Pathology of Jaundice, Liver Failure and Neoplasm Flashcards
What is the earliest sign of jaundice?
scleral icterus (yellow discoloration of the sclera) due to increased serum bilirubin (greater than 2.5 mg/dL).
*** How is bilirubin metabolized?
- At the end of RBCs lifespan (120 days), they are removed from the blood by the macrophages of the reticuloendothelial system (mostly spleen).
- Hemoglobin within the RBCs is broken down into HEME (Fe + protoporphyrin)and GLOBIN (amino acids to be recycled).
- Protoporphyrin (from heme) is converted to unconjugated (indirect) bilirubin (UCB).
- UCB will be carried on albumin to the liver.
- Uridine glucuronyl transferase (UGT) in hepatocytes conjugates bilirubin (CG) to make it water soluble.
- CB is transferred to bile canaliculi to form bile, which is stored in the gallbladder.
- Bile is released into the small bowel to aid in digestion of fats.
- Intestinal flora convert CB to urobilinogen, which is oxidized to STERCOBILIN (makes stool brown) and UROBILIN (partially reabsorbed into blood and filtered by kidney, making urine yellow).
What is extravascular hemolysis or ineffective erythropoiesis?
- excessive destruction of RBCs by reticuloendothelial system or death or RBCs within the bone marrow, respectively.
- In either case, you will get excessive production of UCB (indirect bilirubin), which will overwhelm the conjugating ability of the liver, leading to high levels of UCB in the blood.
*** What are the clinical features of extravascular hemolysis or ineffective erythropoiesis?
- dark urine due to INCREASED urine UROBILINOGEN (UCB is not water soluble and thus is absent from urine, but the liver is conjugating as much bilirubin as it can, hence the excessive urine urobilinogen from CB).
- increased risk for pigmented bilirubin gallstones.
What is physiologic jaundice of the newborn?
- newborn liver has a transiently low conjugating ability due to low uridine glucuronyl transferase (UGT) activity. - This leads to increased UCB in the blood.
What are the clinical features of physiologic jaundice of the newborn?
- UCB is fat soluble (NOT water soluble) and has no where to go, so it deposits in the basal ganglia (KERNICTERUS) leading to neurological deficits and death.
How do you treat physiologic jaundice of the newborn?
- phototherapy (merely makes UCB water soluble; IT DOES NOT CONJUGATE IT).
What is Gilbert syndrome?
- autosomal recessive mildly low UGT enzyme activity.
- This leads to increased UCB in the blood.
What is the clinical feature of Gilbert syndrome?
- jaundice during STRESS (e.g. sever infection)
* Otherwise, not clinically significant.
What is Crigler-Najjar syndrome?
- Absence of UGT enzyme!
- This leads to EXCESSIVELY HIGH UCB.
What is the clinical feature of Crigler-Najjar syndrome?
- Kernicterus
* usually FATAL
What is Dubin-Johnson syndrome?
- autosomal recessive condition causing a deficiency of bilirubin canalicular transport protein.
- Causes an increase in CONJUGATED bilirubin in the blood.
What are the clinical features of Dubin-Johnson syndrome?
- LIVER is DARK, but not clinically significant.
- derivative syndrome called ROTOR SYNDROME= similar to dubin-johnson but lacks liver discoloration.
What happens with biliary tract obstruction (obstructive jaundice)?
- associated with gallstones, pancreatic carcinoma, cholangioicarcinoma, parasites, and liver fluke (Clonorchis sinensis).
- Anything in the bile will then leak into the blood:
- CONJUGATTED bilirubin will be high in the blood because once bilirubin has made it into the biliary tract, it is conjugated, remember.
- DECREASED urine urobilinogen (because it is not making it to the bowel to be converted via bacteria).
- INCREASED alkaline phosphatase
What are the clinical features of biliary tract obstruction (obstructive jaundice)?
- DARK URINE (due to bilirubinuria; conjugated bilirubin is water soluble that has leaked into the blood; NOT UROBILINOGEN).
- pale stool
- pruritus due to increased plasma bile acids.
- hypercholesterolemia with xanthomas (from leaking into the blood from the bile).
- steatorrhea with malabsorption of fat-soluble vitamins.
What will viral hepatitis do?
- causes inflammation and disruption of the hepatocytes and small bile ductules.
- this leads to an INCREASE of both CB and UCB.
What are the clinical features of viral hepatitis?
- DARK URINE due to increased urine bilirubin
- urine UROBILINOGEN is normal or decreased (because less is making it to the bowel due to damaged bile ductules).
- NOTE: if Kawasaki disease, the treatment IS ASPIRIN!
What is hepatic adenoma?
- BENIGN tumor of hepatocytes associated with ORAL CONTRACEPTIVE use and will regress with cessation of drug.
- no central scar like in “focal nodular hyperplasia.”
- no connection to biliary system.
- ESTROGEN and PROGESTERONE RECEPTORS are present in most cases.
What is a risk of haptic adenomas if pt is pregnant?
- rupture and intraperitoneal bleeding, because the tumors are subcapsular (right underneath the capsule of the liver) and grow with exposure to estrogen.
*** What is hepatocellular carcinoma?
- MALIGNANT tumor of hepatocytes.
- more common in males bc males are more likely to get cirrhosis.
- Will see SERUM ELEVATION of ALPHA-FETOPROTEIN (AFP).