cerebellar tonsillar herniation
Introduction
Introduction to cerebellar tonsil The cerebellar tonsil is also known as the Arnold-Chiari malformation, which is a central nervous system dysplasia often associated with a skull base depression. The cerebellar tonsils are adjacent to both sides of the medulla and occipital macropores. When the intracranial pressure is increased, the cerebellar tonsils may be squeezed and embedded in the occipital foramen, causing cerebellar tonsil sputum (occipital foramen), oppressive medulla, and life-threatening. basic knowledge The proportion of sickness: 0.01% Susceptible people: no specific population Mode of infection: non-infectious Complications: hydrocephalus
Cause
Cerebellar tonsil sputum
Cause:
Cerebellar tonsil is caused by abnormal development of the posterior cranial fossa midline structure in the embryonic stage. The main pathological change is that the cerebellar tonsils are tongue-like downward extension, and the lower medullary medulla is more than the occipital macropores and enters the spinal canal, and its continuation The pons and cerebellar vermis are also displaced downwards, which may also cause a series of changes in the aqueduct and the fourth ventricle, the occipital macropores and the subarachnoid stenosis at the beginning of the spinal canal. Some tonsils are as low as a pivot or lower. In severe cases, the visible part of the lower jaw is also inserted into the spinal canal. Due to the above changes, the cerebral nerves such as the pharyngeal, vagus, accessory, and hypoglossal nerves are taken down, and the upper cervical spinal nerve roots are pulled down; the occipital large holes and the upper cervical canal are filled with cerebral hydrops.
Pathogenesis:
Scholars hold different opinions on their pathogenesis. Among them, traction theory is the most popular viewpoint. In this theory, patients with spina bifida and spinal meningocele are fixed in the spina bifida. During the growth and development process, the growth rate of the spine and spinal cord is different, and the spinal cord cannot be normal. Upward movement causes the spinal cord and cerebellum tissue to move downward, resulting in cerebellar tonsil squat. Some scholars believe that the influence of spinal cord traction is mainly limited to the lumbosacral region, and the chest is less affected. At the same time, patients with tethered cord syndrome do not have cerebellar tonsillar mandibular deformity. Therefore, spinal meningocele and cerebellar tonsil are considered. The squat is not related, but the primary deformity of the medulla, cerebellum, spinal occipital bone and brain. During development, the volume of the posterior fossa is small, and the brain tissue grows too much, so that some of the brain, tongue, vagus, vaginal, sublingual, sublingual, etc. The posterior group of cranial nerves and deep cervical nerve roots were pulled down, the occipital foramen and the upper cervical canal were filled, cerebrospinal fluid circulation was blocked, and hydrocephalus was secondary.
Prevention
Cerebellar tonsil prevention
There are no special precautions for this disease. Pay attention to medication safety:
1. Appropriate neurotrophic therapy after surgery may promote the recovery of neurological function to a certain extent, but the use of drugs alone can not curb the increase of nerve damage.
2, symptomatic treatment can usually play an analgesic and anti-dizziness effect, can improve symptoms and improve quality of life, no effect on reducing nerve damage.
3. Appropriate medical treatment is beneficial for those who do not need surgery, have surgical contraindications or are unwilling to undergo surgery.
Complication
Cerebellar tonsil complication Complications hydrocephalus
1. The cerebellar tonsil is prolonged into a wedge shape and enters the occipital foramen or cervical spinal canal. In severe cases, part of the lower iliac crest is also inserted into the spinal canal. The lingual pharyngeal, vagus, accessory, sublingual and other groups of the cranial nerve and deep cervical nerve root are pulled. Move down, the occipital foramen and the upper cervical canal are filled, and the cerebrospinal fluid circulation is blocked by hydrocephalus. This disease is often accompanied by other craniocerebral deformities such as spinal meningocele, cervical spondylolysis and cerebellar hypoplasia.
2. Intraoperative complications.
Symptom
Cerebellar tonsil symptoms Symptoms Common symptoms Intracranial hypertension Arachnoid adhesions Spinal cord Facial facial numbness Eyeball tremor Reflex Hyperthyroidism Dysphagia Difficulty dyspnea Tinnitus
Due to brain stem, upper cervical spinal cord compression, nerve tissue ischemia, cranial nerve-spinal nerve involvement and cerebrospinal fluid circulation, the following symptoms usually occur.
1, medullary, upper cervical spinal cord compression symptoms: manifested as a side or limb movement with different degrees of sensation, hyperreflexia, pathological reflex positive, bladder and anal sphincter dysfunction, dyspnea and so on.
2, cranial nerve, upper cervical nerve symptoms: facial numbness, diplopia, tinnitus, hearing impairment, pronunciation and difficulty in swallowing, pain in the lower part of the pillow.
3, cerebellar symptoms: manifested as nystagmus, gait instability or disorders.
4, intracranial hypertension: due to brain stem and upper neck segment pressure flattened, surrounding arachnoid adhesion thickening, sometimes can form cysts; medullary and cervical spinal cord can be affected by ischemia and cerebrospinal fluid pressure, the formation Secondary cavity lesions, hydrocephalus and so on.
Examine
Examination of cerebellar tonsil
In order to clarify the diagnosis and differential diagnosis, magnetic resonance imaging, CT scanning, vertebral artery angiography, etc. can clearly show the position of cerebellar tonsil. For patients with increased intracranial pressure, pay attention to sudden breathing stop during the examination. Therefore, when doing the above examination, the patient's breathing should be closely observed and emergency measures should be taken in advance.
Diagnosis
Diagnosis and identification of cerebellar tonsil
Need to identify with the cerebellar tonsil medullary joint deformity, other intracranial lesions combined with occipital foramen magnum, cerebellar tonsil mandibular deformity. The tonsils of the cerebellar tonsil are mostly tongue-shaped and often combined with other malformations. The tonsils of the cerebellar tonsils are mostly conical, and can simultaneously show signs of intracranial space-occupying lesions. Identification is not difficult.
