Entrapment
| Classification according to ICD-10 | |
|---|---|
| G93.5 | Compressio cerebri (herniation of the brain (stem)) |
| ICD-10 online (WHO version 2019) | |
An entrapment (English: herniation ) in medicine describes the displacement of parts of the brain due to increased intracranial pressure . A distinction is made between an upper and a lower pinching . In the case of the upper (= descending transtentorial) entrapment, there is a displacement of brain matter under the tentorium cerebelli . In the case of lower (= tonsillar) entrapment, the cerebellar tonsils are pressed through the foramen magnum , an opening in the skull with a connection to the spinal cord, between the medulla oblongata and bony structures. This compresses the Extended Mark . If the respiratory center located there is affected, death results from respiratory failure . Therefore the lower entrapment, in contrast to the upper one, is immediately life threatening.
Other known forms of entrapment are:
- "subfalcine" entrapment of the cingulate gyrus under the falx cerebri
- "Descending transalar" entrapment of frontal lobe mass in the middle fossa
- "Ascending transalar" entrapment of the anterior temporal lobe in the anterior cranial fossa
- "Ascending transtentorial" entrapment of cerebellar mass over the tentorium cerebelli
- "Extracranial" entrapment of brain matter in the hernia of a skull fracture or surgical wound
Ascending entrapments are significantly less common than descending ones, and are mostly caused by locally limited space-occupying processes (especially tumors ). Frequently, multiple entrapments also occur in combination. Subfalcine and transalar entrapment do not immediately lead to a compression of the brainstem, but to disturbances of the blood and liquor flow , which further increase the intracranial pressure and thereby trigger additional, more dangerous entrapment.
course
Entrapment represents the common final stretch of diseases of the brain that are accompanied by an increase in volume . The pathophysiology proceeds as follows: Due to the increased intracranial pressure , the veins are first compressed, then the arteries . First ischemia , then hemorrhagic infarction , this is the actual mechanism that causes the damage to the neurons . The entrapment is preceded by vegetative symptoms such as increased blood pressure and increased breathing rate. Furthermore, there is a constriction of the pupils, the miosis . This is a consequence of the ischemia of the Edinger Westphal nucleus , which increases its spontaneous discharge frequency due to the lack of oxygen and thus causes miosis via the oculomotor nerve . Only in the further course does cell death in the core area cause the pupils to dilate, known as mydriasis . In the further course, when the medulla oblongata is trapped , arterial hypotension occurs .
literature
- Martin Trepel: Neuroanatomy. Structure and function. 3. Edition. Urban & Fischer at Elsevier, 2006, ISBN 3-437-44425-5 .
Individual evidence
- ↑ https://radiopaedia.org/articles/cerebral-herniation ; accessed on April 15, 2018
