Sonographic assessment of the optic nerve sheath in idiopathic intracranial hypertension

The aim of this work was to investigate the potential of ultrasound-based optic nerve sheath diameter (ONSD) measurements in detecting raised intracranial pressure in patients with idiopathic intracranial hypertension (IIH) and to describe ONSD response to lumbar puncture. In ten patients with newly diagnosed IIH, transorbital sonography was carried out to assess ONSD, OND (optic nerve diameter), and optic disc elevation before and after lumbar puncture. Twenty-five patients with other neurological disorders served as controls. Subjects with IIH showed a significantly enlarged ONSD on both sides (6.4 ± 0.6 mm vs. 5.4 ± 0.5 mm in controls; p < 0.001). The best cut-off value of ONSD for detecting raised ICP was 5.8 mm with a sensitivity of 90% and a specificity of 84%. After lumbar puncture, ONSD decreased bilaterally (right 5.8 ± 0.7 mm, p < 0.004; left 5.9 ± 0.7 mm, p < 0.043). No post-puncture changes could be observed with regard to OND and optic disc elevation. Sonographic ONSD evaluation may be useful as an additional tool to identify patients with raised intracranial pressure, as in IIH. Furthermore, our data suggest a potential usefulness of this method for monitoring of treatment effects. The degree of ONSD response to lumbar puncture differs in subjects with IIH, which may possibly be related to findings of a defective CSF circulation in the optic nerve sheath in this disorder, a state that is referred to as optic nerve compartment syndrome.     

Disease activity in idiopathic intracranial hypertension: a 3-month follow-up study

Idiopathic intracranial hypertension (IIH) is a disorder of raised intracranial pressure (ICP) in the absence of identifiable pathology. The purpose of this study was to evaluate the clinical presentation and monitor a 3-month course using frequent optical coherence tomography (OCT) evaluations, visual field testings and lumbar opening pressure measurements. A longitudinal study of 17 patients with newly diagnosed IIH and 20 healthy overweight controls were included in the study. Peripapillary retinal nerve fiber layer thickness (RNFLT) and retinal thickness (RT) measurements (Stratus OCT-3, fast RNFL 3.4 protocol), and Humphrey visual field testing were evaluated at regular intervals. Repeat lumbar puncture was performed at final visit (n = 13). The diagnostic delay was 3 months and initial symptoms were headache (94%), visual blurring (82%) and pulsatile tinnitus (65%). Complete clinical remission was achieved in 65%, partial in 29% and unchanged symptoms in 6%. Total average RNFLT and RT decreased significantly during the follow-up period (p < 0.0001 and p < 0.0001, respectively). Changes in RNFLT and RT correlated with improvements in visual field mean deviation (MD) (RNFLT: p = 0.006; RT: p = 0.03) and pattern standard deviation (PSD) (RNFLT: p = 0.002; RT: p = 0.003). In patients with weight-loss >3.5% of BMI, ICP decreased significantly (p = 0.0003). In patients with weight-loss <3.5% of BMI, changes in ICP were insignificant (p = 0.6). OCT combined with visual field testing may be a valuable objective tool to monitor IIH patients and the short term IIH outcome is positive. Weight-loss is the main predictor of a favorable outcome with respect to CSF pressure.     

Idiopathic intracranial hypertension; immediate resolution of venous sinus “obstruction” after reducing cerebrospinal fluid pressure to < 10 cmH2O

It has been postulated that cerebral venous outflow “obstruction” is a precipitating factor for many cases of idiopathic intracranial hypertension (IIH). We describe a 17-year-old woman with IIH, and “venous obstruction” repeatedly demonstrated on magnetic resonance venography (MRV) that within minutes resolved partially when the cerebrospinal fluid (CSF) pressure was reduced to 11 cmH₂O and completely when the pressure was reduced to 8 cmH₂O. These findings further support the view that raised pressure is the cause of the “obstruction”, rather than the obstruction being the primary cause of the IIH. It also raises questions about how low the CSF pressure should be reduced at therapeutic lumbar puncture.     

Interpretation of lumbar cerebrospinal fluid leukocytosis after cranial surgery: The relevance of aseptic meningitis

Raised white cell count (WCC) in lumbar CSF is a commonly used marker of meningitis. The effect of cranial neurosurgery per se on lumbar WCC is not established. At this single centre, many patients undergo ICPM followed by lumboperitoneal shunt (LPS), with lumbar CSF WCC samples taken during insertion. We aimed to determine the effect of ICP bolt insertion on lumbar CSF WCC. We undertook a retrospective analysis of lumbar CSF samples in patients who had recently undergone 24-h ICPM. Thirty-three patients (16F:7M) aged 43.31 ± 12.1 years (mean ± SD) had lumbar CSF samples after ICPM. Fourteen had CSF sampled within 6 weeks and 19 after 6 weeks of ICPM. Twenty-five samples were taken during LPS insertion, 5 during lumbar drainage/puncture and 3 during LPS revision. All 33 patients were afebrile at the point of CSF sampling. The mean lumbar WCC within 6 weeks of ICPM was significantly higher than the mean lumbar WCC after 6 weeks, being 15.4 ± 18.0 and 2.32 ± 1.79 cells/microlitre respectively respectively. There was no significant increase in RBC. In patients with raised CSF WCC, 60% of raised WCC were predominantly lymphoctyes and 40% predominantly neutrophils. Only one patient grew an organism (S. aureus). We conclude that lumbar CSF WCC can be raised following minor intracranial surgery, despite no clinical sign of infection. We caution against using lumbar CSF WCC values independently as the only marker of infection following neurosurgery.     

超声多模式评估脑出血患者颅内压增高的临床价值

目的 探讨超声多模式联合检查评估脑出血患者颅内压(ICP)增高的临床价值.方法 纳入2019年9月至2021年6月延边大学附属医院重症监护病房内因病情需要行腰椎穿刺术的脑出血患者17例,在腰椎穿刺术前行超声测量视神经鞘直径(ONSD)及经颅多普勒超声(TCD)检查.根据脑脊液压力结果(大于200 mmH2 O定义为颅内...     

Resolution of idiopathic intracranial hypertension after sustained lowering of cerebrospinal fluid pressure

Idiopathic intracranial hypertension(IIH) is a syndrome of headache due to raised intracranial pressure(ICP) where the cerebrospinal fluid(CSF) is normal and there is no alternative pathology on imaging. The aetiology is unknown. This review questions many of the prevailing views regarding aetiology and treatment of IIH. It explores the concept that there is a vicious cycle of fluctuating raised ICP leading to secondary compression of the transverse sinuses and further elevation of ICP. It also raises the question as to whether this vicious cycle could be relieved by prolonged drainage of CSF as seen in Lumbar puncture induced low-pressure headache or alternatively a lumbar drain.     

超声测量的视神经鞘直径与颅内压关系的研究

目的 探讨国内人群超声测量的球后3 mm的视神经鞘直径(ONSD)与颅内压(ICP)的关系,分析可能影响超声测量ONSD的相关因素。方法 收集2015年7月~2016年2月在火箭军总医院神经内科住院的需要行腰椎穿刺术的患者,术前进行ONSD的超声测量,测量时每侧横纵向分别测量两次,两侧共获得8个ONSD测量值,取其平均值作为该受试者ONSD的最终报告值;收集性别、年龄、身高、体重等一般资料。根据腰椎穿刺术时测得的ICP分为ICP正常组及ICP增高组,分别在两组内分析ONSD与以上因素的相关性;从入组的研究对象中选择行头部MRI检查的患者,在T2加权相上最大径(显示晶状体及视神经)的一层图像进行眼球前后径、眼球横径的测量,并分析ONSD与眼球前后径、眼球横径的关系。结果 共入组40例研究对象,ICP正常组27例,ICP增高组13例,分析后得出两组内ICP均是ONSD的相关因素(ICP正常组P0.001;ICP增高组P=0.045),且通过回归分析显示ONSD可作为独立预测ICP增高的因素。同时得出该样本中ONSD与性别、年龄、BMI之间无明显相关。从40例研究对象中选择了24例行头部MRI检查的患者(其中,ICP正常者17例,ICP增高者7例),分析ONSD与眼球径的关系,得出ONSD与眼球横径存在相关(P0.05),ONSD与眼球前后径无明显相关(P0.05)。结论 ONSD与ICP明显相关,ONSD可作为ICP是否增高的预测因素;ONSD与眼球横径有相关性。     

Intracranial hypertension and HIV associated meningoradiculitis.

Two patients with meningoradiculitis associated with HIV presented with symptoms and signs of intracranial hypertension. In the patients described, the raised intracranial pressure resolved after lumbar puncture. After exclusion of opportunistic infection, such patients may be managed with therapeutic lumbar puncture alone.     

Bedside Optic Nerve Sheath Diameter Assessment in the Identification of Increased Intracranial Pressure in Suspected Idiopathic Intracranial Hypertension

ObjectiveWe determined whether the bedside assessment of the optic nerve sheath diameter could identify elevated intracranial pressure in individuals with suspected idiopathic intracranial hypertension.MethodsThis was a single-center, prospective, rater-blinded study performed in a freestanding pediatric teaching hospital. Patients aged 12 to 18 years scheduled for an elective lumbar puncture with the suspicion of idiopathic intracranial hypertension were eligible to participate. Optic nerve sheath diameter was measured via ultrasonography before performing a sedated lumbar puncture for measuring cerebrospinal fluid opening pressure. Abnormal measurements were predefined as optic nerve sheath diameter ≥4.5 mm and a cerebrospinal fluid opening pressure greater than 20 cmH₂O.ResultsThirteen patients participated in the study, 10 of whom had elevated intracranial pressure. Optic nerve sheath diameter was able to predict or rule out elevated intracranial pressure in all patients.ConclusionsNoninvasive assessment of the optic nerve sheath diameter could help to identify patients with elevated intracranial pressure when idiopathic intracranial hypertension is suspected.     

Waveform caused by raised intracranial pressure--application of spectral analysis in the study of waveform

Changes in spectrum of the intracranial pressure (ICP) pulse wave were studied while ICP was raised by the epidural balloon inflation. ICP and systemic blood pressure were estimated in the lateral ventricle and thoracic aorta, respectively. Transmission of pulsation from arterial pressure to ICP was estimated by the amplitude transfer function (TFa). Waveform of ICP pulse was also evaluated by distortion factor to represent how ICP pulse is different form a pure sine wave. The spectra of ICP and arterial pressure showed basically the same pattern; they consisted of fundamental wave (FW) and three harmonic waves (HW 2, HW 3, HW 4). Amplitude and values of TFa of each spectral component were increased as ICP was raised and revealed significant correlation. FW and HW 2 components showed break points when ICP was raised up to 35 mmHg, thereafter increments of amplitude and TFa became more remarkable in the range of higher ICP. TFa and amplitude of each spectral component of ICP pulse revealed significant correlation. These findings proved that changes of ICP pulse were the results of changed efficiency of pulse transmission from arterial pressure to CSF. It was already reported that the cerebrovascular tonus had decisive influences on the transmission of pulsation from arterial pressure to ICP because lowered vascular tonus would diminish the damping effect by arterial wall and facilitate the transmission of arterial pressure pulse to ICP. The break point of amplitude and TFa were considered to indicate that tonus of cerebral artery was remarkably lowered and the autoregulation of cerebral blood flow was exhausted.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of systemic arterial blood pressure on cerebral blood flow in intracranial hypertension.

In five baboons and 11 cats cerebral ischaemia was produced either by inflating an epidural balloon and or by ligating major arteries supplying the brain. Fifteen of the animals developed intracranial hypertension after cerebral ischaemia. If ICP were high, but still significantly lower than MABP, elevation of MABP by noradrenaline infusions was accompanied by a proportional increase of ICP. However, the increase of ICP was lower than that of MABP so that CPP was raised. CBF measured by the 133Xenon clearance technique was significantly increased by arterial hypertension in eight cases. The proportional increase of CPP and CBF by elevation of arterial blood pressure was substantially greater, the lower ICP was immediately after ischaemia. There was no effect of MABP in cases in which ICP equalled MABP.     

Neurointensive care management of raised intracranial pressure caused by severe valproic acid intoxication

Introduction  

We describe the neurointensive care (NIC) management of a patient with severe cerebral swelling and raised intracranial pressure (ICP) after severe sodium valproic acid (VPA) intoxication. A previously healthy 25-year old male with mild tonic-clonic epilepsy was found unconscious with serum VPA levels >10,000 μmol/l. The patient deteriorated to Glasgow Motor Scale score (GMS) 2 and a CT scan showed signs of raised ICP. Early ICP was elevated, >50 mm Hg, and continuous EEG monitoring showed isoelectric readings.     

The effects of carbon dioxide on measuring cerebral spinal fluid pressure

Purpose  The effects of pCO2 on cerebral spinal fluid (CSF) pressure measurement were observed in four patients. Methods  Children presenting with either a diagnosis or suspected diagnosis of IIH, who were undergoing lumbar puncture under a general anaesthetic for pressure measurement, were recruited to study the relationship between pCO2 and CSF pressure measurements. Results  A rise of end-tidal pCO2 by 1 kPa causes a rise of CSF pressure by 3.5–12 cmH20. Conclusion  Controlling of pCO2 is important when measuring CSF pressure to prevent misdiagnosis and over treatment of patients with idiopathic intracranial hypertension (IIH).     

局灶及弥漫性颅高压对脑血流动力学的影响

目的观察局灶性及弥漫性颅高压（ICH）对大脑中动脉（MCA）、基底动脉（BA）、颈内动脉颅外段（ESICA）血流动力学的不同影响,探讨经颅多普勒（TCD）对颅内压的评估价值。方法对118例颅高压患者进行187次腰穿测颅内压（ICP）前行TCD检查,对TCD资料及脑脊液压力进行分析,并与对照组比较。结果随ICP升高,TCD检测血管MCA、BA、ESICA均表现出高阻力血流频谱,脉动指数（PI）增大。ICP与ESICA的平均血流速度（Vm）相关性最大（r=-0．314,P=0．000）,与MCA的PI相关性最大（r=0．758,P=0．000）。局灶性颅高压Vm病侧慢于健侧,PI高于健侧,弥漫性颅高压双侧Vm、PI无显著差异。结论评估局灶性颅高压应检测病变侧MCA,弥漫性颅高压检测双侧MCA均可,在双侧颞窗透声不好时可检测ESICA。     

Vasopressor Use and Effect on Blood Pressure After Severe Adult Traumatic Brain Injury

Background  

We describe institutional vasopressor usage, and examine the effect of vasopressors on hemodynamics: heart rate (HR), mean arterial blood pressure (MAP), intracranial pressure (ICP), cerebral perfusion pressure (CPP), brain tissue oxygenation (PbtO₂), and jugular venous oximetry (SjVO₂) in adults with severe traumatic brain injury (TBI).     

Indomethacin for brain edema following stroke.

Conventional therapies for raised intracranial pressure (ICP) frequently are not effective. We report a patient with raised ICP following a large hemispheric stroke. After conventional therapies had failed, indomethacin was repeatedly administered. After bolus infusion (50 mg), the ICP fell by a mean of 8.1 mm Hg, and the mean arterial blood pressure increased by a mean of 7.1 mm Hg, leading to a mean increase in the cerebral perfusion pressure by 15.3 mm Hg. After 1 h, the ICP had returned to baseline values after most infusions. Continuous infusion of indomethacin was not effective. We conclude that indomethacin may reduce elevated ICP over a short time in patients with ischemic brain edema even after conventional therapy has failed.     

Alpha-Stat Versus pH-Stat Guided Ventilation in Patients with Large Ischemic Stroke Treated by Hypothermia

Background  Moderate hypothermia (MH) is a therapeutic approach for ischemic stroke as well as cardiac arrest. Two different technical strategies of ventilation during MH called alpha- and pH-stat dramatically influence cerebral blood flow (CBF). In turn this might influence neuronal damage and intracranial pressure (ICP). Therefore, effects of ventilation on CBF and ICP were measured in patients undergoing MH because of large ischemic stroke to address optimal ventilation management. Methods  Eight patients (n = 8) with large ischemic stroke in the territory of the middle cerebral artery (MCA) were treated by MH of 33°C within 24 h after symptom onset. MH was applied at least for 72 h. Each day, patients were ventilated repetitively with either alpha-stat or pH-stat for 60 min periods. Alpha-stat was applied between the measurements. ICP, CBF, and mean arterial blood pressure (MABP) were measured. The xenon clearance method was used to assess CBF at the bedside. Results  There were no significant differences between ICP values for alpha-stat or pH-stat during days 1 and 2 after induction of hypothermia. However, ICP was higher in the pH- as compared to the alpha-stat group (P < 0.05) and exceeded a mean of 20 mmHg on day 3. pH-stat led to a significant increase of CBF in all measures (P < 0.05), while MABP was unaffected. Conclusions  pH-stat implies a better CBF to the injured brain, while it might be dangerous by elevating ICP in more subacute stages.     

Optic Nerve Ultrasound for the Detection of Raised Intracranial Pressure

Background  

Optic nerve ultrasonography (ONUS) may help identify raised intracranial pressure (ICP). The optimal optic nerve sheath diameter (ONSD) cut-off for the identification of intracranial hypertension has not been established, with some clinical studies suggesting a higher cut-off than may be expected on the basis of prior laboratory investigation.     

Effects of hypercapnia and arterial hypotension and hypertension on cerebrospinal fluid pulse pressure and intracranial volume-pressure relationships.

In twelve anaesthetised, ventilated dogs the effects of hypercapnia and pharmacologically induced arterial hypotension and hypertension on the interrelation between volume-pressure response (VPR) and cerebro-spinal fluid (CSF) pulse pressure were studied during continuous inflation of a supratentorial extradural balloon. Hypercapnia did not significantly affect the intracranial volume-pressure relationships, but did cause a significant increase in gradient of the relationship between CSF pulse pressure and intracranial pressure (ICP). Alteration of the arterial blood pressure showed opposite effects on VPR and CSF pulse pressure. A decrease in VPR and an increase in pulse pressure were observed during arterial hypotension; the reverse was found during arterial hypertension. The discrepancy between the effects on VPR and CSF pulse pressure of the variables under study was explained by changes in the transient increase in cerebral blood volume per cardiac cycle. On the basis of the results of this study it will be possible, during clinical ICP monitoring, to interpret changes in the CSF pulse pressure to ICP ratio in terms of changes in intracranial volume-pressure relationships.