Hyperbilirubinemia Flashcards
List the causes of Unconjugated Hyperbilirubinemia
Physiological jaundice: due to short fetal RBC life span,
immature UGT, poor enterohepatic circulation. Starts after day
1, peaks at 3-4 days, disappears after 10 days.
● Breastfeeding failure jaundice= Insufficient breast milk intake leads to not enough bowel movements to remove bilirubin
● Breast milk jaundice: Beta-glucuronidase enzyme is naturally present in breast milk and is responsible for breaking down conjugated bilirubin into its unconjugated form. This unconjugated bilirubin is more readily absorbed by the infant’s intestinal cells and can be reabsorbed into the bloodstream.
Later onset, occurs in 2nd-3rd week after birth. Begin feeding
with formula.
● Criggler-Najjar: inherent deficiency of UGT. Type I is more
severe, fatal. May need liver transplant.
● Gilbert: only slight deficiency of UGT, no pathology associated.
●Hemolyis due to Rh incompatibility . Rh neg. mother who has been exposed to a Rh pos. fetus. IgG antibodies attack Rh+ fetus RBCS leading to hemolytic anemia. Direct Coombs test positive
○ If milder, may present with pallor, jaundice, tachycardia lethargy.
If severe, may have generalized edema,pleural effusions, ascites, hepatosplenomegaly,
extramedullary erythropoiesis.
○ May need transfusion as neonate if severe.
○ Prevent maternal sensitization with rhogam. If motherhas been sensitized, then perform serial antibody titers of mother, may want amniocentesis to find out fetal Rh genotype.
Perform plasmapheresis and give IVIG to decrease maternal antibodies.
List the causes of Conjugated Hyperbilirubinemia
-Biliary Atresia
-Dubin Johnson’s Syndrome :
Genetic disorder characterized by impaired hepatic secretion of bilirubin into bile. It is caused by mutations in the ABCC2 gene, which encodes a protein called multidrug resistance-associated protein 2 (MRP2). MRP2 is responsible for transporting conjugated bilirubin from liver cells into bile, facilitating its excretion from the body.
Mutations in the ABCC2 gene lead to decreased or dysfunctional MRP2, resulting in reduced bilirubin excretion.
In Dubin-Johnson syndrome, the impaired bilirubin transport leads to the accumulation of conjugated bilirubin within liver cells, causing them to become pigmented.
This results in a characteristic finding of darkly pigmented liver tissue upon histological examination.
-Rotor syndrome:
Due to defects in specific transport proteins involved in bilirubin handling within liver cells. These proteins may include organic anion-transporting polypeptides (OATPs) and other transporters responsible for the uptake and transport of bilirubin within hepatocytes.
Rotor syndrome can be differentiated from Dubin-Johnson syndrome based on the absence of liver pigmentation and the presence of elevated levels of coproporphyrin in urine.
