Ask a Neurologist. Get Answers to Your Neurology Questions.
Lots of reasons.
Infection, cancer of the colon, colitis, small bowel overgrowth.
If you got really dehydrated you could have an acid base problem, or electrolyte problem, which could cause numbness, or many other symptoms and you would nee to be in the emergency room.
OK, so you might have more questions or want to give me more information: Please use reply to expert if you have further questions. Also, please click a positive rating [hopefully excellent—that’s how we are paid, per rating]. If you forgot something, just use reply and come back. I am here