Lung Abscess


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Lung Abscess

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Lung Abscess

  1. 1. Lung Abscess Presented by Dr. Deena Abdel HadiDirected by Dr. Abdul-Rahman Abu Rubb 1
  2. 2. Background:Definition Necrosis of the pulmonary tissue &formation ofcavities containingnecrotic debris orfluid.caused by microbial infectionThe formation of multiple small )> 2 cm(abscesses is occasionally referred to as necrotizing pneumonia or.lung gangrene 2
  3. 3. Failure to recognize & treat lung abscess is associated.with poor clinical out-come Lung abscess was a devastating disease in thepre-antibiotic era, when 1/3 of the patients died, another1/3 recovered, & the remainder developed debilitating illnesses]i.e. recurrent abscesses,.]chronic empyema, bronchiectasis 3
  4. 4. In the early post-antibiotic period,sulfonamides didn‘timprove the out-come of patients with lung abscess until thepenicillins &tetracyclines. were availableAlthoughresectional surgery was often considered a treatment option in the past,the role of surgery hasgreatly diminished over time coz most patients withun-complicated lung abscess eventually respond to .prolonged antibiotic therapy 4
  5. 5. Lung abscesses can be classified based on the duration. & the likelyetiologyAcute abscesses are less than 4-6 wks old, whereaschronic abscesses .are of longer durationPrimary abscess isinfectious in origin, caused byaspiration or pneumonia . in the healthy host 5
  6. 6. Secondary Abscess: is caused by.)Pre-existing condition )obstruction -.Spread from an extra-pulmonary site -.Bronchiectasis -.An immuno-compromised state -Lung abscesses can be further characterized by the responsible pathogen, such asStaphylococcus lungabscess & anaerobic orAspergillus . lung abscess 6
  7. 7. PathophysiologyLung abscess arises as acomplication of aspiration.pneumonia caused by mouth anaerobesA bacterial inoculums from the gingival crevicereaches the lower airways, & infection is initiatedcoz the bacteria aren‘t cleared by the patient‘s host .defense mechanism 7
  8. 8. Abscesses generally develop in theright lung and involve theposterior segment of the right upperlobe , thesuperior segment of the lower lobe, or both. This isdue to gravitation of the infectiousmaterial from the oropharynx into these dependent .areas 8
  9. 9. Initially, the aspirated material settles in the distalbronchial system and develops into a localizedpneumonitis. Within 24-48 hours, a large area ofinflammation results, consisting of exudate, blood,and necrotic lung tissue. The abscess frequently .connects with a bronchus and partially empties 9
  10. 10. Other mechanisms for lung abscess formation: include:Septic emboli to the lung ,caused by )1.Bacteremia )2 .Tricuspid valve endocarditis 10
  11. 11. MicrobiologyAnaerobes are recovered in up to 89% of the patients,46% of patients with lung abscess had only a mixture ofanaerobes isolated from sputum cultures while43% of patients had a mixture ofanaerobes &.aerobesThe most common anaerobes arePeptosretococcus,Bacteroids ,Fusobacterium species &.Microaerophilic streptococcus 11
  12. 12. Other organisms that may infrequently causelung abscess includeStaphylococcus aureus,Streptococcus pyogens, Streptococcuspneumoniae)rarely(, Klebsiella pneumoniae,Hemophilus influenza, Actinomyces species,.Nocardia species, & Gm negative bacilli 12
  13. 13. . Non-bacterial pathogens may also cause lung abscesses:Theses micro-organisms include.]Parasites ]Paragonimus , Entamoeba )1 Fungi] Aspergillus , Cryptococcus , )2.] Histoplasma , Blastomyces , Coccidioides .Mycobacterium )3 13
  14. 14. History:Anaerobic infectionPatients often present with indolent symptoms that )1.evolve over a period of weeks to months The usual symptoms are )2 fever ,cough with sputum.production ,night sweats ,anorexia &weight lossThe expectorated )3 sputum characteristically isfoul.smelling & bad tasting Patients may develop )4.hemoptysis or pleurisy 14
  15. 15. :Other bacterial pathogensThese patients generally present with conditions )1that are more emergent in nature & are usually.treated while they have bacterial pneumonia )2Cavitation occurs subsequently as parenchymal.necrosis ensues Abscesses from fungi, )3 Nocardia& Mycobacteriatend to have an indolent course & symptoms 15
  16. 16. Physical Patients may havelow-grade fever in anaerobicinfections &.temperature < 38.5 C in other infections. Generally,evidence of gingival disease is presentClinical findings of consolidation may be present :]decreased breath sounds, dullness to percussion, .]bronchial breath sounds, course inspiratory crackles 16
  17. 17. Evidence of pleural friction rub signs of associatedpleural effusion, empyema & pyo-pneumothorax may: be present. Signs includedullness to percussion, contralateral mediastinal shifting].]& absent breath sounds over the effusion .Digital clubbing may develop rapidly 17
  18. 18. CausesThe bacterial infection may reach the lungs inseveral ways .that most common is.aspiration of oro-pharyngeal contents 18
  19. 19. Factors contributing to lung abscess Oral cavity disease Periodontal disease Gingivitis Altered consciousness] inability to protect their ]airways coz of an absent gag reflex Alcoholism Coma Drug abuse Anesthesia 19 Seizures
  20. 20. Immunocompromised hostSteroid chemotherapyMalnutritionMultiple traumaEsophageal diseaseAchalasiaReflux diseaseDepressed cough and gag reflexEsophageal obstruction 20
  21. 21. Bronchial obstructionTumorForeign bodyStrictureGeneralized sepsis 21
  22. 22. patients with 1ry lung disorders.Septic emboli from tricuspid endocarditis .Vasculitic disorders.Cavitating lung malignancies.Pulmonary cystic diseases 22
  23. 23. The following infectious etiologies of pneumoniainfrequently progress to parenchymal necrosis & lung:abscess formation.Pseudomonas aerugenosa -.Klebsiella pneumoniae -.))may result in multiple abscesses Staph. aureus -.Strept. Pneumonia -.Nocardia species -.Fungal species - 23
  24. 24. An abscess may occur2ry to bronchialcarcinoma , thebronchial obstruction causespost-obstructive pneumonia which may abscess formation 24
  25. 25. Differential DiagnosisAlcoholism )1 Pneumocystis Carnii )7 Pleuro-pulmonary )2 .pneumonia . Empyema .Aspiration pneumonia )8.Hydatid Cysts )3 .Bacterial pneumonia )9.Lung Cancer )4 .Fungal pneumonia )10.Mycobacterium )5 .Pulmonary embolism )11 Pneumococcal )6 .Sarcoidosis )12. infections .T.B )13 25
  26. 26. Lab StudiesCBC -. Sputum forgram stain ,culture & sensitivity -acid fast bacilli stain & If T.B. is suspected, - mycobacterial culture. is requestedBlood culture may be helpful in establishing the -. etiologysputum forova & parasite whenever a Obtain - . parasitic cause for lung abscess is suspected 26
  27. 27. HistopathologyA thick-walled lung abscess 27
  28. 28. Histology of lung abscess shows dense inflammatory reaction((low power 28
  29. 29. Histology of lung abscess shows dense inflammatory reaction((high power 29
  30. 30. Imaging Studies:CXR.Irregularly sharp cavity with an air-fluid level inside -Lung abscess as a result of aspiration most frequently -occur in the posterior segments of the upper lobes or.the superior segments of the lower lobe 30
  31. 31. The wall thickness of a lung abscess -progresses from thick to thin and from ill-defined to well-circumscribed as the .surrounding lung infection resolvesThe cavity wall can be smooth or ragged but -is less commonly nodular, which raises the.possibility of cavitating carcinoma 31
  32. 32. The abscess may extend to the pleural surface, -in which case it forms acute angles with the.pleural surfaceUp to one third of lung abscesses may be - -.accompanied by an empyema 32
  33. 33. Pneumococcal pneumoniacomplicated by lung necrosis & abscess formation 33
  34. 34. A lateral CXR shows air fluid level ((characteristic of lung abscess 34
  35. 35. A 54 yr old pt. developed cough with foul- smelling sputum production. A CXR.shows lung abscess in the left lower lobes 35
  36. 36. A 42 y.o. man developed fever & production of foul-smelling sputum. He had a H/O heavy alcohol use & poor dentition, CXR shows lung abscess in the post .segment of the Rt. up. lobe 36
  37. 37. CXR of a patient who had foul-smelling & badtasting sputum, an almost diagnostic feature of anaerobic lung abscess 37
  38. 38. :CT scan -Better in lung anatomy visualization to identify -.empyema from lung infarctionAn abscess is rounded radio-lucent lesion with a think -.wall & ill-defined irregular margins 38
  39. 39. A 42 yr old man developed fever & production of foul-smelling sputum. He had a H/O heavy alcohol abuse & poor dentition, CXR shows lung abscess in the post. Segment of the Rt. Up. Lobe. CT scan shows a thin-walled cavity with .surrounding consolidation 39
  40. 40. ProceduresTrans-tracheal aspirate or trans-thoracic needle -aspiration may provide microbiologic diagnosis,obtaining pleural fluid and blood cultures in patients.with lung abscess is easierFlexible fiberoptic bronchoscopy is performed to -exclude bronchogenic carcinoma whenever bronchial.obstruction is suspected 40
  41. 41. Medical Care:Antibiotic therapyClindamycin ]shown to be Anaerobic lung infection = -superior over parenteral penicillin coz severalanaerobes may produce B-lactamase & therefore .]develop penicillin resistancemetronidazole is an effective drug against Although -anaerobic bacteria, a failure rate of 50% has been.reported 41
  42. 42. In hospitalized patients who have aspirated and -developed a lung abscess, antibiotic therapy should include coverage againstS aureus andEnterobacter andPseudomonas .speciesCefoxitin is a second-generation cephalosporin that -has gram-positive, gram-negative, and anaerobiccoverage. This agent may be used when apolymicrobial infection is suspected as cause of.lung abscess 42
  43. 43. :Duration of therapyMost clinicians prescribe antibiotic therapy generally -for.4-6 weeksCurrent recommendations are that antibiotic - treatment should be continued until thechestradiograph has shown either the resolution of lung .abscess or the presence of a small stable lesion 43
  44. 44. :Response to therapyPatients show clinical improvement, with -improvement of fever, within 3-4 days after.initiating the antibiotic therapyPatients with poor response to antibiotic therapy -include bronchial obstruction with a foreign body orneoplasm or infection with a resistant bacteria, .Mycobacteria, or fungi 44
  45. 45. Surgical Care Surgery isvery rarely required for patients withuncomplicated lung abscesses. The usual indications for surgery arefailure to respond to medicalmanagement, suspected neoplasm, or congenitallung malformation. The surgical procedure .performed is either lobectomy or pneumonectomy 45
  46. 46. Complications.Rupture into pleural space causing empyema )1.Pleural fibrosis )2.Trapped lung )3.Respiratory failure )4.Bronchopleural fistula )5.Pleural cutaneous fistula)6In a patient with coexisting empyema and lung abscess,draining the empyema while continuing prolonged .antibiotic therapy is often necessary 46
  47. 47. PrognosisThe prognosis for lung abscess followingantibiotic treatment is generally favorable.Over 90% of lung abscesses are cured withmedical management alone, unless caused by.bronchial obstruction secondary to carcinoma 47
  48. 48. The EndThank You 48