Difference between revisions of "Diffuse lung diseases"

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'''Diffuse lung diseases''', abbreviated '''DLD''', are a group of uncommon pathologies, also known as '''idiopathic interstitial pneumonias''', abbreviated '''IIPs''', and '''interstitial lung disease'''.  
'''Diffuse lung diseases''', abbreviated '''DLD''', are a group of uncommon pathologies, also known as '''idiopathic interstitial [[pneumonia]]s''', abbreviated '''IIPs''', and '''interstitial lung disease''', abbreviated '''ILD'''.  


They are a subgroup of the [[medical lung diseases]].   
They are a subgroup of the [[medical lung diseases]].   


Diffuse lung disease is the preferred term, as some diseases lumped into this group have involvement of the alveoli, i.e. are not interstitial. Also, some DLDs are not considered idiopathic, e.g. [[LIP]] is caused by [[smoking]].
Diffuse lung disease is the preferred term, as some diseases lumped into this group have involvement of the alveoli, i.e. are not interstitial. Also, some DLDs are not considered idiopathic, e.g. [[DIP]] is caused by [[smoking]].


An introduction to pulmonary pathology is found in the ''[[pulmonary pathology]]'' article.
An introduction to pulmonary pathology is found in the ''[[pulmonary pathology]]'' article.


=Overview - histologic classification=
=Overview=
==Specimens==
*Diffuse lung disease is best assessed on an open biopsy.
**These procedure are quite invasive; thus, not infrequently clinicians will try a transbrochial biopsy that ends-up providing in useful information.
 
===Sign out===
<pre>
LUNG, LEFT, TRANSBRONCHIAL BIOPSY:
- SMALL FRAGMENTS OF LUNG PARENCHYMA WITHOUT SIGNIFICANT CHANGES, SEE MICROSCOPIC
  DESCRIPTION AND COMMENT.
 
COMMENT:
The clinical findings are noted. The size and type of biopsy significantly limit the
interpretation.  Suspected diffuse lung disease (interstitial lung disease)
is best assessed on an open lung biopsy.
</pre>
====Micro====
The sections show small fragments of lung parenchyma. A very small amount of anthracotic
pigment is present. Interstitial fibrosis is not apparent. No granulomata are identified.
No nuclear atypia is identified. Air-space macrophages show minimal pigmentation and are
not present in large numbers. No significant airspace or interstitial inflammation is
identified.
 
==Histologic classification==
*Can be complex,<ref name="pmid12405906">{{cite journal |author=Nicholson AG |title=Classification of idiopathic interstitial pneumonias: making sense of the alphabet soup |journal=Histopathology |volume=41 |issue=5 |pages=381-91 |year=2002 |month=November |pmid=12405906 |doi= |url=http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0309-0167&date=2002&volume=41&issue=5&spage=381}}</ref> and the combined efforts of [[clinician]]s, [[radiologist]]s, and [[pathologist]]s can help in the generation of a more specific diagnosis.<ref name="pmid15256390">{{cite journal |author=Flaherty KR, King TE, Raghu G, ''et al'' |title=Idiopathic interstitial pneumonia: what is the effect of a multidisciplinary approach to diagnosis? |journal=Am. J. Respir. Crit. Care Med. |volume=170 |issue=8 |pages=904-10 |year=2004 |month=October |pmid=15256390 |doi=10.1164/rccm.200402-147OC |url=http://ajrccm.atsjournals.org/cgi/pmidlookup?view=long&pmid=15256390}}</ref><ref name="pmid16738191">{{cite journal |author=Kim DS, Collard HR, King TE |title=Classification and natural history of the idiopathic interstitial pneumonias |journal=Proc Am Thorac Soc |volume=3 |issue=4 |pages=285-92 |year=2006 |month=June |pmid=16738191 |doi=10.1513/pats.200601-005TK |url=http://pats.atsjournals.org/cgi/pmidlookup?view=long&pmid=16738191}}</ref>
*Can be complex,<ref name="pmid12405906">{{cite journal |author=Nicholson AG |title=Classification of idiopathic interstitial pneumonias: making sense of the alphabet soup |journal=Histopathology |volume=41 |issue=5 |pages=381-91 |year=2002 |month=November |pmid=12405906 |doi= |url=http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0309-0167&date=2002&volume=41&issue=5&spage=381}}</ref> and the combined efforts of [[clinician]]s, [[radiologist]]s, and [[pathologist]]s can help in the generation of a more specific diagnosis.<ref name="pmid15256390">{{cite journal |author=Flaherty KR, King TE, Raghu G, ''et al'' |title=Idiopathic interstitial pneumonia: what is the effect of a multidisciplinary approach to diagnosis? |journal=Am. J. Respir. Crit. Care Med. |volume=170 |issue=8 |pages=904-10 |year=2004 |month=October |pmid=15256390 |doi=10.1164/rccm.200402-147OC |url=http://ajrccm.atsjournals.org/cgi/pmidlookup?view=long&pmid=15256390}}</ref><ref name="pmid16738191">{{cite journal |author=Kim DS, Collard HR, King TE |title=Classification and natural history of the idiopathic interstitial pneumonias |journal=Proc Am Thorac Soc |volume=3 |issue=4 |pages=285-92 |year=2006 |month=June |pmid=16738191 |doi=10.1513/pats.200601-005TK |url=http://pats.atsjournals.org/cgi/pmidlookup?view=long&pmid=16738191}}</ref>


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| [[Desquamative interstitial pneumonia]] (DIP)
| [[Desquamative interstitial pneumonia]] (DIP)
| DIP
| DIP
| Smoking
| [[smoking]]
|-
|-
| [[Diffuse alveolar damage]] (DAD)
| [[Diffuse alveolar damage]] (DAD)
Line 32: Line 56:
| [[Respiratory bronchiolitis]]  
| [[Respiratory bronchiolitis]]  
| [[Respiratory bronchiolitis-associated interstitial lung disease|RB-ILD]]
| [[Respiratory bronchiolitis-associated interstitial lung disease|RB-ILD]]
| Smoking
| smoking
|-
|-
| [[Usual interstitial pneumonia]] (UIP)
| [[Usual interstitial pneumonia]] (UIP)
| [[collagen vascular disease|CVD]], [[idiopathic pulmonary fibrosis|IPF]], [[drug toxicity]], [[pneumoconiosis]]
| [[collagen vascular disease|CVD]], [[idiopathic pulmonary fibrosis|IPF]], [[drug toxicity]], [[pneumoconiosis]]
| Allergen (hypersensitivity pneumonitis), idiopathic, autoimmune
| allergen (hypersensitivity pneumonitis), idiopathic, autoimmune
|-
|-
| [[Organizing pneumonia]]
| [[Organizing pneumonia]]
Line 44: Line 68:
| [[Lymphocytic interstitial pneumonia]] (LIP)
| [[Lymphocytic interstitial pneumonia]] (LIP)
| LIP
| LIP
| Viral/autoimmune
| viral/autoimmune
|}
|}
ARDS = adult respiratory distress syndrome, AIP = acute interstitial pneumonia, TRALI = transfusion related acute lung injury, CVD = collagen vascular disease, IPF = idiopathic pulmonary fibrosis.
ARDS = adult respiratory distress syndrome, AIP = acute interstitial pneumonia, TRALI = transfusion related acute lung injury, CVD = [[collagen vascular disease]], IPF = idiopathic pulmonary fibrosis.
 


Notes:
Notes:
*''Usual interstitial pneumonia'' is the most common type of ILD.<ref name="pmid16738196">{{cite journal |author=Visscher DW, Myers JL |title=Histologic spectrum of idiopathic interstitial pneumonias |journal=Proc Am Thorac Soc |volume=3 |issue=4 |pages=322-9 |year=2006 |month=June |pmid=16738196 |doi=10.1513/pats.200602-019TK |url=http://pats.atsjournals.org/cgi/pmidlookup?view=long&pmid=16738196}}</ref>
*''Usual interstitial pneumonia'' is the most common type of ILD.<ref name="pmid16738196">{{cite journal |author=Visscher DW, Myers JL |title=Histologic spectrum of idiopathic interstitial pneumonias |journal=Proc Am Thorac Soc |volume=3 |issue=4 |pages=322-9 |year=2006 |month=June |pmid=16738196 |doi=10.1513/pats.200602-019TK |url=http://pats.atsjournals.org/cgi/pmidlookup?view=long&pmid=16738196}}</ref>
==Gross pathologic DDx by location==
Causes of upper lung fibrosis ''FASSTEN'':<ref name=Ref_TN2005_R13>{{Ref TN2005| R13}}</ref>
*[[Farmer's lung]].
*[[Ankylosing spondylitis]].
*[[Sarcoidosis]].
*[[Silicosis]].
*[[Tuberculosis]] (miliary).
*[[Eosinophilic granuloma]].
*[[Neurofibromatosis]].
Causes of lower lung fibrosis ''BAD RASH'':<ref name=Ref_TN2005_R13>{{Ref TN2005| R13}}</ref>
*[[Bronchiolitis obliterans organizing pneumonia]] (BOOP).
*[[Asbestosis]].
*Drugs (nitrofurantoin, hydralazine, isoniazid (INH), amiodarone).
*[[Rheumatologic disease]].
*[[aspiration pneumonia|Aspiration]].
*[[Scleroderma]].
*Hamman-Rich syndrome (really should be -- ''[[idiopathic pulmonary fibrosis]]'').
Note:
*''Hamman-Rich syndrome'' is another name for [[acute interstitial pneumonia]].<ref name=Ref_WMSP90>{{Ref WMSP|90}}</ref>


=Specific diseases/pattterns=
=Specific diseases/pattterns=
Line 56: Line 101:
==Diffuse alveolar damage==
==Diffuse alveolar damage==
*Abbreviated ''DAD''.
*Abbreviated ''DAD''.
===General===
{{Main|Diffuse alveolar damage}}
DAD is the histologic correlate of:
*Acute respiratory distress syndrome (ARDS).
**[[AKA]] adult respiratory distress syndrome (ARDS) to differentiate it from ''[[respiratory distress syndrome]]'' in infants.
*Acute interstitial pneumonia (AIP).
*Transfusion related acute lung injury (TRALI).
 
The DDx is broad:<ref>{{Ref WMSP|91}}</ref>
*Infection/sepsis.
*Toxic (smoke, oxygen).
*Drug (amiodarone, chemotherapy).
*Trauma/shock.
*Inflammatory.
*Idiopathic.
 
===Microscopic===
Features:<ref name=Ref_Klatt103>{{Ref Klatt|103}}</ref><ref name=pmid16766248>{{Cite journal  | last1 = Castro | first1 = CY. | title = ARDS and diffuse alveolar damage: a pathologist's perspective. | journal = Semin Thorac Cardiovasc Surg | volume = 18 | issue = 1 | pages = 13-9 | month =  | year = 2006 | doi = 10.1053/j.semtcvs.2006.02.001 | PMID = 16766248 }}</ref>
#Exudative:
#*Hyaline membranes - '''key feature'''.
#**Debris (pink crap) lines the alveolar spaces.
#Proliferative:
#*Interstitial thickening.
#*Inflammation (lymphocytes).
#*Hobnailing of alveolar lining cells (hyperplastic pneumocytes).
#*Edema (link pink crap in the alveoli).
#*Masson bodies in the airway.
#*Hyaline material (usu. focal) - '''key feature'''.
#Fibrotic:
#*Interstitial inflammation.
#*Fibrosis.
 
Images:
*[http://commons.wikimedia.org/wiki/File:Hyaline_membranes_-_intermed_mag.jpg DAD - intermed. mag. (WC)].
*[http://en.wikipedia.org/wiki/File:Hyaline_membranes_-_very_high_mag.jpg DAD - very high mag. (WC)].
*[http://commons.wikimedia.org/wiki/File:ARDS.jpg DAD (WC)].


==Usual interstitial pneumonia==
==Usual interstitial pneumonia==
*Abbreviated ''UIP''.
*Abbreviated ''UIP''.
===General===
{{Main|Usual interstitial pneumonia}}
*It is sometimes used incorrectly as a synonym for ''idiopathic pulmonary fibrosis''.  It is a histomorphologic pattern and has a DDx (see below).
*UIP cannot be diagnosed via bronchoscopic or transbronchial biopsy,<ref name=Ref_PPP186>{{Ref PPP|186}}</ref> as it is peripheral.
 
====Epidemiology====
*Disease of the old - rare in under 50 years old.<ref>AC UBC S.102.</ref>
*Dismal prognosis - mean survival after diagnosis ~ 2.8 years.<ref name=pmid9445300>{{Cite journal  | last1 = Bjoraker | first1 = JA. | last2 = Ryu | first2 = JH. | last3 = Edwin | first3 = MK. | last4 = Myers | first4 = JL. | last5 = Tazelaar | first5 = HD. | last6 = Schroeder | first6 = DR. | last7 = Offord | first7 = KP. | title = Prognostic significance of histopathologic subsets in idiopathic pulmonary fibrosis. | journal = Am J Respir Crit Care Med | volume = 157 | issue = 1 | pages = 199-203 | month = Jan | year = 1998 | doi =  | PMID = 9445300 }}</ref>
 
====Differential diagnosis====
UIP is seen in:<ref name=leslie>{{cite book |author=Wick, Mark R.; Leslie, Kevin |title=Practical pulmonary pathology: a diagnostic approach |publisher=Churchill Livingstone |location=Edinburgh |year=2005 |pages= |isbn=0-443-06631-0 |oclc= 156861539|doi= |accessdate=}}</ref>
*Idiopathic pulmonary fibrosis.
*Asbestosis - one ought to see ''ferruginous bodies''.
*Chronic hypersensitivity pneumonitis (extrinsic allergic alveolitis).
*Collagen vascular disease - includes [[systemic lupus erythematosus]], [[rheumatoid arthritis]], [[scleroderma]].<ref>{{Ref PCPBoD8|374}}</ref>
*Chronic drug toxicity.<ref>{{cite journal |author=Rossi SE, Erasmus JJ, McAdams HP, Sporn TA, Goodman PC |title=Pulmonary drug toxicity: radiologic and pathologic manifestations |journal=Radiographics : a review publication of the Radiological Society of North America, Inc |volume=20 |issue=5 |pages=1245-59 |year=2000 |pmid=10992015 |doi=}}</ref>
 
===Radiology===
*Honeycombing - ''multiple'' defects that obliterate the normal lung architecture - multiple spherical voids in the lung parenchyma; radiologically these are seen as lucencies.<ref>[http://www.medcyclopaedia.com/library/topics/volume_v_1/h/honeycombing.aspx http://www.medcyclopaedia.com/library/topics/volume_v_1/h/honeycombing.aspx]</ref>
**Usually subplural, i.e. peripheral lung.
**Classically lower lobe predominant.
*Traction bronchiectasis.
 
Note:
*Cysts - have thin walls (think of emphysema, [[lymphangioleiomyomatosis]] et cetera).
**Cysts may be isolated/not close to a neighbour.
**Medcyclopaedia defines it as: thin-walled, well-demarcated and >1 cm.<ref>[http://www.medcyclopaedia.com/library/topics/volume_v_1/l/lung_cyst.aspx http://www.medcyclopaedia.com/library/topics/volume_v_1/l/lung_cyst.aspx]</ref>
 
===Microscopic===
Features:<ref name=Ref_PPP186-9>{{Ref PPP|186-9}}</ref>
*Fibroblast foci:
**"Crescent-shaped bulge" of fibroblasts -- a rounded projection of spindle cells into the airspace.
**Location: in the areas of transisition between active inflammation and old inflammation.<ref>[http://www.epler.com/IPFWhat%27sIPFDiseaseInformation2.htm http://www.epler.com/IPFWhat%27sIPFDiseaseInformation2.htm]</ref>
**Note: Technically, ''fibroblast foci'' are composed of myofibroblasts.<ref name=Ref_PPP189>{{Ref PPP|189}}</ref>
*Interstitial inflammation.
*Microscopic honeycombing.
**Typically peripheral - cysts lined by ciliated epithelium.
*Spatial heterogeneity - patchy lesional distribution (areas of abnormal and normal lung may appear beside one another).
*Temporal heterogeneity - lesions of differing age side-by-side.<ref name=Ref_WMSP92>{{Ref WMSP|92}}</ref>
 
Notes:
*Disease worse distant from large airways: lower lung field predominance, typically worse at periphery of lobule and lung.<ref>A. Churg. UBC S.103.</ref>
*Heterogeneity of inflammation: airspace macrophages & inflammation minimal in honeycombed foci.


==Asbestosis==
==Asbestosis==
===General===
{{Main|Asbestosis}}
Definition:
*Interstitial lung disease due to asbestos exposure.<ref name=Ref_PCPBoD8_375>{{Ref PCPBoD8|375}}</ref>
**Important to diagnose... asbestosis = compensation.
 
Conditions associated with asbestos exposure (mnemonic ''PALM''):<ref name=Ref_PCPBoD8_375>{{Ref PCPBoD8|375}}</ref>
*Pleural plaques.
*Asbestosis.
*[[Malignant mesothelioma]].
*[[Lung carcinoma]].
 
Possible association with asbestos exposure:
*[[Gestational trophoblastic disease]].<ref name=pmid19900938>{{Cite journal  | last1 = Reid | first1 = A. | last2 = Heyworth | first2 = J. | last3 = de Klerk | first3 = N. | last4 = Musk | first4 = AW. | title = Asbestos exposure and gestational trophoblastic disease: a hypothesis. | journal = Cancer Epidemiol Biomarkers Prev | volume = 18 | issue = 11 | pages = 2895-8 | month = Nov | year = 2009 | doi = 10.1158/1055-9965.EPI-09-0731 | PMID = 19900938 }}</ref>
 
===Microscopic===
Features:
*Histologic appearance as for [[usual interstitial pneumonia]] (UIP).
*''Ferruginous bodies'' - '''key feature'''.
**Segmented twirling baton with long slender fibre within.
 
Images:
*[http://commons.wikimedia.org/wiki/File:Ferruginous_body.jpg Ferruginous bodies (WC)].
*[http://commons.wikimedia.org/wiki/File:Asbestosis_high_mag.jpg Asbestosis (WC)].


==Non-specific interstitial pneumonia==
==Non-specific interstitial pneumonia==
*Abbreviated ''NSIP''.
*Abbreviated ''NSIP''.
{{Main|Non-specific interstitial pneumonia}}


===General===
==Organizing pneumonia==
*Better prognosis than [[UIP]].
{{Main|Organizing pneumonia}}
*Some radiologists and pathologists don't believe in this entity.
 
Associations:<ref name=Ref_WMSP92>{{Ref WMSP|92}}</ref>
*Connective tissue disease.
*[[Rheumatoid arthritis]].
 
===Gross/Radiology===
*No honeycombing.
*Fibrosis usually lower lung zone.
*Patchy ground glass.
 
===Microscopic===
Features:<ref name=Ref_WMSP92>{{Ref WMSP|92}}</ref>
*Diffuse fibrosis:
**Uniform fibrosis (unlike [[UIP]]).
**"Linear fibrosis" has a good prognosis - should be mentioned in the report.
***''Linear fibrosis'' = fibrosis that follows alveolar walls + no architectural distortion.
*+/-Lymphoid nodules - association with collagen vascular disease. (???)
*+/-Focal [[organizing pneumonia]].
 
Notes:
*Inflammation in NSIP usually more prominent than in UIP.
*No honeycombing - key difference between UIP and NSIP.
 
DDx:
*Collagen vascular disease.
*Drug reaction.
*[[Hypersensitivity pneumonitis]] (extrinic allergic alveolitis).
*[[Lymphocytic interstitial pneumonia]] (LIP) - much more inflammation.


==Hypersensitivity pneumonitis==
==Hypersensitivity pneumonitis==
*AKA ''extrinsic allergic alveolitis''
*AKA ''extrinsic allergic alveolitis''
 
{{Main|Hypersensitivity pneumonitis}}
===General===
*Exposure to stuffs... e.g. moldy hay - ''Farmer's lung'', atypical mycobacteria - ''hot tub lung''.
*Upper lung predominant disease.
**Mnemonic ''FASSTEN'' - upper lung field: [[Farmer's lung]], [[Ankylosing spondylitis]], [[Sarcoidosis]], [[Silicosis]], [[Tuberculosis]] (miliary), [[Eosinophilic granuloma]], [[Neurofibromatosis]].
*An immune complex-mediated [[hypersensitivity]]<ref name=pmid8279154>{{Cite journal  | last1 = Kaltreider | first1 = HB. | title = Hypersensitivity pneumonitis. | journal = West J Med | volume = 159 | issue = 5 | pages = 570-8 | month = Nov | year = 1993 | doi =  | PMID = 8279154 | url = http://www.ncbi.nlm.nih.gov/pmc/articles/pmid/8279154/?tool=pubmed }}</ref> (Gell-Coombs classification type III).
**If chronic, may develop into a cell-mediated hypersensitivity (Gell-Coombs classification type IV).<ref>URL: [http://library.med.utah.edu/WebPath/EXAM/IMGQUIZ/pufrm.html http://library.med.utah.edu/WebPath/EXAM/IMGQUIZ/pufrm.html]. Accessed on: 4 December 2011.</ref>
 
===Microscopic===
Features:
* Lesions have centrilobular prominence - '''important feature'''. <ref name=pmid16061708/>
** Allergens enter lung through airway which has a centrilobular location.
* [[Granulomata]] (not typically seen in UIP) - '''important feature'''.<ref name=pmid16061708>{{Cite journal  | last1 = Ohtani | first1 = Y. | last2 = Saiki | first2 = S. | last3 = Kitaichi | first3 = M. | last4 = Usui | first4 = Y. | last5 = Inase | first5 = N. | last6 = Costabel | first6 = U. | last7 = Yoshizawa | first7 = Y. | title = Chronic bird fancier's lung: histopathological and clinical correlation. An application of the 2002 ATS/ERS consensus classification of the idiopathic interstitial pneumonias. | journal = Thorax | volume = 60 | issue = 8 | pages = 665-71 | month = Aug | year = 2005 | doi = 10.1136/thx.2004.027326 | PMID = 16061708 }}</ref>
* Chronic interstitial inflammation consisting primarily of lymphocytes.
* Interstitial fibrosis.
* Air space involvement (alveolitis).
 
Images:
*[http://commons.wikimedia.org/wiki/File:Hypersensitivity_pneumonitis_intermed_mag.jpg Hypersensitivity pneumonitis - intermed. mag. (WC)].
*[http://commons.wikimedia.org/wiki/File:Hypersensitivity_pneumonitis_high_mag.jpg Hypersensitivity pneumonitis - high mag. (WC)].


==Lymphocytic interstitial pneumonia==
==Lymphocytic interstitial pneumonia==
*Often abbreviated '''''LIP'''''.
*Often abbreviated '''''LIP'''''.
===General===
{{Main|Lymphocytic interstitial pneumonia}}
*Associated with autoimmune disorders ([[rheumatoid arthritis]], [[pernicious anemia]], [[Sjoegren syndrome]])<ref>URL: [http://emedicine.medscape.com/article/299643-overview http://emedicine.medscape.com/article/299643-overview]. Accessed on: 2 June 2010.</ref> and immunodeficiency.<ref name=pmid16088689>{{cite journal |author=Nicholson AG |title=Lymphocytic interstitial pneumonia and other lymphoproliferative disorders in the lung |journal=Semin Respir Crit Care Med |volume=22 |issue=4 |pages=409–22 |year=2001 |month=August |pmid=16088689 |doi=10.1055/s-2001-17384 |url=}}</ref>
*Associated with viral infections ([[HIV]], EBV, human T-cell leukemia virus (HTLV) type 1).
**Considered an AIDS-defining diagnosis.<ref>{{Cite journal  | last1 = Turner | first1 = BJ. | last2 = Eppes | first2 = S. | last3 = McKee | first3 = LJ. | last4 = Cosler | first4 = L. | last5 = Markson | first5 = LE. | title = A population-based comparison of the clinical course of children and adults with AIDS. | journal = AIDS | volume = 9 | issue = 1 | pages = 65-72 | month = Jan | year = 1995 | doi =  | PMID = 7893443 }}</ref>
 
===Gross===
*Location: basilar predominance.
*Increased interstitial markings.


===Microscopic===
==Respiratory bronchiolitis-interstitial lung disease==
Features:<ref>URL: [http://emedicine.medscape.com/article/299643-diagnosis http://emedicine.medscape.com/article/299643-diagnosis]. Accessed on: 2 June 2010.</ref>
*Abbreviated ''RB-ILD'' or ''RBILD''.
*Small mature lymphocytes (usually B cells)<ref name=afip_vol2_265>AFIP atlas of nontumour pathology. 2002. Vo. 2. P.265. ISBN 1-881041-79-4.</ref> in the interstitium of the lung.
*[[AKA]] ''respiratory bronchiolitis-associated interstitial lung disease''.
*Plasma cells.
{{Main|Respiratory bronchiolitis-interstitial lung disease}}
*+/-Lymphoid follicles.
 
Negatives:
*No [[vasculitis]].
*No [[necrosis]].
 
Images:
*[http://www.scielo.br/img/revistas/jbpneu/v34n2/en_a02fig01.jpg LIP (scielo.br)].
*[http://path.upmc.edu/cases/case176/micro.html LIP (upmc.edu)].
 
DDx:
*[[Lymphoma]].
*Follicular bronchitis/bronchiolitis.
*Nodular lymphoid hyperplasia.
**This is determined in part by radiology; it has nodules radiographically.
 
===Stains===
To exclude infection:<ref>URL: [http://path.upmc.edu/cases/case176/dx.html http://path.upmc.edu/cases/case176/dx.html]. Accessed on: 8 January 2012.</ref>
*[[GMS stain]] -ve.
*[[Ziehl-Neelsen stain]] -ve.
 
===IHC===
*May be done to exclude lymphoma.
 
==Respiratory bronchiolitis interstitial lung disease==
*Abbreviated ''RBILD''.
**Also written as ''RB-ILD''.
===General===
*May be an early version of ''[[DIP]]''.
 
===Microscopic===
Features:<ref name=Ref_PPP197-8>{{Ref PPP|197-8}}</ref>
*Brown pigmented airspace macrophages - ''smoker's macrophages''.
*Inflammation of the terminal bronchioles.
 
Note:
*The histologic features of RBILD may be present peri-tumoural.


==Desquamative interstitial pneumonia==
==Desquamative interstitial pneumonia==
*Abbreviated ''DIP''.
*Abbreviated ''DIP''.
===General===
{{Main|Desquamative interstitial pneumonia}}
*Thought to be advanced ''[[RBILD]]''.
*Strong association with smoking.<ref name=Ref_WMSP93>{{Ref WMSP|93}}</ref>
**Treatment: stop smoking.
 
===Microscopic===
Features:
*Abundant brown pigmented airspace macrophages - ''smoker's macrophages'' - '''key feature'''.
*Architecture preserved; "linear fibrosis".
 
Notes:
*Some fields of view may be indistinguishable from [[RBILD]].
*Amiodarone toxicity, fibrotic NSIP - may appear similar.
 
Images:
*[http://pathhsw5m54.ucsf.edu/case27/dip27.html DIP (ucsf.edu)].
 
===Stains===
*Macrophages PAS +ve.


=See also=
=See also=

Latest revision as of 03:37, 18 April 2016

Diffuse lung diseases, abbreviated DLD, are a group of uncommon pathologies, also known as idiopathic interstitial pneumonias, abbreviated IIPs, and interstitial lung disease, abbreviated ILD.

They are a subgroup of the medical lung diseases.

Diffuse lung disease is the preferred term, as some diseases lumped into this group have involvement of the alveoli, i.e. are not interstitial. Also, some DLDs are not considered idiopathic, e.g. DIP is caused by smoking.

An introduction to pulmonary pathology is found in the pulmonary pathology article.

Overview

Specimens

  • Diffuse lung disease is best assessed on an open biopsy.
    • These procedure are quite invasive; thus, not infrequently clinicians will try a transbrochial biopsy that ends-up providing in useful information.

Sign out

LUNG, LEFT, TRANSBRONCHIAL BIOPSY:
- SMALL FRAGMENTS OF LUNG PARENCHYMA WITHOUT SIGNIFICANT CHANGES, SEE MICROSCOPIC
  DESCRIPTION AND COMMENT.

COMMENT:
The clinical findings are noted. The size and type of biopsy significantly limit the 
interpretation.  Suspected diffuse lung disease (interstitial lung disease) 
is best assessed on an open lung biopsy.

Micro

The sections show small fragments of lung parenchyma. A very small amount of anthracotic pigment is present. Interstitial fibrosis is not apparent. No granulomata are identified. No nuclear atypia is identified. Air-space macrophages show minimal pigmentation and are not present in large numbers. No significant airspace or interstitial inflammation is identified.

Histologic classification

Idiopathic interstitial pneumonia can be subclassified based on histologic appearance into the following patterns:[4][5]

Histology Clinical Correlates Associations
Desquamative interstitial pneumonia (DIP) DIP smoking
Diffuse alveolar damage (DAD) ARDS, AIP, TRALI ARDS: trauma, infection; TRALI: blood transfusion; AIP: viral (???)
Nonspecific interstitial pneumonia (NSIP) NSIP ???
Respiratory bronchiolitis RB-ILD smoking
Usual interstitial pneumonia (UIP) CVD, IPF, drug toxicity, pneumoconiosis allergen (hypersensitivity pneumonitis), idiopathic, autoimmune
Organizing pneumonia Cryptogenic organizing pneumonia autoimmune (???)
Lymphocytic interstitial pneumonia (LIP) LIP viral/autoimmune

ARDS = adult respiratory distress syndrome, AIP = acute interstitial pneumonia, TRALI = transfusion related acute lung injury, CVD = collagen vascular disease, IPF = idiopathic pulmonary fibrosis.

Notes:

  • Usual interstitial pneumonia is the most common type of ILD.[6]

Gross pathologic DDx by location

Causes of upper lung fibrosis FASSTEN:[7]

Causes of lower lung fibrosis BAD RASH:[7]

Note:

Specific diseases/pattterns

Diffuse alveolar damage

  • Abbreviated DAD.

Usual interstitial pneumonia

  • Abbreviated UIP.

Asbestosis

Non-specific interstitial pneumonia

  • Abbreviated NSIP.

Organizing pneumonia

Hypersensitivity pneumonitis

  • AKA extrinsic allergic alveolitis

Lymphocytic interstitial pneumonia

  • Often abbreviated LIP.

Respiratory bronchiolitis-interstitial lung disease

  • Abbreviated RB-ILD or RBILD.
  • AKA respiratory bronchiolitis-associated interstitial lung disease.

Desquamative interstitial pneumonia

  • Abbreviated DIP.

See also

References

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  2. Flaherty KR, King TE, Raghu G, et al (October 2004). "Idiopathic interstitial pneumonia: what is the effect of a multidisciplinary approach to diagnosis?". Am. J. Respir. Crit. Care Med. 170 (8): 904-10. doi:10.1164/rccm.200402-147OC. PMID 15256390. http://ajrccm.atsjournals.org/cgi/pmidlookup?view=long&pmid=15256390.
  3. Kim DS, Collard HR, King TE (June 2006). "Classification and natural history of the idiopathic interstitial pneumonias". Proc Am Thorac Soc 3 (4): 285-92. doi:10.1513/pats.200601-005TK. PMID 16738191. http://pats.atsjournals.org/cgi/pmidlookup?view=long&pmid=16738191.
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