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41 results

Page 1 of 3

  • 11 - Core imaging in adult hydrocephalus
  • from Section 3 - Diagnosis
  • Edited by Daniele Rigamonti, The Johns Hopkins University School of Medicine
  • Book: Adult Hydrocephalus
  • Published online: 05 February 2014
  • Print publication: 06 February 2014, pp 110-120
  • View abstract

    Summary

    This chapter presents the existing data concerning the epidemiology of selected forms of hydrocephalus, concentrating on congenital and infantile hydrocephalus and idiopathic and secondary normal pressure hydrocephalus (NPH). The epidemiology of congenital and infantile hydrocephalus has been explored in several studies. Casmiro et al. based the diagnosis on absence of known causes of secondary NPH, impaired gait, and CT scans showing findings indicative of NPH. The chapter explores the epidemiology of idiopathic normal pressure hydrocephalus (iNPH) in a Norwegian county of 220000 inhabitants, by actively informing the public and professional health workers about the condition, asking for referral of suspected individuals on a broad clinical basis. The lack of universally accepted guidelines for the diagnosis of iNPH, and the lack of powerful tests to predict shunt success, probably also contribute to the relative low rate of diagnosis, and consequently, of surgery.
  • Epilogue
  • Edited by Daniele Rigamonti, The Johns Hopkins University School of Medicine
  • Book: Adult Hydrocephalus
  • Published online: 05 February 2014
  • Print publication: 06 February 2014, pp 304-304
  • View abstract

    Summary

    This chapter reviews the types of shunt complications, their likelihood, and some clinical examples. Cerebrospinal fluid (CSF) shunting and particularly ventriculoperitoneal shunting is a common procedure used to treat a variety of CSF flow dynamic pathologies including obstructive, communicating, and normal pressure hydrocephalus (NPH) from a variety of etiologies. There are several types of specific long-term complications associated with shunting procedures in addition to those more likely seen in the NPH population in particular. These include underdrainage of CSF, overdrainage of CSF, mechanical failures of the hardware such as alterations in valve resistance over time, malposition of the tubing, and frank breakage, CSF leak, subdural hemorrhage or hygroma, seizure, and infection. Underdrainage conditions arise when shunt systems develop increased resistance across the valve over time, disconnection or kinking of the system components, or migration of the tubing out of an appropriate position for proper drainage and/or reabsorption.
  • 1 - Anatomy and physiology of the cerebrospinal fluid system
  • from Section 1 - Basic sciences
  • Edited by Daniele Rigamonti, The Johns Hopkins University School of Medicine
  • Book: Adult Hydrocephalus
  • Published online: 05 February 2014
  • Print publication: 06 February 2014, pp 1-13
  • View extract

    Summary

    Cerebrospinal fluid (CSF) plays a role in homeostatic hormonal signaling, chemical buffering, circulations of nutrients, and neurodevelopment. The two lateral ventricles drain into the third ventricle through the foramina of Monro. The third ventricle subsequently drains into the fourth ventricle through the narrowest portion of the ventricular system called the cerebral aqueduct. The roof of the fourth ventricle is bounded by the vermis of the cerebellum and the fastigium. CSF production is to a degree dependent on blood perfusion. In instances of increased intracranial pressure (ICP) with subsequent decreased cerebral perfusion, there will be a decrease in CSF production. CSF flows through net bulk flow from the lateral ventricles through the foramen of Monro into the third ventricle, then on into the fourth ventricle through the cerebral aqueduct. The pathways of CSF reabsorption include the ependymal layer of the ventricular system, and endothelial layer of the brain parenchyma.
  • Section 4 - Treatment and outcomes
  • Edited by Daniele Rigamonti, The Johns Hopkins University School of Medicine
  • Book: Adult Hydrocephalus
  • Published online: 05 February 2014
  • Print publication: 06 February 2014, pp 175-246
  • View abstract

    Summary

    The recent and rapid increase of the elderly population in developed nations has heightened the social importance of precise diagnosis and appropriate treatment for idiopathic normal pressure hydrocephalus (iNPH). This chapter reviews various assessment batteries that have been used in iNPH to date. There are many NPH assessing scales, most of which aim to assess level of general activity, severity of respective NPH symptoms, response to interventions such as cerebrospinal fluid (CSF) drainage tests or shunt surgery, and short and long term outcome. Comparative study of the specificity and sensitivity of the neuropsychological tests is necessary to determine the most reliable test for prediction of shunt surgery. The scale consists of the four domains of gait, neuropsychology, balance, and continence. The improvement of cognitive impairment was the major factor in reducing care-giver burden.
  • Section 3 - Diagnosis
  • Edited by Daniele Rigamonti, The Johns Hopkins University School of Medicine
  • Book: Adult Hydrocephalus
  • Published online: 05 February 2014
  • Print publication: 06 February 2014, pp 99-174
  • View abstract

    Summary

    Genetic studies in animal models have started to open new ways for understanding the underlying molecular pathophysiology of hydrocephalus. Human hydrocephalus can be classified as syndromic versus non-syndromic, and congenital versus acquired. Comparative twin studies have been performed to analyze the genetic influences in congenital structural defects including hydrocephalus. Familial hydrocephalus has long been suggested as a heritable disease, with heterogeneous causes, which may result from distinct monogenic or multifactorial disorders. Congenital hydrocephalus (CHC) is usually the consequence of deficient brain development and perturbed cellular function, implicating the important roles that CHC genes play during brain development. The majority of identified hydrocephalus loci and genes are from genetic analysis in hydrocephalic animal models. The pathophysiology of hydrocephalus in the ventricular system has been extensively studied through either down- or up-regulation of certain targeted gene expression, followed by comparative morphological and molecular studies.
  • 21 - Normal pressure hydrocephalus syndrome secondary to hemorrhage, infection, and malignancy
  • from Section 5 - Associated conditions
  • Edited by Daniele Rigamonti, The Johns Hopkins University School of Medicine
  • Book: Adult Hydrocephalus
  • Published online: 05 February 2014
  • Print publication: 06 February 2014, pp 247-255
  • View extract

    Summary

    Normal pressure hydrocephalus (NPH) is characterized by the presence of ventriculomegaly associated with the triad of gait, memory, and urinary problems in the absence of a detectable cause. The characteristic clinical presentation of iNPH, however, also accompanies the insidious onset of hydrocephalus secondary to other processes, such as infection, malignancy, and hemorrhage. This chapter discusses the clinical features, evaluation, and management of secondary and/or compensated hydrocephalus. Most commonly obstruction from aneurysmal subarachnoid hemorrhage, brain malignancy, spinal malignancy, or an infectious etiology can precipitate or directly lead to hydrocephalus. Communicating hydrocephalus is thought to occur in the context of increased cerebrospinal fluid (CSF) production, such as in the case of choroid plexus tumors, or impaired CSF absorption, secondary to leptomeningeal disease or tumor bleeding. Clinical outcomes from endoscopic treatment of neurocysticercosis are better than outcomes after open surgical procedures.
  • 6 - Pathophysiology of gait dysfunction in normal pressure hydrocephalus
  • from Section 2 - Pathophysiology
  • Edited by Daniele Rigamonti, The Johns Hopkins University School of Medicine
  • Book: Adult Hydrocephalus
  • Published online: 05 February 2014
  • Print publication: 06 February 2014, pp 63-69
  • View extract

    Summary

    Several theories have been proposed to explain the pathophysiology of gait dysfunction in normal pressure hydrocephalus (NPH). The variety of potential targets includes midbrain compression or atrophy, cortical dysfunction, cortical-subcortical or intracortical circuit abnormalities, postural disturbance, dopamine signaling abnormalities, and regional cerebral blood flow (rCBF) depression. This chapter presents objective measures of gait dysfunction that have been used clinically, and highlights some of the major theories postulated to explain gait dysfunction in NPH. Gait dysfunction in NPH has characteristic features that include a slow pace, short stride length, wide stance, and low foot-floor elevation. Objective measures of gait can be used to quantify the pattern of walking and step-taking, focusing on walking speed, stride length, cadence, equilibrium, and posture. Recognition of cortical involvement in locomotion stems from multiple research efforts evaluating gait in healthy individuals and those with cognitive disturbances.
  • Section 2 - Pathophysiology
  • Edited by Daniele Rigamonti, The Johns Hopkins University School of Medicine
  • Book: Adult Hydrocephalus
  • Published online: 05 February 2014
  • Print publication: 06 February 2014, pp 63-98
  • View abstract

    Summary

    Cerebrospinal fluid (CSF) plays a role in homeostatic hormonal signaling, chemical buffering, circulations of nutrients, and neurodevelopment. The two lateral ventricles drain into the third ventricle through the foramina of Monro. The third ventricle subsequently drains into the fourth ventricle through the narrowest portion of the ventricular system called the cerebral aqueduct. The roof of the fourth ventricle is bounded by the vermis of the cerebellum and the fastigium. CSF production is to a degree dependent on blood perfusion. In instances of increased intracranial pressure (ICP) with subsequent decreased cerebral perfusion, there will be a decrease in CSF production. CSF flows through net bulk flow from the lateral ventricles through the foramen of Monro into the third ventricle, then on into the fourth ventricle through the cerebral aqueduct. The pathways of CSF reabsorption include the ependymal layer of the ventricular system, and endothelial layer of the brain parenchyma.
  • Section 5 - Associated conditions
  • Edited by Daniele Rigamonti, The Johns Hopkins University School of Medicine
  • Book: Adult Hydrocephalus
  • Published online: 05 February 2014
  • Print publication: 06 February 2014, pp 247-303
  • View abstract

    Summary

    This chapter describes the cerebrospinal fluid (CSF) dynamics and how fluid inside the central nervous system (CNS) is generated, stored, and absorbed within the context of a mathematical model developed by A. Marmarou. It explains the main Lumbar infusion techniques in theory and their practical applications by various clinics. Clinical prognostic applications of infusion methods can be classified into two groups: transient and steady-state. External lumbar drainage (ELD) is a prognostic tool for which the accuracy of prediction rate can be more than 90%. The test is based on the idea of simulating the shunt operation in real life by withdrawing CSF for relatively long time durations at drainage rates roughly comparable to regular shunt drainage. ELD yields the most accurate prognostic indications since it simulates the shunt for an extended time duration, which also helps to exclude some placebo effects.
  • 10 - The differential diagnosis of normal pressure hydrocephalus
  • from Section 3 - Diagnosis
  • Edited by Daniele Rigamonti, The Johns Hopkins University School of Medicine
  • Book: Adult Hydrocephalus
  • Published online: 05 February 2014
  • Print publication: 06 February 2014, pp 99-109
  • View extract

    Summary

    The recently updated Japanese guidelines draw attention to a specific MRI pattern of disproportionately enlarged subarachnoid space hydrocephalus (DESH), believed to be pathognomonic of idiopathic normal pressure hydrocephalus (iNPH). This chapter discusses why establishing the diagnosis of NPH remains a challenge fifty years after its classic description. The original diagnosis of NPH relied upon the presence of mild dementia, gait, and urinary difficulties (Hakim's triad) seen in association with ventriculomegaly on pneumo-encephalogram. More sensitive cognitive evaluation of iNPH patients requires specific tests for the assessment of subcortical frontal lobe deficits such as the Rey Auditory Verbal Learning Test, Stroop test, Grooved Pegboard, Trail Making A and B Test, and digit span test. This diagnostic test provides information about cerebrospinal fluid (CSF) dynamics and predicts outcome. It consists in either removal of CSF accompanied by pre and post functional evaluation, or an infusion (bolus or continuous) test.
  • 16 - Hydrocephalus shunt procedures
  • from Section 4 - Treatment and outcomes
  • Edited by Daniele Rigamonti, The Johns Hopkins University School of Medicine
  • Book: Adult Hydrocephalus
  • Published online: 05 February 2014
  • Print publication: 06 February 2014, pp 175-189
  • View extract

    Summary

    This chapter describes many of the techniques and protocols that can be used to minimize the risk of shunt failure, focusing on the surgical procedure at each anatomic location for proximal and distal catheter placement. It includes the extended discussions of ventricular and lumbar proximal catheters, and peritoneal, atrial, pleural, and other distal catheters. Valves can be divided into four different categories: differential pressure valves, flow-regulated valves, antisiphon valves, and adjustable valves. Antisiphon valves are used to prevent the siphoning of cerebrospinal fluid (CSF) into the distal compartment. Antisiphon devices (ASDs) are primarily used in management of normal pressure hydrocephalus (NPH) patients in the adult population to prevent the formation of subdural hematomas and hygromas, and in the management of hydrocephalus in the pediatric population to prevent the slit ventricle syndrome and proximal catheter obstruction.

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