Ch. 14 Liver Part 1 Bilirubin, Cirrhosis, Failure Flashcards
RBCs are broken down in the ___, the resulting bilirubin gets transported to the ___. There it gets conjugated to glucuronic acid by the enzyme ___ and excreted through the ___. It is broken down in the bowel to ___ which is excreted in the feces or recycled and is excreted in the urine.
RBCs are broken down in the spleen, the resulting bilirubin gets transported to the liver. There is gets conjugated to glucuronic acid by the enzyme UGT and excreted through the bile canaliculi. It is broken down in the bowel to urobilinogen which is excreted in the feces or recycled and is excreted in the urine.
Name 3 general causes of jaundice
Overproduction of bilirubin
Interference with hepatic uptake or metabolism of bilirubin
Impairment of bile excretion.
What kind of bilirubin is abundant in jaundice related to hemolytic anemia?
Unconjugated bilirubin due to increased destruction of erythrocytes
Ineffective erythropoiesis can also cause unconjugated hyperbilirubinemia
Your new patient wants you to be aware that he has a familial disease in which his liver doesn’t clear bilirubin as well as normally, and he also has some issues with drug metabolism.
What syndrome does he have?
Does it impair his liver?
What’s the more severe, more nefarious-sounding version of this disease?
Gilbert syndrome
Inadequate synthesis of the UGT enzyme due to mutations in the promoter region causing reduced transcription.
Causes mild unconjugated hyperbilirubinemia without functional or structural liver disease.
Crigler-Najjar is the disease caused by complete absence of UGT, lethal until phototherapy was discovered to make UCB water-soluble.
Your pregnant patient is admitted for her scheduled C-section, and mentions that she has been a bit yellow around the edges and her urine has been dark recently, but she otherwise feel fine.
When you perform the C-section, you notice that her liver is so dark it’s almost black. What syndrome does she have and what causes it?
Dubin-Johnson syndrome
Caused by inability of liver to secrete conjugated bilirubin into the bile
Black liver due to accumulation of dark brown granules in the hepatocytes, shift in ratio of urinary coproporphyrin isomer I and III from the normal 1:3.
Rotor syndrome is the same thing but the liver has normal pigmentation
What causes neonatal jaundice?
How is it treated?
Hepatic UGT activity is lower than that of adults, and the newborn liver has underdeveloped conjugating and excreting capacities
Leads to transient unconjugated hyperbilirubinemia
Phototherapy used to turn unconjugated bilirubin into a water soluble form (Kinda like water into wine, but with light)
What is cholestasis?
What resulting elevation causes pruritus?
Describe the microscopic appearance of cholestasis
Defect in transport of bile across canalicular membrane for a variety of reasons
Elevation of serum bile acids cause pruritus
Presence of brownish bile pigment within dilated canaliculi and in hepatocytes. If the obstruction is extra hepatic, the hepatocytes have hydropic swelling, impregnation with bile pigment, and a reticulated appearance (called feathery degeneration) if the bile ducts rupture, it causes a bile lake (golden yellow deposits surrounded by degenerating hepatocytes).
What hepatic condition is described as regenerative nodules surrounded by fibrous septa?
What are the two subcategories of appearance and their most likely causes?
Cirrhosis
Micronodular (small nodules, thin connective tissue septa) Usually caused by alcoholic injury.
Macronodular: (broad connective tissue septa) Usually caused by chronic hepatitis
Accumulation of what chemical leads to hepatic encephalopathy in liver failure?
What is the major cause of death in acute liver failure?
Ammonia
Cerebral edema (often with uncal and cerebellar herniation)
What brain cells are increased in size and number, and have swelling and nuclear inclusions in patients who have died of chronic liver disease?
Alzheimer type II astrocytes
What are some common neurological symptoms of hepatic encephalopathy?
Asterixis (flapping tremor of the hands), hyperactive reflexes, extensor toe responses and decerebrate posture in the late stage.
What are three changes in blood chemistry and endocrine function associated with hepatic failure?
Coagulation defections, hypoalbuminemia leading to edema, and hyperestrogenism
