<prompt> Blood Urea Nitrogen is decreased in:Hypo-ammonemiaHyper-ammonemiaHyperventilationHypoventilation  <response>: Blood Urea Nitrogen is decreased in urea cycle defects,where Hyper-ammonemia occurs Cf 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. 