Intravascular hemolysis and jaundice

[medInUSA]

Can you guys help me out on this discrepency please:

According to Rapid Review path by goljan, in intravascular hemolysis since the amount of hemoglobin bound to haptoglobin is so small the unconjugated bilirubin is not significantly increased. (page 215) And I see no reason why the conjugated bilirubin should be increased since there is no obstruction in the liver or bile ducts and the liver should be functioning normally. So then according to Goljan there should be no jaundice in patients with intravascular hemolysis.

However in reality in diseases with intravascular hemolysis such as G6PD deficiency there is juandice

"Jaundice and splenomegaly may be present during a crisis."
http://www.emedicine.com/med/topic900.htm

Also my hemotology professor confirmed that there is jaundice in intravascular hemolysis.

So is Goljan wrong when he said that unconjugated bilirubin is not significantly increased, or am I missing something??

thanks in advance.

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[naegleria brain]

i believe at first haptoglobin binds the released hemoglobin causing stabilization of the free bilirubin levels. with continued hemolysis, however, haptoglobin synthesis is overwhelmed by the rapidly increasing levels of bilirubin, and then you do get jaundice followed by bilirubinemia

 

[CenterMass]

Somewhere on SDN is a running list of errors from Goljan Rapid Review. You may find some confirmation there.

 

[Miami_med]

My understanding:

There is only so much Haptoglobin in the blood. During a crisis, it is overwhelmed, and huge amounts of unconjugated bilirubin spill into the blood. The liver can only conjugate the bilirubin so fast. Thus, the bilirubin backs up, open bile ducts or not, and jaundice is the result.

 

[ENThopeful]

bump.. anyone have an answer to this question?

is there jaundice with intravascular hemolysis?

 

[Dirt]

bump.. anyone have an answer to this question?

is there jaundice with intravascular hemolysis?

Depends on the degree of hemolysis and the cause (be it something acute or chronic).

There is no doubt though that intravascular hemolysis can cause jaundice.

 

[Dirt]

According to Rapid Review path by goljan, in intravascular hemolysis since the amount of hemoglobin bound to haptoglobin is so small the unconjugated bilirubin is not significantly increased. (page 215)

After re-reading this it looks like an obvious typo.

If the amount of Hb bound to HP is small, then the amount left to be degraded into bilirubin would be large.

For the sentence to make sense the amount of Hb bound to Hp would have to be large.

 

[cpants]

"Regardless of cause, hemolysis leads to hemoglobinemia, hemoglobinuria, and hemosiderinuria. The conversion of the heme pigment to bilirubin can result in unconjugated hyperbilirubinemia and jaundice...Haptoglobin, a circulating protein that binds and clears free hemoglobin, is often absent from the plasma."

Robbins Basic Pathology, pg. 424.

 

[ENThopeful]

ahh thank you that clears it up