This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urea cycle, Subject name: Biochemistry
Blood Urea Nitrogen is decreased in: 
Select and explain. 
A. Hypo-ammonemia, B. Hyper-ammonemia, C. Hyperventilation, D. Hypoventilation
B: Hyper-ammonemia
Answer: B: Hyper-ammonemia 
Explanation: Blood Urea Nitrogen is decreased in urea cycle defects,where Hyper-ammonemia occurs C/f of urea cycle defects:- Increased blood glutamine Decreased BUN (Blood Urea Nitrogen) Cerebral oedema Vomiting Lethargy Blurred vision Slurred speech & hyperventilation. Note:-Severe ammonia toxicity can lead to coma and eventually death.