Papilledema after acute head injury

Estimation of Physiologic Pressures: Invasive and Non-Invasive Techniques, AI Models, and Future Perspectives

The measurement of physiologic pressure helps diagnose and prevent associated health complications. From typical conventional methods to more complicated modalities, such as the estimation of intracranial pressures, numerous invasive and noninvasive tools that provide us with insight into daily physiology and aid in understanding pathology are within our grasp. Currently, our standards for estimating vital pressures, including continuous BP measurements, pulmonary capillary wedge pressures, and hepatic portal gradients, involve the use of invasive modalities. As an emerging field in medical technology, artificial intelligence (AI) has been incorporated into analyzing and predicting patterns of physiologic pressures. AI has been used to construct models that have clinical applicability both in hospital settings and at-home settings for ease of use for patients. Studies applying AI to each of these compartmental pressures were searched and shortlisted for thorough assessment and review. There are several AI-based innovations in noninvasive blood pressure estimation based on imaging, auscultation, oscillometry and wearable technology employing biosignals. The purpose of this review is to provide an in-depth assessment of the involved physiologies, prevailing methodologies and emerging technologies incorporating AI in clinical practice for each type of compartmental pressure measurement. We also bring to the forefront AI-based noninvasive estimation techniques for physiologic pressure based on microwave systems that have promising potential for clinical practice.

Sensitivity of Papilledema as a Sign of Increased Intracranial Pressure

Our study evaluates the sensitivity of papilledema as a sign of high intracranial pressure in children. Patients younger than 18 years old, diagnosed with increased ICP, and who had received dilated fundus examination between 2019 and 2021 were retrospectively reviewed. Factors including the patient's age, sex, aetiology, duration of signs or symptoms, intracranial pressure (ICP), and presence of papilledema were evaluated. We included 39 patients in this study, whose mean age was 6.7 years. The 31 patients without papilledema had a mean age of 5.7 years, and 8 patients (20%) with papilledema had a mean age of 10.4 (p < 0.037). The mean duration of signs or symptoms was nine weeks in patients without papilledema and seven weeks in those with papilledema (p = 0.410). The leading causes of increased ICP with papilledema were supratentorial tumor (12.5%), infratentorial tumor (33.3%), and hydrocephalus (20%) (p = 0.479). Papilledema was statistically significantly more common in older patients. We found no statistical significance between sex, diagnosis, and symptoms. The relatively low incidence of papilledema (20%) in our study shows that papilledema's absence does not ensure the absence of increased ICP, especially in younger patients.

Optic Nerve Ultrasound Evaluation in Children: A Review

Managing patients with neurocritical illness requires monitoring and treating elevated intracranial pressure (ICP), especially in cases in children. In terms of precise and real-time measurements, invasive ICP measurements are presently the gold standard for the initial diagnosis and follow-up ICP assessments. As a rapid and non-invasive way to detect elevated ICP, point-of-care ultrasonography (POCUS) of optic nerve sheath diameter (ONSD) has been proposed. The utility of bedside POCUS of ONSD to detect elevated ICP with excellent diagnostic test accuracy in adults has already been demonstrated. Nonetheless, data on the relationship between POCUS of ONSD and ICP in children are scarce. Therefore, the purpose of this review is to point out the most recent findings from the pediatric published literature and briefly discuss what was assessed with ONSD ultrasound examination, and also to describe and discuss the diagnostic procedures available for optic nerve ultrasound appraisal. A search of the medical databases PubMed and Scopus was carried out. The terms such as "ocular ultrasonography", "ICP assessment", "children", "point-of-care ultrasound", and "POCUS" were searched. In conclusion, the use of the standardized A-scan technique coupled with the B-scan technique should be suggested to provide data that are as accurate, precise, repeatable, and objective as possible.

Echographic criteria for the assessment of the optic nerve condition in intracranial hypertension

Purpose: to develop objective acoustic criteria of the condition of the optic nerve and its sheaths for an early diagnosis of intracranial hypertension (IH). Material and methods. The research involved 24 patients (average age 35.8 ± 8.5 years) with suspected IH. The control group consisted of 48 healthy subjects (average age 28.5 ± 9.5 years). Ultrasound examination of the retrobulbar part of the optic nerve (ON) included the measurement of the ON thickness with sheaths (ONSD) and without sheaths (OND) and the calculation of the ratio K = ONSD/ OND. Echodensitometry was used to evaluate the echographic density of the parenchyma and the sheaths of the optic nerve. All patients were tested with magnetic resonance imaging (MRI) to analyse brain images. Results. The biometrical parameters of ON in healthy subjects were as follows: ONS 2.64 ± 0.21 mm and ONSD — 4.60 ± 0.34 mm. In patients with suspected IH the average parameters of the ON diameter were as follows: ONS — 2.57 ± 0.25 mm and ONSD — 5.81 ± 0.42 mm. A comparative assessment of the ON thickness with and without sheaths showed that in the control group the values of ONS did not exceed 3.5 mm and ONSD did not exceed 5.0 mm. In patients with IH, the values of ONSD were significantly higher than those in the control group (p < 0.05). The ratio coefficient (K)=ONSD/ONS in the group of healthy subjects ranged from 1.53 to 2.0 and averaged 1.75 ± 0.14. In patients with IH the values of K exceeded 2.0 (2,40 ± 0.18). The analysis of acoustic density data showed a significant variability in the parameters of the ON sheaths echodensitometry in IH patients as compared to the norm. Conclusion. The echography of the ON makes it possible to determine the acoustic and biometric parameters of the ON with high accuracy, to assess its structure and relationship with the surrounding tissues. The ratio coefficient (K) of ONSD/ONS makes it possible to determine IH in the early stages of the disease, even in the absence of objective clinical criteria.

Blunt and Penetrating Severe Traumatic Brain Injury

Severe traumatic brain injury is a common problem. Current practices focus on the importance of early resuscitation, transfer to high-volume centers, and provider expertise across multiple specialties. In the emergency department, patients should receive urgent intracranial imaging and consideration for tranexamic acid. Close observation in the intensive care unit environment helps identify problems, such as seizure, intracranial pressure crisis, and injury progression. In addition to traditional neurologic examination, patients benefit from use of intracranial monitors. Monitors gather physiologic data on intracranial and cerebral perfusion pressures to help guide therapy. Brain tissue oxygenation monitoring and cerebromicrodialysis show promise in studies.

The Effects of Acute Intracranial Pressure Changes on the Episcleral Venous Pressure, Retinal Vein Diameter and Intraocular Pressure in a Pig Model

PURPOSE

Orbital veins such as the retinal veins and episcleral veins drain into the cavernous sinus, an intracranial venous structure. We studied the effects of acute intracranial pressure (ICP) elevation on episcleral venous pressure, intraocular pressure and retinal vein diameter in an established non-survival pig model.

METHODS

In six adult female domestic pigs, we increased ICP in 5 mm Hg increments using saline infusion through a lumbar drain. We measured ICP (using parenchymal pressure monitor), intraocular pressure (using pneumatonometer), episcleral venous pressure (using venomanometer), retinal vein diameter (using OCT images) and arterial blood pressure at each stable ICP increment. The average baseline ICP was 5.4 mm Hg (range 1.5-9 mm Hg) and the maximum stable ICP ranged from 18 to 40 mm Hg. Linear mixed models with random intercepts were used to evaluate the effect of acute ICP increase on outcome variables.

RESULTS

With acute ICP elevation, we found loss of retinal venous pulsation and increased episcleral venous pressure, intraocular pressure and retinal vein pressure in all animals. Specifically, acute ICP increase was significantly associated with episcleral venous pressure (β = 0.31; 95% CI 0.14-0.48, p < .001), intraocular pressure (β = 0.37, 95%CI 0.24-0.50; p < .001) and retinal vein diameter (β = 11.29, 95%CI 1.57-21.00; p = .03) after controlling for the effects of arterial blood pressure.

CONCLUSION

We believe that the ophthalmic effects of acute ICP elevation are mediated by increased intracranial venous pressure producing upstream pressure changes within the orbital and retinal veins. These results offer exciting possibilities for the development of non-invasive ophthalmic biomarkers to estimate acute ICP elevations following significant neuro-trauma.

Review: pathophysiology of intracranial hypertension and noninvasive intracranial pressure monitoring

Measurement of intracranial pressure (ICP) is crucial in the management of many neurological conditions. However, due to the invasiveness, high cost, and required expertise of available ICP monitoring techniques, many patients who could benefit from ICP monitoring do not receive it. As a result, there has been a substantial effort to explore and develop novel noninvasive ICP monitoring techniques to improve the overall clinical care of patients who may be suffering from ICP disorders. This review attempts to summarize the general pathophysiology of ICP, discuss the importance and current state of ICP monitoring, and describe the many methods that have been proposed for noninvasive ICP monitoring. These noninvasive methods can be broken down into four major categories: fluid dynamic, otic, ophthalmic, and electrophysiologic. Each category is discussed in detail along with its associated techniques and their advantages, disadvantages, and reported accuracy. A particular emphasis in this review will be dedicated to methods based on the use of transcranial Doppler ultrasound. At present, it appears that the available noninvasive methods are either not sufficiently accurate, reliable, or robust enough for widespread clinical adoption or require additional independent validation. However, several methods appear promising and through additional study and clinical validation, could eventually make their way into clinical practice.

Point-of-care ultrasound of optic nerve sheath diameter to detect intracranial pressure in neurocritically ill children - A narrative review

The rapid diagnosis of increased intracranial pressure is urgently needed for therapeutic reasons in neurocritically ill children, however this can rarely be achieved without invasive procedures. Point-of-care ultrasound of the optic nerve sheath diameter has been proposed as a non-invasive and reliable means to detect increased intracranial pressure in adults. Accordingly, clinicians may be able to use this technique to initiate early treatment and monitor the effectiveness of treatment in conjunction with other clinical examination and diagnostic modalities. Two meta-analyses and a systematic review have been published on this topic in adults. However, data on the correlation between optic nerve sheath diameter and intracranial pressure in neurocritically ill children are scarce. The aim of this review was to briefly describe what is being measured with point-of-care ultrasound of the optic nerve sheath diameter, summarize the most recent findings from adult literature, and provide an update of current work in children.

Diagnosis of elevated intracranial pressure in critically ill adults: systematic review and meta-analysis

OBJECTIVES

To summarise and compare the accuracy of physical examination, computed tomography (CT), sonography of the optic nerve sheath diameter (ONSD), and transcranial Doppler pulsatility index (TCD-PI) for the diagnosis of elevated intracranial pressure (ICP) in critically ill patients.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Six databases, including Medline, EMBASE, and PubMed, from inception to 1 September 2018.

STUDY SELECTION CRITERIA

English language studies investigating accuracy of physical examination, imaging, or non-invasive tests among critically ill patients. The reference standard was ICP of 20 mm Hg or more using invasive ICP monitoring, or intraoperative diagnosis of raised ICP.

DATA EXTRACTION

Two reviewers independently extracted data and assessed study quality using the quality assessment of diagnostic accuracy studies tool. Summary estimates were generated using a hierarchical summary receiver operating characteristic (ROC) model.

RESULTS

40 studies (n=5123) were included. Of physical examination signs, pooled sensitivity and specificity for increased ICP were 28.2% (95% confidence interval 16.0% to 44.8%) and 85.9% (74.9% to 92.5%) for pupillary dilation, respectively; 54.3% (36.6% to 71.0%) and 63.6% (46.5% to 77.8%) for posturing; and 75.8% (62.4% to 85.5%) and 39.9% (26.9% to 54.5%) for Glasgow coma scale of 8 or less. Among CT findings, sensitivity and specificity were 85.9% (58.0% to 96.4%) and 61.0% (29.1% to 85.6%) for compression of basal cisterns, respectively; 80.9% (64.3% to 90.9%) and 42.7% (24.0% to 63.7%) for any midline shift; and 20.7% (13.0% to 31.3%) and 89.2% (77.5% to 95.2%) for midline shift of at least 10 mm. The pooled area under the ROC (AUROC) curve for ONSD sonography was 0.94 (0.91 to 0.96). Patient level data from studies using TCD-PI showed poor performance for detecting raised ICP (AUROC for individual studies ranging from 0.55 to 0.72).

CONCLUSIONS

Absence of any one physical examination feature is not sufficient to rule out elevated ICP. Substantial midline shift could suggest elevated ICP, but the absence of shift cannot rule it out. ONSD sonography might have use, but further studies are needed. Suspicion of elevated ICP could necessitate treatment and transfer, regardless of individual non-invasive tests.

REGISTRATION

PROSPERO CRD42018105642.

Inpatient and Emergency Room Ophthalmology Consultations at a Tertiary Care Center

Background

An ophthalmology consultation service is of significant benefit to patients in the hospital and is an instructive component of a residency education program. Ophthalmology consultations in a hospital present unique challenges to those seen in an outpatient clinic, for which the consulting ophthalmologist should be prepared. The purpose of this study was to profile the emergency room and inpatient ophthalmology consultations seen at an academic institution.

Methods

A prospective study of 581 patients was conducted on inpatient and emergency room ophthalmology consultations at the University of Illinois at Chicago over twelve months. Characteristics such as the consulting service, type of and reason for consultation, subspecialty staffing service, diagnosis, and suitability for in-hospital evaluation were recorded.

Results

Consultations were received from either inpatient wards (59.4%) or the Emergency Department (40.6%). The most common inpatient consulting services were internal medicine (22%), followed by neurosurgery (16%) and neurology (7%). All the consultations were categorized as acute (72.3%), chronic (6.0%), or screening (21.7%). Consultations categorized as screening included papilledema (31.0%), fungemia (20.6%), syndromic evaluation (19.8%), visual field evaluation (17.5%), and miscellaneous evaluation (11.1%). We classified the ophthalmic diagnoses into 63 unique diagnoses. Amongst the ophthalmic subspecialties, neuro-ophthalmologic diagnoses were the most common (32.0%), followed by retina (20.1%) and cornea (19.4%). Neuro-ophthalmology had the highest proportion of screening consultations (36.6%), while glaucoma had the least overall number of consultations (10.1%), and the least proportion of screening consultations (3.6%). A significant proportion of nonacute consultations (19.0%) was deemed to be more suitable for outpatient evaluation.

Discussion

Consultation databases can be useful in preparing trainees for in-hospital clinical care. A wide range of ocular pathologies may present to the ophthalmology consultant, from acute trauma to screening for systemic syndromes. Some consultations may be more suitable for outpatient evaluation which may help optimize patient care.

Retinal Findings in Young Children With Increased Intracranial Pressure From Nontraumatic Causes

OBJECTIVES

Increased intracranial pressure (ICP) has been suggested in legal settings as an alternative cause of retinal hemorrhages (RHs) in young children who may have sustained abusive head trauma. We assessed the prevalence and characteristics of RHs in children with increased ICP.

METHODS

We conducted a prospective, multicenter study of children <4 years old with newly diagnosed increased ICP as determined by using direct measurement and/or clinical criteria. Infants who were premature, neonates, and suspected survivors of abusive head trauma were excluded on the basis of nonocular findings. Fundus examinations were performed; extent, number, and type of RH in each of 4 distinct retinal zones were recorded.

RESULTS

Fifty-six children (27 boys) were studied (mean age 15.4 months; range 1-43 months). All of the children had elevated ICP that required intervention. One child had papilledema. No child (0%; 95% confidence interval: 0%-6.4%) or eye (0%; 95% confidence interval: 0%-3.3%) was found to have an RH. Causes of increased ICP included hydrocephalus, intraventricular hemorrhage, congenital malformations, malfunctioning shunts, and the presence of intracranial space-occupying lesions.

CONCLUSIONS

Although acute increased ICP can present in children with a pattern of peripapillary superficial RHs in the presence of papilledema, our study supports the conclusion that RHs rarely occur in the absence of optic disc swelling and do not present beyond the peripapillary area in the entities we have studied.

Papilledema in children with hydrocephalus: incidence and associated factors

OBJECTIVE The aim of this study was to report the incidence of and the factors associated with papilledema in children with hydrocephalus. METHODS Patients younger than 15 years of age who had been diagnosed with hydrocephalus and treated by extra-ventricular drainage or ventriculoperitoneal shunt surgery between 2005 and 2015 were retrospectively reviewed. Factors including patient age and sex, etiology of hydrocephalus, duration of signs or symptoms, intracranial pressure (ICP), and presence of papilledema were evaluated. RESULTS Forty-six patients, whose mean age was 6.3 ± 4.7 years, were included in the study. The 19 patients without papilledema had a mean age of 2.7 ± 2.7 years, and the 27 patients with papilledema had a mean age of 8.8 ± 4.2 years (p < 0.001). The mean ICP was 19.9 ± 10.0 cm H₂O among those without papilledema and 33.3 ± 9.1 cm H₂O among those with papilledema (p < 0.001). The mean duration of signs or symptoms was 3.0 ± 4.6 months in the patients without papilledema and 3.4 ± 3.9 months in those with papilledema (p = 0.704). The patients with papilledema were older and presented with higher ICP than those without. The causes of hydrocephalus were tumor (59%), congenital anomaly (19%), hemorrhage (13%), and infection (9%). CONCLUSIONS Papilledema was more common in patients who were older, who had higher ICP, and whose hydrocephalus had been induced by brain tumor. However, since papilledema was absent in 41% of the children with hydrocephalus, papilledema's absence does not ensure the absence of hydrocephalus, especially in younger patients.

Raised intracranial pressure and retinal haemorrhages in childhood encephalopathies

AIM

To explore the relationship between raised intracranial pressure (RICP) and retinal haemorrhages in traumatic and non-traumatic childhood encephalopathies.

METHOD

A prospective study of 112 children (35 females and 77 males, age range 0.01mo-17y 8.3mo; mean 5y 8.6mo, median 4y 5.6mo) included 57 accidental traumatic brain injuries (ATBIs), 21 inflicted traumatic brain injuries (ITBIs), and 34 non-traumatic encephalopathy cases. Measurements included intracranial pressure (ICP), cerebral perfusion pressure, pressure-time index of ICP, and number, zone, and layer of retinal haemorrhages on retinal imaging.

RESULTS

Group I had measured elevated ICP (n=42), Group II had clinical and/or radiological signs of RICP (n=21), and Group III had normal ICP (n=49). In the combined Groups I and II, 38% had retinal haemorrhages. Multiple logistic regression confirmed that the presence of retinal haemorrhages was significantly related to the presence of RICP independent of age and aetiology; however, the occurrence and overall numbers were not significantly related to the specific ICP level. The numbers of intraretinal (nerve-fibre layer and dot blot) retinal haemorrhages were significantly greater in those with RICP. The ITBI population was significantly different from the other combined aetiological categories.

INTERPRETATION

The study results indicate a complex RICP/retinal haemorrhage relationship. There was no evidence of existing retinal haemorrhages being exacerbated or new retinal haemorrhages developing during periods of confirmed RICP.

A Practical Concussion Physical Examination Toolbox

CONTEXT

With heightened awareness of concussion, there is a need to assess and manage the concussed patient in a consistent manner. Unfortunately, concussion physical examination has not been standardized or supported by evidence. Important questions remain about the physical examination.

EVIDENCE ACQUISITION

Review of ClinicalKey, Cochrane, MEDLINE, and PubMed prior to July 2015 was performed using search terms, including concussion, mTBI, physical examination, mental status, cranial nerves, reflexes, cervical, vestibular, and oculomotor. The references of the pertinent articles were reviewed for other relevant sources.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 3.

RESULTS

The pertinent physical examination elements for concussion include evaluation of cranial nerves, manual muscle testing, and deep tendon reflexes; inspecting the head and neck for trauma or tenderness and cervical range of motion; Spurling maneuver; a static or dynamic balance assessment; screening ocular examination; and a mental status examination that includes orientation, immediate and delayed recall, concentration, mood, affect, insight, and judgment. Other examination elements to consider, based on signs, symptoms, or clinical suspicion, include testing of upper motor neurons, cervical strength and proprioception, coordination, pupillary reactivity, and visual acuity; examination of the jaw, temporomandibular joint, and thoracic spine; fundoscopic evaluation; orthostatic vital signs; assessment of dynamic visual acuity; and screening for depression, anxiety, substance abuse disorders, and preinjury psychiatric difficulties.

CONCLUSION

Various elements of the physical examination, such as screening ocular examination, cervical musculoskeletal examination, static and/or dynamic balance assessment, and mental status examination, appear to have utility for evaluating concussion; however, data on validity are lacking.

Non-invasive assessment of intracranial pressure

Monitoring of intracranial pressure (ICP) is invaluable in the management of neurosurgical and neurological critically ill patients. Invasive measurement of ventricular or parenchymal pressure is considered the gold standard for accurate measurement of ICP but is not always possible due to certain risks. Therefore, the availability of accurate methods to non-invasively estimate ICP has the potential to improve the management of these vulnerable patients. This review provides a comparative description of different methods for non-invasive ICP measurement. Current methods are based on changes associated with increased ICP, both morphological (assessed with magnetic resonance, computed tomography, ultrasound, and fundoscopy) and physiological (assessed with transcranial and ophthalmic Doppler, tympanometry, near-infrared spectroscopy, electroencephalography, visual-evoked potentials, and otoacoustic emissions assessment). At present, none of the non-invasive techniques alone seem suitable as a substitute for invasive monitoring. However, following the present analysis and considerations upon each technique, we propose a possible flowchart based on the combination of non-invasive techniques including those characterizing morphologic changes (e.g., repetitive US measurements of ONSD) and those characterizing physiological changes (e.g., continuous TCD). Such an integrated approach, which still needs to be validated in clinical practice, could aid in deciding whether to place an invasive monitor, or how to titrate therapy when invasive ICP measurement is contraindicated or unavailable.

Papilledema: epidemiology, etiology, and clinical management

Papilledema is optic disc swelling due to high intracranial pressure. Possible conditions causing high intracranial pressure and papilledema include intracerebral mass lesions, cerebral hemorrhage, head trauma, meningitis, hydrocephalus, spinal cord lesions, impairment of cerebral sinus drainage, anomalies of the cranium, and idiopathic intracranial hypertension (IIH). Irrespective of the cause, visual loss is the feared morbidity of papilledema, and the main mechanism of optic nerve damage is intraneuronal ischemia secondary to axoplasmic flow stasis. Treatment is directed at correcting the underlying cause. In cases where there is no other identifiable cause for intracranial hypertension (ie, IIH) the available options include both medical and surgical modalities. Weight loss and diuretics remain the mainstays for treatment of IIH, and surgery is typically reserved for patients who fail, are intolerant to, or non-compliant with maximum medical therapy.

Yield and clinical efficacy of funduscopic examinations performed in the pediatric emergency room

Consultations by ophthalmologists to rule out papilledema are frequently requested by emergency room (ER) physicians. The clinical setting and optimal timing for examination are not well established, and the impact on patient management is unclear. We evaluated the yield of emergency funduscopic examinations, aiming at establishing the optimal timing and efficacy of the consultation. The medical records of all children aged 0-18 years referred for funduscopic examinations from the ER between June 2010 and May 2011 were reviewed. Of 19,772 ER visits, 1,920 (9.7 %) were seen by an ophthalmologist and 479 (2.4 %) to rule out papilledema. Headache (44.5 %) and head trauma (18.4 %) were the most common indications. Sixty percent of the 479 patients had been symptomatic for <24 h, all having normal eye exams. Only 6/479, with diverse etiologies, depicted papilledema. Among these six children, visual complaints associating with headache were statistically significant to suggest the presence of papilledema (p = 0.014). Seventy-one of the 479 children underwent neuroimaging studies despite normal funduscopic examinations. A single tumor case (medulloblastoma), symptomatic for weeks, had normal funduscopy.

CONCLUSION

The vast majority of ER consultations to rule out papilledema show normal findings, particularly among children with signs and symptoms lasting for <24 h. The yield of funduscopy may be higher if visual disturbances are reported. If neuroimaging studies are considered, emergency room ophthalmological consultation is probably not warranted, except for young infants with neurological signs and symptoms in whom retinal hemorrhages suggestive of physical abuse must be ruled out.

Surgical treatment of elevated intracranial pressure: decompressive craniectomy and intracranial pressure monitoring

Surgical techniques that address elevated intracranial pressure include (1) intraventricular catheter insertion and cerebrospinal fluid drainage, (2) removal of an intracranial space-occupying lesion, and (3) decompressive craniectomy. This review discusses the role of surgery in the management of elevated intracranial pressure, with special focus on intraventricular catheter placement and decompressive craniectomy. The techniques and potential complications of each procedure are described, and the existing evidence regarding the impact of these procedures on patient outcome is reviewed. Surgical management of mass lesions and ischemic or hemorrhagic stroke occurring in the posterior fossa is not discussed herein.

Intracranial Pressure Monitoring: Invasive versus Non-Invasive Methods-A Review

Monitoring of intracranial pressure (ICP) has been used for decades in the fields of neurosurgery and neurology. There are multiple techniques: invasive as well as noninvasive. This paper aims to provide an overview of the advantages and disadvantages of the most common and well-known methods as well as assess whether noninvasive techniques (transcranial Doppler, tympanic membrane displacement, optic nerve sheath diameter, CT scan/MRI and fundoscopy) can be used as reliable alternatives to the invasive techniques (ventriculostomy and microtransducers). Ventriculostomy is considered the gold standard in terms of accurate measurement of pressure, although microtransducers generally are just as accurate. Both invasive techniques are associated with a minor risk of complications such as hemorrhage and infection. Furthermore, zero drift is a problem with selected microtransducers. The non-invasive techniques are without the invasive methods' risk of complication, but fail to measure ICP accurately enough to be used as routine alternatives to invasive measurement. We conclude that invasive measurement is currently the only option for accurate measurement of ICP.

Papilledema: the vexing issues

Papilledema has long been recognized as a valuable sign of increased intracranial pressure (ICP). But because papilledema is based on interruption of the energy-dependent process of axoplasmic flow, it appears late after a rise in ICP. Papilledema is usually present in chronically high ICP but sometimes asymmetrically in the 2 eyes and rarely in 1 eye only. Distinguishing it from other optic neuropathies that produce elevated optic discs is challenging, especially in the chronic phase, when visual function may be impaired. Papilledema is often an unrecognized cause of optic disc edema in inflammatory and compressive meningeal disorders that interfere with cerebrospinal fluid (CSF) passage through the arachnoid granulations. Its detection is particularly critical in patients with noncompliant ventricles or extraventricular blockage of cerebrospinal flow because imaging may fail to disclose conventional signs of high ICP. Therefore, patients with indwelling CSF shunts, tuberous sclerosis, chronic granulomatous meningitis, or meningiomatosis should be periodically examined for papilledema so that timely ICP-lowering measures can be instituted to preserve vision.

Papilloedema as a non-invasive marker for raised intra-cranial pressure following decompressive craniectomy for severe head injury

BACKGROUND

Decompressive craniectomy is an extremely useful surgical procedure for decreasing intra cranial pressure following severe head injury. However, there is anecdotal evidence to suggest that some of these patients may continue to have raised intracranial pressure in spite of an apparently adequate Decompressive craniectomy.

AIMS AND OBJECTIVES

(1) To assess whether fundoscopic findings accurately reflect changes in ICP in severe head injury. (2) To study the temporal course of fundoscopic findings in patients with severe head injury following decompressive craniectomy and to correlate fundoscopy findings with ventriculomegaly (if any) on serial Computerized tomography in these patients.

MATERIALS AND METHODS

In this prospective study from November 2008 to March 2009, 32 patients severe head injury (GCS ≤8) admitted at the Department of Neurosurgery, JPN Apex Trauma Center, All India Institute of Medical Sciences, New Delhi who underwent a wide (>80 cubic cm) decompressive craniectomy with a lax duraplasty for severe head injury were subjected to fundoscopic examinations on the 1st, 3rd, 5th, 7th and 14th post operative days along with serial C.T. imaging studies to check for ventriculomegaly. Ventriculomegaly was defined as dilatation of temporal horn >2mm along with ballooning of III ventricle and/or presence of peri-ventricular lucency. Seven severe head injury patients who were conservatively managed with continuous ICP monitoring were also subjected to serial fundoscopic examinations.

RESULTS

32 patients who underwent decompressive craniectomy for severe head injury were evaluated during the study period. The age group of the patients ranged from 12 to 75 years. The mean GCS on admission was 6/15 (range 3/15-8/15). There were 12 cases of acute traumatic subdural hemorrhage and 20 cases of intracerebral contusion (frontal/temporal regions). Fundoscopic examination showed papilloedema in 81% (n=26) on the first post operative day, 66% (n=21) on the third post operative day, 28% (n=9) on the fifth post operative day, 13% (n=4) on the seventh post operative day and 6% (n=2) at 14 days post-operatively. In 4 (13%) patients papilloedema reappeared on fundoscopy after one week of surgery. Of these, only 1 (3%) patient had ventriculomegaly on CT scans. Lumbar drain was placed in 2 of these patients and resulted in prompt resolution of papilloedema. In the 7 patients who were managed conservatively and had ICP monitoring, serial fundoscopic examination were found to accurately reflect the ICP readings in all cases. No papilloedema was seen in any of the patients when ICP was below 20mm of Hg and papilloedema appeared in all cases where the ICP was ≥20mm of Hg.

CONCLUSION

Fundoscopy is an extremely useful non-invasive tool to assess changes in intracranial pressure in severe head injury. Reappearance of papilloedema in the postoperative period even in the absence of ventriculomegaly indicates raised ICP and should be treated aggressively.

Sensitivity of papilledema as a sign of shunt failure in children

PURPOSE

Papilledema is considered one of the cardinal ophthalmologic signs of shunt failure. However, the prevalence of papilledema in children with shunt malfunction has not been systematically investigated. The purpose of this study is to determine the sensitivity of papilledema as a sign of shunt failure in children.

METHODS

A prospective evaluation was undertaken of all children (n = 29; <19 years of age) with surgically confirmed shunt malfunction who were treated at Arkansas Children's Hospital between July 2007 and April 2008. Each child had a dilated fundus examination and/or RetCam photograph while under anesthesia immediately before shunt repair. The optic disk was evaluated for the presence of papilledema and pallor. Intracranial pressure was measured during surgical shunt repair at the discretion of the neurosurgeon.

RESULTS

Twenty-nine patients had surgically confirmed shunt failure. Patient's age ranged from 36 days to 18 years, 8 months. Four patients (14%) had papilledema, and 1 patient had severe optic disk pallor. The remaining 24 patients had flat optic disks. Five patients had flat optic disks despite an intracranial pressure >/=300 mm H(2)O.

CONCLUSIONS

Papilledema is not a sensitive sign of shunt failure. Even children with severe elevations in intracranial pressure from shunt malfunction may have flat optic disks. Therefore, physicians that evaluate children with shunts should be aware that a normal optic disk does not preclude shunt malfunction.

A comparison of idiopathic intracranial hypertension with and without papilledema

OBJECTIVE

To compare clinical features, visual characteristics, and treatment of idiopathic intracranial hypertension patients with and without papilledema.

BACKGROUND

Idiopathic intracranial hypertension does not often occur without papilledema. This study estimates the prevalence and compares the clinical characteristics of idiopathic intracranial hypertension patients with and without papilledema.

METHODS

We performed a cross-sectional analysis of all idiopathic intracranial hypertension patients diagnosed at the University of Utah Neuro-Ophthalmology Unit between 1990 and 2003. Patient records were reviewed for presence of papilledema and other signs, symptoms, and treatment characteristics. Each patient without papilledema was matched to the patient with papilledema who was closest to his/her age and sex. McNemar's and Wilcoxon-signed rank sum tests were used to compare characteristics between matched pairs.

RESULTS

Among all patients (n = 353), the prevalence of those without papilledema was 5.7% (n = 20). Patients without papilledema reported photopsias (20%), and were found to have spontaneous venous pulsations (75%) and non-physiologic visual field constriction (20%) more often than did those with papilledema. Mean opening pressure, although above normal, was lower in patients without papilledema (mean = 309 mm cerebrospinal fluid) compared with those with papilledema (mean = 373 mm cerebrospinal fluid, P = .031). Idiopathic intracranial hypertension patients without papilledema had more frequent diagnostic lumbar punctures than did patients with papilledema. Visual acuities and treatment were similar between groups.

CONCLUSIONS

The clinical presentation of idiopathic intracranial hypertension without papilledema is only somewhat different from that of idiopathic intracranial hypertension with papilledema. The lower opening pressure in patients without papilledema may explain variations in symptoms and signs between the 2 groups. When there are visual field changes in idiopathic intracranial hypertension without papilledema, non-physiologic visual loss should be considered.

Management of intracranial hypertension

Effective management of intracranial hypertension involves meticulous avoidance of factors that precipitate or aggravate increased intracranial pressure. When intracranial pressure becomes elevated, it is important to rule out new mass lesions that should be surgically evacuated. Medical management of increased intracranial pressure should include sedation, drainage of cerebrospinal fluid, and osmotherapy with either mannitol or hypertonic saline. For intracranial hypertension refractory to initial medical management, barbiturate coma, hypothermia, or decompressive craniectomy should be considered. Steroids are not indicated and may be harmful in the treatment of intracranial hypertension resulting from traumatic brain injury.

Management of intracranial hypertension

Effective treatment of intracranial hypertension involves meticulous avoidance of factors that precipitate or aggravate increased intracranial pressure. When intracranial pressure becomes elevated, it is important to rule out new mass lesions that should be surgically evacuated. medical management of increased intracranial pressure should include sedation and paralysis, drainage of cerebrospinal fluid, and osmotherapy with either mannitol or hypertonic saline. For intracranial hypertension refractory to initial medical management, barbiturate coma, hypothermia, or decompressive craniectomy should be considered. Steroids are not indicated and may be harmful in the treatment of intracranial hypertension resulting from traumatic brain injury.

Clinical findings precede objective diagnostic testing in the identification of increased ICP in syndromic craniosynostosis

Crouzon syndrome is an autosomal dominant disorder resulting in facial dysmorphism and craniosynostosis involving multiple cranial sutures. A common but often unrecognized early complication associated with craniosynostosis is a finding of increased intracranial pressure (ICP). This increase in ICP can lead to optic atrophy, neuronal damage, and mental deficits. The case of a 21-month-old girl with Crouzon syndrome is described. Although the child was clinically asymptomatic, a routine ophthalmic exam revealed papilledema and subsequently increased intracranial pressure and craniosynostosis were found. Cranial expansion and bicanthal advancement were performed to relieve the increased pressure. In cases such as these, long-term follow-up is essential because of the progressive nature of the disorder as well as the possibility of a recurrence of elevated intracranial pressure and a need for secondary decompressive surgery.

Severe papilledema identified 3 weeks after head injury

A 62-year-old woman presented with rapidly developed visual disturbance without associated headache or nausea 3 weeks after head injury. Ophthalmologic examination revealed bilateral severe papilledema with retinal hemorrhage, and intracranial pressure (ICP) was 17.5 cmH2O estimated by lumbar puncture. Computed tomography and magnetic resonance (MR) imaging showed no evidence of increased ICP, except dilation of the subarachnoid space around the optic nerves with distortion of the nerves. Her visual acuity remarkably improved after steroid and glycerol treatment, and optic fundus examination revealed bilateral clear optic papillae without atrophic changes. Follow-up MR imaging demonstrated that the bilateral optic nerves had regained the normal appearance. These results indicate that the bilateral papilledema was caused by increased subarachnoid pressure around the bilateral optic nerves. We conclude that papilledema can occur with a mildly increased ICP and trapped subarachnoid cerebrospinal fluid around the optic nerves, and papilledema may progress after the ICP is normalized. Papilledema is a warning sign for increased ICP, associated with future visual loss from retinal hemorrhage. Therefore, repeated funduscopic investigation is necessary for the early diagnosis and treatment of papilledema.

The diagnostic value of optic disc evaluation in acute elevated intracranial pressure

PURPOSE

Ophthalmologists often are asked to evaluate the optic disc for evidence of acute increased intracranial pressure (ICP). The authors studied the incidence of papilledema in a population of patients with a documented acute increase in ICP.

METHODS

Included in this study were 37 patients with acute elevated ICP due to a spontaneous hemorrhage or craniocerebral trauma. In all patients, the ICP was monitored continuously. Fundus examination was performed twice daily on at least 7 consecutive days.

RESULTS

According to the level and duration of the ICP, the patients were divided into three groups. Group 1 included 13 patients who had a slightly elevated ICP (range, 20-30 mmHg) on at least 3 consecutive days. In this group, 3 of 13 patients demonstrated venous congestion on the fifth or sixth day. No swelling of the optic disc was seen in this group. Group 2 included seven patients with an elevated ICP, with values ranging from 30 to 70 mmHg lasting for at least 3 consecutive days. In this group, one patient had a blurred disc margin on the sixth day. Group 3 included 17 patients with shortlasting ICP values, ranging from 30 to 60 mmHg for less than 72 hour. Neither papilledema nor abnormalities of fundus vessels were seen in this group.

CONCLUSION

Papilledema in acute elevation of ICP is an uncommon event. Its absence does not preclude the presence of ICP elevation.

The effectiveness of papilledema as an indicator of raised intracranial pressure in children with craniosynostosis

Craniosynostosis management partially depends on the detection and treatment of elevated intracranial pressure (ICP). Examination for papilledema is considered to be the most reliable screening method for identifying raised ICP, but its effectiveness has not been defined. One hundred and twenty-two children with craniosynostosis who underwent funduscopic examinations and then Camino ICP monitoring were studied. All eye examinations were performed by an ophthalmologist after pharmacological pupillary dilation. Fifteen patients (12%) had papilledema. Subsequent ICP monitoring showed that the median ICP was 12.7 mm Hg, with 41 patients (34%) having elevated ICPs (> 15 mm Hg). Those with papilledema had higher ICPs (17.5 +/- 3.2 versus 12.7 +/- 5.5 mm Hg), were older (5.9 +/- 4.7 versus 1.9 +/- 2.6 years), and were more likely to have craniofacial syndromes (73 versus 41%) than those without papilledema (P < 0.05). Patients with both elevated ICPs and papilledema were older (5.9 +/- 4.7 versus 1.6 +/- 1.4 years) and more likely to have multiple-suture synostosis (92 versus 61%) than those with elevated ICPs and no papilledema (P < 0.05). The presence of papilledema was a specific (98%) indicator of raised ICP, but its sensitivity was age-dependent. It was 100% sensitive in children older than 8 years, but it indicated elevated ICP in only 22% of younger patients. These results suggest that ICP monitoring to document elevated ICP is unnecessary in children older than 8 years who have detailed ophthalmological examinations. In the younger child, the presence of papilledema reliably indicates elevated ICP but its absence does not rule out elevated ICP; formal ICP measurement has a greater role in detecting elevated ICP in these patients.

Late-onset papilledema following spinal injury. Case report

Papilledema, is a known complication of various spinal pathologies. It has, however, been only infrequently reported following spinal injury, and may be overlooked in these cases. Presented herein is a 27 year old male who suffered thoracic and lumbar spinal injuries. Papilledema following mild increase in intracranial pressure (IICP) developed 3 weeks following trauma, and subsided within 8 weeks. The importance of routine repeat ophthalmoscopic examinations following spinal injury to detect changes characteristic of IICP is emphasized.

Brain death and intraocular pressure

The authors report on the behavior of the intraocular pressure of 20 patients who had sustained severe head injury. The 8 patients who retained normal intraocular pressure all survived. The 12 patients who developed intraocular hypotony all suffered brain death. Although optic disc edema was not noted in any brain-dead patients, we did find signs of fundus ischemia in most.