temporary blindness

My son experiences temporary blindness when he stands up about twice a week. It sometimes lasts a few seconds, but the longest has been about 15 seconds. What might be the cause if any?

[Neuro Forum]

Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.

Without the ability to examine your and obtain a history, I can not tell you what the exact cause of his symptoms is. However I will try to provide you with some useful information.

One potential cause for vision changes that are postural (occuring with changes with posture and specifically when going from lying down to sitting or sitting to standing) is that there is a drop in blood pressure that is occurring. Normally, there are specific blood pressure and heart rate responses that an individual mounts in response to changes in posture. Often, these include a small drop in blood pressure and an increase in heart rate when one assumes a standing posture. If a person is dehydrated, due to poor water intake or excessive sweating, diarrhea, vomiting, or for whatever other reason, the blood pressure may drop excessively on first standing, then the body compensates for it. Other causes of postural (what is termed orthostatic) symptoms is a problem in the autonomic nervous system. The autonomic nervous system is the part of the nervous system that controls blood pressure, heart rate, and other functions. Orthostatic symptoms can also occur if there is narrowing of the arteries to the back of the brain; this would most commonly occur in older adults who have artherosclerosis.

Evaluation by a general physician (internist, family physician) is recommended for your son.

Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.