in lung abscess o These patients generally present with conditions that are more emergent in nature and are usually treated while they have bacterial pneumonia. o Cavitation occurs subsequently as parenchymal necrosis ensues. o Abscesses from fungi, Nocardia species, and Mycobacteria species tend to have an indolent course and gradually progressive symptoms.
PhysicalThe findings on physical examination of a patient with lung abscess are variable. Physical findings maybe secondary to associated conditions such as underlying pneumonia or pleural effusion. The physicalexamination findings may also vary depending on the organisms involved, the severity and extent ofthe disease, and the patients health status and comorbidities. • Patients with lung abscesses may have low-grade fever in anaerobic infections and temperatures higher than 38.5°C in other infections. • Generally, patients with in lung abscess have evidence of gingival disease. • Clinical findings of concomitant consolidation may be present (eg, decreased breath sounds, dullness to percussion, bronchial breath sounds, course inspiratory crackles). • The amphoric or cavernous breath sounds are only rarely elicited in modern practice. • Evidence of pleural friction rub and signs of associated pleural effusion, empyema, and pyopneumothorax may be present. Signs include dullness to percussion, contralateral shift of the mediastinum, and absent breath sounds over the effusion. • Digital clubbing may develop rapidly.Abscesses generally develop in the right lung and involve the posterior segment of the right upperlobe, the superior segment of the lower lobe, or both. This is due to gravitation of the infectiousmaterial from the oropharynx into these dependent areas. Initially, the aspirated material settles in thedistal bronchial system and develops into a localized pneumonitis. Within 24-48 hours, a large area ofinflammation results, consisting of exudate, blood, and necrotic lung tissue. The abscess frequentlyconnects with a bronchus and partially empties.After pyogenic pneumonitis develops in response to the aspirated infected material, liquefactivenecrosis can occur secondary to bacterial proliferation and an inflammatory reaction to produce anacute abscess. As the liquefied necrotic material empties through the draining bronchus, a necroticcavity containing an air-fluid level is created. The infection may extend into the pleural space andproduce an empyema without rupture of the abscess cavity. The infectious process can also extend tothe hilar and mediastinal lymph nodes, and these too may become purulent.Anaerobic necrotizing pneumoniaUsually, anaerobic necrotizing pneumonia is chiefly restricted to one pulmonary segment or lobe,although it may progress to encompass an entire lung or both lungs. This type of anaerobic lunginfection is the most serious. The inflammatory process often spreads quickly and causes destructioncharacterized by greenish staining of the lung and a huge amount of putrid tissue, resulting inpulmonary gangrene. These patients are gravely ill with a progressive septic course. Leukocytosis isobvious, and the sputum is putrid.Secondary lung abscessIn cases of secondary lung abscess, the fundamental process (eg, bacteremia, endocarditis, septicthrombophlebitis, subphrenic infection) is generally apparent along with the pulmonary pathology.Infections below the diaphragm may extend to the lung or pleural space by way of the lymphatics,either directly through the diaphragm or via defects in it.The most typical hematogenous lung abscesses are observed in persons with staphylococcalbacteremia, especially in children. These abscesses are multiple and are located in the periphery ofthe lung. Infections may arise in or posterior to an obstruction (eg, an enlarged mediastinal lymphnode) and migrate to the lungs. Septic emboli from bacterial endocarditis or emboli from deep pelvicveins may result in metastatic lung abscess. Septic emboli are suggested when multiple lesionsappear over an extended period.Fewer than 5% of bland pulmonary infarcts become secondarily infected. Secondary infection ofinfarcts is suggested if fever and leukocytosis are present. Abscess formation may also occur within anecrotic pulmonary tumor.Amebic lung abscess
Patients who develop an amebic lung abscess often have symptoms associated with a liver abscess.These may include right upper quadrant pain and fever. After perforation of the liver abscess into thelung, the individual may develop a cough and expectorate a chocolate or anchovy paste–like sputumthat has no odor. The patient may give a history of diarrhea and travel outside the country.Diagnosis and WorkupDiagnosisThe diagnosis of a typical lung abscess can usually be confirmed based on history and physicalexamination findings. Approximately 10-20% of patients with anaerobic lung abscess have no obviousoral cavity disease or predisposition to aspiration, which are the 2 most important factors in thedevelopment of anaerobic lung infection.Evaluation of expectorated sputum is the first step in the diagnosis of a patient with a lung abscess.Perform a Gram stain and culture for both gram-positive and gram-negative organisms and specialstaining for acid-fast bacteria and fungi. Generally, in patients with a typical anaerobic lung abscess,sputum analysis is not useful, but the analysis is helpful to exclude other causes of lung abscess (eg,tuberculosis, aerobic bacteria). The sputum Gram stain in patients with anaerobic lung abscessesoften shows numerous polymorphonuclear leukocytes along with a mixture of bacteria, some of whichare contaminants of oral flora.Because of the presence of anaerobes in the oral cavity, cultures of these microorganisms are notworthwhile. Regular aerobic culture of expectorated sputum should always be performed. When asingle predominant organism is cultured, it is accepted to be the pathogen.Empyema fluid, if accessible, provides an excellent medium. Occasionally, particularly with metastaticlung abscesses, blood culture findings may be positive. Most patients never have appropriatespecimens obtained for culture; most are treated empirically and do well despite the lack of exactmicrobiologic culture results.Chest radiographsThe chest radiograph of a lung abscess is not pathognomic in the early stages, ie, beforecommunication is achieved between the abscess cavity and draining bronchus. An area of thickpneumonic consolidation precedes the emergence of the typical cavitary air-fluid form. The distinctivecharacteristic of lung abscess, the air-fluid level, can only be observed on a chest x-ray film taken withthe patient upright or in the lateral decubitus position. In the presence of associated pleural thickening,atelectasis, or pneumothorax, the air-fluid level may be obscured. When better anatomic interpretationis required, CT scans have proven very useful.Opportunistic lung abscesses are more difficult to diagnose. They occur in patients at the extremes ofage and in patients with multiple medical problems. Under these conditions, multiple abscesses oftenevolve, and most of these are nosocomial. Typically, the microbial flora in these patients is gram-negative. Similar to aspiration-induced lung abscess, cavitation is generally apparent on chestradiographs 2 weeks after the onset of cough, fever, and pleuritic chest pain.Chest CT scan images are valuable for demonstrating cavitation within an area of consolidation, forevaluating the thickness and regularity of the abscess wall, and for determining the exact position ofthe abscess with regard to the chest wall and bronchus. CT scan images can also aid in evaluating theextent of bronchial involvement proximal or distal to the abscess.Invasive diagnostic proceduresInvasive diagnostic techniques occasionally recommended to diagnose lung abscesses includetranstracheal aspirates, transthoracic aspirates, and fiberoptic bronchoscopy. These procedures mustbe performed prior to the institution of antibiotic therapy in order to acquire dependable microbiologicaldata. The indications and comparative benefits of such procedures are controversial and depend to agreat extent on operator ability. Most pulmonologists believe that these diagnostic procedures shouldnot be performed routinely in patients with possible anaerobic lung abscesses; they should bereserved for patients with atypical presentations.
Fiberoptic bronchoscopy is a useful adjunct in the diagnostic evaluation of patients with lung abscess.Secretions obtained from the lower respiratory tract via either lavage or brush can be submitted forculture and sensitivity. Rigid, sterile, and aseptic technique is crucial (eg, use of lidocaine withoutpreservatives, minimal use of topical anesthetic, specimen transport under anaerobic conditions,avoidance of delays in processing), although prior or concurrent antibiotic therapy can cause confusingresults.Thus, in patients who have a classic history and radiological presentation of anaerobic lung abscess,the medically sound decision may be to start with empirical antibiotic therapy without priorbronchoscopy. However, for patients with atypical presentations or unclear diagnoses, bronchoscopyshould be considered. Bronchoscopy may also be used to exclude the presence of a foreign body orneoplasm.If no specimens are available for analysis and diagnosis, percutaneous transtracheal aspiration is aneasy, safe, and dependable way of establishing the specific cause of a lung abscess. This procedureshould be avoided in patients with coagulation disorders or bleeding tendencies and in those for whomit is difficult to provide adequate oxygenation.For patients with amebic liver abscess, Entamoeba histolytica may be recovered from the sputum. Thevast majority of patients with extraintestinal amebiasis have high titers of hemoagglutinin in the serum.Differential diagnosisCavitary lesions in the lung parenchyma have several causes, but a patient with an acute presentationof an illness with air-fluid levels should elicit consideration of a lung abscess. Lung parenchymal cysticlesions and secondarily infected bullae can occasionally confuse the picture. The prior existence ofthese lesions, as documented by old radiographs and the segmental location, are not typical of lungabscess.Patients with squamous cell bronchial carcinomas can also present with cavitary lesions that aresometimes difficult to differentiate from lung abscesses. Realizing that the wall of the carcinomatousabscess is usually thicker and more irregular than that of the primary abscess is helpful. Further, foulsputum, no response to antibiotics, and the absence of fever may help distinguish the 2 entities.Because an abscess distal to bronchial obstruction usually occurs in an area of lobar pneumonitis andatelectasis—but otherwise appears as a primary abscess—early bronchoscopy is recommended in allcases.Antibiotics in lung abscess • Anaerobic organisms1 o First choice - Clindamycin (Cleocin 3) o Alternative - Penicillin o Oral therapy - Clindamycin, metronidazole (Flagyl), amoxicillin (Amoxil) • Gram-negative organisms o First choices - Cephalosporins, aminoglycosides, quinolones o Alternatives - Penicillins and cephalexin (Biocef) o Oral therapy - Trimethoprim/sulfamethoxazole (Septra) • Pseudomonal organisms: First choices include aminoglycosides, quinolones, and cephalosporin. • Gram-positive organisms o First choices - Oxacillin (Bactocill), clindamycin, cephalexin, nafcillin (Nafcil), and amoxicillin o Alternatives - Cefuroxime (Ceftin) and clindamycin o Oral therapy - Vancomycin (Lyphocin) • Nocardial organisms: First choices include trimethoprim/sulfamethoxazole and tetracycline (Sumycin).Drainage
Most lung abscesses communicate with the tracheobronchial tree early in the course of the infectionand drain spontaneously during the course of therapy. Dependent drainage (with appropriate positionsbased on the pulmonary segment) is commonly advocated using chest physical therapy andsometimes bronchoscopy. Bronchoscopy can also facilitate abscess drainage by aspiration of theappropriate bronchus through the bronchoscope. Transbronchial drainage by catheterization of theappropriate bronchus under fluoroscopy has been successful.Generally, augmenting this passive drainage with invasive procedures is unnecessary. In fact,attempts at therapeutic bronchoscopy may sometimes produce adverse consequences. Reports havebeen received of bronchoscopy-induced release of large amounts of purulent material from theinvolved lung segment into other parts of the lung, occasionally inducing acute respiratory failure,acute respiratory distress syndrome (ARDS), or both.Course of treatmentIf treatment is started in the acute stage of the disease and is continued for 4-6 weeks, approximately85-95% of patients with anaerobic lung abscesses respond to medical management alone. Successfulmedical therapy resolves symptoms with no radiographic evidence or only a residual thin-walled cysticcavity (<2 cm after 4-6 wk of antibiotic therapy).The success of medical therapy is dependent on the duration of symptoms and the size of the cavitybefore the initiation of therapy. Antibiotic therapy is rarely successful if symptoms are present forlonger than 12 weeks before the initiation of antibiotic therapy or if the original diameter of the cavity ismore than 4 cm. When patients with lung abscesses do not respond to proper medical therapy,consider the probability of an underlying malignancy.Surgical TreatmentContraindications to surgerySeveral important factors must be considered prior to undertaking surgery. Because of the high risk ofspillage of the abscess into the contralateral lung, it is almost essential that a double-lumen tube beused to protect the airway. If this is not available, surgery poses a very high risk of abscess in theother lung and a risk of ARDS. In such cases, postponing the surgery is a wise decision. Another, less-satisfactory method to deal with this problem includes positioning the patient in the prone position. Thesurgeon must be skilled in resecting the abscess and in rapid clamping of the bronchus to preventspillage into the trachea. These factors are extremely important when dealing with the surgical aspectsof treating a lung abscess. If doubt persists, postponing the surgery is best.Surgical treatment is now rarely necessary and is almost never the initial choice in the treatment oflung abscesses. In current practice, fewer than 15% of patients need surgical intervention for theunchecked disease and for complications that occur in both the acute and chronic stages of thedisease.Surgical management is reserved for specific indications such as little or no response to medicaltreatment, inability to eliminate a carcinoma as a cause, critical hemoptysis, and complications of lungabscess (eg, empyema, bronchopleural fistula). In addition, if after 4-6 weeks of medical treatment anotable residual cavity remains and the patient is symptomatic, surgical resection is advocated.The results of surgery are difficult to assess because of the varying patient population and thetremendous increase in illicit drug abuse, alcoholism, AIDS, and infections by gram-negative andopportunistic organisms. These factors have increased the incidence of lung abscess and theassociated morbidity.A great deal of caution is needed during anesthesia when patients with lung abscess undergo surgerybecause spillage of the abscess material into the uninvolved lung can occur. Therefore, a double-lumen endotracheal tube is used in all cases.Indications for surgery • Probable carcinoma • Significant hemoptysis
Percutaneous drainagePercutaneous drainage of a complicated abscess (ie, one associated with fever and signs of sepsis) isbeneficial in selected patients who do not respond to adequate medical therapy.2 These are ventilator-dependent patients who are not candidates for extensive thoracic procedures.Other indications for drainage include ongoing sepsis despite adequate antimicrobial therapy,progressively enlarging lung abscess in imminent danger of rupture, failure to wean from mechanicalventilation, and contamination of the opposite lung. In current practice, most of these lung abscessesare drained under CT guidance.2Results achieved with percutaneous drainage show it to be safe and effective compared to surgery.Percutaneous drainage is rarely complicated by empyema, hemorrhage, or bronchopleural fistula.Although a few patients who undergo percutaneous drainage develop bronchopleural fistulas, most ofthese fistulas close spontaneously with resolution of the abscess cavity. Percutaneous drainage maybe used to stabilize and prepare critically ill patients for surgery.Hospital-acquired gram-negative infections are usually due to nosocomial organisms (eg,Pseudomonas, Enterobacter, Proteus). Patients with these infections are often elderly, debilitated withnumerous major medical disorders, or have sustained multiple trauma. These patients are typicallytreated in a critical care unit.The infection is usually with a resistant organism originating from a single source. The lung abscessappears rapidly as an area of pneumonitis with associated pleural involvement. These patients oftenrequire percutaneous drainage as an emergency procedure. Unfortunately, the infection is systemicand often out of control, and the pulmonary pathology represents only one aspect of a multiorganinvolvement with a rapidly deteriorating course.Among fungal infections, Candida albicans has become a major organism in lung abscesses. Fungalinfections are difficult to treat, and amphotericin/fluconazole and surgical drainage remain the onlymodalities of treatment; however, at best, they have had only limited success.Complications and PrognosisComplicationsApproximately one third of lung abscesses are complicated by empyema. This may be observed withor without bronchopleural fistulas. Hemoptysis is a common complication of a lung abscess and can betreated with bronchial artery embolization. Occasionally, the hemoptysis can be massive, thusrequiring urgent surgery. Brain abscess may also be a complication in patients who receive inadequatetreatment.PrognosisThe prognosis of patients with lung abscesses depends on the underlying or predisposing pathologicevent and the speed with which appropriate therapy is established. Negative prognostic factors includea large cavity (>6 cm), necrotizing pneumonia, multiple abscesses, immunocompromise, ageextremes, associated bronchial obstruction, and aerobic bacterial pneumonia. The mortality rateassociated with an anaerobic lung abscess is less than 15%, although it is slightly higher in patientswith necrotizing anaerobic pneumonia and pneumonia caused by gram-negative bacteria. Theprognosis associated with amebic lung abscess is good when treatment is prompt.