13. Genetic Disorders of GI Flashcards
When is Crigler-Najjar going to present?
In the neonatal stage of life.
What is kernicterus?
Bilirubin deposition in the brain.
What drug can be used to treat Crigler-Najjar, and how does it work?
Phenobarbital.
Only works for type II, but increases UDP glucuronyl transferase mRNA synthesis and activity.
What disease should we associate with jaundice s/p stress, fasting, or ethanol intake?
Gilbert syndrome.
What is the genetic cause of Gilbert syndrome?
Defect in the gene promoter for UGT1A1 (UDP-glucuronyl transferase 1A1).
Resulting in a decrease of UGT1A1 activity and decreasing bilirubin conjugation.
Is Gilbert’s syndrome conjugated or unconjugated bilirubinemia?
Unconjugated bilirubinemia.
What does a rifampin test come back positive for?
Either Gilbert’s syndrome or chronic liver disease.
Why might you need to avoid certain medications if you have Gilberts syndrome or Crigler-Najjar Type I?
Because UGT1A1 is nonfunctional, and is necessary to metabolize certain medications – like Ironotecan
Is Dubin-Johnson syndrome conjugated or unconjugated hyperbilirubinemia?
Conjugated hyperbilirubinemia.
What causes the black liver in Dubin-Johnson?
Impaired excretion of epinephrine metabolites.
What common medication can exacerbate the symptoms of Rotor syndrome?
Oral contraceptives – they compete for common transport proteins with conjugated bilirubin.
Dubin-Johnson and Rotor syndrome both show direct hyperbilirubinemia. What other lab value can allow you to distinguish between the two?
Urine coproporphyrin levels.
Coproporphyrin levels are elevated in Rotor syndrome but normal in Dubin-Johnson syndrome.
What does Coombs test test for?
Isoimmune hemolytic disease.
What disease should we consider from this lecture if the patient presents with CNS symptoms such as Parkinson -like symptoms, flailing, or dementia.
Wilson’s disease.
Wilson’s disease is a major risk factor for several liver diseases, including what important three presented in this lecture?
Hepatitis, cirrhosis, and hepatocellular carcinoma.
