Acoustic neuroma refers to a tumor originating from the auditory nerve sheath. The exact name should be auditory nerve sheath tumor. It is one of the common intracranial tumors. It is a benign tumor, mostly from the vestibular superior nerve, followed by the vestibular lower nerve. Generally, it is single-sided, and there are fewer occurrences on both sides. Most patients with acoustic neuroma are adults, with peaks ranging from 30 to 50 years old. The younger the age, the less common.
Director Jia Dong of the Department of Neurosurgery, Tangdu Hospital of the Fourth Military Medical University pointed out that in clinical terms, it is generally divided into three stages: early, middle and late according to its condition. Among them, early symptoms mostly occur in the ear. When the tumor volume is small, the patient will have one side of tinnitus, hearing loss and dizziness. A few patients have deafness after a long time. Tinnitus may be accompanied by paroxysmal vertigo or nausea or vomiting; intermediate symptoms often appear on the face, when the tumor continues to increase, oppress the ipsilateral facial nerve and trigeminal nerve, the patient may have facial muscle twitching and decreased secretion of lacrimal gland, or mild Peripheral facial paralysis. Trigeminal nerve damage manifests as facial numbness, pain, decreased tactile sensation, decreased corneal reflex, poor diaphragm muscle and masticatory muscles, or muscle atrophy. The late symptoms are mostly cerebellar cerebral horn syndrome and the posterior cranial nerve. When the tumor is large, the brain stem, cerebellum and posterior cranial nerve are compressed, causing cross-biasing and partial sensory disturbance. The patient will have cerebellar Disorders, gait instability, difficulty in pronunciation, hoarseness, difficulty swallowing, eating and coughing. Cerebrospinal fluid circulatory obstruction may have headache, vomiting, vision loss, papilledema or secondary optic atrophy.
With regard to the examination of typical acoustic neuroma, Director Jia Dong believes that most of the diagnosis can be confirmed by imaging and neurological examination.
First, radiological examination. Radiological examinations generally use skull X-ray, CT and MRI scans. When the patient has an acoustic neuroma, the skull X-ray film will show: the flat bone of the rock sees the enlargement of the inner ear canal, bone erosion or bone resorption; CT shows that the tumor is of equal density or low density, a few are high-density images, and the tumor is more It is round or irregular, located in the inner auditory canal area, with multiple internal auditory canal expansion, and the enhancement effect is obvious; MRI can be expressed as a slightly lower or equal signal on the MRIT1-weighted image and a high signal on the T2-weighted image. The fourth ventricle is deformed under pressure, and the brainstem and cerebellum are also deformed and displaced. After injection of contrast agent, the tumor parenchyma was significantly enhanced and the cystic zone was not strengthened.
Second, neurological examination. Because patients with acoustic neuroma have only tinnitus and deafness in the early stage, they often visit the ear department. Commonly used are hearing tests and vestibular nerve function tests. Among them, there are four types of hearing tests. The hearing test method can distinguish hearing impairment from the conduction system, cochlear or auditory nerve obstacle hearing test, type I is normal or middle ear disease; type II is cochlear hearing loss; Type IV is the auditory threshold of the auditory neuropathy. If the pitch subsides more than 30dB for the auditory nerve disorder, the short enhancement sensitivity test score is 60% to 100% for cochlear lesions, and the binaural alternating volume balance test has a cochlear lesion with an additive phenomenon, and the middle ear or auditory neuropathy without supplementation.
Because acoustic neuroma originates from the vestibular part of the auditory nerve, vestibular neurological function tests are also helpful in diagnosis. In the early stage of cold and hot water test, the vestibular dysfunction of the diseased side was almost completely found, and the reaction completely disappeared or partially disappeared. This is a common method of diagnosing acoustic neuroma. However, since the fibers emitted from the vestibular nucleus are located in the shallower part of the cerebral pons when crossing to the contralateral side, they are easily compressed by the cerebral cerebellopontine angle tumor, and about 10% of the vestibular function of the healthy side can be damaged.
About the symptoms of acoustic neuroma and the director of the Department of Neurosurgery, Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Jia Dong, introduced here. Director Jia Dong reminded patients to go to the relevant specialist hospitals immediately when they found themselves suffering from acoustic neuroma. Do not delay the time and delay treatment.