Quiz 4: Liver

Question 1

Synthesized Liver Products

Answer 1

Proteins, Coag factors, ammonia, carbohydrates, fat, ketones, Vit A, enzymes, ect

Question 2

Bilirubin

Answer 2

Complexes with albumin for transport to liver, is then conjugated to make bilirubin diglucuronide (water-soluble), then excreted in the bile (secreted by liver and stored in Gallbladder) and broken down into urobilinogen

Question 3

Pre-hepatic jaundice

Answer 3

Caused by excessive erythrocyte destruction, the rate of hemolysis exceeds the liver’s ability to take up bilirubin for conjugation shown by an increased level of unconjugated bilirubin in the serum

Question 4

Gilberts syndrome

Answer 4

Hepatic jaundice, a defect in the ability of hepatocytes to take up bilirubin due to a transport problem with the bilirubin, shown by mild increase in the serum level of unconjugated bilirubin

Question 5

Crigler-Najjar disease

Answer 5

Partial or complete deficiency of UDP-glycuronyltransferase, no conjugated bilirubin is formed causing an increase in serum levels of unconjugated bilirubin

Question 6

Dubin-Johnson syndrome

Answer 6

Defective liver cell excretion of bilirubin due to impaired transport in the hepatocytes of conjugated bilirubin, this is shown by increased serum level of conjugated bilirubin

Question 7

Neonatal physiological jaundice

Answer 7

Low UDP-glycuronyltransferase at birth, it takes several days for the liver to synthesize an adequate amount of the enzyme to catalyze bilirubin conjugation causing increased serum levels of unconjugated bilirubin

Question 8

Intrahepatic cholestasis

Answer 8

May be caused by hepatocyte injury such as cirrhosis bile duct injury or neoplasms

Question 9

Posthepatic jaundice

Answer 9

Occurs when an obstruction blocks the flow of bile to the intestines can be caused by gallstones neoplasms or inflammation, it is characterized by a significantly increased level of conjugated bilirubin in serum, an increased level of unconjugated bilirubin in serum, an increased conjugated bilirubin in the urine, decreased urine and fecal urobilinogen, and stool that is pale

Question 10

Reye syndrome

Answer 10

Unknown cause of the symptoms include encephalopathy, neurologic abnormalities like seizures or coma, and abnormal liver function tests due to hepatic destruction. Occurs mainly in children usually after a viral infection or aspirin therapy

Question 11

Serum enzymes marking hepatocellular necrosis

Answer 11

ALT: specific for hepatocyte injury
AST: less specific than ALT significant presence in other tissues
LD: least specific, significant presence in other tissues

Question 12

Serum enzymes marking cholestasis

Answer 12

Alkaline phosphatase

Gamma-glutamyl transferase

Question 13

Other serum enzymes to assess liver disorders

Answer 13

Total bilirubin, direct bilirubin (conjugated), indirect bilirubin (Unconjugated), albumin, ammonia, AFP

Question 14

Jendrassik-Grof total bilirubin test

Answer 14

Bilirubin + sodium acetate + caffeine sodium benzoate + diazotized sulfanilic acid gives purple azobilirubin + alkaline tartrate gives green-blue azobilirubin (600 nm)

Question 15

Jendrassik-Grof total bilirubin test error sources/ranges

Answer 15

Hemolysis, lipemia, avoid exposure to sunlight and fluorescent lighting
Infants: Total: 2-6 mg/dL
Adults: total: 0.2-1.0 mg/dL
Indirect: 0.2-0.8 mg/dL
Direct: 0-0.2 mg/dL

Question 16

Urobilinogen Test Methodology

Answer 16

Urinary urobilinogen combines with aminobenzaldehyde to give a colored complex
Increase: Hemolytic disease, hepatocellular disease
Decrease: Posthepatic obstruction, impairing excretion of bilirubin to the intestines

Question 17

Porphyrin Formation

Answer 17

Requires enzymes uroporphyrinogen, coproporphyrinogen, and protoporphyrinogen
If any of these are deficient, it causes an EXCESS FORMATION of the corresponding porphyrin which can build up in BM and Liver

Question 18

Porphyrin Testing

Answer 18

From a 24hr urine sample, needs light protection (brown plastic) and additives to keep pH around 7

Question 19

Watson-Schwartz Test

Answer 19

Uses p-dimethylaminobenzaldehyde to form a red product with porphobilinogen