If the cratinine getting down to 2.83 n the blood uria rises to 147 what may b the reason?

Kidney disease: A creatinine of 2.83 and blood urea nitrogen of 147 are very elevated, and that person has kidney disease or damage. It is important to have more information, such as what other conditions that the person might have, how long have these numbers been elevated, and what the urinalysis looks like. Without these other data, it is difficult to make a diagnosis.