Diagnosis: In principle, it should be consistent with a sudden onset, hearing loss to a nadir within a short period of time, a non-fluctuating sensorineural hearing loss, no symptoms of cranial nerve damage other than the eighth cranial nerve, no clear etiology, and can have a causative factor. There is still disagreement regarding the criteria for the degree of hearing loss in sudden deafness. The foreign literature mostly defines sudden deafness as a 30 dB decrease in the mean hearing threshold at three adjacent frequencies. The current diagnostic criteria in China is a hearing loss of greater than 20 dB at more than 2 consecutive frequencies on pure tone audiometry. Pathogenesis: Many factors may cause sudden deafness, mainly inner ear microcirculation disorders, viral infections, viral and vascular combination factors, vascular striation dysfunction, trauma, poisoning, tumors, etc., and rupture of the vagus round window membrane. 1. Inner ear microcirculation disorder is one of the main causes of morbidity. The cochlear blood supply vessels are terminal vessels without collateral circulation and poor local circulatory compensatory capacity; at the same time, elevated systemic blood pressure and partial pressure of carbon dioxide in the body circulation may cause ectolymphatic hypoxia in the cochlea, decreased oxygen supply to the auditory organs, higher oxygen consumption for physiological activities of auditory hair cells, and poor tolerance to hypoxia. Causes of cochlear microcirculatory dysfunction include microthromboembolism, reduced blood flow, vasospasm, inflammatory swelling of vascular endothelial cells, or changes in ion concentration. 2, Viral infection directly destroys hair cells and ganglion cells. 3. Excessive immune response in the inner ear can lead to self-destruction of the cochlea. Symptoms: 1. Deafness. It can occur within a few hours or days, and the hearing loss can gradually increase and stop progressing only after several days. The degree of deafness varies and can lead to total deafness in severe cases. Unilateral deafness is common, and occasionally occurs bilaterally or sequentially. Some patients have the possibility of self-healing. 2. Tinnitus. There may be tinnitus before and after hearing loss, with varying frequency and a variety of tinnitus sounds, including machine murmur and cicada sound. 3. Vertigo. Some patients can have vertigo at the same time, and the duration varies, but all of them can be relieved. According to clinical observation, it is more difficult to recover hearing in patients with vertigo than in those without vertigo. Treatment There are many treatment options, but the most effective drugs are: vasodilator, hormone, thrombolytic, neurotropic. The effects of other adjuvant treatments such as hyperbaric oxygen, acupuncture point injection, and tympanic chamber injection are still under observation and discussion.