Cryptogenic organizing pneumonia pathophysiology: Difference between revisions
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===Pathogenesis=== | ===Pathogenesis=== | ||
*It is understood that [disease name] is the result of / is mediated by / is produced by / is caused by either [hypothesis 1], [hypothesis 2], or [hypothesis 3]. | *It is understood that [disease name] is the result of / is mediated by / is produced by / is caused by either [hypothesis 1], [hypothesis 2], or [hypothesis 3]. | ||
*[Pathogen name] is usually transmitted via the [transmission route] route to the human host. | *[Pathogen name] is usually transmitted via the [transmission route] route to the human host. | ||
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1) Injury phase- early phase of cryptogenic organizing pneumonia. | 1) Injury phase- the early phase of cryptogenic organizing pneumonia. | ||
*It is characterized by the deposition of plasma proteins in the alveolar lumen. | *It is characterized by the deposition of plasma proteins in the alveolar lumen. | ||
*Mechanism of early phase is imbalance between coagulation and fibrinolytic cascade and activation of coagulation process which leads to fibrin deposition and further flooding of migratory inflammatory in the alveolar lumen of plasma proteins (permeability edema), | *Mechanism of early phase is an imbalance between coagulation and fibrinolytic cascade and activation of coagulation process which leads to fibrin deposition and further flooding of migratory inflammatory in the alveolar lumen of plasma proteins (permeability edema), , w Fibrin deposition may be prominent, as in the acute fibrinous variant of OP. The fibrillar material mostly consists of fibronectin, type III collagen, and proteoglycans, with a minority of type I collagen. Morphological and ultrastructural studies indicate the denudation of the epithelial basal laminae and extensive necrosis of alveolar epithelial type I cells, suggesting that alveolar epithelial injury forming gaps within the basal lamina may be the first event triggering this process. The capillary endothelial injury is often associated with epithelial lesions. Hyaline membranes are not found, in contrast to diffuse alveolar damage (DAD). | ||
The second stage (proliferating phase) corresponds to the formation of fibroinflammatory buds. Fibrin is progressively fragmented by macrophages and inflammatory cells. Activated fibroblasts migrate through gaps of the basal lamina into the fragmented fibrin and inflammatory cells, where they proliferate, differentiate into myofibroblasts, and form cell clusters within the distal airspaces. Inflammatory cells and fibrin are progressively replaced by aggregated fibroblasts/myofibroblasts intermixed with a loose connective matrix tissue rich in collagen (especially collagen I), fibronectin, procollagen type III and proteoglycans. Alveolar epithelial cells proliferate, restoring the continuity of the alveolar-capillary membrane and the integrity of the alveolar unit. | The second stage (proliferating phase) corresponds to the formation of fibroinflammatory buds. Fibrin is progressively fragmented by macrophages and inflammatory cells. Activated fibroblasts migrate through gaps of the basal lamina into the fragmented fibrin and inflammatory cells, where they proliferate, differentiate into myofibroblasts, and form cell clusters within the distal airspaces. Inflammatory cells and fibrin are progressively replaced by aggregated fibroblasts/myofibroblasts intermixed with a loose connective matrix tissue rich in collagen (especially collagen I), fibronectin, procollagen type III and proteoglycans. Alveolar epithelial cells proliferate, restoring the continuity of the alveolar-capillary membrane and the integrity of the alveolar unit. | ||
Revision as of 15:12, 28 February 2018
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Cryptogenic Organizing Pneumonia Microchapters |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Serge Korjian M.D.
Overview
Pathophysiology
- The organizing pneumonia pathogenesis model is very similar to the that of cutaneous wound healing.
- Following an insult, a recovery phase characterized by the organisation of inflammatory exudates with resulting intra-alveolar fibrosis ensues.
- Although the intra-alveolar fibrosis resembles that present in usual interstitial pneumonia (UIP), it is however not associated with irreversible fibrosis. In contrast, cryptogenic organizing pneumonia is characterized by it's favorable response to corticosteroid therapy.[1]
Pathophysiology
Pathogenesis
- It is understood that [disease name] is the result of / is mediated by / is produced by / is caused by either [hypothesis 1], [hypothesis 2], or [hypothesis 3].
- [Pathogen name] is usually transmitted via the [transmission route] route to the human host.
- Following transmission/ingestion, the [pathogen] uses the [entry site] to invade the [cell name] cell.
- [Disease or malignancy name] arises from [cell name's, which are [cell type] cells that are normally involved in [function of cells].
- The progression to [disease name] usually involves the [molecular pathway].
- The pathophysiology of [disease/malignancy] depends on the histological subtype.
1) Injury phase- the early phase of cryptogenic organizing pneumonia.
- It is characterized by the deposition of plasma proteins in the alveolar lumen.
- Mechanism of early phase is an imbalance between coagulation and fibrinolytic cascade and activation of coagulation process which leads to fibrin deposition and further flooding of migratory inflammatory in the alveolar lumen of plasma proteins (permeability edema), , w Fibrin deposition may be prominent, as in the acute fibrinous variant of OP. The fibrillar material mostly consists of fibronectin, type III collagen, and proteoglycans, with a minority of type I collagen. Morphological and ultrastructural studies indicate the denudation of the epithelial basal laminae and extensive necrosis of alveolar epithelial type I cells, suggesting that alveolar epithelial injury forming gaps within the basal lamina may be the first event triggering this process. The capillary endothelial injury is often associated with epithelial lesions. Hyaline membranes are not found, in contrast to diffuse alveolar damage (DAD).
The second stage (proliferating phase) corresponds to the formation of fibroinflammatory buds. Fibrin is progressively fragmented by macrophages and inflammatory cells. Activated fibroblasts migrate through gaps of the basal lamina into the fragmented fibrin and inflammatory cells, where they proliferate, differentiate into myofibroblasts, and form cell clusters within the distal airspaces. Inflammatory cells and fibrin are progressively replaced by aggregated fibroblasts/myofibroblasts intermixed with a loose connective matrix tissue rich in collagen (especially collagen I), fibronectin, procollagen type III and proteoglycans. Alveolar epithelial cells proliferate, restoring the continuity of the alveolar-capillary membrane and the integrity of the alveolar unit.
The third stage (mature phase) is characterized by “mature” fibrotic buds clearly delineated inside the alveolar space. Inflammatory cells and fibrin deposits are no longer found in alveolar buds, which are mostly constituted by typical myofibroblasts (with cytoplasmic filaments orientated toward the cell axis), organized in concentric rings alternating with layers of collagen bundles. At this stage, the connective network consists of thin collagen-I fibers together with thinner fibrils of collagen and procollagen type III, and fibronectin.
In a fourth stage (resolution phase), this process resolves without significant sequelae, similar to reversible wound healing in the skin. The relative preservation of the alveolar basal laminae is considered to be required for the reversibility of the lesions.
Genetics
- [Disease name] is transmitted in [mode of genetic transmission] pattern.
- Genes involved in the pathogenesis of [disease name] include [gene1], [gene2], and [gene3].
- The development of [disease name] is the result of multiple genetic mutations.
Associated Conditions
Gross Pathology
- On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
Microscopic Pathology
- On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
References
- ↑ Cordier JF (2006). "Cryptogenic organising pneumonia". Eur Respir J. 28 (2): 422–46. doi:10.1183/09031936.06.00013505. PMID 16880372.