Portal hypertension pathophysiology

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Portal Hypertension Microchapters

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:

Overview

Portal venous pressure is determined by portal blood flow and portal vascular resistance. Increased portal vascular resistance is often the main factor responsible for it. The consequences of portal hypertension are due to blood being forced down alternate channels by the increased resistance to flow through the portal system. Due to formation of alternate channels initially some of the portal blood and later most of it is shunted directly to the systemic circulation bypassing the liver.

Pathophysiology

Physiology

  • Vascular resistance (R) has to be measured through Pouseuille’s law formula:<math display="block">R = {8 \eta L\over \pi r^4}</math>η= Viscosity; L= Length of vessel; r= Radius of vessel; π=22/7
  • When the (R) measurement formula is integrated in Ohm's law it becomes as the following:

<math display="block">\Delta P= P_2-P_1 = {Q\times 8 \eta L\over \pi r^4}</math>



 
 
Anatomical (irreversible component)
• Functional/vascular tone (reversible component)
 
 
 
 
 
• Opening of pre-existing vascular channels
• Formation of new vascular channels
 
• Systemic vasodilation (r)
• Increasing plasma volume (Q)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
lntra-hepatic resistance (r)
 
 
 
 
 
Portosystemic collaterals (Q)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Increased resistance to portal blood flow (R)
 
 
 
 
 
Increased systemic/splanchnic blood flow (Q)
(hyperdynamic circulation)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Elevated portal pressure (P)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Portal hypertension
 
 
 
 
 
 

Pathogenesis

Increased resistance

Hyperdynamic circulation in portal hypertension

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

  1. Greenway CV, Stark RD (1971). "Hepatic vascular bed". Physiol. Rev. 51 (1): 23–65. PMID 5543903.
  2. Schiff, Eugene (2012). Schiff's diseases of the liver. Chichester, West Sussex, UK: John Wiley & Sons. ISBN 9780470654682.
  3. Beker, Simón G.; Valencia-Parparcén, Joel (1968). "Portal hypertension syndrome". The American Journal of Digestive Diseases. 13 (12): 1047–1054. doi:10.1007/BF02233549. ISSN 0002-9211.
  4. SCHAFFNER F, POPER H (1963). "Capillarization of hepatic sinusoids in man". Gastroenterology. 44: 239–42. PMID 13976646.
  5. Reynolds TB, Hidemura R, Michel H, Peters R (1969). "Portal hypertension without cirrhosis in alcoholic liver disease". Ann. Intern. Med. 70 (3): 497–506. PMID 5775031.
  6. Rubanyi GM (1991). "Endothelium-derived relaxing and contracting factors". J. Cell. Biochem. 46 (1): 27–36. doi:10.1002/jcb.240460106. PMID 1874796.
  7. Epstein, Franklin H.; Vane, John R.; Änggård, Erik E.; Botting, Regina M. (1990). "Regulatory Functions of the Vascular Endothelium". New England Journal of Medicine. 323 (1): 27–36. doi:10.1056/NEJM199007053230106. ISSN 0028-4793.
  8. Rockey DC, Weisiger RA (1996). "Endothelin induced contractility of stellate cells from normal and cirrhotic rat liver: implications for regulation of portal pressure and resistance". Hepatology. 24 (1): 233–40. doi:10.1002/hep.510240137. PMID 8707268.
  9. Mosca P, Lee FY, Kaumann AJ, Groszmann RJ (1992). "Pharmacology of portal-systemic collaterals in portal hypertensive rats: role of endothelium". Am. J. Physiol. 263 (4 Pt 1): G544–50. PMID 1415713.
  10. Colombato LA, Albillos A, Groszmann RJ (1992). "Temporal relationship of peripheral vasodilatation, plasma volume expansion and the hyperdynamic circulatory state in portal-hypertensive rats". Hepatology. 15 (2): 323–8. PMID 1735537.
  11. Genecin P, Polio J, Colombato LA, Ferraioli G, Reuben A, Groszmann RJ (1990). "Bile acids do not mediate the hyperdynamic circulation in portal hypertensive rats". Am. J. Physiol. 259 (1 Pt 1): G21–5. PMID 2372062.
  12. Casadevall, María; Panés, Julián; Piqué, Josep M.; Marroni, Norma; Bosch, Jaume; Whittle, Brendan J. R. (1993). "Involvement of nitric oxide and prostaglandins in gastric mucosal hyperemia of portal-hypertensive anesthetized rats". Hepatology. 18 (3): 628–634. doi:10.1002/hep.1840180323. ISSN 0270-9139.
  13. Sieber CC, Groszmann RJ (1992). "In vitro hyporeactivity to methoxamine in portal hypertensive rats: reversal by nitric oxide blockade". Am. J. Physiol. 262 (6 Pt 1): G996–1001. PMID 1616049.
  14. Albillos A, Colombato LA, Lee FY, Groszmann RJ (1993). "Octreotide ameliorates vasodilatation and Na+ retention in portal hypertensive rats". Gastroenterology. 104 (2): 575–9. PMID 8425700.

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