Hello thank you for trusting HCM Dear possible causes are 1.defecation syncope:caused by a reflex of the involuntary nervous system called the vasovagal reaction. The vasovagal reaction leads the heart to slow down (bradycardia) and, at the same time, it leads the nerves to the blood vessels in the legs to permit those vessels to dilate (widen). The result is that the heart puts out less blood, the blood pressure drops, and what blood is circulating tends to go into the legs rather than to the head. The brain is then deprived of oxygen, and the fainting episode occurs. 2.seizure episode:atonic seizures type of seizure that consist of a brief lapse in muscle tone that are caused by temporary alterations in brain function. 3.BPPV: dislodge of otolith debris may cause this problem. 4.postural hypotension:it may be secondary due to cardiac ir autonomic dysfunction. other many causes for syncope I mentioned mist possible causes.if your feelings like this anytime in future you may lie down immediately.dont drive lovely. please consult your neurophysician/ent specialist they will examine and treat you accordingly. take care