Tabes Dorsalis pathophysiology: Difference between revisions
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== Overview == | == Overview == | ||
It is understood that tabes dorsalis is caused by [[tertiary syphilis]] from [[treponema pallidum]] infection. Tabes dorsalis is a manifestation of invasion of [[treponema pallidum]] [[Spirochaete|spirochete]]<nowiki/> to the [[Dorsal column|dorsal column of spinal cord]] in [[tertiary syphilis]]. In tabes dorsalis, the preganglionic portion of the dorsal roots of [[spinal nerves]] is infiltrated with [[Lymphocyte|lymphocytes]] and [[plasma cells]], and invasion of [[treponema pallidum]] [[Spirochaete|spirochete]]<nowiki/>s to [[Posterior column|posterior columns]] of the [[spinal cord]] makes it [[Atrophy|atrophic]]. The [[demyelination]] of the [[Axoneme|axones]] of the [[neurons]] is the main cause of symptoms and it affects the [[neurons]] in the [[Dorsal root ganglion|dorsal root ganglia]] and [[Posterior columns|posterior columns of the spinal cord]]. | The [[Syphilis|syphilis disease]] is the sole cause of tabes dorsalis. [[Treponema pallidum|Treponema pallidum]] is usually transmitted via direct contact with the infected lesion ([[sexual contact]]) or [[blood transfusion]] (rare). It is understood that tabes dorsalis is caused by [[tertiary syphilis]] from [[treponema pallidum]] infection. Tabes dorsalis is a manifestation of invasion of [[treponema pallidum]] [[Spirochaete|spirochete]]<nowiki/> to the [[Dorsal column|dorsal column of spinal cord]] in [[tertiary syphilis]]. In tabes dorsalis, the preganglionic portion of the dorsal roots of [[spinal nerves]] is infiltrated with [[Lymphocyte|lymphocytes]] and [[plasma cells]], and invasion of [[treponema pallidum]] [[Spirochaete|spirochete]]<nowiki/>s to [[Posterior column|posterior columns]] of the [[spinal cord]] makes it [[Atrophy|atrophic]]. The [[demyelination]] of the [[Axoneme|axones]] of the [[neurons]] is the main cause of symptoms and it affects the [[neurons]] in the [[Dorsal root ganglion|dorsal root ganglia]] and [[Posterior columns|posterior columns of the spinal cord]]. | ||
== Pathophysiology == | == Pathophysiology == | ||
===Pathogenesis of syphilis=== | ===Pathogenesis of syphilis=== | ||
The pathogenesis of syphilis may be described in the following steps:<ref name="pmid21694502">{{cite journal| author=Carlson JA, Dabiri G, Cribier B, Sell S| title=The immunopathobiology of syphilis: the manifestations and course of syphilis are determined by the level of delayed-type hypersensitivity. | journal=Am J Dermatopathol | year= 2011 | volume= 33 | issue= 5 | pages= 433-60 | pmid=21694502 | doi=10.1097/DAD.0b013e3181e8b587 | pmc=3690623 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21694502 }} </ref><ref name="pmid1386838">{{cite journal| author=Fitzgerald TJ| title=The Th1/Th2-like switch in syphilitic infection: is it detrimental? | journal=Infect Immun | year= 1992 | volume= 60 | issue= 9 | pages= 3475-9 | pmid=1386838 | doi= | pmc=257347 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1386838 }} </ref><ref name="pmid10194456">{{cite journal| author=Singh AE, Romanowski B| title=Syphilis: review with emphasis on clinical, epidemiologic, and some biologic features. | journal=Clin Microbiol Rev | year= 1999 | volume= 12 | issue= 2 | pages= 187-209 | pmid=10194456 | doi= | pmc=88914 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10194456 }} </ref><ref name="pmid1911961">{{cite journal| author=Engelkens HJ, ten Kate FJ, Vuzevski VD, van der Sluis JJ, Stolz E| title=Primary and secondary syphilis: a histopathological study. | journal=Int J STD AIDS | year= 1991 | volume= 2 | issue= 4 | pages= 280-4 | pmid=1911961 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1911961 }} </ref><ref name="pmid3285346">{{cite journal| author=Thomas DD, Navab M, Haake DA, Fogelman AM, Miller JN, Lovett MA| title=Treponema pallidum invades intercellular junctions of endothelial cell monolayers. | journal=Proc Natl Acad Sci U S A | year= 1988 | volume= 85 | issue= 10 | pages= 3608-12 | pmid=3285346 | doi= | pmc=280263 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3285346 }} </ref><ref name="pmid18800002">{{cite journal| author=Quatresooz P, Piérard GE| title=Skin homing of Treponema pallidum in early syphilis: an immunohistochemical study. | journal=Appl Immunohistochem Mol Morphol | year= 2009 | volume= 17 | issue= 1 | pages= 47-50 | pmid=18800002 | doi=10.1097/PAI.0b013e3181788186 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18800002 }} </ref><ref name="pmid3734178">{{cite journal| author=Tanabe JL, Huntley AC| title=Granulomatous tertiary syphilis. | journal=J Am Acad Dermatol | year= 1986 | volume= 15 | issue= 2 Pt 2 | pages= 341-4 | pmid=3734178 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3734178 }} </ref><ref name="pmid7001910">{{cite journal| author=Baker-Zander S, Sell S| title=A histopathologic and immunologic study of the course of syphilis in the experimentally infected rabbit. Demonstration of long-lasting cellular immunity. | journal=Am J Pathol | year= 1980 | volume= 101 | issue= 2 | pages= 387-414 | pmid=7001910 | doi= | pmc=1903600 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=7001910 }} </ref><ref name="pmid18008231">{{cite journal| author=Sheffield JS, Wendel GD, McIntire DD, Norgard MV| title=Effect of genital ulcer disease on HIV-1 coreceptor expression in the female genital tract. | journal=J Infect Dis | year= 2007 | volume= 196 | issue= 10 | pages= 1509-16 | pmid=18008231 | doi=10.1086/522518 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18008231 }} </ref><ref name="pmid1191529">{{cite journal| author=Abell E, Marks R, Jones EW| title=Secondary syphilis: a clinico-pathological review. | journal=Br J Dermatol | year= 1975 | volume= 93 | issue= 1 | pages= 53-61 | pmid=1191529 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1191529 }} </ref><ref name="pmid26100683">{{cite journal| author=Pastuszczak M, Jakiela B, Jaworek AK, Wypasek E, Zeman J, Wojas-Pelc A| title=Association of Interleukin-10 promoter polymorphisms with neurosyphilis. | journal=Hum Immunol | year= 2015 | volume= 76 | issue= 7 | pages= 469-72 | pmid=26100683 | doi=10.1016/j.humimm.2015.06.010 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26100683 }} </ref> | * The [[Syphilis|syphilis disease]] is the sole cause of tabes dorsalis. | ||
* The pathogenesis of [[syphilis]] may be described in the following steps:<ref name="pmid21694502">{{cite journal| author=Carlson JA, Dabiri G, Cribier B, Sell S| title=The immunopathobiology of syphilis: the manifestations and course of syphilis are determined by the level of delayed-type hypersensitivity. | journal=Am J Dermatopathol | year= 2011 | volume= 33 | issue= 5 | pages= 433-60 | pmid=21694502 | doi=10.1097/DAD.0b013e3181e8b587 | pmc=3690623 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21694502 }} </ref><ref name="pmid1386838">{{cite journal| author=Fitzgerald TJ| title=The Th1/Th2-like switch in syphilitic infection: is it detrimental? | journal=Infect Immun | year= 1992 | volume= 60 | issue= 9 | pages= 3475-9 | pmid=1386838 | doi= | pmc=257347 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1386838 }} </ref><ref name="pmid10194456">{{cite journal| author=Singh AE, Romanowski B| title=Syphilis: review with emphasis on clinical, epidemiologic, and some biologic features. | journal=Clin Microbiol Rev | year= 1999 | volume= 12 | issue= 2 | pages= 187-209 | pmid=10194456 | doi= | pmc=88914 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10194456 }} </ref><ref name="pmid1911961">{{cite journal| author=Engelkens HJ, ten Kate FJ, Vuzevski VD, van der Sluis JJ, Stolz E| title=Primary and secondary syphilis: a histopathological study. | journal=Int J STD AIDS | year= 1991 | volume= 2 | issue= 4 | pages= 280-4 | pmid=1911961 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1911961 }} </ref><ref name="pmid3285346">{{cite journal| author=Thomas DD, Navab M, Haake DA, Fogelman AM, Miller JN, Lovett MA| title=Treponema pallidum invades intercellular junctions of endothelial cell monolayers. | journal=Proc Natl Acad Sci U S A | year= 1988 | volume= 85 | issue= 10 | pages= 3608-12 | pmid=3285346 | doi= | pmc=280263 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3285346 }} </ref><ref name="pmid18800002">{{cite journal| author=Quatresooz P, Piérard GE| title=Skin homing of Treponema pallidum in early syphilis: an immunohistochemical study. | journal=Appl Immunohistochem Mol Morphol | year= 2009 | volume= 17 | issue= 1 | pages= 47-50 | pmid=18800002 | doi=10.1097/PAI.0b013e3181788186 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18800002 }} </ref><ref name="pmid3734178">{{cite journal| author=Tanabe JL, Huntley AC| title=Granulomatous tertiary syphilis. | journal=J Am Acad Dermatol | year= 1986 | volume= 15 | issue= 2 Pt 2 | pages= 341-4 | pmid=3734178 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3734178 }} </ref><ref name="pmid7001910">{{cite journal| author=Baker-Zander S, Sell S| title=A histopathologic and immunologic study of the course of syphilis in the experimentally infected rabbit. Demonstration of long-lasting cellular immunity. | journal=Am J Pathol | year= 1980 | volume= 101 | issue= 2 | pages= 387-414 | pmid=7001910 | doi= | pmc=1903600 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=7001910 }} </ref><ref name="pmid18008231">{{cite journal| author=Sheffield JS, Wendel GD, McIntire DD, Norgard MV| title=Effect of genital ulcer disease on HIV-1 coreceptor expression in the female genital tract. | journal=J Infect Dis | year= 2007 | volume= 196 | issue= 10 | pages= 1509-16 | pmid=18008231 | doi=10.1086/522518 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18008231 }} </ref><ref name="pmid1191529">{{cite journal| author=Abell E, Marks R, Jones EW| title=Secondary syphilis: a clinico-pathological review. | journal=Br J Dermatol | year= 1975 | volume= 93 | issue= 1 | pages= 53-61 | pmid=1191529 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1191529 }} </ref><ref name="pmid26100683">{{cite journal| author=Pastuszczak M, Jakiela B, Jaworek AK, Wypasek E, Zeman J, Wojas-Pelc A| title=Association of Interleukin-10 promoter polymorphisms with neurosyphilis. | journal=Hum Immunol | year= 2015 | volume= 76 | issue= 7 | pages= 469-72 | pmid=26100683 | doi=10.1016/j.humimm.2015.06.010 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26100683 }} </ref> | |||
** [[Treponema pallidum|Treponema pallidum]] is usually transmitted via direct contact with the infected lesion ([[sexual contact]]) or [[blood transfusion]] (rare). | |||
[[Treponema pallidum| | ** The [[incubation period]] varies with the size of innoculum (9-90 days). | ||
*Following transmission, [[Treponema pallidum|''Treponema pallidum'']] uses the intact or abraded [[mucous membrane]] to enter the body. | *Following transmission, [[Treponema pallidum|''Treponema pallidum'']] uses the intact or abraded [[mucous membrane]] to enter the body. | ||
*It then disseminates to the [[lymphatics]] and blood stream to gain access to any organ of the body. | *It then disseminates to the [[lymphatics]] and blood stream to gain access to any organ of the body. | ||
*Syphilis uses [[fibronectin]] molecules to attach to the [[endothelial]] surface of the vessels in organs resulting in [[Inflammation|inflammatio]]<nowiki/>n and obliteration of the small blood vessels causing [[vasculitis]] ([[endarteritis obliterans]]). | |||
*Syphilis uses [[fibronectin]] molecules to attach to the [[endothelial]] surface of the vessels in organs resulting in | |||
*Organism has slow replication rate (30-33 hrs) and evades the initial host immune response. | *Organism has slow replication rate (30-33 hrs) and evades the initial host immune response. | ||
*It may seed to different organs of the body especially the [[cardiovascular system]] and [[central nervous system]] resulting in tertiary syphilis. | *It may seed to different organs of the body especially the [[cardiovascular system]] and [[central nervous system]] resulting in tertiary syphilis. | ||
| Line 29: | Line 24: | ||
===Immune response=== | ===Immune response=== | ||
Different stages of syphilis results from the interaction between the [[antigen]] and the [[host immune response]].<ref name="pmid21694502">{{cite journal| author=Carlson JA, Dabiri G, Cribier B, Sell S| title=The immunopathobiology of syphilis: the manifestations and course of syphilis are determined by the level of delayed-type hypersensitivity. | journal=Am J Dermatopathol | year= 2011 | volume= 33 | issue= 5 | pages= 433-60 | pmid=21694502 | doi=10.1097/DAD.0b013e3181e8b587 | pmc=3690623 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21694502 }} </ref><ref name="pmid1386838">{{cite journal| author=Fitzgerald TJ| title=The Th1/Th2-like switch in syphilitic infection: is it detrimental? | journal=Infect Immun | year= 1992 | volume= 60 | issue= 9 | pages= 3475-9 | pmid=1386838 | doi= | pmc=257347 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1386838 }} </ref> | Different stages of syphilis results from the interaction between the [[antigen]] and the [[host immune response]].<ref name="pmid21694502">{{cite journal| author=Carlson JA, Dabiri G, Cribier B, Sell S| title=The immunopathobiology of syphilis: the manifestations and course of syphilis are determined by the level of delayed-type hypersensitivity. | journal=Am J Dermatopathol | year= 2011 | volume= 33 | issue= 5 | pages= 433-60 | pmid=21694502 | doi=10.1097/DAD.0b013e3181e8b587 | pmc=3690623 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21694502 }} </ref><ref name="pmid1386838">{{cite journal| author=Fitzgerald TJ| title=The Th1/Th2-like switch in syphilitic infection: is it detrimental? | journal=Infect Immun | year= 1992 | volume= 60 | issue= 9 | pages= 3475-9 | pmid=1386838 | doi= | pmc=257347 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1386838 }} </ref> | ||
*The initial infection in primary syphilis is limited due to [[Th1 response|T helper 1 response]] and lack of the [[antibody]] response. | |||
*It is speculated that there is a shift from [[T helper 17 cell|T helper 1]] to [[Th2 response]] during secondary syphilis. | |||
*[[Cytotoxic T cells]] and an incomplete humoral response is mainly responsible for persistence of infection and tissue damage in tertiary syphilis. | *[[Cytotoxic T cells]] and an incomplete humoral response is mainly responsible for persistence of infection and tissue damage in tertiary syphilis. | ||
*Ineffective [[Type IV hypersensitivity|type 4 delayed hypersensitivity]] reaction containing [[macrophages]] and sensitized [[T cells]] is mainly responsible for the [[gumma]] formation in various organs. | *Ineffective [[Type IV hypersensitivity|type 4 delayed hypersensitivity]] reaction containing [[macrophages]] and sensitized [[T cells]] is mainly responsible for the [[gumma]] formation in various organs. | ||
=== | === Pathogenesis of tabes dorsalis === | ||
* It is understood that tabes dorsalis is caused by tertiary syphilis from [[treponema pallidum]] infection. | |||
* Tabes dorsalis is a manifestation of invasion of [[treponema pallidum]] spirochetes to the [[dorsal column]] of spinal cord in tertiary syphilis. | |||
* In tabes dorsalis, the preganglionic portion of the [[Dorsal root|dorsal roots of spinal nerves]] is infiltrated with [[lymphocytes]] and [[plasma cells]], and invasion of [[treponema pallidum]] spirochetes to posterior columns of the [[spinal cord]] makes it atrophic. | |||
* The [[demyelination]] of the axones of the neurons is the main cause of symptoms and it affects the neurons in the [[dorsal root ganglia]] and posterior columns of the [[spinal cord]]. | |||
== | ==Genetics== | ||
There is no known genetic mutation that is associated with syphilis. However, [[neurosyphilis]] may be associated with the gene polymorphism for [[IL-10]] production with increased levels seen in the patients with neurosyphilis.<ref name="pmid26100683">{{cite journal| author=Pastuszczak M, Jakiela B, Jaworek AK, Wypasek E, Zeman J, Wojas-Pelc A| title=Association of Interleukin-10 promoter polymorphisms with neurosyphilis. | journal=Hum Immunol | year= 2015 | volume= 76 | issue= 7 | pages= 469-72 | pmid=26100683 | doi=10.1016/j.humimm.2015.06.010 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26100683 }} </ref> | |||
==Associated conditions== | |||
* Syphilis is associated with increased transmission of [[HIV]].<ref name="pmid18008231" /> | |||
** The underlying mechanism may be related to the accumulation of [[dendritic cells]] containing [[CCR5]] co-receptors at the site of infection, the same receptor entity binding the HIV. | |||
* | |||
* | |||
== | ==Microscopic pathology== | ||
On microscopic [[histopathological]] analysis, characteristic findings of tabes dorsalis are:<ref name="pmid21694502">{{cite journal| author=Carlson JA, Dabiri G, Cribier B, Sell S| title=The immunopathobiology of syphilis: the manifestations and course of syphilis are determined by the level of delayed-type hypersensitivity. | journal=Am J Dermatopathol | year= 2011 | volume= 33 | issue= 5 | pages= 433-60 | pmid=21694502 | doi=10.1097/DAD.0b013e3181e8b587 | pmc=3690623 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21694502 }} </ref> | |||
*[[endarteritis obliterans|Small vessel inflammation (endarteritis obliterans)]] | |||
*Granulomatous lesions ([[gumma]]) containing central necrosis, [[inflammatory cells]], such as [[lymphocytes]], [[macrophages]], [[plasma cells]] and [[Fibroblast|fibroblasts]]. | |||
== References == | == References == | ||
Latest revision as of 20:16, 28 February 2018
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Tabes Dorsalis Microchapters |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Mohamadmostafa Jahansouz M.D.[2]
Overview
The syphilis disease is the sole cause of tabes dorsalis. Treponema pallidum is usually transmitted via direct contact with the infected lesion (sexual contact) or blood transfusion (rare). It is understood that tabes dorsalis is caused by tertiary syphilis from treponema pallidum infection. Tabes dorsalis is a manifestation of invasion of treponema pallidum spirochete to the dorsal column of spinal cord in tertiary syphilis. In tabes dorsalis, the preganglionic portion of the dorsal roots of spinal nerves is infiltrated with lymphocytes and plasma cells, and invasion of treponema pallidum spirochetes to posterior columns of the spinal cord makes it atrophic. The demyelination of the axones of the neurons is the main cause of symptoms and it affects the neurons in the dorsal root ganglia and posterior columns of the spinal cord.
Pathophysiology
Pathogenesis of syphilis
- The syphilis disease is the sole cause of tabes dorsalis.
- The pathogenesis of syphilis may be described in the following steps:[1][2][3][4][5][6][7][8][9][10][11]
- Treponema pallidum is usually transmitted via direct contact with the infected lesion (sexual contact) or blood transfusion (rare).
- The incubation period varies with the size of innoculum (9-90 days).
- Following transmission, Treponema pallidum uses the intact or abraded mucous membrane to enter the body.
- It then disseminates to the lymphatics and blood stream to gain access to any organ of the body.
- Syphilis uses fibronectin molecules to attach to the endothelial surface of the vessels in organs resulting in inflammation and obliteration of the small blood vessels causing vasculitis (endarteritis obliterans).
- Organism has slow replication rate (30-33 hrs) and evades the initial host immune response.
- It may seed to different organs of the body especially the cardiovascular system and central nervous system resulting in tertiary syphilis.
Immune response
Different stages of syphilis results from the interaction between the antigen and the host immune response.[1][2]
- The initial infection in primary syphilis is limited due to T helper 1 response and lack of the antibody response.
- It is speculated that there is a shift from T helper 1 to Th2 response during secondary syphilis.
- Cytotoxic T cells and an incomplete humoral response is mainly responsible for persistence of infection and tissue damage in tertiary syphilis.
- Ineffective type 4 delayed hypersensitivity reaction containing macrophages and sensitized T cells is mainly responsible for the gumma formation in various organs.
Pathogenesis of tabes dorsalis
- It is understood that tabes dorsalis is caused by tertiary syphilis from treponema pallidum infection.
- Tabes dorsalis is a manifestation of invasion of treponema pallidum spirochetes to the dorsal column of spinal cord in tertiary syphilis.
- In tabes dorsalis, the preganglionic portion of the dorsal roots of spinal nerves is infiltrated with lymphocytes and plasma cells, and invasion of treponema pallidum spirochetes to posterior columns of the spinal cord makes it atrophic.
- The demyelination of the axones of the neurons is the main cause of symptoms and it affects the neurons in the dorsal root ganglia and posterior columns of the spinal cord.
Genetics
There is no known genetic mutation that is associated with syphilis. However, neurosyphilis may be associated with the gene polymorphism for IL-10 production with increased levels seen in the patients with neurosyphilis.[11]
Associated conditions
- Syphilis is associated with increased transmission of HIV.[9]
- The underlying mechanism may be related to the accumulation of dendritic cells containing CCR5 co-receptors at the site of infection, the same receptor entity binding the HIV.
Microscopic pathology
On microscopic histopathological analysis, characteristic findings of tabes dorsalis are:[1]
- Small vessel inflammation (endarteritis obliterans)
- Granulomatous lesions (gumma) containing central necrosis, inflammatory cells, such as lymphocytes, macrophages, plasma cells and fibroblasts.
References
- ↑ 1.0 1.1 1.2 Carlson JA, Dabiri G, Cribier B, Sell S (2011). "The immunopathobiology of syphilis: the manifestations and course of syphilis are determined by the level of delayed-type hypersensitivity". Am J Dermatopathol. 33 (5): 433–60. doi:10.1097/DAD.0b013e3181e8b587. PMC 3690623. PMID 21694502.
- ↑ 2.0 2.1 Fitzgerald TJ (1992). "The Th1/Th2-like switch in syphilitic infection: is it detrimental?". Infect Immun. 60 (9): 3475–9. PMC 257347. PMID 1386838.
- ↑ Singh AE, Romanowski B (1999). "Syphilis: review with emphasis on clinical, epidemiologic, and some biologic features". Clin Microbiol Rev. 12 (2): 187–209. PMC 88914. PMID 10194456.
- ↑ Engelkens HJ, ten Kate FJ, Vuzevski VD, van der Sluis JJ, Stolz E (1991). "Primary and secondary syphilis: a histopathological study". Int J STD AIDS. 2 (4): 280–4. PMID 1911961.
- ↑ Thomas DD, Navab M, Haake DA, Fogelman AM, Miller JN, Lovett MA (1988). "Treponema pallidum invades intercellular junctions of endothelial cell monolayers". Proc Natl Acad Sci U S A. 85 (10): 3608–12. PMC 280263. PMID 3285346.
- ↑ Quatresooz P, Piérard GE (2009). "Skin homing of Treponema pallidum in early syphilis: an immunohistochemical study". Appl Immunohistochem Mol Morphol. 17 (1): 47–50. doi:10.1097/PAI.0b013e3181788186. PMID 18800002.
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- ↑ 11.0 11.1 Pastuszczak M, Jakiela B, Jaworek AK, Wypasek E, Zeman J, Wojas-Pelc A (2015). "Association of Interleukin-10 promoter polymorphisms with neurosyphilis". Hum Immunol. 76 (7): 469–72. doi:10.1016/j.humimm.2015.06.010. PMID 26100683.