The special clinical problem of symptomatic hydrocephalus with normal cerebrospinal fluid pressure: Observations on cerebrospinal fluid hydrodynamics
Abstract
In a series of personally observed cases, three of which are reported in detail, the authors have noted that a state of symptomatic hydrocephalus may exist in the presence of normal CSF pressure. The patients had exhibited mental dullness, inattentiveness, psychomotor retardation, unsteadiness of gait, and incontinence of urine, a syndrome which may be mistakenly ascribed to a degenerative or traumatic vascular disease of the cerebrum. Ventriculo-atrial shunt corrected this condition and permitted recovery by lowering the CSF pressure 20 or more mm of water.
An important factor, heretofore overlooked, in explaining this symptomatic hydrocephalus with relatively normal CSF pressure is that the force exerted on the ventricular wall represents a product of pressure times surface area. A given pressure exerts a greater force in a large ventricular system than in a small one. A pressure of 170 or 180 mm H2O in ventricles that are three times normal size may produce symptoms, whereas it would not do so in a normal-sized ventricular system.
This hydraulic press hypothesis must be applied in all cases of hydrocephalus. Without some knowledge of ventricular size in this condition, the CSF pressure cannot be accurately evaluated. This physical principle applies not only to adult hydrocephalus but also to infantile hydrocephalus, where the cranium expands, and to certain types of porencephaly and postoperative meningeal cysts and possibly syringomyelia.
Résumé
Dans une série de cas personnels, dont trois sont rappelés en détail, les auteurs ont noté qu'il peut y avoir une hydrocéphalie symptomatique malgré une pression normale du LCR. Les patients montrent un certain ralentissement mental, un défaut de l'attention, un retard psychomoteur, une incertitude de la marche, une incontinence urinaire, syndrome qui peut être attribué à tord à une affection dégénérative ou traumatique vasculaire du cerveau. Un shunt ventriculo-atrial a corrigé ces symptômes et a permis une récupération en abaissant la pression du LCR à 20 mm ou plus d'eau.
Un facteur important qui semble avoir été méconnu jusqu'ici pour expliquer cette hydrocéphalie symptomatique avec une pression relativement normale du liquide est que la force exercée sur la paroi ventriculaire représente le résultat de la pression exercée sur une surface assez large. La pression déterminée exerce en effet une plus grande force dans un système ventriculaire large que dans un système ventriculaire petit. Une pression de 170 ou 180 mm d'eau dans des ventricules qui ont trois fois la taille normale peut produire des symptômes qu'une telle pression ne produirait pas sur des systèmes ventriculaires de taille normale.
Cette hypothèse d'une pression hydraulique peut s'appliquer à tous les cas d'hydrocéphalie. Ces principes physiques ne sont pas seulement appliquables à l'hydrocéphalie de l'adulte mais également à l'hydrocéphalie infantile oú le crâne se distend et à certains types de porencéphalie et de kystes méningés post-opératories et peut être à la syringomyélie.
Zusammenfassung
In einer Reihe persönlich beobachteter Fälle, von welchen über drei ausführlich berichtet wird, haben die Autoren bemerkt, dass ein symptomatischer Hydrozephalus in Gegenwart eines normalen Liquordrucks bestehen kann. Die Patienten hatten geistige Abstumpfung, Unaufmerksamkeit, psychomotorische Verzögerung, schwankenden Gang und Harnfluss aufgewiesen, ein Syndrom, das versehentlich einem degenerativen oder traumatischen Gefässleiden des Gehirns zugeschrieben werden kann. Dieser Zustand wurde durch einen Ventrikel-Atriumshunt korrigiert und durch Senkung des Liquordrucks um 20 oder mehr mm H2O wurde die Genesung ermöglicht.
Ein wichtiger, bisher übersehener Faktor bei der Erklärung dieses symptomatischen Hydrozephalus bei relativ normalem Liquordruck ist, dass die auf die Ventrikelwand ausgeübte Kraft ein Produkt von Druck mal Oberfläche darstellt. Ein gegebener Druck übt in einem grossen Ventrikelsystem eine grössere Kraft aus als in einem kleinen. Ein Druck von 170 oder 180 mm H2O kann in Ventrikeln, die dreimal so gross wie normal sind, Symptome hervorrufen, während die in einem Ventrikelsystem von normaler Grösse nicht der Fall wäre.
Diese “hydraulische Pressenhypothese” muss in allen Fällen von Hydrozephalus angewandt werden. Ohne eine gewisse Kenntnis der Ventrikelgrösse bei diesem Zustand lässt sich der Liquordruck nicht genau bewerten. Dieses physikalische Prinzip gilt nicht nur für Hydrozephalus bei Erwachsenen, sondern auch bei Kindern, bei denen sich der Schädel ausweitet wie auch für gewisse Arten von Porenzephalie, postoperativen Meningealzysten und möglicherweise Syringomyelie.
Resumen
En una serie de casos personales tres de los cuales son estudiados en detalle, los autores han notado que puede haber une hidrocefalia sintomática a pesar de una presión normal del LCR. Los pacientes muestran un cierto enlentecimiento mental, un déficit de la atención, un retardo psicomotor, una incertitud de la marcha, una incontinencia urinaria, síndrome que puede ser atribuido erroneamente a una afección degenerative o traumática vascular del cerebro. Un shunt ventrículo-artial ha corregido estos síntomas y ha permitido una recuperación, descendiendo la presión del LCR a 20 mm o más de agua.
Un factor importante que parece haber sido desconodido hasta aquí para explicar esta hidrocefalia sintomática con una presión relativamente normal del líquido es que la fuerza ejercida sobre la pared ventricular representa el resultado de la preción ejercida sobre una superficie bastante amplia. La presión determinada ejerce en efecto una fuerza mayor en un sistema ventricular grande que en un sistema ventricular pequeño. Una presión de 170 ó 180 mm de agua en ventrículos que puede producir síntomas que no tendrían lugar si esa misma presión actuara sobre sistemas ventriculares de tabla normal.
Esta hipótesis de una presión hidráulica puede aplicarse a todos los casos de hidrocefalia. Estos principios físicos no son solamente aplicables a la hidrocefalía del adulto, sino igualmente a la hidrocefalía infantil donde el cráneo se distiende y a ciertos tipos de porencefalía y de quistes meníngeos post-operatorios y, puede ser, a la siringomielia.
Реферат
У pядa нaблюдaeмы aвтopaми бoльныч, из кoтopыч тpoe дoлoжeны пoдpoбнo, былa oтмeчeнa вoзмoжнocть нaличия cимптoмaтичecкoй гидpoцeфaлии пpи нopмaльнoм дaвлeнии ликвopa. У бoльныч имeлocь зaтpyднeниe интeлeктyaльнoй дeятeльнocти, нapyшeниe внимaния, пcичoмoтopнaя зaтopмoжeннocть, шaткocть пoчoдки, нeдepжaниe мoчи — cиндpoм, кoтopый oщибoчнo мoжнo пpипиcaть дeгeнepaтивнoмy или cocyдиcтoмy зaбoлeвaнию гoлoвнoгo мoзгa. Бeнтpикyлoaтpиaльный aнacтoмoз (ventriculo-atrial shunt) ycтpaнил этo cocтoяниe и oбecпeчил выздopoвлeниe бoльныч блaгoдapя пoнижeнию дaвлeния ликвopa нa 20 или мм H2O.
Б oбьяcнeнии этoй cимптoмaтичecкoй гидpoпeфaлии c oтнocитeльнo нopмaльным дaвлeниeм ликвopa вaжным фaктopoм, кoтopый дo cич пop нe yчитывaли, являeтcя тo, чтo cилa дaвлeния нa cтeнкy жeлyдoчкa пpeдcтaвляeт coбoй пpoизвeдeниe дaвлeния нa плoщaдь пoвepчнocти. Дaннoe дaвлeниe coздaeт в бoльшoй вeнтpикyляpнoй cиcтeмe бoльшyю cилy, чeм в мaлoй. Дaвлeниe 170–180 мм H2O в жeлyдoчкaч, oбъeм кoтopыч в тpи paзa пpeвышaeт нopмaльный, мoжeт вызыьaть пoявлeниe cимптoмoв, тoгдa кaк этoгo нe пpoизoйдeт пpи вeнтpикyляpнoй cиcтeмe нopмaльнoгo paзмepa.
Этy гипoтeзy гидpaвличecкoгo пpecca cлeдyeт пpимeнять вo вceч cлyчaяч гидpoцeфaлии. Бeз знaния пpимepнoгo paзмepa жeлyдoчкoв пpи этoм cocтoянии нeльзя пpaвильнo oцeнить дaвлeниe ликвopa. Дaнный физичecкий пpинцип пpимeним нe тoлькo к гидpoцeфaлии y взpocлыч, нo и к дeтcкoй гидpoцeфaлии, пpи кoтopoй yвeличивaeтcя oбъeм чepeпa, a тaкжe к нeкoтopым фopмaм пopэнцeфaлии, пocлeoпepaциoнныч мeнингeaльныч киcт и, вoзмoжнo, к cиpингoмиэлии.
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