Difference between revisions of "Category:Liver - Developmental Pathology"

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== [[Portosystemic Shunt]] ==
 
== [[Portosystemic Shunt]] ==
  
  
== Hepatic microvascular dysplasia ==
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== [[Hepatic Microvascular Dysplasia]] ==
 
 
*Small intrahepatic portal vessels and portal endothelial hyperplasia which allows abnormal communication between portal and systemic circulation.
 
*Can develop as a separate entity or in conjunction with a portosystemic shunt.
 
*Can cause c/s similar to those of PSS.
 
*[[Control of Feeding - Anatomy & Physiology#The Vomit Reflex|Vomiting]], [[Diarrhoea|diarrhoea]], [[Urinary System - Anatomy & Physiology|urinary tract]] changes associated with ammonium biurate urolithiasis, stunted growth, prolonged recovery from anesthesia.
 
*Average age of presentation =3yrs.
 
*Mainly small dogs, esp. Yorkies
 
*Females>males
 
===Histology===
 
  
**Arteriolarization of central veins
 
**smooth muscle proliferation (segmental) within the walls of central veins
 
**random distribution of small calibre vessels
 
**endothelial hyperplasia within portal triads
 
**dilation of periacinar vascular spaces.
 
**May also see decreased diameter of intrahepatic veins.
 
*Can’t be accurately distinguished from PSS alone.
 
*Seen in older dogs than PSS
 
*Higher MCV, serum postprandial bile acid concentrations, serum albumin and cholesterol concentrations when PSS and HMD together, compared to HMD alone.
 
  
 
== Idiopathic noncirrhotic portal hypertension ==
 
== Idiopathic noncirrhotic portal hypertension ==

Revision as of 12:05, 7 June 2010

Portosystemic Shunt

Hepatic Microvascular Dysplasia

Idiopathic noncirrhotic portal hypertension

JAVMA paper

  • Portal hypertension
  • Sustained impairment of forward venous flow anywhere along the path from the portal vein to the right side of the heart.
  • Luminal (thrombosis, parasites) or extraluminal obstruction (hepatic fibrosis or nodular regeneration) or relative restriction of flow due to massive portal volume overload (arterioportal fistulas).
  • Hepatomegaly associated with posthepatic obstruction
  • Microhepatica – associated with prehepatic/hepatic causes.
  • Hepatic encephalopathy and GI bleeding not associated with posthepatic causes.
  • Most common causes are RHS heart failure and severe diffuse hepatobiliary disease that results in cirrhosis.

Histology

  • indistinguishable from microvascular dysplasia or surgically created portosystemic shunts
    • Portal triad arteriole proliferation
    • portal veins small to large
    • variable portal triad fibrosis
    • hepatic lobule size variation
    • arterioles scattered throughout hepatic parenchyma
    • portal veins – small
    • expanded perivenular connective tissue by arterioles and distended lymphatics.