The patient is dizzy all at once, and the causes are considered as follows: 1. The patient is considered to be caused by postural hypotension will otoliths if it occurs during the change of position. In the case of otoliths, the patient will show episodes of dizziness with visual rotation at specific head positions, with characteristic signs, and the patient will have rotational nystagmus. 2. Patients who experience dizziness all at once may be caused by systemic diseases, cerebrovascular diseases, such as transient ischemic attacks, hypertension and other diseases that can also cause patients to experience episodes of dizziness all at once. It is important to pay attention to the form of dizziness attacks and the relief of the patient. If the dizziness lasts for a long time, the patient should seek timely medical attention for examination and treatment.