Lung abscess
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2008-05-27T18:38:18Z
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{{Infobox_Disease |
Name = {{PAGENAME}} |
Image = Lung abscess.jpg|
Caption = Lung section showing apical abscess|
DiseasesDB = 7607 |
ICD10 = {{ICD10|J|85||j|85}} |
ICD9 = {{ICD9|513.0}} |
ICDO = |
OMIM = |
MedlinePlus = |
eMedicineSubj = med |
eMedicineTopic = 1332 |
MeshID = D008169 |
}}
'''Lung abscess''' is [[necrosis]] of the [[pulmonary]] tissue and formation of cavities (more than 2 cm)<ref>{{cite journal |author=Bartlett JG, Finegold SM |title=Anaerobic pleuropulmonary infections |journal=Medicine (Baltimore) |volume=51 |issue=6 |pages=413–50 |year=1972 |pmid=4564416 |doi=}}</ref> containing necrotic debris or fluid caused by [[microbial]] infection.
This pus-filled cavity is often caused by aspiration, which may occur during altered consciousness. [[Alcoholism]] is the most common condition predisposing to lung abscesses.
Lung Abscess is considered '''primary'''(60%<ref name="medscape">{{cite web |url=http://www.medscape.com/viewarticle/534860 |title=Pneumonia and Other Pulmonary Infections: Lung Abscess, Medscape |accessdate=2007-06-20 |format= |work=}}</ref>) when it results from existing lung [[parenchymal]] process and is termed '''secondary''' when it complicates another process e.g. [[Blood vessel|vascular]] [[emboli]] or follows rupture of [[extrapulmonary]] [[abscess]] into lung.
== Causes ==
;Conditions contributing to lung abscess
*Aspiration of [[oropharyngeal]] or [[gastric]] secretion
*Septic emboli
*[[Necrotizing]] [[pneumonia]]
*[[Vasculitis]]: [[Wegener's 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.
;Organisms
In the post-antibiotic era pattern of frequency is changing. In older studies anaerobes were found in up to 90% cases but they are much less frequent now<ref>{{cite journal |author=Bartlett JG |title=The role of anaerobic bacteria in lung abscess |journal=Clin. Infect. Dis. |volume=40 |issue=7 |pages=923–5 |year=2005 |pmid=15824980 |doi=10.1086/428586}}</ref>.
*[[Anaerobic bacteria]]: [[Peptostreptococcus]], [[Bacteroides]], [[Fusobacterium]] species,
*[[Microaerophilic]] [[streptococcus]] : ''[[Streptococcus milleri]]''
*[[Aerobic bacteria]]: [[Staphylococcus]], [[Klebsiella]], [[Haemophilus]], [[Pseudomonas]],[[Nocardia]], [[Escheria coli]], [[Streptococcus]], [[Mycobacteria]]<ref name="pmid10084487">{{cite journal |author=Hirshberg B, Sklair-Levi M, Nir-Paz R, Ben-Sira L, Krivoruk V, Kramer MR |title=Factors predicting mortality of patients with lung abscess. |journal=Chest |volume=115 |issue=3 |pages=746–50 |year=1999 |pmid=10084487 |doi=}}</ref>
*[[Fungus|Fungi]]: [[Candida (genus)|Candida]], [[Aspergillus]]
*Parasites: [[Entamoeba histolytica]],
== Symptom and sign ==
Onset of symptoms is often gradual, but in necrotizing staphylococcal or gram-negative bacillary pneumonias patients can be acutely ill. [[Cough]], fever with shivering and [[night sweats]] 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) <ref name="Moreira">{{cite journal |author=Moreira Jda S, Camargo Jde J, Felicetti JC, Goldenfun PR, Moreira AL, Porto Nda S |title=Lung abscess: analysis of 252 consecutive cases diagnosed between 1968 and 2004 |journal=Jornal brasileiro de pneumologia : publicaça̋o oficial da Sociedade Brasileira de Pneumologia e Tisilogia |volume=32 |issue=2 |pages=136–43 |year=2006 |pmid=17273583 |doi=}}</ref>. Affected individuals may also complaint chest pain, shortness of breath, [[lethargy]] and other features of chronic illness.
Patients are generally [[cachexia|cachectic]] at presentation. Finger [[clubbing]] is present in one third of patients<ref name="Moreira"/>. Dental decay is common especially in alcoholics and children. On examination of chest there will be features of consolidation such as localised dullness on [[percussion]], [[Breath sounds|bronchial breath sound]] etc.
== Diagnosis ==
;Chest Xray and other imaging studies
Abscess is often [[unilateral]] and single involving posterior segments of the upper lobes and the apical segments of the lower lobes as these areas are gravity dependent when lying down. Presence of air-fluid levels implies rupture into the [[bronchial tree]] or rarely growth of gas forming organism.
;Laboratory studies
Raised inflammatory markers ( high [[Erythrocyte sedimentation rate|ESR]], [[C-reactive protein|CRP]]) are usual but not specific. Examination of sputum is important in any pulmonary infections and here often reveals mixed flora. [[Respiration (physiology)|Transtracheal]] of [[bronchus|Transbronchial]] (via bronchoscopy) aspirates can also be cultured. Fibre optic [[bronchoscopy]] is often performed to exclude obstructive lesion; it also helps in bronchial drainage of pus.
== Management==
Broadspectrum [[antibiotic]] to cover mixed flora is the mainstay of treatment. Pulmonary physiotherapy and postural drainage are also important. Surgical procedures are required in selective patients for drainage or pulmonary resection.
== Complications ==
Rare now a days but include spread of infection to other lung segments, [[bronchiectasis]], [[empyema]], and [[bacteraemia]] with [[metastasis|metastatic]] infection such as [[brain abscess]]<ref name="medscape"/>.
== Prognosis ==
Most cases respond to antibiotic and prognosis is usually excellent unless there is a debilitating underlying condition. Mortality from lung abscess alone is around 5% and is improving.
==See also==
*Other chronic lung infections
**[[Empyema]]
**[[Bronchiectasis]]
*[[Abscess]]
*[[Pleural effusion]]
==External links==
* [http://www.merck.com/mrkshared/mmanual/section6/chapter74/74a.jsp Merck]
* {{Chorus|02036}}
==References==
{{reflist}}
{{Respiratory pathology}}
[[Category:pulmonology]]
[[es:Absceso pulmonar]]
[[nl:Longabces]]
[[pl:Ropień płuc]]
[[ru:Абсцесс лёгких]]
[[fi:Keuhkopaise]]