Adult Hydrocephalus

Front Matter
	Copyright
	Dedication
	Contents
	Contributors
	Prologue
Section 1 Basic sciences
	1 Anatomy and physiology of the cerebrospinal fluid system
		Introduction
			Water distribution of the brain
			CSF function
			CSF composition
		Anatomy of the CSF system
			Anatomy of the lateral ventricles
			Anatomy of the foramina of Monro
			Anatomy of the third ventricle
			Cerebral aqueduct
			Anatomy of the fourth ventricle
			Overview of the cisterns
			Cerebral convexity CSF spaces
			Spinal CSF anatomy
		CSF production
			Choroid plexus
				Structure
				CSF secretion
				Other functions
			Interstitial fluid contribution to CSF production
		CSF flow
			Cellular composition of the ventricles
			CSF flow through the ventricles
			CSF flow through the cranial subarachnoid cisterns and Virchow–Robin spaces
			CSF flow through the spinal central canal and subarachnoid space
			Other possible routes of CSF circulation
		CSF absorption
			Arachnoid granulations
			Lymphatic drainage
			Windkessel effect on CSF drainage
		Conclusion
	2 Neuropathology of human hydrocephalus
		Introduction
		Factors leading to ventricular enlargement
		Consequences of ventricular enlargement and pathogenesis of brain damage in hydrocephalus
			NPH and white matter and cerebrovascular disease
			Hydrocephalus and the extracellular fluid
			NPH and Alzheimer’s disease
			NPH and autopsy findings
			Secondary reactive changes due to hydrocephalus
			Altered neurons and connections in the hydrocephalic brain
		Summary
		Conflict of interest disclaimer
		Funding support
	3 Animal models of hydrocephalus
		Ethics of animal models
		Formal requirements – general to any experimental model
		Requirements and challenges for models of hydrocephalus
		Existing and preferred models
			Hydrocephalus induced by physical or chemical agents
			Genetically determined hydrocephalus in inbred strains or by genetic manipulation
		Recent and current research areas in experimental hydrocephalus
		Normal pressure hydrocephalus (NPH)
	4 Genetics of hydrocephalus
		Introduction
		Genetic epidemiology
			Twin studies
			Epidemiology
		Genetics in hydrocephalus
			Human hydrocephalus
				Idiopathic normal pressure hydrocephalus
				Congenital hydrocephalus
			Animal hydrocephalic models
				Quantitative trait locus (QTL)
				Monogenic congenital hydrocephalus
		Genetic basis for pathophysiology  of hydrocephalus
			Loss of the key molecular cues during early development
				Subcommissural organ (SCO) defects
				Ciliopathies
				Deficient water channels
				Disrupted apoptotic pathways
				Neural tube defects
				Altered immune response
				Unknown causes
			Enhanced expression during early development
		Conclusion
	5 The epidemiology of hydrocephalus
		Introduction
		Epidemiology of specific types of hydrocephalus
			Congenital and infantile hydrocephalus
			Idiopathic normal pressure hydrocephalus (iNPH)
			Secondary normal pressure hydrocephalus
			The frequency of surgery for iNPH and sNPH
Section 2 Pathophysiology
	6 Pathophysiology of gait dysfunction in normal pressure hydrocephalus
		Introduction
		Objective measures of gait dysfunction in NPH
		Tentative theories to explain gait dysfunction in NPH
			Midbrain atrophy or compression
			Cortical dysfunction
			Cortical-subcortical and intracortical circuit abnormalities
			Postural dysfunction
			Dopamine signaling abnormalities
			Decreased regional cerebral blood flow
		Conclusion
	7 The pathophysiologic basis of cognitive dysfunction in idiopathic normal pressure hydrocephalus
		Introduction
		Putative pathogenic mechanisms of iNPH
		General features of cognitive impairment in iNPH
		Neuropsychological evaluation in iNPH
		Localization of neuropsychological deficits in iNPH
			Attention/Executive/Psychomotor
			Memory
			Visuospatial
			Motor skills
		Response to CSF drainage (tap test, external lumbar drainage, shunt)
		Differential diagnosis/comorbidities
		Differential diagnostic considerations
		Conclusions
	8 Incontinence and lower urinary tract symptoms in normal pressure hydrocephalus
		Introduction
		Dementia and incontinence
		Differential diagnosis
		Pathophysiology of incontinence in NPH
			Normal micturitional physiology
			Pathophysiology of incontinence and lower urinary tract symptoms in NPH
		Evaluation of urinary symptoms in NPH patients
			Terminology
			Urologic history
			Validated questionnaires
			Physical examination
			Diagnostic testing
			Urodynamic testing
		Characterization of lower urinary tract symptoms in NPH
			The Virginia Commonwealth University experience
		Treatment of NPH-mediated incontinence
			Short-term results for incontinence after shunt surgery
			Long-term results for incontinence after shunt surgery
		Conclusions
		Dedication
	9 Normal pressure hydrocephalus grading scales
		Introduction
		Scales
			General activity
			NPH symptomatology assessment
				Qualitative assessment
				Quantitative or semiquantitative assessment
				Combination of qualitative and quantitative assessment
			Comorbidity
			Caregiver burden scale
			Comparison between scales
		Conclusion
Section 3 Diagnosis
	10 The differential diagnosis of normal pressure hydrocephalus
		Introduction
		The neurological examination of the NPH patient
		The diagnostic work-up of the NPH patient
			Gait dysfunction
			Cognitive deficit
			Urinary dysfunction
			Imaging evaluation
			Invasive evaluation of CSF physiology
				Spinal tap test (STT)
				Continuous spinal or ventricular drainage
				Infusion test
				Intracranial pressure (ICP) measurements
				iNPH grading scales
		Outcome
		Final thoughts
	11 Core imaging in adult hydrocephalus
		Introduction
		Conventional X-rays
		Ultrasonography
		CT imaging
			Diagnosis of hydrocephalus
			Volumetric analysis (VA) by CT or MRI of the CSF spaces
			Postoperative management: shunt malfunction
		MRI
			Phase-contrast MRI
			MRI with gadolinium enhancement
		Radionuclide shunt patency test
	12 Imaging of the cerebrospinal fluid circulation
		Imaging of flows
			Temporal normalization
			Aliasing correction
			CSF flow parameters
		CSF and blood flow interaction
		Imaging of CSF disorders
	13 Cerebrospinal fluid dynamics and infusion techniques
		Introduction
		CSF dynamics
		Lumbar infusion techniques
			Bolus injection
			Volume removal
			Gradual infusion methods
				Constant flow infusion
				Constant pressure infusion
		External lumbar drainage and tap test
		Discussion
		Conclusions
	14 Monitoring of intracranial pressure and assessment of cerebrospinal fluid dynamics
		Main mechanisms and models of CSF circulation and pressure–volume compensation
		ICP monitoring
			Pulse waveform
			Assessment of B waves
			Cerebrospinal pressure–volume compensatory reserve – RAP index
			Cerebrovascular pressure reactivity (PRx)
			Example of clinical use of ICP monitoring: pediatric hydrocephalus
		CSF dynamics: infusion test
			Rout and baseline CSF pressure
			Elastance coefficient (or elasticity)
			Analysis of slow waves, compensatory reserve, and pressure reactivity during infusion study
		Who needs a shunt: CSF dynamics perspective
		Vascular components of CSF circulation
			Transcranial Doppler-derived pressure autoregulation
			CO2 reactivity
			Cerebral blood flow studies
		Conclusion
		Acknowledgments
	15 Cerebrospinal fluid biomarkers in idiopathic normal pressure hydrocephalus
		History of setting up biomarkers in idiopathic normal pressure hydrocephalus
		Rationale for their use
		Diagnostic versus prognostic biomarkers
			CSF biomarkers in the differential diagnosis with Alzheimer’s dementia
			CSF biomarkers in the differential diagnosis with vascular dementia
			CSF biomarkers in the differential diagnosis with Parkinson’s disease
			Prognostic biomarkers
		Summary of current evidence
			Summary of currently available evidence
		Experimental problems
		Quo vadis?
Section 4 Treatment and outcomes
	16 Hydrocephalus shunt procedures
		Introduction
		Valves
		Antisiphon devices (ASD)
		General surgical principles and postoperative care
		Proximal catheter placement
			Ventricular catheter insertion
				Procedure
				Discussion and complications
		Distal catheter insertion
			Peritoneal catheter insertion
				Procedure
				Discussion and complications
			Atrial catheter insertion
				Procedure
				Discussion and complications
			Pleural catheter insertion
				Procedure
				Discussion and complications
			Other distal catheter locations
			Lumbar catheter insertion
				Procedure
				Discussion and complications
		Shunt infections
		Conclusion
	17 Hydrocephalus shunts
		Hardware
		Laboratory shunt testing
			Testing protocol
			Hydrodynamic properties of contemporary shunts
		Shunt testing in vivo
		Shunt registry
		The future of shunt technology
		Acknowledgments
	18 Management of shunts in normal pressure hydrocephalus
		Introduction
		Types of shunt complications
		Underdrainage and overdrainage
			Imaging
		Shunt complication rates
		Ventriculoperitoneal shunt complications and infections in NPH patients
		Shunt infections
			Common pathogens and common sources of shunt infections and their sequelae
			Treatment strategies aimed at reducing shunt infection rates
		Conclusion
	19 Endoscopic third ventriculostomy
		Indications and outcome
			ETV in adult patients
			ETV in children and the role of age and etiology dependence
			ETV in previously shunted patients
			ETV in communicating hydrocephalus
				ETV in idiopathic normal pressure hydrocephalus
			Intraoperative factors influencing the success of ETV
		Definition of success after ETV and diagnosis of ETV failure
		Management of ETV failure
		Advantages/disadvantages of ETV compared to VP shunt placement
		Preoperative planning and anatomic eligibility for ETV
			MRI: flow dynamics measurement
		Surgical technique of ETV, avoidance of complications
		Reported complications
		Postoperative care and follow-up
		Summary
	20 Outcome of idiopathic normal pressure hydrocephalus
		Introduction
		Proper selection criteria for diagnosis of iNPH
		Deficiencies in identifying the degree of clinical impairment and therefore clinical improvement
		Standardized management protocols related to outcome
			Shunt management
			Standardized outcome assessment
			The time period for short-term and long-term outcome
			Clinical judgment
		Impact of complications after surgery
		Impact of comorbidities
		Conclusion
Section 5 Associated conditions
	21 Normal pressure hydrocephalus syndrome secondary to hemorrhage, infection, and malignancy
		The syndrome of compensated hydrocephalus
			Late-onset idiopathic aqueductal stenosis (LIAS)
			The syndrome of longstanding overt ventriculomegaly (LOVA) and the syndrome of hydrocephalus in young and  middle-aged adults (SHYMA)
		Hydrocephalus secondary to other processes
			Hydrocephalus and malignancies
			Hydrocephalus following subarachnoid hemorrhage (SAH)
			Hydrocephalus following infection (post-infective)
		Conclusion
	22 Low-pressure syndromes and cerebrospinal fluid leaks
		Epidemiology
		Pathogenesis
		Clinical presentation
			Positional headaches
			Miscellaneous symptoms
		Diagnosis
			Cranial computed tomography
			Cranial magnetic resonance imaging
			Myelography
			Radionuclide cisternography
			Spinal MRI
			Lumbar puncture
		Diagnostic criteria
		Treatment, outcomes, and future directions
	23 Management of the adult with congenital hydrocephalus
		Introduction
		Transitioning neurosurgical care
			Pediatric neurosurgery perspective
			Adult neurosurgery perspective
			Patient and family perspective
			Recommendations
		Achieving shunt independence
			Endoscopic third ventriculostomy (ETV)
			ETV failure and complications
		Management of chronically shunted patients
			Slit ventricle syndrome (SVS)
			Management strategies
		Clinical and neuropsychological outcomes
			Clinical outcomes
			Neuropsychological outcomes
	24 Management of hydrocephalus with associated cerebrospinal fluid pathologies
		Introduction
		Case 1. Hydrocephalus associated with a posterior fossa cyst
		Case 2. Posterior fossa cyst without hydrocephalus
		Case 3. Hydrocephalus associated with Chiari I malformation
		Case 4. Normal pressure hydrocephalus associated with cerebellar arachnoid cyst
		Case 5. Hydrocephalus with multiple arachnoid cysts
		Case 6. Hydrocephalus associated with a giant suprasellar arachnoid cyst diagnosed in a fetus
		Case synopsis and discussion
		The role of cognition and cognitive assessment
		The role of neuroimaging and MRI
		The role of multimodal surgical management
		The role of disease classification
		Conclusions
		Acknowledgments
	25 Chiari malformation and hydrocephalus in adults
		Introduction
		What is the Chiari I malformation?
		Hydrocephalus and Chiari I: which came first?
		Hydrocephalus and the Chiari II malformation
		The Chiari I malformation and benign intracranial hypertension or pseudotumor cerebri
		Conclusion
	26 Pseudotumor cerebri syndrome
		History
		Nomenclature
		Dandy criteria (modified)
		Clinical features
		Signs
		Associated conditions
		Investigations
			Neuroradiology
			Lumbar puncture
			CSF composition
		Pathophysiology
		Management
			Medical interventions
			Surgical interventions
		Conclusions
		Acknowledgments
		Conflict of interest
	Epilogue
Index
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