Experimental normal-pressure hydrocephalus is accompanied by increased transmantle pressure

1984 ◽  
Vol 61 (2) ◽  
pp. 322-327 ◽  
Author(s):  
E. Scott Conner ◽  
Lorraine Foley ◽  
Peter McL. Black

✓ This research was directed at the pathophysiology of normal-pressure hydrocephalus. The experimental method consisted of accurate and simultaneous measurement of the pressure within the ventricle and over the cerebral convexity in cats with hydrocephalus but normal ventricular pressure. Hydrocephalus was induced by the intracisternal injection of kaolin. Prior to the induction of hydrocephalus, the difference between the ventricular pressure and the pressure over the convexity (the transmantle pressure) was small (0.27 ± 0.31 cm saline, mean ± standard deviation). After the induction of normal-pressure hydrocephalus in seven animals, there was a statistically significant elevation of the transmantle pressure to 3.4 ± 3.9 cm saline (p < 0.05, Student's paired t-test). There was no similar increase in animals injected with lactated Ringer's solution. This finding supports the theory that it is the transmantle pressure, and not the ventricular pressure, that is the physiological determinant of ventricular dilatation. The theory explains why hydrocephalus can develop and persist despite normal ventricular pressure.

1984 ◽  
Vol 61 (3) ◽  
pp. 510-514 ◽  
Author(s):  
Norihiko Tamaki ◽  
Tadaki Kusunoki ◽  
Toshimitsu Wakabayashi ◽  
Satoshi Matsumoto

✓ Cerebral hemodynamics in 31 patients with suspected normal-pressure hydrocephalus were studied by means of the xenon-133 (133Xe) inhalation method and on dynamic computerized tomography (CT) scanning. Cerebral blood flow (CBF) is reduced in all patients with dementia. Hypoperfusion was noted in a frontal distribution in these patients compared with normal individuals. There was no difference in CBF patterns between patients with good and those with poor outcome. The CBF was increased following cerebrospinal fluid (CSF) shunting in patients who responded to that procedure: increase in flow correlated with clinical improvement, frontal and temporal lobe CBF was most markedly increased, and the CBF pattern became normal. In contrast, CBF was decreased after shunt placement in patients who were considered to have suffered from degenerative dementia, as evidenced by non-response to shunting. Dynamic computerized tomography studies demonstrated that patients with a good outcome showed a postoperative reduction in mean transit time of contrast material, most prominent in the frontal and temporal gray matter, and slight in the deep frontal structures, but not in the major cerebral vessels. Patients with poor outcome after shunting, however, had an increase in transit time in all regions. This corresponded well with the results as determined by the 133Xe inhalation method.


1972 ◽  
Vol 36 (1) ◽  
pp. 50-59 ◽  
Author(s):  
Richard L. Rovit ◽  
Mannie M. Schechter ◽  
Benbienizi Ortega ◽  
Ray A. Brinker

✓ Eight patients with “normal pressure hydrocephalus” are presented who demonstrated radiographic and occasional clinical evidence of progressive dilatation of the ventricles following pneumoencephalography. The characteristic pneumographic signs of tentorial obstruction to the flow of cerebrospinal fluid (CSF) had been documented in the original air contrast study. The authors postulate that pneumoencephalography in patients with normal pressure hydrocephalus may result in a sudden displacement of CSF from the ventricles into the already compromised basal cisterns, leading to further obstruction of CSF outflow and progressive ventricular dilatation. Other mechanisms such as reduction in the potential resorptive capacity of the ventricular ependyma by air replacing ventricular fluid may play a part. The value of repeat radiological studies 24 and 48 hours after the original pneumogram is emphasized both as an aid in the radiological diagnosis of normal pressure hydrocephalus and as an additional parameter for studying problems in CSF flow and absorption.


1980 ◽  
Vol 53 (2) ◽  
pp. 252-255 ◽  
Author(s):  
Tung Pui Poon ◽  
Edward J. Arida ◽  
Wolodymyr P. Tyschenko

✓ The authors report a case of cerebral cysticercosis which presented with generalized nonspecific neurological signs and symptoms attributed to acute aqueductal obstruction, with concomitant intracranial hypertension. These were characteristic intracranial calcifications along with angiographically demonstrated signs of hydrocephalus. Contrast encephalography clearly demonstrated aqueductal obstruction. Pathologically, the aqueductal obstruction was shown to be due to parasitic invasion of the brain stem with compression of the aqueduct. The presence of typical intracranial calcification in conjunction with either obstructive or normal-pressure hydrocephalus should alert the observer to the possibility of cerebral cysticercosis.


1984 ◽  
Vol 60 (5) ◽  
pp. 961-971 ◽  
Author(s):  
Michael J. Rosner ◽  
Donald P. Becker

✓ The presence of lactic acidosis in the cerebrospinal fluid of patients suffering brain injury as the result of trauma, subarachnoid hemorrhage, neoplasia, or ischemia has been well documented. The authors theorized that this acidosis becomes harmful in itself, and that treatment with an alkalinizing agent (tris(hydroxymethyl)aminomethane: tromethamine) capable of penetrating the blood-brain barrier would be efficacious. Fifteen pairs of mongrel cats were subjected to a 2.85-atmosphere fluid-percussion injury (LD80), and were supported by respirators for up to 72 hours prior to being placed in cages for an additional 4 days of observation. Experimental cats underwent continuous infusion of tromethamine (begun 10 minutes after injury); control animals were infused with an equal volume of lactated Ringer's solution. Twenty percent of the control group survived until sacrificed on Day 7 post-injury. Survival in the tromethamine group was 60% (p < 0.05), and morbidity also appeared to be reduced in the treated cats. Intracranial pressure (ICP) in treated cats was 60% (p < 0.05) of that in the control cats after respirator support for 3 days. Tromethamine infusion was associated with improved survival, decreased morbidity, and decreased ICP when compared with results in control animals. The literature with regard to central nervous system acidosis has been reviewed in an attempt to clarify and define this problem.


2004 ◽  
Vol 100 (5) ◽  
pp. 855-866 ◽  
Author(s):  
Maria A. Poca ◽  
Maria Mataró ◽  
Maria Del Mar Matarín ◽  
Fuat Arikan ◽  
Carmen Junqué ◽  
...  

Object. Data from many studies have demonstrated that shunt insertion in patients with idiopathic normal-pressure hydrocephalus (NPH) is associated with high morbidity and a lack of significant improvement; however, the use of strict diagnostic and treatment protocols can improve the results of surgery in these patients. The primary aim in this prospective study was to analyze the results of shunt placement in 43 patients with idiopathic NPH. A secondary aim was to determine the relationship between several clinical and neuroimaging factors, and patient outcome after surgery. Methods. Thirty men and 13 women with a mean age of 71.1 ± 6.9 years participated in this study. All patients underwent clinical, neuropsychological, and radiological assessment before and 6 months after surgery. In all patients continuous monitoring of intracranial pressure was performed using a fiberoptic extradural sensor. In 31 patients cerebrospinal fluid dynamics were also determined. Eighty-six percent of patients showed clinical improvement after shunt insertion, 11.6% showed no change, and 2.3% exhibited some worsening. Gait improved in 81.4% of the patients, sphincter control in 69.8%, and cognitive dysfunction in 39.5%. There was no treatment-related death. Early or late postsurgical complications occurred in six patients (14%), although all of these complications were minor or were satisfactorily resolved. The complete clinical triad, cortical sulci size, and periventricular lucencies were related to outcome, whereas patient age, symptom duration, ventricular dilation, and the degree of presurgical dementia were unrelated to outcome. Conclusions. Given the correct diagnosis, shunt insertion can produce marked improvement in patients with idiopathic NPH syndrome, causing few deaths and few clinically relevant complications.


2001 ◽  
Vol 95 (6) ◽  
pp. 970-973 ◽  
Author(s):  
Koreaki Mori

Object. A cooperative study was undertaken to identify factors that could be used to predict a favorable outcome after extracranial cerebrospinal fluid (CSF) diversion (shunting) in patients with suspected idiopathic normal-pressure hydrocephalus (NPH). Methods. Questionnaires concerning patients with suspected idiopathic NPH were sent to 14 members of the Committee for Scientific Research on Intractable Hydrocephalus, sponsored by the Ministry of Health and Welfare of Japan. After the questionnaires were returned, a retrospective analysis of the responses was undertaken. To be included in the study, patients had to be 65 years of age or older and had to have undergone surgery between October 1995 and October 1998. Clinical measures included degrees of gait disturbance, dementia, and urinary incontinence as evaluated before, 3 months after, and 3 years after shunt placement. Diagnostic tests in various combinations included lumbar puncture in which CSF was withdrawn; intracranial pressure monitoring; measurements of CSF outflow resistance, level of serum α-1-antichymotrypsin, cerebral arteriovenous differences of oxygen content, and cerebral blood flow; and computerized tomography cisternography. In this study, 120 patients were identified as having idiopathic NPH and these patients underwent placement of shunts. A ventriculoperitoneal shunt with a programmable valve was used in two thirds of the patients. At the end of 3 months (early assessment), there was an 80% overall rate of clinical improvement, which dropped to 73.3% of the 105 patients who could be evaluated at the end of the 3-year study. Of the three variables, gait disturbance was most improved, both at early and late testing periods. Shunt complications occurred in 22 (18.3%) of the patients. Conclusions. Patients suspected of having idiopathic NPH did not form a homogeneous group, making it difficult to select those who would most likely respond to CSF diversion. Of the diagnostic studies, the most reliable result was improvement in clinical symptoms following a lumbar puncture in which CSF was withdrawn. The use of a programmable valve is recommended because it offers advantages in preventing problems of over- and underdrainage.


2004 ◽  
Vol 100 (6) ◽  
pp. 1036-1040 ◽  
Author(s):  
Ullrich Meier ◽  
Sven Mutze

Object. It is well known that in patients with communicating hydrocephalus or normal-pressure hydrocephalus (NPH), ventricular size decreases following implantation of shunts with differential pressure valves. The aim of this study was to determine whether ventricular size correlates with a positive clinical outcome following shunt placement. Methods. Hydrostatic valves (dual-switch valves) were implanted in 80 patients with NPH at Unfallkrankenhaus, Berlin, between September 1997 and January 2002. One year postoperatively, these patients underwent computerized tomography scanning, and their ventricular size was ascertained using the Evans Index. Among 80% of the patients who showed no postoperative change in ventricular volume, 59% nonetheless had good to excellent clinical improvements, 17% satisfactory improvement, and 24% no improvement. Furthermore, a moderate reduction in ventricular size was observed in 14% of patients in this cohort. Among these, 36% experienced good to excellent clinical improvements, 28% satisfactory improvement, and 36% unsatisfactory improvement. A marked reduction in ventricular size was observed in 6% of the patients. Of this latter group, 60% demonstrated good to excellent outcomes, whereas 40% had unsatisfactory outcomes. Conclusions. Favorable outcomes following the implantation of a hydrostatic shunt in patients with NPH did not correlate with decreased ventricular volume 1 year after surgery. In fact, better clinical outcomes were observed in patients with little or no alteration in ventricular size, compared with those in patients with a marked decrease in ventricular size. A postoperative change in ventricular volume should be assessed differently in patients with NPH compared with those suffering from hypertensive hydrocephalus.


2002 ◽  
Vol 97 (1) ◽  
pp. 73-79 ◽  
Author(s):  
Richard C. Anderson ◽  
Jessica J. Grant ◽  
Robert de la Paz ◽  
Steven Frucht ◽  
Robert R. Goodman

Object. The syndrome of normal-pressure hydrocephalus (NPH) refers to the clinical triad of gait disturbance, dementia, and urinary incontinence in association with idiopathic ventriculomegaly and normal intracranial pressure. Ventriculoperitoneal (VP) shunt placement often yields significant clinical improvements, sometimes without apparent reduction of ventricular size. The authors hypothesized that careful volumetric measurements would show a decrease in ventricular volume in these patients. Methods. Twenty consecutive patients with NPH underwent placement of VP shunts equipped with programmable valves. In 11 patients pre- and postoperative neuroimaging was performed, which allowed volumetric analysis. Volumetric measurements of the lateral ventricles were calculated in triplicate by National Institutes of Health image-processing software to assess standard computerized tomography (CT) scans (eight patients) or magnetic resonance (MR) images (three patients) obtained before and after shunt placement. Ventricular volumes were also assessed by an independent neuroradiologist. Postoperative studies were performed at a time of clinical improvement, between 1 and 9 months postsurgery (mean 5 months). Preoperative and postoperative Unified Parkinson's Disease Rating Scale evaluations were performed in four patients. Significant clinical improvement occurred in all patients after shunt placement (mean follow-up period 17.5 months). Although 10 (91%) of 11 patients demonstrated a calculable decrease in volume in the lateral ventricles (mean decrease 39%), formal interpretation of neuroimages indicated a definite decrease in lateral ventricular volume in only three (27%) of 11 patients. Conclusions. Volumetric measurements obtained to compare preoperative and postoperative CT or MR studies obtained in patients with NPH in whom clinical improvement was seen after shunt placement surgery show a demonstrable decrease in ventricular size. Volumetric measurements may be helpful in clinical assessment postoperatively and in guiding programmable valve pressure settings.


1983 ◽  
Vol 59 (5) ◽  
pp. 902-904 ◽  
Author(s):  
Naman A. Salibi ◽  
Gerald L. Lourie ◽  
Herbert Lourie

✓ The authors present two cases of normal-pressure hydrocephalus that simulated Pick's disease radiographically and that were initially diagnosed as cortical atrophy. In both cases, Sylvian cisternoperitoneal shunts improved the clinical picture only temporarily, but ventriculoperitoneal shunting produced dramatic relief of all symptoms.


1984 ◽  
Vol 61 (3) ◽  
pp. 501-509 ◽  
Author(s):  
John Vassilouthis

✓ A series of 40 patients with the syndrome of normal-pressure hydrocephalus is presented. Diagnosis was based on clinical and computerized tomography (CT) scan criteria and was followed by the insertion of a ventriculoperitoneal shunt in every instance. All patients responded favorably to treatment (four of them had a fair outcome), and this response was maintained. There was one postoperative death, but no other serious complications. This study demonstrates that it is possible to diagnose the syndrome of normal-pressure hydrocephalus on the basis of clinical and CT scan criteria without any other invasive investigations. Such patients should respond favorably to an adequately functioning shunting system.


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