Pathology of the GI Tract- Liver and Gallbladder (1) Flashcards
What are two causes of conjugated hyperbilirubinemia?
- deficiency of canalicular membrane transporters (Dubin-Johnson syndrome or Rotor syndrome) 2. impaired bile flow from duct obstruction or autoimmune cholangiopathies
what tests assess the hepatocyte integrity?
AST, ALT, and LDH
what tests assess the biliary excretory function?
serum bilirubin, serum bile salts, alk phos, GGT
what tests assess the true functions of the liver?
albumin, coagulation factos (PT/PTT/INR), ammonia
which test is particularly sensitive for liver disease?
GGT
elevated ALP can suggest what?
either liver or bone disease
what is the pattern of liver function tests seen in a person with obstructive liver disease?
elevated ALP and bilirubin
injured or dysfunctional hepatocytes in a variety of disorders may demonstrate several potentially reversible morphologic changes. These include?
steatosis, cholestasis, ballooning (ballooning may form Mallory hyaline)
what is the pattern of cell death seen in acute toxic or ischemic injuries or in severe viral or autoimmune hepatitis?
coagulative necrosis
what is the principal cell type involved in scar deposition in the liver?
hepatic stellate cell
regeneration of the liver occurs by two major mechanisms, what are they?
proliferation of remaining hepatocytes and repopulation from progenitor cells
what are the stimuli for stellate cell activation?
inflammatory cytokines (TNF-alpha), altered interactions with ECM, and toxins and ROS
in chronic liver disease, surviving hepatocytes replicate in an effort to restore the parenchyma, forming what?
regenerative nodules- predominant feature in most cirrhotic livers
what defines hepatic failure?
80-90% of functional capacity must be lost
what defines acute liver failure?
an acute liver illness associated with encephalopathy and coagulopathy that occurs within 26 weeks of the initial liver injury in the absence of pre-existing liver disease
50% of ALF in the US is due to what?
acetaminophen
acute liver failure is usually associated with what?
massive hepatic necrosis
what are two cases that may result in acute liver failure with widespread dysfunction of liver cells?
diffuse microvesicular steatosis or idiosyncratic reactions to toxins
what are the clinical features of acute hepatic failure?
nausea, vomiting, icterus and jaundice, itching, and elevated liver enzymes; life threatening coagulation abnormalities; hepatic encephalopathy (asterixis)
what is chronic liver failure most often associated with?
cirrhosis
what are the leading causes of chronic liver failure worldwide?
chronic hepatitis B, chronic hepatitis C, nonalcoholic fatty liver disease, and alcoholic liver disease
what are the non-specific early symptoms of chronic liver failure?
anorexia, weight loss, and weakness
what are the specific features of chronic liver failure?
palmar erythema, spider angiomata, hypogonadism, and gynecomastia (symptoms of acute liver failure+ portal hypertension)
what are the major prehepatic conditions that lead to portal hypertension?
obstructive thrombosis, narrowing of the portal vein, or massive splenomegaly with increased splenic vein blood flow
what is the main posthepatic causes of portal hypertension?
severe right sided heart failure, constrictive pericarditis, and hepatic vein outflow obstruction
what is the dominant intrahepatic cause of portal hypertension?
cirrhosis
what is ascites?
the accumulation of fluid in the peritoneal cavity
what are the principal sites of shunts that form in cases of chronic portal hypertension?
veins around and within the rectum, esophagogastric junction, the retroperitoneum, and the falciform ligament of the liver
what are the four major consequences of portal hypertension?
hepatic encephalopathy, ascites, the formation of portosystemic venous shunts, and congestive splenomegaly
