Increased Tissue Pressure Induces Demyelinated Lesions and Necroses in the Brain

Ulrich Barz,Helmut Barz,Almut Schreiber

doi:10.3844/amjnsp.2015.1.7

Abstract

A general brain edema increases the size of the brain tissue and stretches the elastic neuronal and glial fibers. Myelinated fibers are more elastic than unmyelinated fibers. The stretching of the neuronal fibers leads particular in regions of the white matter or areas surrounded by myelinated fiber tracts to an increased tissue pressure. This physical principle can be the reason for demyelination and tissue necrosis. The higher the tissue pressure, the lower the blood perfusion. We support the pressure-hypothesis by comparison with well-known pressure related pathologies of the nervous system and other organs. One convincing example is the central pontine myelinolysis. A general or local tissue edema may lead especially in the periventricular and the deep white matter, but also in the cerebellum, the brain stem and the spinal cord to the formation of hypoxemic lesions. In consequence, this could result in diseases like leukoaraiosis, Binswanger encephalopathy, idiopathic intracranial hypertension and Multiple Sclerosis (MS). In cases of brain tissue swelling, capsula-like structures may lead to a rapid increase in tissue pressure within the enclosed areas. This may occur particularly at the optic nerve. A reduced reabsorption of Cerebrospinal Fluid (CSF) can also lead to an increase of the pressure in the Central Nervous System (CNS).

Highlights

A particular aspect of this paper is the demonstration of the close connection between tissue edema and a consecutive increase in tissue pressure
There is clear evidence that the lesions in many demyelinating diseases are caused by a local reduction in the blood circulation
This occurs seldomly due to cardiac insufficiency or blood vessel disorders but may be due to an increase in brain tissue pressure often caused by edema and consecutive tensile and compressive forces by stretched swollen gray and white matter

Summary

Introduction

A particular aspect of this paper is the demonstration of the close connection between tissue edema and a consecutive increase in tissue pressure. No consideration was given to a possible increased tissue pressure (e.g., by edema) as a cause for the reduction of blood flow and for hypoxemic lesions. A classic example of pressure induced necrosis is the CPM This often fatal disease (paralysis, “locked in syndrome”) is primarily initiated by an electrolyte disturbance with edematous tissue swelling, especially at the center of the pons. The partial necrosis of the pregnancy induced hyperplastic pituitary gland as a complication of severe uterine bleeding during birth (Sheehan-syndrome) is caused by a local increase of tissue pressure due to edema in the fossa hypophysialis. The increased pressure in the periventricular white matter, resulting in inadequate blood perfusion, may explain the formation of the spatial periventricular demyelinated lesions in disorders of the white matter like Binswanger’s encephalopathy and leukoaraiosis (Baust et al, 1963; Beggs, 2013). The constant metabolic formation of fluid by the brain tissue and the limited ability for the reabsorption of CSF may be the reason for that phenomenon (Miller and Adams, 1992; Jacobson et al, 1990)

Discussion

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Conclusion

Funding Information