First catch of the year.
I have a question regarding your OUWB lectures. I’m trying to grasp why hyperglycemia causes an increase in serum tonicity and decrease in serum sodium, but hyperlipidemia causes no change in serum tonicity and a decrease in serum sodium. For hyperglycemia, I understand that the glucose contributes to the serum osmolarity and can’t passively cross the membrane so causes water to move. However, I’m confused with the situation with lipids and was wondering if you could clarify. Thank you so much!
I may have over indexed on false hyponatremia stuff. This is something you need to be familiar with but a detailed understanding of the mechanism of pseudohyponatremia.
The student had perfect knowledge of the mechanism behind hyperglycemia induced hyponatremia associated with hyperglycemia.
The lipid situation is just a lab error. The lipids fool the lab machine into thinking the sodium is low. It is not low. That is why the osmolality is normal. The osmolality detector is not fooled by the high fats (or proteins) in the blood.
You will not need to know the mechanism for the lab error. I tried to explain it but that may be a situation where I causes more confusion than provided clarity.
