This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Medicine
A patient underwent Bhadrenalectomy in views of B/L pheochromocytoma 1 day later developed lethargy fatigue low BP and pulse normal No signs of volume deficit likely course 
Select and explain. 
A. Addisonian Crisis, B. SIADH, C. DI, D. Cerebral salt wasting DISEASE
A: Addisonian Crisis
Answer: A: Addisonian Crisis 
Explanation: ref harissons 21st ed