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Normal Pressure Hydrocephalus: A Simple Hypothesis

Normal pressure hydrocephalus (NPH) is a brain disorder in which excess cerebrospinal fluid (CSF) accumulates in the brain’s ventricle, while the pressure of the fluid is usually normal. It is usually characterized by abnormal gait, urinary incontinence, and (potentially reversible) dementia. It is most commonly seen in older adults, but it’s not easy to diagnose exactly and to be treated. The usual treatment is surgical installation of a ventriculoperitoneal shunt to drain excess CSF into the lining of the abdomen where the CSF will eventually be absorbed.

To better understand its pathophysiology, in this paper, in combination with many theories that have been published in recent years and the experience of diagnosing and operating on hydrocephalus patients, the authors presented a hypothesis, a model for observable but unexplained facts, but also “progressive focusing”, a qualitative method where some experimental facts were used in an effort to understand a disease that was not fully charted. The hypothesis had evolved during the search for a meaningful explanation to known problems regarding the normal pressure hydrocephalus diagnosis. And the authors mainly introduced the following parts: the ApoE3 theory, head size, arachnoid granulations and the subpial theory.

And the conclusion showed that the pathology regarding CSF absorption lied in the subpial spaces in the basal cisternas and along the great vessels entering the brain. Here the idiopathic NPH was caused by reduced pulse pressure, which was needed to press the CSF into the venules. Here the ApoE3/3 genotype with the largest head percentile seemed to be the most vulnerable. For the acquired type of NPH the disruption of the subpial space reduced the entrance and subsequent resorption of CSF. And the arachnoid granulations played no role in resorption of CSF, but were rather most likely sensory and secretory organs necessary to control intracranial venous pressure.

Article by Gardar Gudmundsson, from Uppsalir Medical Center, Reykjavik, Iceland.

Full access: http://mrw.so/1cs7iB

Image by Finda TopDoc, from Flickr-cc.

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