Intracranial and Intraocular Pressure at the Lamina Cribrosa: Gradient Effects

Purpose of Review

A pressure difference between the intraocular and intracranial compartments at the site of the lamina cribrosa has been hypothesized to have a pathophysiological role in several optic nerve head diseases. This paper reviews the current literature on the translamina cribrosa pressure difference (TLCPD), the associated pressure gradient, and its potential pathophysiological role, as well as the methodology to assess TLCPD.

Recent Findings

For normal-tension glaucoma (NTG), initial studies indicated low intracranial pressure (ICP) while recent findings indicate that a reduced ICP is not mandatory.

Summary

Data from studies on the elevated TLCPD as a pathophysiological factor of NTG are equivocal. From the identification of potential postural effects on the cerebrospinal fluid (CSF) communication between the intracranial and retrolaminar space, we hypothesize that the missing link could be a dysfunction of an occlusion mechanism of the optic nerve sheath around the optic nerve. In upright posture, this could cause an elevated TLCPD even with normal ICP and we suggest that this should be investigated as a pathophysiological component in NTG patients.

     

High resolution transbulbar sonography in children with suspicion of increased intracranial pressure

Purpose

To evaluate the accuracy of high resolution transbulbar sonography for the estimation of intracranial pressure (ICP) in children.

Methods

In children and adolescents with acute neurologic symptoms of various origin, transbulbar sonography was performed. Besides measurement of the optic nerve sheath diameter (ONSD), the ultrastructure of the subarachnoid space of the optic nerve sheath was evaluated. The results of transbulbar sonography were correlated with clinical data based on cross-sectional imaging, ICP measurement, and ophthalmologic examination.

Results

Eighty-one patients (age 3–17.8 years, mean 11.7 years) were included. In 25 children, cross-sectional imaging and ICP measurement revealed increased intracranial pressure. The mean ONSD was 6.85?±?0.81 mm. Twenty patients (20/25, 80 %) had a microcystic appearance of the subarachnoid space of the optic nerve. In 56 children without evidence of increased intracranial pressure, the mean ONSD was 5.77?±?0.48 mm. Forty-nine patients (49/56, 87.5 %) had a normal homogenous appearance of the subarachnoid space. The ONSD in children with increased intracranial pressure was significantly higher than in patients without (p?<?0.001).

Conclusion

High resolution transbulbar sonography of the optic nerve is a useful technique for the rapid and non-invasive estimation of intracranial pressure in children. Besides measurement of the optic nerve sheath diameter, evaluation of the ultrastructure of the subarachnoid space of the optic nerve is a helpful parameter.

     

Endoscopic third ventriculostomy: the best option in the treatment of persistent hydrocephalus after posterior cranial fossa tumour removal?

Background

Ten to 40% of children operated on for a posterior fossa tumour require a further surgical procedure for the management of a persisting active ventricular dilation. The management of this kind of hydrocephalus is still controversial.

Objective

To prospectively evaluate the effectiveness of post-operative endoscopic third ventriculostomy (ETV) in the management of persistent active hydrocephalus in a series of children operated on for a posterior cranial fossa tumour.

Methods

The management protocol consisted of: (1) placement of a peri-operative antibiotic impregnated external ventricular catheter (Bactiseal®) and tumour removal, (2) post-operative intracranial pressure (ICP) monitoring through the external ventricular drainage, (3) ETV in case of persistent ventricular dilation and persistently abnormal high ICP values and (4) ventriculoperitoneal shunt implantation in case of ETV failure.

Results

Thirty on a total of 104 children (28.8%) operated on between January 2001 and February 2007 at our institution needed a further surgical treatment for the persistence of the hydrocephalus after the removal of their posterior cranial fossa tumour. They were sub-divided in two groups according to the early (group 1—21 patients) or later (group 2—nine patients) definition of the persistence of an active ventricular dilation based on clinical, radiological and ICP monitoring data. ETV was successful in 90.0% of the patients in the present series (27/30 patients), without statistically significant differences among the two groups considered.

Conclusions

Post-operative ETV should be considered the best option to treat persistent hydrocephalus after the removal of posterior fossa tumours.

     

A Precision Medicine Approach to Cerebral Edema and Intracranial Hypertension after Severe Traumatic Brain Injury: Quo Vadis?

Purpose of Review

Standard clinical protocols for treating cerebral edema and intracranial hypertension after severe TBI have remained remarkably similar over decades. Cerebral edema and intracranial hypertension are treated interchangeably when in fact intracranial pressure (ICP) is a proxy for cerebral edema but also other processes such as extent of mass lesions, hydrocephalus, or cerebral blood volume. A complex interplay of multiple molecular mechanisms results in cerebral edema after severe TBI, and these are not measured or targeted by current clinically available tools. Addressing these underpinnings may be key to preventing or treating cerebral edema and improving outcome after severe TBI.

Recent Findings

This review begins by outlining basic principles underlying the relationship between edema and ICP including the Monro-Kellie doctrine and concepts of intracranial compliance/elastance. There is a subsequent brief discussion of current guidelines for ICP monitoring/management. We then focus most of the review on an evolving precision medicine approach towards cerebral edema and intracranial hypertension after TBI. Personalization of invasive neuromonitoring parameters including ICP waveform analysis, pulse amplitude, pressure reactivity, and longitudinal trajectories are presented. This is followed by a discussion of cerebral edema subtypes (continuum of ionic/cytotoxic/vasogenic edema and progressive secondary hemorrhage). Mechanisms of potential molecular contributors to cerebral edema after TBI are reviewed. For each target, we present findings from preclinical models, and evaluate their clinical utility as biomarkers and therapeutic targets for cerebral edema reduction. This selection represents promising candidates with evidence from different research groups, overlap/inter-relatedness with other pathways, and clinical/translational potential.

Summary

We outline an evolving precision medicine and translational approach towards cerebral edema and intracranial hypertension after severe TBI.

     

Reversible cerebral vasoconstriction syndrome and posterior reversible encephalopathy syndrome associated with intracranial hypotension

Background

Many demographic and physiological variables have been associated with TBI outcomes. However, with small sample sizes, making spurious inferences is possible. This paper explores the effect of sample sizes on statistical relationships between patient variables (both physiological and demographic) and outcome.

Methods

Data from head-injured patients with monitored arterial blood pressure, intracranial pressure (ICP) and outcome assessed at 6 months were included in this retrospective analysis. A univariate logistic regression analysis was performed to obtain the odds ratio for unfavorable outcome. Three different dichotomizations between favorable and unfavorable outcomes were considered. A bootstrap method was implemented to estimate the minimum sample sizes needed to obtain reliable association between physiological and demographic variables with outcome.

Results

In a univariate analysis with dichotomized outcome, samples sizes should be generally larger than 100 for reproducible results. Pressure reactivity index, ICP, and ICP slow waves offered the strongest relationship with outcome. Relatively small sample sizes may overestimate effect sizes or even produce conflicting results.

Conclusion

Low power tests, generally achieved with small sample sizes, may produce misleading conclusions, especially when they are based only on p values and the dichotomized criteria of rejecting/not-rejecting the null hypothesis. We recommend reporting confidence intervals and effect sizes in a more complete and contextualized data analysis.

     

A spectrum of intracranial vascular high-flow arteriovenous shunts in RASA1 mutations

Purpose and background

We describe three paediatric cases with different intracranial fast-flow shunts presenting early in life, all with capillary malformation–arteriovenous malformation syndrome and RASA1 verified mutations. Intracranial arteriovenous fast-flow shunts are rare vascular malformations typically presenting early in life and have been associated with cutaneous capillary malformations, characterized as capillary malformation–arteriovenous malformation syndrome. Heterozygous RASA1 gene mutations have been found to be disease causing with high penetrance for the typical cutaneous findings, but only some individuals with the syndrome have intracranial lesions.

Cases

One infant presented with a vein of Galen malformation responsible for hydrodynamic disorders, one neonate suffered from severe cardiac insufficiency related to a superior sagittal sinus dural malformation with high-flow fistulas, and one baby was treated at infant age of a choroidal arteriovenous fistula discovered antenatally.

Results and conclusions

We report the follow-up of these three cases with RASA1 gene mutation and comment on the possible role of evaluation for vascular lesions and capillary malformation–arteriovenous malformation syndrome in patients and their families, with intracranial fast-flow shunts.

     

The Effect of Positive End-Expiratory Pressure on Intracranial Pressure and Cerebral Hemodynamics

Background

Lung protective ventilation has not been evaluated in patients with brain injury. It is unclear whether applying positive end-expiratory pressure (PEEP) adversely affects intracranial pressure (ICP) and cerebral perfusion pressure (CPP). We aimed to evaluate the effect of PEEP on ICP and CPP in a large population of patients with acute brain injury and varying categories of acute lung injury, defined by PaO₂/FiO₂.

Method

Retrospective data were collected from 341 patients with severe acute brain injury admitted to the ICU between 2008 and 2015. These patients experienced a total of 28,644 paired PEEP and ICP observations. Demographic, hemodynamic, physiologic, and ventilator data at the time of the paired PEEP and ICP observations were recorded.

Results

In the adjusted analysis, a statistically significant relationship between PEEP and ICP and PEEP and CPP was found only among observations occurring during periods of severe lung injury. For every centimeter H₂O increase in PEEP, there was a 0.31 mmHg increase in ICP (p = 0.04; 95 % CI [0.07, 0.54]) and a 0.85 mmHg decrease in CPP (p = 0.02; 95 % CI [?1.48, ?0.22]).

Conclusion

Our results suggest that PEEP can be applied safely in patients with acute brain injury as it does not have a clinically significant effect on ICP or CPP. Further prospective studies are required to assess the safety of applying a lung protective ventilation strategy in brain-injured patients with lung injury.

     

Secondary Headaches in Children and Adolescents: What Not to Miss

Introduction

Headaches are a common occurrence in childhood and adolescence. Most children presenting with a chief complaint of headache have a self-limited infectious disorder or primary headache syndrome that should not require extensive workup.

Purpose of Review

Differentiating these conditions from other more serious causes of headache in children can sometimes be difficult. This article aims to provide information regarding “red flags” that should indicate a need for concern for disorders that require more urgent evaluation.

Recent Findings

Long-held beliefs about specific “red flags” that have been analyzed in recent years as to their validity and new criteria for the diagnosis of idiopathic intracranial hypertension have been elaborated based on study. These publications are reviewed in this article.

Summary

Knowledge of past and current literature on secondary headache in children, combined with thorough history taking and examination, should help determine when there is concern for a serious secondary cause for headache in children and adolescents and direct workup.

     

Effects of Early Bedside Cycle Exercise on Intracranial Pressure and Systemic Hemodynamics in Critically Ill Patients in a Neurointensive Care Unit

Background

Physiotherapy is an important part of treatment after severe brain injuries and stroke, but its effect on intracranial and systemic hemodynamics is minimally investigated. Therefore, the aim of this study was to assess the effects of an early bedside cycle exercise on intracranial and systemic hemodynamics in critically ill patients when admitted to a neurointensive care unit (NICU).

Methods

Twenty critically ill patients suffering from brain injuries or stroke were included in this study performed in the NICU at Sahlgrenska University Hospital. One early implemented exercise session was performed using a bedside cycle ergometer for 20 min. Intracranial and hemodynamic variables were measured two times before, three times during, and two times after the bedside cycling exercise. Analyzed variables were intracranial pressure (ICP), cerebral perfusion pressure (CPP), mean arterial blood pressure (MAP), heart rate (HR), peripheral oxygen saturation (SpO₂), cardiac output (CO), stroke volume (SV), and stroke volume variation (SVV). The cycling intervention was conducted within 7 ± 5 days after admission to the NICU.

Results

Cycle exercise increased MAP (p = 0.029) and SV (p = 0.003) significantly. After exercise CO, SV, MAP, and CPP decreased significantly, while no changes in HR, SVV, SpO₂, or ICP were noted when compared to values obtained during exercise. There were no differences in data obtained before versus after exercise.

Conclusion

Early implemented exercise with a bedside cycle ergometer, for patients with severe brain injuries or stroke when admitted to a NICU, is considered to be a clinically safe procedure.

     

The relationship between transorbital ultrasound measurement of the optic nerve sheath diameter (ONSD) and invasively measured ICP in children.

Purpose

The aim of this study was to investigate the relationship between optic nerve sheath diameter (ONSD) measurement and invasively measured intracranial pressure (ICP) in children.

Methods

ONSD measurement was performed prior to invasive measurement of ICP. The mean binocular ONSD measurement was compared to the ICP reading. Physiological variables including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse rate, temperature, respiratory rate and end tidal carbon dioxide (ETCO2) level were recorded at the time of ONSD measurement. Diagnostic accuracy analysis was performed at various ICP thresholds and  repeatability, intra- and inter-observer variability, correlation between measurements in different imaging planes as well the relationship over the entire patient cohort were examined in part I of this study.

Results

Data from 174 patients were analysed. Repeatability and intra-observer variability were excellent (α?=?0.97–0.99). Testing for inter-observer variability revealed good correlation (r?=?0.89, p?<?0.001). Imaging in the sagittal plane demonstrated a slightly better correlation with ICP (r?=?0.66, p?<?0.001). The ONSD measurement with the best diagnostic accuracy for detecting an ICP?≥?20 mmHg over the entire patient cohort was 5.5 mm, sensitivity 93.2 %, specificity 74 % and odds ratio (OR) of 39.3.

Conclusion

Transorbital ultrasound measurement of the OSND is a reliable and reproducible technique, demonstrating a good relationship with ICP and high diagnostic accuracy for detecting raised ICP.

     

Consideration of the Intracranial Pressure Threshold Value for the Initiation of Traumatic Brain Injury Treatment: A Xenon CT and Perfusion CT Study

Background

Monitoring of intracranial pressure (ICP) is considered to be fundamental for the care of patients with severe traumatic brain injury (TBI) and is routinely used to direct medical and surgical therapy. Accordingly, some guidelines for the management of severe TBI recommend that treatment be initiated for ICP values >20 mmHg. However, it remained to be accounted whether there is a scientific basis to this instruction. The purpose of the present study was to clarify whether the basis of ICP values >20 mmHg is appropriate.

Subject and Methods

We retrospectively reviewed 25 patients with severe TBI who underwent neuroimaging during ICP monitoring within the first 7 days. We measured cerebral blood flow (CBF), mean transit time (MTT), cerebral blood volume (CBV), and ICP 71 times within the first 7 days.

Results

Although the CBF, MTT, and CBV values were not correlated with the ICP value at ICP values ≤20 mmHg, the CBF value was significantly negatively correlated with the ICP value (r = ?0.381, P < 0.05) at ICP values >20 mmHg. The MTT value was also significantly positively correlated with the ICP value (r = 0.638, P < 0.05) at ICP values >20 mmHg.

Conclusion

The cerebral circulation disturbance increased with the ICP value. We demonstrated the cerebral circulation disturbance at ICP values >20 mmHg. This study suggests that an ICP >20 mmHg is the threshold to initiate treatments. An active treatment intervention would be required for severe TBI when the ICP was >20 mmHg.

     

Noninvasive Intracranial Pressure Assessment in Acute Liver Failure

Background

Elevated intracranial pressure (ICP) is an important cause of death following acute liver failure (ALF). While invasive ICP monitoring (IICPM) is most accurate, the presence of coagulopathy increases bleeding risk in ALF. Our objective was to evaluate the accuracy of three noninvasive ultrasound-based measures for the detection of concurrent ICP elevation in ALF—optic nerve sheath diameter (ONSD) using optic nerve ultrasound (ONUS); middle cerebral artery pulsatility index (PI) on transcranial Doppler (TCD); and ICP calculated from TCD flow velocities (ICPtcd) using the estimated cerebral perfusion pressure (CPPe) technique.

Methods

In this retrospective study, consecutive ALF patients admitted over a 6-year period who underwent IICPM as well as measurement of ONSD, TCD-PI or ICPtcd were included. ONSD was measured offline by a blinded investigator from deidentified videos. The ability of highest ONSD, TCD-PI, and ICPtcd to detect concurrent invasive ICP?>?20 mmHg was assessed using receiver operating characteristic (ROC) curves. The ROC area under the curve (AUC) was calculated with 95% confidence interval (95% CI) and evaluated against the null hypothesis of AUC?=?0.5. Noninvasive measures were also evaluated as predictors of in-hospital death.

Results

Forty-one ALF patients were admitted during the study period. In total, 27 (66%) underwent IICPM, of these, 23 underwent ONUS and 21 underwent TCD. Eleven out of 23 (48%) patients died (two from intracranial hypertension). Results of ROC analysis for detection of concurrent ICP?>?20 mmHg were as follows: ONSD AUC?=?0.59 (95% CI 0.37–0.79, p?=?0.54); TCD-PI AUC?=?0.55 (95% CI 0.34–0.75, p?=?0.70); and ICPtcd AUC?=?0.90 (0.72–0.98, p?<?0.0001). None of the noninvasive measures were significant predictors of death.

Conclusions

In patients with ALF, neither ONSD nor TCD-PI reliably detected concurrent ICP elevation on invasive monitoring. Estimation of ICP (ICPtcd) using the TCD CPPe technique was associated with concurrent ICP elevation. Additional studies of TCD CPPe in larger numbers of ALF patients may prove worthwhile.

     

Guideline for Reversal of Antithrombotics in Intracranial Hemorrhage

Background

The use of antithrombotic agents, including anticoagulants, antiplatelet agents, and thrombolytics has increased over the last decade and is expected to continue to rise. Although antithrombotic-associated intracranial hemorrhage can be devastating, rapid reversal of coagulopathy may help limit hematoma expansion and improve outcomes.

Methods

The Neurocritical Care Society, in conjunction with the Society of Critical Care Medicine, organized an international, multi-institutional committee with expertise in neurocritical care, neurology, neurosurgery, stroke, hematology, hemato-pathology, emergency medicine, pharmacy, nursing, and guideline development to evaluate the literature and develop an evidence-based practice guideline. Formalized literature searches were conducted, and studies meeting the criteria established by the committee were evaluated.

Results

Utilizing the GRADE methodology, the committee developed recommendations for reversal of vitamin K antagonists, direct factor Xa antagonists, direct thrombin inhibitors, unfractionated heparin, low-molecular weight heparin, heparinoids, pentasaccharides, thrombolytics, and antiplatelet agents in the setting of intracranial hemorrhage.

Conclusions

This guideline provides timely, evidence-based reversal strategies to assist practitioners in the care of patients with antithrombotic-associated intracranial hemorrhage.

     

Evaluation of a New Multiparameter Brain Probe for Simultaneous Measurement of Brain Tissue Oxygenation,Cerebral Blood Flow,Intracranial Pressure,and Brain Temperature in a Porcine Model

Background

A novel multiparameter brain sensor (MPBS) allows the simultaneous measurement of brain tissue oxygenation (ptiO₂), cerebral blood flow (CBF), intracranial pressure (ICP), and brain temperature with a single catheter. This laboratory investigation evaluates the MPBS in an animal model in relation to established reference probes.

Methods

The study group consisted of 17 juvenile male pigs. Four MPBS and four reference probes were implanted per pig and compared simultaneously. The measured parameters were challenged by standardized provocations such as hyperoxia, dobutamine, and norepinephrine application, hypercapnia and hypoxia in combination with and without a controlled cortical impact (CCI) injury. Mean values over 2 min were collected for predefined time points and were analyzed using Bland–Altman plots.

Results

The protocol was successfully conducted in 15 pigs of which seven received CCI. ICP and ptiO₂ were significantly influenced by the provocations. Subtraction of MPBS from reference values revealed a mean difference (limits of agreement) of 3.7 (??20.5 to 27.9) mm Hg, ??2.9 (??7.9 to 2.1) mm Hg, and 5.1 (??134.7 to 145.0) % for ptiO₂, ICP, and relative CBF, respectively.

Conclusions

The MPBS is a promising measurement tool for multiparameter neuromonitoring. The conducted study demonstrates the in vivo functionality of the probe. Comparison with standard probes revealed a deviation which is mostly analogous to other multiparameter devices. However, further evaluation of the device is necessary before it can reliably be used for clinical decision making.

     

Cerebral Critical Closing Pressure: Is the Multiparameter Model Better Suited to Estimate Physiology of Cerebral Hemodynamics?

Background

Cerebral critical closing pressure (CrCP) is the level of arterial blood pressure (ABP) at which small brain vessels close and blood flow stops. This value is always greater than intracranial pressure (ICP). The difference between CrCP and ICP is explained by the tone of the small cerebral vessels (wall tension). CrCP value is used in several dynamic cerebral autoregulation models. However, the different methods for calculation of CrCP show frequent negative values. These findings are viewed as a methodological limitation. We intended to evaluate CrCP in patients with severe traumatic brain injury (TBI) with a new multiparameter impedance-based model and compare it with results found earlier using a transcranial Doppler (TCD)–ABP pulse waveform-based method.

Methods

Twelve severe TBI patients hospitalized during September 2005–May 2007. Ten men, mean age 32 years (16–61). Four had decompressive craniectomies (DC); three presented anisocoria. Patients were monitored with TCD cerebral blood flow velocity (FV), invasive ABP, and ICP. Data were acquired at 50 Hz with an in-house developed data acquisition system. We compared the earlier studied “first harmonic” method (M1) results with results from a new recently developed (M2) “multiparameter method.”

Results

M1: In seven patients CrCP values were negative, reaching ?150 mmHg. M2: All positive values; only one lower than ICP (ICP 60 mmHg/ CrCP 57 mmHg). There was a significant difference between M1 and M2 values (M1 < M2) and between ICP and M2 (M2 > ICP).

Conclusion

M2 results in positive values of CrCP, higher than ICP, and are physiologically interpretable.

     

Mindfulness Meditation for Chronic Pain: Systematic Review and Meta-analysis

Background

Chronic pain patients increasingly seek treatment through mindfulness meditation.

Purpose

This study aims to synthesize evidence on efficacy and safety of mindfulness meditation interventions for the treatment of chronic pain in adults.

Method

We conducted a systematic review on randomized controlled trials (RCTs) with meta-analyses using the Hartung-Knapp-Sidik-Jonkman method for random-effects models. Quality of evidence was assessed using the GRADE approach. Outcomes included pain, depression, quality of life, and analgesic use.

Results

Thirty-eight RCTs met inclusion criteria; seven reported on safety. We found low-quality evidence that mindfulness meditation is associated with a small decrease in pain compared with all types of controls in 30 RCTs. Statistically significant effects were also found for depression symptoms and quality of life.

Conclusions

While mindfulness meditation improves pain and depression symptoms and quality of life, additional well-designed, rigorous, and large-scale RCTs are needed to decisively provide estimates of the efficacy of mindfulness meditation for chronic pain.

     

Treatment and outcomes of primary intracranial teratoma

Purpose

Until recently, postoperative adjuvant treatment for intracranial teratomas has remained controversial because of the rarity of the tumors and the heterogeneity of histologic types. To define optimal therapy modalities, we retrospectively analyzed the treatment of patients with intracranial teratomas.

Methods

Between 1979 and 2007, 31 patients with intracranial teratomas were treated at our institution. The median age of the 31 patients was 14.8 years. The median follow-up time was 72.7 months (range 11～291 months). Perioperative radiochemotherapy was done in 19 patients. Proper chemotherapy regimens were followed, such as PE (cisplatin and VP-16), PVB (cisplatin, VP-16, and bleomycin), ICE (carboplatin, VP-16, and ifosfamide), and NGGCT (etoposide, carboplatin, bleomycin, and cyclophosphamide with mesna).

Results

Eight patients experienced recurrence, and a second operation was carried out in six patients. Fifteen patients survived for more than 5 years without recurrence, irrespective of having received adjuvant therapies. The 5-year survival rate of the 31 patients was 74%.

Conclusion

Treatment of intracranial teratomas is very difficult because of the heterogeneity of the tumor cells from totipotent origins. Accurate histological diagnosis of teratoma subtypes is the most important factor for adequate treatment, and proper therapeutic protocols are needed to cure teratomas.

     

Perinatal (fetal and neonatal) astrocytoma: a review

Introduction

The purpose of this review is to document the various types of astrocytoma that occur in the fetus and neonate, their locations, initial findings, pathology, and outcome. Data are presented that show which patients are likely to survive or benefit from treatment compared with those who are unlikely to respond.

Materials and methods

One hundred one fetal and neonatal tumors were collected from the literature for study.

Results

Macrocephaly and an intracranial mass were the most common initial findings. Overall, hydrocephalus and intracranial hemorrhage were next. Glioblastoma (GBM) was the most common neoplasm followed in order by subependymal giant cell astrocytoma (SEGA), low-grade astrocytoma, anaplastic astrocytoma, and desmoplastic infantile astrocytoma (DIA). Tumors were detected most often toward the end of the third trimester of pregnancy.

Conclusion

A number of patients were considered inoperable since their tumor occupied much of the intracranial cavity involving large areas of the brain. High-grade astrocytomas were more common than low-grade ones in this review. Fetuses and neonates with astrocytoma have a mixed prognosis ranging from as low as 20 % (GBM) to a high of 90 %. The overall survival was 47/101 or 46 %.

     

Hyperpyrexia as the Presenting Symptom of Intracranial Hypotension

Introduction

Hyperpyrexia is a severely elevated core body temperature secondary to an elevated hypothalamic set thermo-regulatory threshold. Hyperthermia is an elevated core body temperature beyond the normal hypothalamic set thermo-regulatory threshold. Intracranial hypotension can present with a wide variety of symptoms ranging from orthostatic headache up to coma. We report a rare case of hyperpyrexia associated with intracranial hypotension.

Methods

A case report of a 55-year-old female patient with a history of angiogram-negative subarachnoid hemorrhage status post-ventriculoperitoneal (VP) shunt placement six years prior to admission who suddenly developed encephalopathy and high fever. Conventional management of the fever was unsuccessful.

Results and Management

Brain magnetic resonance imaging revealed signs of significant intracranial hypotension. When the VP shunt was tapped, no cerebrospinal fluid (CSF) could be obtained. Once the VP shunt settings were adjusted, the patient’s encephalopathy and hyperpyrexia resolved.

Conclusion

Hyperpyrexia might be a presenting symptom of intracranial hypotension, likely, secondary to hypothalamic dysfunction and compression. In our case, hyperpyrexia was reversible as the intracranial hypotension was emergently treated. Spontaneous intracranial hypotension might be difficult to diagnose, especially if it presented with non-classical symptoms like fever; thus, physicians should be aware of such association.

     

Intracranial Pressure During Pressure Control and Pressure-Regulated Volume Control Ventilation in Patients with Traumatic Brain Injury: A Randomized Crossover trial

Introduction

Mechanical ventilation with control of partial arterial CO₂ pressures (PaCO₂) is used to treat or stabilize intracranial pressure (ICP) in patients with traumatic brain injury (TBI). Pressure-regulated volume control (PRVC) is a ventilator mode where inspiratory pressures are automatically adjusted to deliver the patient a pre-set stable tidal volume (TV). This may result in a more stable PaCO₂ and thus a more stable ICP compared with conventional pressure control (PC) ventilation. The aim of this study was to compare PC and PRVC ventilation in TBI patients with respect to ICP and PaCO₂.

Methods

This is a randomized crossover trial including eleven patients with a moderate or severe TBI who were mechanically ventilated and had ICP monitoring. Each patient was administered alternating 2-h periods of PC and PRVC ventilation. The outcome variables were ICP and PaCO₂.

Results

Fifty-two (26 PC, 26 PRVC) study periods were included. Mean ICP was 10.8 mmHg with PC and 10.3 mmHg with PRVC ventilation (p = 0.38). Mean PaCO₂ was 36.5 mmHg (4.87 kPa) with PC and 36.1 mmHg (4.81 kPa) with PRVC (p = 0.38). There were less fluctuations in ICP (p = 0.02) and PaCO₂ (p = 0.05) with PRVC ventilation.

Conclusions

Mean ICP and PaCO₂ were similar for PC and PRVC ventilation in TBI patients, but PRVC ventilation resulted in less fluctuation in both ICP and PaCO₂. We cannot exclude that the two ventilatory modes would have impact on ICP in patients with higher ICP values; however, the similar PaCO₂ observations argue against this.