Difference between revisions of "Hypersensitivity pneumonitis"

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#redirect [[Diffuse_lung_diseases#Hypersensitivity_pneumonitis]]
{{ Infobox diagnosis
| Name      = {{PAGENAME}}
| Image      =
| Width      =
| Caption    =
| Synonyms  = extrinsic allergic alveolitis
| Micro      = centrilobular prominence of lesions, [[granulomata]], chronic interstitial inflammation consisting primarily of lymphocytes, interstitial fibrosis, air space involvement (alveolitis)
| Subtypes  =
| LMDDx      = [[usual interstitial pneumonia]], [[asbestosis]]
| Stains    =
| IHC        =
| EM        =
| Molecular  =
| IF        =
| Gross      =
| Grossing  =
| Site      = [[lung]] - see ''[[diffuse lung diseases]]''
| Assdx      =
| Syndromes  =
| Clinicalhx = allergen exposure
| Signs      =
| Symptoms  =
| Prevalence = uncommon
| Bloodwork  =
| Rads      = upper lung predominant
| Endoscopy  =
| Prognosis  = usu. good if allergen exposure eliminated
| Other      =
| ClinDDx    = other [[diffuse lung diseases]], esp. [[idiopathic pulmonary fibrosis]]
| Tx        = eliminate allergen exposure
}}
'''Hypersensitivity_pneumonitis''', abbreviated '''[[HP]]''', is a [[diffuse lung diseases]] caused by an allergen.
 
It is also known as '''extrinsic allergic alveolitis''', abbreviated '''EAA'''.
 
==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).
 
DDx:
*[[Usual interstitial pneumonia]].
 
===Images===
<gallery>
Image:Hypersensitivity_pneumonitis_low_mag.jpg | Hypersensitivity pneumonitis - low mag. (WC/Nephron)
Image:Hypersensitivity_pneumonitis_intermed_mag.jpg | Hypersensitivity pneumonitis - intermed. mag. (WC/Nephron)
Image:Hypersensitivity_pneumonitis_high_mag.jpg | Hypersensitivity pneumonitis - high mag. (WC/Nephron)
</gallery>
 
==See also==
*[[Diffuse lung diseases]].
 
==References==
{{Reflist|2}}


[[Category:Diagnosis]]
[[Category:Diagnosis]]
[[Category:Diffuse lung diseases]]

Revision as of 02:52, 30 May 2014

Hypersensitivity pneumonitis
Diagnosis in short
Synonyms extrinsic allergic alveolitis
LM centrilobular prominence of lesions, granulomata, chronic interstitial inflammation consisting primarily of lymphocytes, interstitial fibrosis, air space involvement (alveolitis)
LM DDx usual interstitial pneumonia, asbestosis
Site lung - see diffuse lung diseases
Clinical history allergen exposure
Prevalence uncommon
Radiology upper lung predominant
Prognosis usu. good if allergen exposure eliminated
Clin. DDx other diffuse lung diseases, esp. idiopathic pulmonary fibrosis
Treatment eliminate allergen exposure

Hypersensitivity_pneumonitis, abbreviated HP, is a diffuse lung diseases caused by an allergen.

It is also known as extrinsic allergic alveolitis, abbreviated EAA.

General

Microscopic

Features:

  • Lesions have centrilobular prominence - important feature. [3]
    • Allergens enter lung through airway which has a centrilobular location.
  • Granulomata (not typically seen in UIP) - important feature.[3]
  • Chronic interstitial inflammation consisting primarily of lymphocytes.
  • Interstitial fibrosis.
  • Air space involvement (alveolitis).

DDx:

Images

  • Hypersensitivity pneumonitis - low mag. (WC/Nephron)

  • Hypersensitivity pneumonitis - intermed. mag. (WC/Nephron)

  • Hypersensitivity pneumonitis - high mag. (WC/Nephron)

See also

References

  1. ↑ Kaltreider, HB. (Nov 1993). "Hypersensitivity pneumonitis.". West J Med 159 (5): 570-8. PMID 8279154. http://www.ncbi.nlm.nih.gov/pmc/articles/pmid/8279154/?tool=pubmed.
  2. ↑ URL: http://library.med.utah.edu/WebPath/EXAM/IMGQUIZ/pufrm.html. Accessed on: 4 December 2011.
  3. ↑ 3.0 3.1 Ohtani, Y.; Saiki, S.; Kitaichi, M.; Usui, Y.; Inase, N.; Costabel, U.; Yoshizawa, Y. (Aug 2005). "Chronic bird fancier's lung: histopathological and clinical correlation. An application of the 2002 ATS/ERS consensus classification of the idiopathic interstitial pneumonias.". Thorax 60 (8): 665-71. doi:10.1136/thx.2004.027326. PMID 16061708.
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