<s>[INST] My son was standing and talking to someone outside. When he went to walk away his vision went black, he had trouble controlling his extremities and felt nauseated. When he got back inside he sat down and said he was sweating. After a few minutes he said he still feels sick and has a headache but his vision is better. What could have caused this and is there anything we can do besides wait? Thank you, Mike Howard [/INST] Hello! Thank you for your question on Chat Doctor! I understand your concern, and would like to explain that his symptoms may be related to different disorders like : 1- Low blood pressure. As his symptoms occurred while standing up, a low blood pressure or an orthostatic hypotension, may be the cause of his symptomatology. I recommend to closely monitor his blood pressure during sitting and standing up position. A head up tilt test may be necessary to exclude an orthostatic hypotension. 2. Low blood sugar: hypoglycemia could cause a similar clinical scenario. I recommend performing a routine blood test (to exclude chronic anemia) and blood glucose levels. 3. A seizure. A partial seizure may mimic these symptoms. If the above tests result normal, an EEG and a brain CT scan may be necessary to exclude a possible seizure and possible intracranial causes. Meanwhile, I recommend taking plenty of water and have some rest. Hope to have been of help! Best regards,  </s>