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The translaminar pressure gradient in sustained zero gravity, idiopathic intracranial hypertension, and glaucoma.
MedLine Citation:
PMID:  22981592     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Papilledema has long been associated with elevated intracranial pressure. Classically, tumors, idiopathic intracranial hypertension, and obstructive hydrocephalus have led to an increase in intracranial pressure causing optic nerve head edema and observable optic nerve swelling. Recent reports describe astronauts returning from prolonged space flight on the International Space Station with papilledema (Mader et al., 2011) [1]. Papilledema has not been observed in shorter duration space flight. Other recent work has shown that the difference in intraocular pressure (IOP) and cerebrospinal fluid pressure (CSFp) may be very important in the pathogenesis of diseases of the optic nerve, especially glaucoma (Berdahl and Allingham, 2009; Berdahl, Allingham, et al., 2008; Berdahl et al., 2008; Ren et al., 2009; Ren et al., 2011) [2-6]. The difference in IOP and CSFp across the lamina cribrosa is known as the translaminar pressure difference (TLPD). We hypothesize that in zero gravity, CSF no longer pools in the caudal spinal column as it does in the upright position on earth. Instead, CSF diffuses throughout the subarachnoid space resulting in a moderate but persistently elevated cranial CSF pressure, including the region just posterior to the lamina cribrosa known as the optic nerve subarachnoid space (ONSAS). This small but chronically elevated CSFp could lead to papilledema when CSFp is greater than the IOP. If the TLPD is the cause of optic nerve head edema in astronauts subjected to prolonged zero gravity, raising IOP and/or orbital pressure may treat this condition and protect astronauts in future space travels from the effect of zero gravity on the optic nerve head. Additionally, the same TLPD concept may offer a deeper understanding of the pathogenesis and treatment options of idiopathic intracranial hypertension (IIH), glaucoma and other diseases of the optic nerve head.
Authors:
John P Berdahl; Dao Yi Yu; William H Morgan
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-9-13
Journal Detail:
Title:  Medical hypotheses     Volume:  -     ISSN:  1532-2777     ISO Abbreviation:  Med. Hypotheses     Publication Date:  2012 Sep 
Date Detail:
Created Date:  2012-9-17     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7505668     Medline TA:  Med Hypotheses     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2012 Elsevier Ltd. All rights reserved.
Affiliation:
Vance Thompson Vision, University of South Dakota, 1310 W, 22nd St., Sioux Falls, SD 57105, United States. Electronic address: johnberdahl@gmail.com.
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