Prescribing Safety Assessment (PSA) Practice Exam

How can an upper gastrointestinal bleed lead to elevated urea levels?

1. It causes fluid overload

2. Urea is a breakdown product of proteins from absorbed blood

3. It decreases blood pressure

4. It results in increased creatinine production

The correct answer is: Urea is a breakdown product of proteins from absorbed blood

The elevation of urea levels following an upper gastrointestinal bleed primarily results from the absorption of blood into the gastrointestinal tract. Blood is comprised of various components, including proteins. When an individual experiences an upper gastrointestinal bleed, the digested blood leads to an increased protein load in the intestines. As the body absorbs this protein, it undergoes metabolism, producing urea as a byproduct of protein breakdown. Urea synthesis occurs in the liver through the urea cycle, and the resulting urea is released into the bloodstream. Consequently, during an upper gastrointestinal bleed, the absorption of hemoglobin and other blood proteins significantly raises the amounts of protein being metabolized and, hence, increases urea production. Understanding this mechanism highlights the intricate relationship between gastrointestinal bleeding and metabolic processes. In contrast, fluid overload, changes in blood pressure, or increased creatinine production do not directly explain the specific rise in urea levels related to the metabolic response to absorbed blood during such an event.