Discrepancies between brain CT imaging and severely raised intracranial pressure proven by ventriculostomy in adults with pneumococcal meningitis

Comparison of international guidelines for CT prior to lumbar puncture in patients with suspected meningitis

PURPOSE

To compare the performance of multiple international guidelines in selecting patients for head CT prior to lumbar puncture (LP) in suspected meningitis, focusing on identification of potential contraindications to immediate LP.

METHODS

Retrospective study of 196 patients with suspected meningitis presenting to an emergency department between March 2013 and March 2023 and undergoing head CT prior to LP. UK Joint Specialist Society Guidelines (UK), European Society of Clinical Microbiology and Infectious Diseases (ESCMID) and Infectious Diseases Society of America (IDSA) guidelines were evaluated by cross-referencing imaging criteria with clinical characteristics present at time of presentation. Sensitivity of each guideline for recommending neuroimaging in cases with brain shift on CT was evaluated, along with the number of normal studies and incidental or spurious findings.

RESULTS

2/196 (1%) patients had abnormal CTs with evidence of brain shift, while 14/196 (7%) had other abnormalities on CT without brain shift. UK, ESCMID and IDSA guidelines recommended imaging in 10%, 14% and 33% of cases respectively. All three guidelines recommended imaging pre-LP in 2/2 (100%) cases with brain shift. IDSA guidelines recommended more CT studies with normal findings (59 vs 16 and 24 for UK and ESCMID guidelines respectively) and CT abnormalities without brain shift (4 vs 1 and 2 respectively) than the other guidelines.

CONCLUSION

UK, ESCMID and IDSA guidelines are all effective at identifying the small cohort of patients who benefit from a head CT prior to LP. Following the more selective UK/ESCMID guidelines limits the number of normal studies and incidental or spurious CT findings.

Immunocompromised teenager with meningitis caused by Ureaplasma parvum

Infection in the immunocompromised patient is often challenging on multiple levels. It can be difficult to distinguish between manifestations of the underlying disease, infection or malignancy. Symptoms may be vague or even absent, deviations in the common inflammatory parameters discrete, imaging findings scarce and the causative microbe may be a true pathogen as well as opportunistic. Here, we report an immunosuppressed female in her late teens with a purulent meningitis due to Ureaplasma parvum-a very rare cause of infection in the central nervous system of adults. We wish to highlight the relevance of intracellular pathogens and the need to actively search for these microbes, especially when response to broad-spectrum antibiotic treatment is absent. Furthermore, we emphasise the need for adequate molecular microbial diagnostics in search of microbes that are difficult to identify by culture and where serology and antigen tests may be absent or unreliable due to immune suppression.

Detection and Management of Elevated Intracranial Pressure in the Treatment of Acute Community-Acquired Bacterial Meningitis: A Systematic Review

Acute bacterial meningitis (ABM) is associated with severe morbidity and mortality. The most prevalent pathogens in community-acquired ABM are Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae. Other pathogens may affect specific patient groups, such as newborns, older patients, or immunocompromised patients. It is well established that ABM is associated with elevated intracranial pressure (ICP). However, the role of ICP monitoring and management in the treatment of ABM has been poorly described.An electronic search was performed in four electronic databases: PubMed, Web of Science, Embase, and the Cochrane Library. The search strategy chosen for this review used the following terms: Intracranial Pressure AND (management OR monitoring) AND bacterial meningitis. The search yielded a total of 403 studies, of which 18 were selected for inclusion. Eighteen studies were finally included in this review. Only one study was a randomized controlled trial. All studies employed invasive ICP monitoring techniques, whereas some also relied on assessment of ICP-based on clinical and/or radiological observations. The most commonly used invasive tools were external ventricular drains, which were used both to monitor and treat elevated ICP. Results from the included studies revealed a clear association between elevated ICP and mortality, and possibly improved outcomes when invasive ICP monitoring and management were used. Finally, the review highlights the absence of clear standardized protocols for the monitoring and management of ICP in patients with ABM. This review provides an insight into the role of invasive ICP monitoring and ICP-based management in the treatment of ABM. Despite weak evidence certainty, the present literature points toward enhanced patient outcomes in ABM with the use of treatment strategies aiming to normalize ICP using continuous invasive monitoring and cerebrospinal fluid diversion techniques. Continued research is needed to define when and how to employ these strategies to best improve outcomes in ABM.

Noninvasive intracranial pressure monitoring in central nervous system infections

Intracranial pressure (ICP) monitoring constitutes an important part of the management of traumatic brain injury. However, its application in other brain pathologies such as neuroinfections like acute bacterial meningitis is unclear. Despite focus on aggressive, prompt treatment, morbidity and mortality from acute bacterial meningitis remain high. Increased ICP is well-known to occur in severe neuroinfections. The increased ICP compromise cerebral perfusion pressure and may ultimately lead to brain stem herniation. Therefore, controlling the ICP could also be important in acute bacterial meningitis. However, risk factors for complications due to invasive monitoring among these patients may be significantly increased due to higher age and levels of comorbidity compared to the traumatic brain injury patient from which the ICP treatment algorithms are developed. This narrative review evaluates the different modalities of ICP monitoring with the aim to elucidate current status of non-invasive alternatives to invasive monitoring as a decision tool and eventually monitoring. Non-invasive screening using ultrasound of the optical nerve sheath, transcranial doppler, magnetic resonance imaging or preferably a combination of these modalities, provides measurements that can be used as a decision guidance for invasive ICP measurement. The available data do not support the replacement of invasive techniques for continuous ICP measurement in patients with increased ICP. Non-invasive modalities should be taken into consideration in patients with neuroinfections at low risk of increased ICP.

Intracranial pressure dynamics and cerebral vasomotor reactivity in community-acquired bacterial meningitis during neurointensive care

OBJECTIVE

Community-acquired bacterial meningitis (CABM) is a severe condition associated with high mortality. In this study the first aim was to evaluate the incidence of intracranial pressure (ICP) insults and disturbances in cerebral vasomotor reactivity and the second aim was to evaluate the management and clinical outcome of CABM patients treated in the neurointensive care unit (NICU).

METHODS

CABM patients who were treated in the NICU of Uppsala University Hospital, Sweden, during 2008-2020 were included in the study. Data on demographics, admission variables, treatment, ICP dynamics, vasomotor reactivity, and short-term clinical outcome were evaluated in these patients.

RESULTS

Of 97 CABM patients, 81 (84%) received ICP monitoring, of whom 22% had ICP > 20 mm Hg during 5% or more of the monitoring time on day 1, which decreased to 9% on day 3. For those patients with ICP monitoring, 46% required CSF drainage, but last-tier ICP treatment, including thiopental (4%) and decompressive craniectomy (1%), was rare. Cerebral vasomotor reactivity was disturbed, with a mean pressure reactivity index (PRx) above 0.2 in 45% of the patients on day 1, and remained high for the first 3 days. In total, 81 (84%) patients had a favorable outcome (Glasgow Coma Scale motor score [GCS M] 6) at discharge, 9 (9%) patients had an unfavorable outcome (GCS M < 6) at discharge, and 7 (7%) patients died in the NICU. Those with favorable outcome had significantly better cerebral vasomotor reactivity (lower PRx) than the two other outcome groups (p < 0.01).

CONCLUSIONS

Intracranial hypertension was frequent following severe CABM and CSF drainage was often sufficient to control ICP. Cerebral vasomotor reactivity was commonly disturbed and associated with poor outcome. Clinical outcome was slightly better than in earlier studies.

Real-Time Evaluation of Optic Nerve Sheath Diameter (ONSD) in Awake, Spontaneously Breathing Patients

(1) Background: Reliable ultrasonographic measurements of optic nerve sheath diameter (ONSD) to detect increased intracerebral pressure (ICP) has not been established in awake patients with continuous invasive ICP monitoring. Therefore, in this study, we included fully awake patients with and without raised ICP and correlated ONSD with continuously measured ICP values. (2) Methods: In a prospective study, intracranial pressure (ICP) was continuously measured in 25 patients with an intraparenchymatic P-tel probe. Ultrasonic measurements were carried out three times for each optic nerve in vertical and horizontal directions. ONSD measurements and ICP were correlated. Patients with ICP of 2.0–10.0 mmHg were compared with patients suffering from an ICP of 10.1–24.2 mmHg. (3) Results: In all patients, the ONSD vertical and horizontal measurement for both eyes correlated well with the ICP (Pearson R = 0.68–0.80). Both measurements yielded similar results (Bland-Altman: vertical bias: −0.09 mm, accuracy: ±0.66 mm; horizontal bias: −0.06 mm, accuracy: ±0.48 mm). For patients with an ICP of 2.0–10.0 mmHg compared to an ICP of 10.1–24.2, ROC (receiver operating characteristic) analyses showed that ONSD measurement accurately predicts elevated ICP (optimal cut-off value 5.05 mm, AUC of 0.91, sensitivity 92% and specificity 90%, p < 0.001). (4) Conclusions: Ultrasonographic measurement of ONSD in awake, spontaneously breathing patients provides a valuable method to evaluate patients with suspected increased ICP. Additionally, it provides a potential tool for rapid assessment of ICP at the bedside and to identify patients at risk for a poor neurological outcome.

The role of ICP monitoring in meningitis

Intracranial pressure (ICP) monitoring has been widely accepted in the management of traumatic brain injury. However, its use in other pathologies that affect ICP has not been advocated as strongly, especially in CNS infections. Despite the most aggressive and novel antimicrobial therapies for meningitis, the mortality rate associated with this disease is far from satisfactory. Although intracranial hypertension and subsequent death have long been known to complicate meningitis, no specific guidelines targeting ICP monitoring are available. A review of the literature was performed to understand the pathophysiology of elevated ICP in meningitis, diagnostic challenges, and clinical outcomes in the use of ICP monitoring.

Use of intracranial pressure monitoring in bacterial meningitis: a 10-year follow up on outcome and intracranial pressure versus head CT scans

BACKGROUND

The aim of this study was to evaluate the clinical outcome of patients with severe bacterial meningitis where intracranial pressure (ICP) monitoring has been performed.

METHODS

A retrospective observational study including patients admitted 1st^. January 2005 to 31st^. December 2014. Thirty nine patients age 18-89 years were included. All the patients received intensive care with mechanical ventilation, ICP monitoring, sedation, antibiotics and corticosteroids according to current guidelines. Clinical outcome was defined as death during hospitalization or survival at hospital discharge.

RESULTS

The most common pathogen was Streptococcus pneumoniae (26; 67%). Thirteen patients died (33%) and neurologic impairment was noted in twenty two (84.6%) surviving patients. In S. pneumoniae cases patients with adverse outcome were significantly older (p = 0.0024) and immunosuppressed (p = 0.034). Lower mean-cerebral perfusion pressure (CPP) was found to correlate with adverse outcome (p = 0.005). Cerebrospinal fluid (CSF) was drained in fourteen patients. Increased ICP (>20 mmHg) was observed in twenty four patients. No significant correlation was found between measured ICP and head CT scans with signs of elevated ICP.

CONCLUSIONS

Patients with severe meningitis should be admitted to intensive care units and evaluated for ICP monitoring regardless of head CT findings.

Transocular Doppler and optic nerve sheath diameter monitoring to detect intracranial hypertension

Background:

Increases in intracranial pressure (ICP) require a rapid recognition to allow for adequate treatments. The aim of this study was to determine whether transocular Doppler and optic nerve sheath diameter (ONSD) monitoring could reliably identify increases in ICP.

Materials and Methods:

This is a cross-sectional case-control study, which was carried out on 2013. Subjects were chosen from patients who admitted to the neurology and neurosurgery departments and the intensive care unit of Alzahra Hospital (Isfahan, Iran). To measure the ICP, the authors used ultrasound to measure the diameter of the optic nerve sheath and transocular Doppler (TOD) to measure blood flew velocity in ophthalmic artery (OA) and ophthalmic vein (OV) in both groups.

Results:

The mean of ONSD was 4.8 mm (SD 0.77) in patients with raised ICP and 3.2 mm (SD 0.3) in healthy volunteers which was significant (P < 0.001). The mean (SD) of TOD parameters were also significantly more in OA and OV of patients with raised ICP.

Conclusion:

Ultrasound methods has been proposed as an alternative safe technique for invasive ICP measuring methods.

Infektionen

In diesem Kapitel werden zunächst die für die Neurointensivmedizin wesentlichen bakteriellen Infektionen (Meningitis, spinale und Hirnabszesse, Spondylodiszitis, septisch-embolische Herdenzephalitis) abgehandelt, die trotz gezielt eingesetzter Antibiotika und neurochirurgischer Therapieoptionen noch mit einer erheblichen Morbidität und Mortalität behaftet sind. Besonderheiten wie neurovaskuläre Komplikationen, die Tuberkulose des Nervensystems, Neuroborreliose, Neurosyphilis und opportunistische Infektionen bei Immunsuppressionszuständen finden hierbei besondere Berücksichtigung. Der zweite Teil dieses Kapitels behandelt akute und chronische Virusinfektionen des ZNS sowie in einem gesonderten Abschnitt die HIVInfektion und HIV-assoziierte Krankheitsbilder sowie Parasitosen und Pilzinfektionen, die in Industrieländern seit Einführung der HAART bei HIV zwar eher seltener, aber mit zunehmender Globalisierung auch in unseren Breiten immer noch anzutreffen sind.

Optic nerve sheath diameter as a marker for evaluation and prognostication of intracranial pressure in Indian patients: An observational study

BACKGROUND AND AIMS

The aim was to evaluate efficacy of optic nerve sheath diameter (ONSD) by ultrasound as a noninvasive method for detecting raised intracranial pressure (ICP) in intensive care unit, to compare with computed tomography/magnetic resonance imaging (MRI) findings of raised ICP and to prognosticate ONSD value with treatment.

MATERIALS AND METHODS

We conducted a prospective, observational study on 101 adults by including 41 healthy individuals in group A as control and 60 patients in group B admitted with fever, headache, vomiting, and altered sensorium. We examined them in supine position using 10 MHz linear array probe on closed eyelid. ONSD was measured 3 mm behind the globe in each eye. A mean binocular ONSD > 4.6 mm in female and 4.8 mm in male was considered abnormal. Midline shift, edema, effacement or ONSD > 5.0 mm on T2 MRI suggestive of elevated ICP was used to evaluate ONSD accuracy.

RESULTS

Group A mean ONSD was 4.6 mm in females and 4.8 mm in males. Group B mean ONSD for 17 females was 5.103 ± 0.6221 mm (P = 0.002) and for 43 males 5.081 ± 0.5799 mm (P = 0.032). Radiological sign of raised ICP was confirmed in 35 patients (females = 11 and males = 24) with high ONSD value. Sensitivity of detecting raised ICP by ONSD was 84.6% in females and 75% in males while specificity was 100% in both genders. Out of 25 patients without radiological signs of raised ICP 10 patients showed high ONSD (females = 4.735 mm and males = 4.907 mm). ONSD was well prognosticated with treatment modalities.

CONCLUSION

Bedside ocular ultrasonography for measuring ONSD can be used an early test for diagnosing raised ICP as it is a noninvasive, cost effective bedside test, which can be repeated for re-evaluation.

Neuro-intensive treatment targeting intracranial hypertension improves outcome in severe bacterial meningitis: an intervention-control study

OBJECTIVE

To evaluate the efficacy of early intracranial pressure (ICP)-targeted treatment, compared to standard intensive care, in adults with community acquired acute bacterial meningitis (ABM) and severely impaired consciousness.

DESIGN

A prospectively designed intervention-control comparison study of adult cases from September 2004 to January 2012.

PATIENTS

Included patients were confirmed ABM-cases, aged 16-75 years, with severely impaired mental status on admission. Fifty-two patients, given ICP-targeted treatment at the neuro-intensive care unit, and 53 control cases, treated with conventional intensive care, were included. All the patients received intensive care with mechanical ventilation, sedation, antibiotics and corticosteroids according to current guidelines. Additional ICP-treatment in the intervention group included cerebrospinal fluid drainage using external ventricular catheters (n = 48), osmotherapy (n = 21), hyperventilation (n = 13), external cooling (n = 9), gram-doses of methylprednisolone (n = 3) and deep barbiturate sedation (n = 2) aiming at ICP <20 mmHg and a cerebral perfusion pressure of >50 mmHg.

MEASUREMENTS

The primary endpoint was mortality at two months and secondary endpoint was Glasgow outcome score and hearing ability at follow-up at 2-6 months.

OUTCOMES

The mortality was significantly lower in the intervention group compared to controls, 5/52 (10%) versus 16/53 (30%; relative risk reduction 68%; p<0.05). Furthermore, only 17 patients (32%) in the control group fully recovered compared to 28 (54%) in the intervention group (relative risk reduction 40%; p<0.05).

CONCLUSIONS

Early neuro-intensive care using ICP-targeted therapy, mainly cerebrospinal fluid drainage, reduces mortality and improves the overall outcome in adult patients with ABM and severely impaired mental status on admission.

Individual patient data systematic review and meta-analysis of optic nerve sheath diameter ultrasonography for detecting raised intracranial pressure: protocol of the ONSD research group

BACKGROUND

The purpose of the optic nerve sheath diameter (ONSD) research group project is to establish an individual patient-level database from high quality studies of ONSD ultrasonography for the detection of raised intracranial pressure (ICP), and to perform a systematic review and an individual patient data meta-analysis (IPDMA), which will provide a cutoff value to help physicians making decisions and encourage further research. Previous meta-analyses were able to assess the diagnostic accuracy of ONSD ultrasonography in detecting raised ICP but failed to determine a precise cutoff value. Thus, the ONSD research group was founded to synthesize data from several recent studies on the subject and to provide evidence on the diagnostic accuracy of ONSD ultrasonography in detecting raised ICP.

METHODS

This IPDMA will be conducted in different phases. First, we will systematically search for eligible studies. To be eligible, studies must have compared ONSD ultrasonography to invasive intracranial devices, the current reference standard for diagnosing raised ICP. Subsequently, we will assess the quality of studies included based on the QUADAS-2 tool, and then collect and validate individual patient data. The objectives of the primary analyses will be to assess the diagnostic accuracy of ONSD ultrasonography and to determine a precise cutoff value for detecting raised ICP. Secondly, we will construct a logistic regression model to assess whether patient and study characteristics influence diagnostic accuracy.

DISCUSSION

We believe that this IPD MA will provide the most reliable basis for the assessment of diagnostic accuracy of ONSD ultrasonography for detecting raised ICP and to provide a cutoff value. We also hope that the creation of the ONSD research group will encourage further study.

TRIAL REGISTRATION

PROSPERO registration number: CRD42012003072.

[Interest of optic nerve sheath diameter ultrasonography in dectecting non-invasively raised intracranial pressure]

Intracranial hypertension is an emergency suspected from clinical symptoms, imaging data and ophthalomologic signs. Intracranial hypertension is confirmed by invasive intracranial monitoring, which is the gold standard technique to measure intracranial pressure (ICP). Because of complications, hemorrhage or infection, non-invasive methods have been developed such as neuroimaging, transcranial Doppler sonography and optic nerve sheath diameter (ONSD) ultrasonography. We have reviewed ONSD technique that detects intracranial hypertension related volume variations of subarachnoid space along the retro bulbar segment of the optic nerve. Technique, indications and prospects are discussed.

Infektionen

Trotz Weiterentwicklung moderner Antibiotika in den letzten Jahren sind die Letalitätszahlen der bakteriellen (eitrigen) Meningitis weiterhin hoch; Überlebende haben häufig neurologische Residuen. Die ungünstigen klinischen Verläufe der bakteriellen Meningitis sind meist Folge intrakranieller Komplikationen, wie z. B. eines generalisierten Hirnödems, einer zerebrovaskulären arteriellen oder venösen Beteiligung oder eines Hydrozephalus.

Intracranial pressure monitoring in childhood meningitis with coma: a national survey of neurosurgeons in the United States

OBJECTIVES

To describe the beliefs and attitudes of U.S. neurosurgeons regarding the use of intracranial pressure monitors among comatose children with meningitis.

DESIGN AND SETTING

A questionnaire was administered by mail between March and July 2009, to a random sample of 500 adult neurosurgeons and to all 228 pediatric neurosurgeons in the Congress of Neurologic Surgeons.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The response rate was 60%. Abnormal computed tomography scans, either with brain swelling or hydrocephalus, and older child age were likely to prompt neurosurgeons to consider monitoring intracranial pressure, whereas etiology of meningitis did not impact the decision to monitor intracranial pressure. Fifty-two percent of neurosurgeons believed computed tomography scans were inaccurate in detecting elevated intracranial pressure in comatose children with meningitis, 22% believed otherwise, and 26% were uncertain. Only 25% of neurosurgeons felt there was sufficient medical evidence to monitor intracranial pressure in comatose children with meningitis, with higher frequency among adult than pediatric (30% vs. 16%; p < .01) neurosurgeons. Eighty-one percent of neurosurgeons disagreed with the notion that comatose children with meningitis were too ill to benefit from placement of intracranial pressure monitors. Pediatric neurosurgeons reported a higher frequency than adult neurosurgeons of having placed more (more than five) intracranial pressure monitors in comatose children with meningitis (42% vs. 28%; p < .01).

CONCLUSIONS

Most neurosurgeons are willing to consider monitoring intracranial pressure among comatose children with meningitis in the presence of abnormal findings on computed tomography scan and with older patient age. These findings are instructive in view of the current uncertainty and equipoise in clinical practice regarding intracranial pressure monitoring in these critically ill children.

Ultrasonography of optic nerve sheath diameter for detection of raised intracranial pressure: a systematic review and meta-analysis

PURPOSE

To evaluate the diagnostic accuracy of ultrasonography of optic nerve sheath diameter (ONSD) for assessment of intracranial hypertension.

METHODS

Systematic review without language restriction based on electronic databases, with manual review of literature and conference proceedings until July 2010. Studies were eligible if they compared ultrasonography of ONSD with intracranial pressure (ICP) monitoring. Data were extracted independently by three authors. Random-effects meta-analysis and meta-regression were performed.

RESULTS

Six studies including 231 patients were reviewed. No significant heterogeneity was detected for sensitivity, specificity, positive and negative likelihood ratios or diagnostic odds ratio. For detection of raised intracranial pressure, pooled sensitivity was 0.90 [95% confidence interval (CI) 0.80-0.95; p for heterogeneity, p (het) = 0.09], pooled specificity was 0.85 (95% CI 0.73-0.93, p (het) = 0.13), and the pooled diagnostic odds ratio was 51 (95% CI 22-121). The area under the summary receiver-operating characteristic (SROC) curve was 0.94 (95% CI 0.91-0.96).

CONCLUSIONS

Ultrasonography of ONSD shows a good level of diagnostic accuracy for detecting intracranial hypertension. In clinical decision-making, this technique may help physicians decide to transfer patients to specialized centers or to place an invasive device when specific recommendations for this placement do not exist.

The role of cranial CT in the investigation of meningitis

Objective

To assess the usage of cranial computed tomography (CT) in patients admitted with meningitis.

Design

Retrospective study.

Setting

Heart of England NHS foundation trust, a teaching hospital in the West Midlands.

Participants

Two groups of adult patients admitted with meningitis between April 2001 and September 2004 and from September 2006 until September 2009.

Main outcome measures

The numbers of patients having cranial CT and lumbar puncture and whether any complications had arisen following lumbar puncture. The appropriateness of the CT request according to local criteria.

Results

A total of 111 patients were admitted in the initial time period and 47 patients in the second time period. In the first group, 67 patients underwent CT (61%), compared with 36 patients (80%) in the second group. There were eight abnormal scans (12%) in the initial group including three patients with radiological features of cerebral oedema. Of these patients, one underwent lumbar puncture and had no neurological sequelae. In the second group, there were five abnormal scans (14%) with one presenting a contraindication for lumbar puncture due to mild ventricular dilatation. A lumbar puncture was performed in this patient without complication. All patients with abnormal scans had clinical features to suggest raised intracranial pressure. CT scan requests were considered inappropriate in 26% of patients in the initial study period and 56% of patients in the second study period.

Conclusion

More patients with meningitis are undergoing CT and the number of inappropriate requests are increasing. There are few abnormal CT scans presenting a contraindication for lumbar puncture and the majority of these patients usually have clinical signs to suggest raised intracranial pressure.

Decompressive craniectomy guided by cerebral microdialysis and brain tissue oxygenation in a patient with meningitis

Bacterial meningitis remains a life-threatening disease mainly due to intracranial hypertension. However, decompressive craniectomy (DC) and the use of cerebral microdialysis (MD) and brain tissue oxygen pressure measurement (pTiO(2) ) are poorly described in this disease. We report a case of a 56-year-old woman admitted for severe bacterial meningitis complicating mastoiditis. Despite maximal medical treatment, intracranial pressure increased above 30 mmHg, with a decline in pTiO(2) and MD results indicating cerebral ischaemia. A bilateral DC was performed. Neurological outcome was favourable, and on discharge, the patient was able to live independently. This is the first report of DC in meningitis guided by cerebral MD and pTiO(2) . Invasive multimodal neuromonitoring should be used in severe meningitis and DC could be considered in the case of refractory intracranial hypertension.

Cranial computed tomography 2: use in clinical practice

The importance of cranial computed tomography in the diagnosis and follow up of intracranial pathology cannot be underestimated. Clinicians at every level should have a basic understanding of this technique. This second part discusses the practical use of computed tomography in the clinical setting.

Use of T2-weighted magnetic resonance imaging of the optic nerve sheath to detect raised intracranial pressure

Introduction

The dural sheath surrounding the optic nerve communicates with the subarachnoid space, and distends when intracranial pressure is elevated. Magnetic resonance imaging (MRI) is often performed in patients at risk for raised intracranial pressure (ICP) and can be used to measure precisely the diameter of optic nerve and its sheath. The objective of this study was to assess the relationship between optic nerve sheath diameter (ONSD), as measured using MRI, and ICP.

Methods

We conducted a retrospective blinded analysis of brain MRI images in a prospective cohort of 38 patients requiring ICP monitoring after severe traumatic brain injury (TBI), and in 36 healthy volunteers. ONSD was measured on T2-weighted turbo spin-echo fat-suppressed sequence obtained at 3 Tesla MRI. ICP was measured invasively during the MRI scan via a parenchymal sensor in the TBI patients.

Results

Measurement of ONSD was possible in 95% of cases. The ONSD was significantly greater in TBI patients with raised ICP (>20 mmHg; 6.31 ± 0.50 mm, 19 measures) than in those with ICP of 20 mmHg or less (5.29 ± 0.48 mm, 26 measures; P < 0.0001) or in healthy volunteers (5.08 ± 0.52 mm; P < 0.0001). There was a significant relationship between ONSD and ICP (r = 0.71, P < 0.0001). Enlarged ONSD was a robust predictor of raised ICP (area under the receiver operating characteristic curve = 0.94), with a best cut-off of 5.82 mm, corresponding to a negative predictive value of 92%, and to a value of 100% when ONSD was less than 5.30 mm.

Conclusions

When brain MRI is indicated, ONSD measurement on images obtained using routine sequences can provide a quantitative estimate of the likelihood of significant intracranial hypertension.

Decompressive craniectomy in a case of intractable intracranial hypertension due to pneumococcal meningitis

A young woman suffering from S. pneumoniae meningitis developed intractable intracranial hypertension with a GCS of 3. Intracranial pressure (ICP) ranged above 30 mmHg despite maximal medical treatment and continuous CSF drainage. We performed a wide bilateral decompressive craniectomy (DC) with duraplasty and we observed an immediate and stable drop of her ICP. When discharged she was independent. DC has been rarely used to control ICP in encephalitis patients and recently only in one case of meningitis. This operation could be a valuable option when all other measures to decrease ICP have failed; when necessary, it should be performed according to some rules otherwise it could be harmful for the patient. Conclusive data on the impact of DC on the final outcome of such patients are not available yet.

Infektionen

Trotz Weiterentwicklung moderner Antibiotika in den letzten Jahren sind die Letalitätszahlen der bakteriellen (eitrigen) Meningitis weiterhin hoch; Überlebende haben häufig neurologische Residuen. Die ungünstigen klinischen Verläufe der bakteriellen Meningitis sind meist Folge intrakranieller Komplikationen, wie z. B. eines generalisierten Hirnödems, einer zerebrovaskulären arteriellen oder venösen Beteiligung oder eines Hydrozephalus. Als Folge dieser Komplikationen kommt es häufig zu einem Anstieg des intrakraniellen Drucks. Bei schweren, komplizierten klinischen Verläufen der bakteriellen Meningitis kommen oft adjuvante Therapiemaßnahmen (z. B. intravenöse Gabe von hyperosmolaren Substanzen, externe Ventrikeldrainage) zum Einsatz. Bei Nachweis einer meningitisassoziierten septischen Sinus-/Venenthrombose erfolgt die dosisadaptierte intravenöse Heparintherapie.

Lumbar puncture and brain herniation in acute bacterial meningitis: a review

There has been controversy regarding the risk of cerebral herniation caused by a lumbar puncture (LP) in acute bacterial meningitis (ABM). This review discusses in detail the issues involved in this controversy. Cerebral herniation occurs in about 5% of patients with ABM, accounting for about 30% of the mortality. In many reports, LP is temporally strongly associated with this event of herniation and is most likely causative based on pathophysiologic arguments. Although a computed tomography (CT) scan of the head is useful to find contraindications to an LP, a normal CT scan in ABM does not mean that an LP is safe. Clinical signs of "impending" herniation are the best predictors of when to delay an LP because of the risk of precipitating herniation, even with a normal CT scan. Some of these clinical signs to be considered are deteriorating level of consciousness (particularly to a Glasgow Coma Scale of <or= 11), brainstem signs (including pupillary changes, posturing, or irregular respirations), and a very recent seizure. The risk of not doing an LP when it is contraindicated because of concern of the risk of herniation is extremely small. In those considered high risk for herniation, interventions to control intracranial pressure, such as attention to airway, breathing, and circulation, with a mannitol infusion and antibiotics started, should be the priorities, followed by an urgent CT scan and not an LP.

Cryptococcus gattii infection causing fulminant intracranial hypertension

Cryptococcus neoformans variety gattii (C. gattii) causes infection in predominantly immunocompetent individuals. The majority of cases present with headache due to meningitis and its natural history normally follows an indolent course. We report a fatal case of fulminant cryptococcaemia culminating in severe intracranial hypertension due to C. gattii. Such cases of fulminant disease are rare and highlight a number of important therapeutic and diagnostic considerations. We discuss the atypical nature of this patient's illness, the major complications of C. gattii meningitis and the role of computed tomography (CT) in preventing serious sequelae from lumbar puncture. The management of intracranial hypertension (ICH) in critically ill patients is also reviewed.

Emergency diagnosis and treatment of adult meningitis

Despite the existence of antibiotic therapies against acute bacterial meningitis, patients with the disease continue to suffer significant morbidity and mortality in both high and low-income countries. Dilemmas exist for emergency medicine and primary-care providers who need to accurately diagnose patients with bacterial meningitis and then rapidly administer antibiotics and adjunctive therapies for this life-threatening disease. Physical examination may not perform well enough to accurately identify patients with meningitis, and traditionally described lumbar puncture results for viral and bacterial disease cannot always predict bacterial meningitis. Results from recent studies have implications for current treatment guidelines for adults with suspected bacterial meningitis, and it is important that physicians who prescribe the initial doses of antibiotics in an emergency setting are aware of guidelines for antibiotics and adjunctive steroids. We present an overview and discussion of key diagnostic and therapeutic decisions in the emergency evaluation and treatment of adults with suspected bacterial meningitis.

Population-based study of incidence and risk factors for cerebral edema in pediatric diabetic ketoacidosis

OBJECTIVES

To determine incidence, outcomes, and risk factors for pediatric cerebral edema with diabetic ketoacidosis (CEDKA) in Canada.

STUDY DESIGN

This was a case-control study nested within a population-based active surveillance study of CEDKA in Canada from July 1999 to June 2001. Cases are patients with DKA <16 years of age with cerebral edema. Two unmatched control subjects per case are patients with DKA without cerebral edema.

RESULTS

Thirteen cases of CEDKA were identified over the surveillance period for an incidence rate of 0.51%; 23% died and 15% survived with neurologic sequelae. CEDKA was present at initial presentation of DKA in 19% of cases. CEDKA was associated with lower initial bicarbonate ( P = .001), higher initial urea ( P = .001), and higher glucose at presentation ( P = .014). Although there was a trend to association with higher fluid rates and treatment with bicarbonate, these were not independent predictors.

CONCLUSIONS

CEDKA remains a significant problem with a high mortality rate. No association was found between the occurrence of CEDKA and treatment factors. The presence of cerebral edema before treatment of DKA and the association with severity of illness suggest that prevention of DKA is the key to avoiding this devastating complication.