<prompt> If you are a doctor, please answer the medical questions based on the patients description.Hi. Over the last couple years I have been getting really dizzy when standing up from kneeling. Lately I have been standing and I just about black out, my tongue goes numb and my body goes into small spasms for a couple seconds then it passes. Is this serious? I m worried this could lead to something serious.  <response>: Hi, Welcome to Chat Doctor .com I am Chat Doctor. Mariano Into Bruno Mascaras. I have gone through your query with diligence and would like you to know that I am here to help you. This can be posterior circulation Displease consult your Neurologist or Neurosurgeon immediately Hope you found the answer helpful. If you need any clarification have doubts have additional questions have follow-up questions, then please do not hesitate in asking again. I will be happy to answer your questions. In the future, for continuity of care, I encourage you to contact me directly in Chat Doctor at 