GI disorders pt 2 (2)

what is the liver's relationship with glucose/carbs

it breaks down glycogen for glucose, synthesizes glucose from amino acids, and converts carbs to triglycerides for adipose tissue storage

what is the liver's relationship with fats

oxidized FFA to ketoacids, synthesizes cholesterol, phospholipids and lipoproteins

what is the liver's relationship with proteins

produces proteins like albumin that help with the plasma colloidal osmotic pressure

portal hypertension

characterized by increased resistance to flow in the portal venous system and sustained increase in portal venous pressure

what happens to collateral vessels during portal hypertension

the collateral vessels open and develop between the portal vein and systemic veins creating a portal-systemic venous collaterals

Splenomegaly

enlargement of spleen that can happen in portal hypertension due to increased pressure in the splenic vein

hypersplenism

increased sequestering of all blood cell types

what can hypersplenism lead to...

thrombocytopenia

since the liver produces over 25% of the body's lymph, portal hypertension (also cirrhosis) can lead to...

the lymph to be expelled into the peritoneal cavity (ascites) due to increased pressure in the lymphatic vessels, can also affect the plasma to be expelled from the blood capillaries (more ascites)

pre-hepatic portal hypertension

causes of portal hypertension includes obstructive thrombosis, narrowing of the portal vein before entering liver, and massive splenomegaly with increase splenic blood flow ~ this of causes that affect vessels before reaching the liver

post-hepatic portal hypertension

portal hypertension due to obstruction of vessels leaving the liver ~ right-sided heart failure and hepatic vein outflow obstruction

intra-hepatic portal hypertension

Caused by cirrhosis, in which bands of fibrous tissue and nodules distort normal liver tissue and increase resistance to blood flow

portal hypertension can lead to varices, which are

distended (enlarged) collateral veins, which can rupture and cause life-threatening hemorrhage

portal systemic shunt

surgical procedure to divert some of blood from portal system to systemic system to reduce portal hypertension in end-stage cirrhosis

transjugular intrahepatic portosystemic shunt

stent is passed over wire to connect portal vein to hepatic vein and bypass liver capillaries

ascites

abnormal accumulation of fluid in the abdomen (peritoneal cavity)

what is the most common cause of ascites

cirrhosis

a diseased liver can produce nitric oxide which can...

decrease effective circulating blood volume, which will ignite responses to increase plasma volume and accelerate portal hypertension and ascites formation

bacterial peritonitis

infection of the peritoneum which ignites an inflammatory response with increase capillary permeability ~ infection can also be due to translocation of bacteria in gut to the peritoneal cavity

paracentesis

surgical puncture to remove fluid from the abdomen ~ used for bacterial culture and microscopic analysis

enterohepatic circulation

from the portal circulation, the bile salts move into the liver cell and the recycled (90% of bile salts are reabsorbed)

what is hemoglobin broken down to form

biliverdin, which is rapidly converted into free bilirubin

what is the track of free bilirubin?

it is attached to an albumin, absorbed through the hepatocytes cell membrane in liver and converted to conjugated bilirubin (soluble in bile)

what happen to conjugated bilirubin

secreted as a part of the bile and secreted into the small intestine (via bile ducts) here, 50% is converted into a highly soluble substance called urobilinogen

what happens to urobilinogen

it is excreted via kidneys

jaundice results from...

abnormally high amount of bilirubin in the blood

what are the major causes of jaundice

Excessive destruction of RBCs (hemolysis); decreased uptake of bilirubin by liver; decreased conjugation of bilirubin by liver; obstruction of bile flow (gall stones) out of liver

what in the manifestation of jaundice

yellowish or greenish pigmentation of the skin and sclera ~ bilirubin has a strong affinity to elastic fibers

what are the two types of jaundice

Obstructive jaundice

Hemolytic jaundice

intra-hepatic obstructive jaundice

disturbances in hepatocyte function and/or obstruction of bile canaliculi ~ accumulates in liver ~ Disorders that directly affect the ability of the liver

extra-hepatic obstructive jaundice

obstructed bile ducts/flow outside the liver ~ conjugated bilirubin can't enter duodenum

what is a major cause of pre-hepatic jaundice

excessive breakdown (hemolysis) of RBCs at a rate excessing the liver's ability to remove bilirubin from blood

what are many newborns plagued with until the hepatic mechanisms are fully mature in the first 2 weeks of their life

transient (short-time) and mild unconjugated hyperbilirubinemia

cholestasis

pathologic condition of impaired bile formation and flow, leading to accumulation of bile pigment in the parenchymal tissues of the liver

what can elevated plasma bile acid cause... think salts and skin

pruritus (itchyness)

hepatitis

refers to acute or chronic inflammation of the liver

acute hepatitis is associated with...

viruses and infections

viral hepatitis

systemic viral disease that primarily affects the liver

hepatitis A, B, C, D, E can cause...

acute hepatitis

what can hepatitis B and C lead to...

chronic liver disease, hepato-cellular carcinoma, and liver failure

which viral hepatitis can produce carriers and which can't

HBV, HCV, HDV can ~ HAV can not

which factors increase the risk of becoming a carrier

age at time of infection (early in life) and immune status

what is the sequence of hepatitis

Incubation phase

Prodromal (preicteric) phase ~ begins around 2 wks with flu-like symptoms

Icteric phase ~ 2-6 weeks; hallmark sign is jaundice

Recovery phase 6-8 week

hepatitis A

benign and self-limiting disease with a brief incubation period ~ symptoms... think fever ~ virus is hardy and can survive extended periods ~ immunoglobulins before or after exposure can help

where is hepatitis A found

feces, bile, and blood of infected individuals ~ transmitted by the fecal-oral route after uptake HAV replicates in the liver

hepatitis B

transmitted through contact with infected blood, body fluids, or contaminated needles ~ immunoglobulins before or after contaminations can help~ maternal transmission is possible

hepatitis B is also involved in which other hepatitis development

HDV

what is more seen as a serious health problem, HAV or HBV

HBV

post-transfusion hepatitis is commonly which viral hepatitis

HCV - hepatitis C

what are other modes of catching HCV

IV drug use, needle stick injuries (tattoos, acupuncture, body piercing), and unprotected sex

50-80% of HCV often lead to

chronic hepatitis, cirrhosis, end-stage liver failure, and hapato-cellular cancer

autoimmune hepatitis

chronic and progressive form that may show hepatomegaly, splenomegaly, and jaundice, also other S/S

fulminant hepatitis

a clinical syndrome resulting in severe impairment or necrosis of liver cells ~ acute liver failure ~ leading to onset of hepatic encephalopathy

what is the leading cause of acute liver failure in the US

acetaminophen overdose

hepatic encephalopathy

complex neurologic syndrome with impaired cerebral functions and impaired neurotransmission ~ seizures, coma, and death

cirrhosis

irreversible inflammatory disease that disrupts liver function and even structure (fibrotic tissue synthesis) ~ a multiple-system disease

what are the common causes of cirrhosis

HBV, HCV

excessive alcohol

idiopathic

hemochromatosis ~ hereditary

glycogen or lipid storage diseases ~ hereditary

how does the liver looks in extreme cases of cirrhosis

cobblestone appearance dues to formation of fibrous bands

what two things can lead to spontaneous bacterial peritonitis

ascites and cirrhosis

alcohol liver disease

when the liver produces more enzymes to metabolize the high alcohol intake - liver enlargement

alcoholic fatty liver

mildest form of alcohol liver disease ~ fat deposits within the liver is cause by increase lipogenesis and decreased fatty acid oxidation by hepatocytes

alcoholic steatohepatitis

precursor of cirrhosis characterized by inflammation, degeneration and necrosis of hepatocytes with release of bioactive inflammatory mediators ~ irreversible fibrosis

alcoholic cirrhosis

end result ~ toxic effects of alcohol metabolism on the liver with immunologic alterations, inflammatory cytokines, oxidative stress from lipid peroxidation and malnutrition

the oxidation of alcohol to... can lead to...

acetaldehyde... lead to altered liver cell finction

what is the intermediate stage between fatty liver and cirrhosis in alcoholics

alcoholic hepatitis ~ inflammation and necrosis of liver cells, rapid onset of jaundice

liver failure results from

sudden and massive liver destruction or progressive damage to liver (commonly caused by ethanol)

biliary cirrhosis

cirrhosis beginning in bile canaliculi and ducts and not the liver cells

what are the two forms of biliary cirrhosis

primary (autoimmune) when t-lymphocytes and antibody mediated destruction of the small intra-hepatic bile ducts

secondary (obstruction) ~ partial or complete obstruction of common bile duct

what is the most common cause of gallbladder problems

obstruction (cholelithiasis) or inflammation (cholecystitis)

cholelithiasis types

cholesterol stones: most common, formed by supersaturated bile with cholesterol

pigmented (cirrhosis) stones: formed by increased levels of unconjugated bilirubin

cholecystitis

gallbladder becomes inflamed and may result in ischemia, necrosis, and perforation

pancreatitis

inflammation of the pancreas ~ relatively rare ~ caused by injury/damage to pancreatic cells and ducts causing leakage of pancreatic enzymes into pancreatic tissue

what can happen to the pancreatic tissue when exposed to the pancreatic enzymes

it can lead to autodigestion (self-digestion) and cause injury to other blood vessels and organs

liver cancer is increasingly due to chronic hepatitis of which two viral hepatitis

HBV and HCV

where do hepatocellular carcinoma develop

hepatocytes in the liver ~ described as massive nodules that can diffuse throughout

where do cholangiocellular carcinoma develop

develops in the bile ducts ~ associated with sclerosing cholangitis

what is the mortality rate of pancreatic cancer

100% it is robust and spread fast

where does majority of the tumors arise from in pancreatic cancer

exocrine glands (95%) ~ affecting ducts, not glands

ductal adenocarcinomas

pancreatic tumors from metaplastic exocrine cells in the ducts

with the ductal adenocarcinoma affecting ducts, where can it infiltrate

superior mesenteric artery, vena cave, aorta, and form emoli (clots)