If a patient suddenly becomes dizzy, accompanied by fainting, there are several causes as follows: 1. The most common cause is the case of acute hypoglycemia in endocrinology, when the patient’s blood sugar is less than 3.9 mmol/L, a hypoglycemic reaction will occur, and if the blood sugar continues to decrease, a hypoglycemic coma will occur, and a sudden dizziness, accompanied by fainting, will also occur in a hypoglycemic coma. 2. Acute cerebrovascular accidents, such as acute In acute cerebrovascular accidents, such as acute stroke, transient ischemic attack, acute cerebral hemorrhage, acute cerebral embolism, and acute cerebral infarction, patients may also experience sudden dizziness and fainting when there is a sudden ischemic attack in the cerebral vasculature. 3, In acute coronary syndrome, such as acute myocardial infarction, patients may also experience sudden dizziness and fainting. 4, In acute poisoning, such as acute In acute poisoning, such as acute gas poisoning or drug poisoning, there will also be sudden onset of dizziness accompanied by fainting.