Intracranial Pressure in Primary Open Angle Glaucoma, Normal Tension Glaucoma, and Ocular Hypertension: A Case–Control Study

Authors: John P. Berdahl 1 , Michael P. Fautsch 2 , Sandra S. Stinnett 1 and R. Rand Allingham 1

1From the Duke University Eye Center, Durham, North Carolina; and the
2Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota.

PURPOSE. To compare intracranial pressure (ICP) in subjects with primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG; subset of POAG), and ocular hypertension (OHT) with that in subjects with no glaucoma.

METHODS. The study was a retrospective review of medical records of 62,468 subjects who had lumbar puncture between 1985 and 2007 at the Mayo Clinic. Of these, 57 POAG subjects, 11 NTG subjects (subset of POAG), 27 OHT subjects, and 105 control subjects met the criteria and were analyzed. A masked comparison of the relationship between ICP and other ocular and nonocular variables was performed by using univariate and multivariate analyses.

RESULTS. ICP was significantly lower in POAG compared with age-matched control subjects with no glaucoma (9.1 ± 0.77 mm Hg vs. 11.8 ± 0.71 mm Hg; P < 0.0001). Subjects with NTG also had reduced ICP compared with the control subjects (8.7 ± 1.16 mm Hg vs. 11.8 ± 0.71 mm Hg; P < 0.01). ICP was higher in OHT than in age-matched control subjects (12.6 ± 0.85 mm Hg vs. 10.6 ± 0.81 mm Hg; P < 0.05).

CONCLUSIONS. ICP is lower in POAG and NTG and elevated in OHT. ICP may play an important role in the development of POAG and NTG and in preventing the progression of OHT to POAG. Further prospective and experimental studies are warranted to determine whether ICP has a fundamental role in the pathogenesis of glaucoma.

NICEM consensus on neurological monitoring in acute neurological disease

Authors: Peter J. D. Andrews, Giuseppe Citerio, Luca Longhi, Kees Polderman, Juan Sahuquillo, Peter Vajkoczy and Neuro-Intensive Care and Emergency Medicine (NICEM) Section of the European Society of Intensive Care Medicine

This manuscript summarises the consensus on neuromonitoring in neuro-intensive care promoted and organised by the Neuro-Intensive Care and Emergency Medicine (NICEM) Section of the European Society of Intensive Care Medicine (ESICM). It is expected that continuous monitoring using multi-modal techniques will help to overcome the limitations of each individual method and will provide a better diagnosis. More specific treatment can then be applied; however, it remains to be determined which combination of parameters is optimal. The questions discussed and addressed in this manuscript are: (1) Who should have ICP monitoring and for how long? (2) What ICP technologies are available and what are their relative advantages/disadvantages? (3) Should CPP monitoring and autoregulation testing be used? (4) When should brain tissue oxygen tension (PbrO2) be monitored? (5) Should structurally normal or abnormal tissue be monitored with PbrO2? (6) Should microdialysis be considered in complex cases? It is hoped that this document will prove useful to clinicians working in NICU and also to those developing specialist NICU services within their hospital practice.

Monitoring Intracranial Pressure in Traumatic Brain Injury

Authors: Martin Smith, MBBS, FRCA

Increased intracranial pressure (ICP) is an important cause of secondary brain injury, and ICP monitoring has become an established component of brain monitoring after traumatic brain injury. ICP cannot be reliably estimated from any specific clinical feature or computed tomography finding and must actually be measured. Different methods of monitoring ICP have been described but intraventricular catheters and microtransducer systems are most widely used in clinical practice. ICP is a complex variable that links ICP and cerebral perfusion pressure and provides additional information from identification and analysis of pathologic ICP wave forms. ICP monitoring can also be augmented by measurement of indices describing cerebrovascular pressure reactivity and pressure-volume compensatory reserve. There is considerable variability in the use of ICP monitoring and treatment modalities among head injury centers. However, there is a large body of clinical evidence supporting the use of ICP monitoring to detect intracranial mass lesions early, guide therapeutic interventions, and assess prognosis, and it is recommended by consensus guidelines for head injury management. There remains a need for a prospective, randomized, controlled trial to identify the value of ICP monitoring and management after head injury. (Anesth Analg 2008;106:240 –8)

Noninvasive Monitoring of Intracranial Pressure

Authors: Djordje Popovic1,3,*, Michael Khoo1 and Stefan Lee 2

(1Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, 2 Department of Neurosurgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, 3 Advanced Brain Monitoring Inc., Carlsbad, CA)

Recent Patents on Biomedical Engineering 2009, 2, 165-179
Received: April 29, 2009; Accepted: May 6, 2009; Revised: May 9, 2009

Increased intracranial pressure (ICP) is one of the major causes of secondary brain ischemia that accompanies a variety of pathological conditions, most notably, traumatic brain injury (TBI), stroke, and intracranial hemorrhages. However, aside from a few Level I trauma centers, ICP monitoring is rarely a part of the clinical management of patients with these conditions because of the invasiveness of the standard monitoring methods (which require insertion of a catheter into the cranium), additional risks they present for patients, high costs associated with the procedure, and the limited access to trained personnel, i.e., a neurosurgeon. Alternative methods have therefore been sought with which ICP can be measured noninvasively. This article reviews nearly 30 such methods patented over the past 25 years, which included ultrasound “time-of-flight” techniques, transcranial Doppler, methods based on acoustic properties of the cranial bones, EEG, MRI, tympanic membrane displacement, oto-acoustic emission, ophthalmodynamometry, and ultrasound measurements of optic nerve sheath diameter. At present, none of the methods is sufficiently accurate to allow for routine clinical use although several hold promise. Future developments should integrate further refinements of the existing methods, combined use of multiple sensors and/or technologies, and large clinical validation studies on relevant populations.  

Brain Injury In Sports

Source: Brain Injury Resource Center

An estimated 300,000 sports related traumatic brain injuries, TBIs, of mild to moderate severity , most of which can be classified as concussions, (i.e., conditions of temporary altered mental status as a result of head trauma, occur in the United States each year.  The proportion of these concussions that are repeat injuries is unknown; however, there is an increased risk for subsequent TBI among persons who have had at least one previous TBI .  Repeated mild brain injuries occurring over an extended period (i.e., months or years can result in cumulative neurologic and cognitive deficits, but repeated mild brain injuries occurring within a short period (i.e., hours, days, weeks) can be catastrophic or fatal.  The latter phenomenon, termed "second impact syndrome" has been reported more frequently since it was first characterized in 1984.  This page describes two cases of second impact syndrome and presents recommendations developed by the American Academy of Neurology to prevent recurrent brain injuries in sports and their adverse consequences.

Traumatic Brain Injury in Children and Adolescents (Psychiatric Disorders at One Year)

Authors: Jeffrey E. Max, M.B.B.Ch., Donald A. Robin, Ph.D., Scott D. Lindgren, Ph.D., Wilbur L. Smith, Jr., M.D., Yutaka Sato, M.D., Philip J. Mattheis, M.D., Julie A. G. Stierwalt, M.A. and Carlos S. Castillo, M.D.

J Neuropsychiatry Clin Neurosci 10:290-297, August 1998 © 1998 American Psychiatric Press, Inc. 

Factors predictive of psychiatric outcome in the second 6 months following traumatic brain injury (TBI) in 43 children and adolescents were assessed prospectively. The outcome measure was the presence of a psychiatric disorder not present before the injury ("novel"). Out of six models tested, four were predictive of novel psychiatric disorder: preinjury family function, family psychiatric history, socioeconomic class/intellectual function, and behavior/adaptive function. Post hoc analyses suggested that preinjury family functioning measured by a structured interview was a significant predictive variable. Severity of injury, when reclassified as severe versus mild/moderate TBI, significantly predicted novel psychiatric disorders. These data suggest that some children, identifiable through clinical assessment, are at increased risk for psychiatric disorders following TBI.

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