This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Death and postmortem changes, Subject name: Forensic Medicine
CSF is preserved for examination in case of 
Select and explain. 
A. Alcoholic poisoning, B. Arsenic poisoning, C. Copper poisoning, D. Organophosphorous poisoning
A: Alcoholic poisoning
Answer: A: Alcoholic poisoning 
Explanation: Alcohol is evenly distributed throughout the body water, and crosses the blood brain barrier easily. Hence is detected in CSF. And so causes, dependence and tolerance. CSF should be drawn out as early as possible. There is sustained increase of potassium levels in CSF within 20 hrs after death. Ref: K.S,Narayan Reddy's Synopsis of Forensic Medicine and Toxicology, 29th edition, Chapter 29, page- 316.