Amyloid purpura
Amyloid purpura is a condition marked by bleeding under the skin (purpura) in some individuals with amyloidosis.[1] Its cause is unknown, but coagulation defects caused by amyloid are thought to contribute.
Cause
The precise cause of amyloid purpura is unknown, but several mechanisms are thought to contribute.[2] One may be a decrease in the level of circulating factor X,[2] a clotting factor necessary for coagulation. The proposed mechanism for this decrease in factor X is that circulating amyloid fibrils bind and inactivate factor X.[2] Another contributing factor may be enhanced fibrinolysis,[2] the breakdown of clots. Subendothelial deposits of amyloid may weaken blood vessels and lead to the extravasation of blood.[2][3] Amyloid deposits in the gastrointestinal tract and liver may also play a role in the development of amyloid purpura.[2]
Distribution
Amyloid purpura usually occurs in the webbing of the neck and in the face.[2]
Epidemiology
Amyloid purpura affects a minority of individuals with amyloidosis.[1] For example, purpura is present early in the disease in approximately 15% of patients with primary systemic amyloidosis.[4]
References
- ↑ 1.0 1.1 Eder L, Bitterman H (2007). “Image in clinical medicine. Amyloid purpura”. N. Engl. J. Med. 356 (23): 2406. doi:10.1056/NEJMicm061510. PMID 17554122. Unknown parameter
|month=ignored (help) - ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Gamba G, Montani N, Anesi E; et al. (2000). “Clotting alterations in primary systemic amyloidosis” (PDF). Haematologica. 85 (3): 289–92. PMID 10702818. Unknown parameter
|month=ignored (help) - ↑ Amyloidosis, Immunoglobulin-Related at eMedicine
- ↑ Kyle RA, Gertz MA (1995). “Primary systemic amyloidosis: clinical and laboratory features in 474 cases”. Semin. Hematol. 32 (1): 45–59. PMID 7878478. Unknown parameter
|month=ignored (help)
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