Identification of demyelinating lesions and application of McDonald criteria when confronted with white matter lesions on brain MRI

INTRODUCTION

White matter lesions (WML) on magnetic resonance imaging (MRI) are common in clinical practice. When analyzing WML, radiologists sometimes propose a pathophysiological mechanism to explain the observed MRI abnormalities, which can be a source of anxiety for patients. In some cases, discordance may appear between the patient's clinical symptoms and the identification of the MRI-appearing WML, leading to extensive diagnostic work-up. To avoid misdiagnosis, the analysis of WML should be standardized, and a consensual MRI reading approach is needed.

OBJECTIVE

To analyze the MRI WML identification process, associated diagnosis approach, and misinterpretations in physicians involved in WML routine practice.

METHODS

Through a survey distributed online to practitioners involved in WML diagnostic work-up, we described the leading causes of MRI expertise misdiagnosis and associated factors: clinical experience, physicians' subspecialty and location of practice, and type of device used to complete the survey. The survey consisted of sixteen T2-weighted images MRI analysis, from which ten were guided (binary response to lesion location identification), four were not shown (multiple possible answers), and two were associated with dissemination in space (DIS) McDonald criteria application. Two independent, experienced practitioners determined the correct answers before the participants' completion.

RESULTS

In total, 364 participants from the French Neuro Radiological (SFNR), French Neurological (SFN), and French Multiple Sclerosis (SFSEP) societies completed the survey entirely. According to lesion identification, 34.3% and 16.9% of the participants correctly identified juxtacortical and periventricular lesions, respectively, whereas 56.3% correctly identified non-guided lesions. Application of the 2017 McDonald's DIS criteria was correct for 35.3% of the participants. According to the global survey scoring, factors independently associated with correct answers in multivariate analysis were MS-expert subspecialty (P<0.001), young clinical practitioners (P=0.02), and the use of a computer instead of a smartphone to perform WML analysis (P=0.03).

CONCLUSION

Our results highlight the difficulties regarding WML analysis in clinical practice and suggest that radiologists and neurologists should rely on each other to ensure the diagnosis of multiple sclerosis and related disorders and limit misdiagnoses.

Protein binding investigation of first-line and second-line antituberculosis drugs

Data on protein binding are incomplete for first-line antituberculosis drugs, and lacking for second-line antituberculosis drugs that are used extensively for multi-drug-resistant tuberculosis (levofloxacin, linezolid and moxifloxacin). Thus, the main purposes of this study were to investigate: (i) the relationship between carrier protein concentration and drug binding; and (ii) the feasibility of predicting free drug concentration using in-vitro and in-vivo results. In-vitro experiments were performed on spiked plasma mimicking real-case samples (drug combinations from clinical practice). Median in-vivo protein binding was 1.5% for ethambutol, 9.7% for isoniazid, 0.7% for pyrazinamide and 88.2% for rifampicin; and median in-vitro protein binding was 26.2% for levofloxacin, 12.8% for linezolid and 46.3% for moxifloxacin. Albumin concentration (<30 g/L) had a moderate impact on moxifloxacin binding and a strong impact on levofloxacin, linezolid and rifampicin binding. Determination of the free drug concentration seems to be of little value for ethambutol, isoniazid, moxifloxacin and pyrazinamide; limited value for linezolid because of its low binding; and major value for rifampicin in hypoalbuminaemic patients with tuberculosis, and levofloxacin because total concentration was an inaccurate reflection of free concentration. The free concentration predicted by the mathematical model was suitable for levofloxacin and linezolid, whereas the real free concentration should be measured for rifampicin. Further investigations should be carried out to investigate the benefit of using free concentration for levofloxacin, linezolid and rifampicin, particularly in the critical period of active tuberculosis associated with hypoalbuminaemia.

Months-long seismicity transients preceding the 2023 MW 7.8 Kahramanmaraş earthquake, Türkiye

Short term prediction of earthquake magnitude, time, and location is currently not possible. In some cases, however, documented observations have been retrospectively considered as precursory. Here we present seismicity transients starting approx. 8 months before the 2023 MW 7.8 Kahramanmaraş earthquake on the East Anatolian Fault Zone. Seismicity is composed of isolated spatio-temporal clusters within 65 km of future epicentre, displaying non-Poissonian inter-event time statistics, magnitude correlations and low Gutenberg-Richter b-values. Local comparable seismic transients have not been observed, at least since 2014. Close to epicentre and during the weeks prior to its rupture, only scarce seismic activity was observed. The trends of seismic preparatory attributes for this earthquake follow those previously documented in both laboratory stick-slip tests and numerical models of heterogeneous earthquake rupture affecting multiple fault segments. More comprehensive earthquake monitoring together with long-term seismic records may facilitate recognizing earthquake preparation processes from other regional deformation transients.

Assessment of the Androstenedione Assay on a Roche Analytical Platform and Comparison with Different Methods

BACKGROUND

D4-androstenedione (D4ASD) is an intermediate hormone of androgen biosynthesis by the gonads and the adrenal glands. The interest in D4ASD concentration assessment resides in diagnostics of androgenic hyperproduction pathologies. Currently, many D4ASD quantification methods are available on the market including immunological methods that remain problematic due to the possible cross-reactivity with endogenous or exogenous steroids.

METHODS

Recently Roche® launched a new fully automated instrument for the measurement of D4ASD concentration. In this paper, the criteria of analytical performance (repeatability and intermediate precision) of the D4ASD Roche® assay were assessed and compared with 2 different methods including a radioimmunoassay (RIA) as well as a liquid chromatography tandem mass spectrometry (LC-MS/MS) method.

RESULTS

Repeatability and intermediate precision of the D4ASD Roche® were acceptable according to the prede-fined RICOS standard (CV ≤ 7.9%) and the assay showed a good correlation with other assays considering the 95% CI obtained for the slope and the y-intercept.

CONCLUSIONS

This method demonstrates acceptable criteria of analytical performance with an intermediate imprecision and a trueness within the fixed acceptance limits.

Severe vitamin D deficiency in patients admitted to the emergency department with severe sepsis is associated with an increased 90-day mortality

BACKGROUND

The role of vitamin D in the response to infection has been increasingly acknowledged. However, the influence of severe vitamin D deficiency on the outcome of patients admitted for severe sepsis is unknown. Hence, this study aimed to investigate the association between severe vitamin D deficiency and sepsis-related outcomes in patients presenting to the ED.

METHODS

This single centre prospective study included patients presenting to the ED with severe sepsis from April 2014 until December 2017. 25-Hydroxy vitamin D (25(OH)D) was measured in a blood sample drawn within 24 hours of admission to the ED, and severe vitamin D deficiency was defined as 25(OH)D <12 ng/mL. 90-day mortality was compared between patients with and without severe vitamin D deficiency by a multivariable analysis adjusting for confounders and according to a Kaplan-Meier survival analysis.

RESULTS

263 patients were initially screened and 164 patients with severe sepsis were included in this study, 18% of whom had septic shock. Severe vitamin D deficiency was present in 46% of patients. The overall 90-day mortality rate was 26.2% and the median length of stay was 14 days. In a logistic regression accounting for sepsis severity and age-adjusted comorbidities, severe vitamin D deficiency was associated with increased mortality (OR=2.69 (95% CI 1.03 to 7.00), p=0.043), and lower chances of hospital discharge (sub-HR=0.66 (95% CI 0.44 to 0.98)). In the subgroup of patients admitted to the intensive care unit, severe vitamin D deficiency was associated with an increased 28-day adjusted mortality (HR=3.06 (95% CI 1.05 to 8.94), p=0.04) and lower chances of discharge (sub-HR=0.51 (95% CI 0.32 to 0.81)).

CONCLUSIONS

Severe vitamin D deficiency at ED admission is associated with higher mortality and longer hospital stay in patients with severe sepsis.

Two-site evaluation of the Roche Elecsys Vitamin D total III assay

Objectives

The high request for vitamin D testing in the last decades has led manufacturers to develop assays on automated immunoassay platforms. The objective of this study was to evaluate the performance of the new Elecsys Vitamin D total III assay for the measurement of total 25(OH)D.

Methods

A total of 844 serum samples collected in two clinical laboratories were used to evaluate the new Roche Elecsys Vitamin D total III assay. Comparisons with Roche Elecsys Vitamin D total II and liquid chromatography tandem mass spectrometry (LC-MS/MS) were carried out. Additionally, assay imprecision, linearity, matrix effects, biotin interference, cross-reactivity with 24,25(OH)2D3 and 3-epi-25(OH)D3, and outlier rate were evaluated for the Elecsys Vitamin D total III assay.

Results

Only the comparison between LC-MS/MS and Roche Elecsys Vitamin D total III achieved the optimal specification for bias (i.e., <3.4%). Imprecision, linearity and matrix effects showed acceptable results. The biotin interference threshold was increased up to 1,200 ng/mL and the outlier rate was low (0.26%). The cross-reactivity with 24,25(OH)2D3 and 3-epi-25(OH)D3 was weak or modest in available patient samples. However, using SRM972a with a high level of 3-epi-25(OH)D3 (enriched) revealed an important cross-reactivity with both Roche Elecsys Vitamin D total II and III assays (+74.7% and +73.7%).

Conclusions

In conclusion, the Roche Elecsys Vitamin D total III assay presents several advantages compared to the previous assay generation: higher biotin interference threshold, broader measuring range, and better comparability with LC-MS/MS. However, the cross-reactivity toward 3-epi-25(OH)D3 is still problematic in high titer samples.

Intraoperative cerebral blood flow monitoring in neurosurgery: A review of contemporary technologies and emerging perspectives

Intraoperative monitoring of cerebral blood flow (CBF) has become an invaluable adjunct to vascular and oncological neurosurgery, reducing the risk of postoperative morbidity and mortality. Several technologies have been developed during the last two decades, including laser-based techniques, videomicroscopy, intraoperative MRI, indocyanine green angiography, and thermography. Although these technologies have been thoroughly studied and clinically applied outside the operative room, current practice lacks an optimal technology that perfectly fits the workflow within the neurosurgical operative room. The different available technologies have specific strengths but suffer several drawbacks, mainly including limited spatial and/or temporal resolution. An optimal CBF monitoring technology should meet particular criteria for intraoperative use: excellent spatial and temporal resolution, integration in the operative workflow, real-time quantitative monitoring, ease of use, and non-contact technique. We here review the main contemporary technologies for intraoperative CBF monitoring and their current and potential future applications in neurosurgery.

Expert consensus statement on acute hepatic porphyria in Belgium

Acute hepatic porphyrias (AHP) are a group of four different rare to ultra-rare, severely debilitating, and sometimes fatal diseases that significantly impact patients' lives: 5-aminolevulinic acid (ALA) dehydratase deficiency porphyria (ADP), acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), and variegate porphyria (VP). Based on literature estimates, a conservative estimate of the number of AHP patients in Belgium requiring treatment, defined as patients experiencing recurrent attacks and/or chronic debilitating symptoms, is likely limited to 11-34 patients. These patients face a considerable unmet need, as there is currently no pharmaceutical treatment available that effectively prevents attacks and has an impact on other chronic symptoms of the disease.A panel consisting of the two European Porphyria Network¹ (EPNet) centers in Belgium (Center for inborn errors of metabolism of UZ Leuven and the 'Centre Belge des Porphyries' of Erasme Hospital and LHUB-ULB) participated in an advisory board on 24 January 2020. Representatives of the sponsoring pharmaceutical company, Alnylam Pharmaceuticals, organized and attended the meeting. The objective of the meeting was to obtain expert input on the state-of-the-art clinical practice of AHP in Belgium. Following this meeting, this expert consensus statement was drafted, in collaboration with and coordinated by the EPNet centers in Belgium. This statement provides an overview of the state-of-the art in AHP, by means of a concise overview of AHP pathophysiology, clinical manifestations, and burden of disease, (Belgian) epidemiology, treatments, and proposed organization of care.

MRI characteristics of MOG-Ab associated disease in adults: An update

Our knowledge of the radiological spectrum of myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD) is growing rapidly. An update on the radiological features of the disease, and its evolution is thus necessary. Magnetic resonance imaging (MRI) has an increasingly important role in the differential diagnosis of MOGAD particularly from aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD), and multiple sclerosis (MS). Differentiating these conditions is of prime importance because the management is different between the three inflammatory diseases, and thus could prevent further attack-related disability. Therefore, identifying the MRI features suggestive of MOGAD has diagnostic and prognostic implications. We herein review optic nerve, spinal cord and the brain MRI findings from MOGAD adult patients, and compare them to AQP4-NMOSD and MS.

Simultaneous determination of 8 beta-lactams and linezolid by an ultra-performance liquid chromatography method with UV detection and cross-validation with a commercial immunoassay for the quantification of linezolid

Linezolid and beta-lactams are anti-infective drugs frequently used in intensive care unit patients. Critical illness could induce alterations of pharmacokinetic parameters due to changes in the distribution, the metabolism and the elimination process. Therapeutic drug monitoring (TDM) is therefore recommended to prevent mainly under-dosing of beta-lactams or hematological and neurological toxicities of linezolid. In Multi-or Extensively-Drugs Resistant-Tuberculosis Bacteria, the regimen could include linezolid with meropenem and amoxicillin/clavulanate justifying the development of a method allowing their simultaneous quantification. The aim of this work was to develop an in-house ultra-performance liquid chromatography method with UV detection (UHPLC-PDA) allowing the simultaneous determination of 8 beta-lactams (amoxicillin, aztreonam, cefepime, ceftazidime, ceftriaxone, cefuroxime, meropenem and piperacillin) and linezolid and to cross-validate the linezolid quantification with a new commercial immunoassay (ARK kit) tested on a Cobas analyzer. The main advantages of the immunoassay are a 24/24 h random access assay which is fully automated and results provided within 2 h. The interference due to potential co-administrated drugs was evaluated on both methods. The preanalytical factors (type of matrix, stability) for linezolid were also investigated. The influence of hemolysis, icteria or lipemia on the spectroscopic detection of the immunoassay was assessed. The analytical performances were evaluated using the accuracy profiles approach with acceptance limits fixed at ±30%. Seventy patient samples were measured using both methods. No cross-reaction with the tested anti-infective drugs as well as no influence of hemolysis, lipemia, icteria were observed. The linezolid concentration could be measured on heparinized plasma or serum without a significant difference and remained stable for at least 72h at 4°C.The UHPLC-PDA method performed well in the analytical range investigated (0.25-50 mg/L for meropenem, 0.75-50 mg/L for linezolid and 1-200 mg/L for other beta-lactams) with an intermediate precision and a relative bias below 7.6 and 7.7%, respectively. The analytical range of the immunoassay was narrower, from 0.85 to 18.5 mg/L. The precision and relative bias were lower than 8.1% and 4.2%, respectively. Results obtained on clinical samples showed an acceptable difference between methods with a mean bias of -1.8% [95% confidence interval: -5.2% - 1.6%]. To conclude, both methods showed acceptable performance to perform TDM of linezolid considering the therapeutic through target of 2-8 mg/L. The choice of the method should be made according to the degree of emergency of the response required and the field of application justifying or not the simultaneous quantification of beta-lactams and linezolid.

Advanced multiparametric magnetic resonance imaging of multinodular and vacuolating neuronal tumor

BACKGROUND AND PURPOSE

Multinodular and vacuolating neuronal tumor (MVNT) of the cerebrum is a rare brain lesion with suggestive imaging features. The aim of our study was to report the largest series of MVNTs so far and to evaluate the utility of advanced multiparametric magnetic resonance (MR) techniques.

METHODS

This multicenter retrospective study was approved by our institutional research ethics board. From July 2014 to May 2019, two radiologists read in consensus the MR examinations of patients presenting with a lesion suggestive of an MVNT. They analyzed the lesions' MR characteristics on structural images and advanced multiparametric MR imaging.

RESULTS

A total of 64 patients (29 women and 35 men, mean age 44.2 ± 15.1 years) from 25 centers were included. Lesions were all hyperintense on fluid-attenuated inversion recovery and T2-weighted imaging without post-contrast enhancement. The median relative apparent diffusion coefficient on diffusion-weighted imaging was 1.13 [interquartile range (IQR), 0.2]. Perfusion-weighted imaging showed no increase in perfusion, with a relative cerebral blood volume of 1.02 (IQR, 0.05) and a relative cerebral blood flow of 1.01 (IQR, 0.08). MR spectroscopy showed no abnormal peaks. Median follow-up was 2 (IQR, 1.2) years, without any changes in size.

CONCLUSIONS

A comprehensive characterization protocol including advanced multiparametric magnetic resonance imaging sequences showed no imaging patterns suggestive of malignancy in MVNTs. It might be useful to better characterize MVNTs.

[White matter hyperintensities in ageing: Pathophysiology, associated cognitive disorders and prevention]

White matter hyperintensities (WMH), also known as leukoaraïosis are very common neuroradiological manifestations in the elderly. The main risk factors for WMH are age and high blood pressure. The vascular origin of these lesions is classically accepted and WMH are considered as one feature of the small vessel disease. WMH may be associated with clinical symptoms, depending notably on their importance according to age. They are associated with increased mortality, strokes and changes in cognition with a higher risk of dementia (vascular dementia or Alzheimer's disease). Modification of vascular risk factors could have a beneficial effect, but few evidences from controlled trials are available.

Multinodular and Vacuolating Posterior Fossa Lesions of Unknown Significance

Multinodular and vacuolating neuronal tumor of the cerebrum is a rare supratentorial brain tumor described for the first time in 2013. Here, we report 11 cases of infratentorial lesions showing similar striking imaging features consisting of a cluster of low T1-weighted imaging and high T2-FLAIR signal intensity nodules, which we referred to as multinodular and vacuolating posterior fossa lesions of unknown significance. No relationship was found between the location of the lesion and clinical symptoms. A T2-FLAIR hypointense central dot sign was present in images of 9/11 (82%) patients. Cortical involvement was present in 2/11 (18%) of patients. Only 1 nodule of 1 multinodular and vacuolating posterior fossa lesion of unknown significance showed enhancement on postcontrast T1WI. DWI, SWI, MRS, and PWI showed no malignant pattern. Lesions did not change in size or signal during a median follow-up of 3 years, suggesting that multinodular and vacuolating posterior fossa lesions of unknown significance are benign malformative lesions that do not require surgical intervention or removal.

Main inherited neurodegenerative cerebellar ataxias, how to recognize them using magnetic resonance imaging?

Ataxia is a neurodegenerative disease resulting from brainstem, cerebellar, and/or spinocerebellar tracts impairments. Symptoms onset could vary widely from childhood to late-adulthood. Autosomal cerebellar ataxias are considered as one of the most complex group in neurogenetics. In addition to their genetic heterogeneity, there is an important phenotypic variability in the expression of cerebellar impairment, complicating the genetic mutation research. A pattern recognition approach using brain MRI measures of atrophy, hyperintensities and iron-induced hypointensity of the dentate nuclei, could be therefore helpful in guiding genetic research. This review will discuss a pattern recognition approach that, associated with the age at disease onset, and clinical manifestations, may help neuroradiologists differentiate the most frequent profiles of ataxia.

Neuraxial analgesia is not associated with an increased risk of post-partum relapses in MS

Background:

Obstetrical analgesia remains a matter of controversy because of the fear of neurotoxicity of local anesthetics on demyelinated fibers or their potential relationship with subsequent relapses.

Objective:

To assess the impact of neuraxial analgesia on the risk of relapse during the first 3 months post-partum, with a focus on women who experienced relapses during pregnancy.

Methods:

We analyzed data of women followed-up prospectively during their pregnancies and at least 3 months post-partum, collected in the Pregnancy in Multiple Sclerosis (PRIMS) and Prevention of Post-Partum Relapses with Progestin and Estradiol in Multiple Sclerosis (POPARTMUS) studies between 1992–1995 and 2005–2012, respectively. The association of neuraxial analgesia with the occurrence of a post-partum relapse was estimated by logistic regression analysis.

Results:

A total of 389 women were included, 215 from PRIMS and 174 from POPARTMUS. In total, 156 women (40%) had neuraxial analgesia. Overall, 24% experienced a relapse during pregnancy and 25% in the 3 months post-partum. Women with a pregnancy relapse were more likely to have a post-partum relapse (odds ratio (OR) = 1.83, p = 0.02), independently of the use of neuraxial analgesia. There was no association between neuraxial analgesia and post-partum relapse (OR = 1.08, p = 0.78).

Conclusion:

Neuraxial analgesia was not associated with an increased risk of post-partum relapses, whatever multiple sclerosis (MS) activity during pregnancy.

[Diagnosis and treatment of nephrolithiasis and prevention of recurrences]

despite fluctuations, the prevalence of nephrolithiasis has significantly increased during the last decades in industrialized nations worldwide (1 to 15 %), which has a significant impact on the cost of healthcare. This increased prevalence is mainly explained by diet modifications. Environmental, metabolic and genetic factors may also influence the formation of kidney stones. As a consequence, the medical management of this disease is preferentially multidisciplinary and involves urologists, nephrologists, radiologists, biologists and dietitians. Urological management : may be mandatory during any acute and/or remote phase of an episode of renal colic, in case of residual stones. Several techniques are available: insertion of double J stent, extracorporeal shock wave lithotripsy, ureteroscopy (flexible or rigid), percutaneous nephrolithotomy and more occasionally, open surgery. Nephrological management: is justified in the course of the acute episode and aims to identify the causal factor(s) of kidney stones formation. The diagnostic approach involves a thorough interrogation (personal medical and surgical history, details of the kidney stone disease and family medical history) as well as a metabolic assessment. Moreover, given the high rate of recurrence (about 50 % within 5 to 10 years), individualized secondary prevention measures are necessary. The recommendations should take into account the identified risk factors and any metabolic abnormalities.

Serum β-lactam concentrations in critically ill patients with cirrhosis: a matched case-control study

BACKGROUND & AIMS

The pharmacokinetics of β-lactam antibiotics have not been well defined in critically ill patients with cirrhosis.

METHODS

We reviewed data from critically ill patients with cirrhosis and matched controls in whom routine therapeutic drug monitoring of two broad-spectrum β-lactam antibiotics (piperacillin/tazobactam and meropenem) had been performed. Serum drug concentrations were measured twice by high-performance liquid chromatography. Antibiotic pharmacokinetics were calculated using a one-compartment model. We considered that therapy was adequate when serum drug concentrations were between 4 and 8 times the minimal inhibitory concentration of Pseudomonas aeruginosa during optimal periods of time for each drug (≥ 50% for piperacillin/tazobactam; ≥ 40% for meropenem).

RESULTS

We studied 38 patients with cirrhosis (16 for piperacillin/tazobactam and 22 for meropenem) and 38 matched controls. Drug dosing was similar in the two groups. The pharmacokinetics analysis showed a lower volume of distribution of meropenem (P = 0.05) and a lower antibiotic clearance of piperacillin/tazobactam (P = 0.009) in patients with cirrhosis than in the matched controls. Patients with cirrhosis were more likely than those without cirrhosis to have excessive serum β-lactam concentrations (P = 0.015), in particular for piperacillin/tazobactam.

CONCLUSIONS

Standard β-lactam antibiotics regimens resulted in excessive serum concentrations in two thirds of the patients with cirrhosis. This was particularly true for piperacillin/tazobactam, probably because of reduced drug clearance.

Elevated β-lactam concentrations associated with neurological deterioration in ICU septic patients

BACKGROUND

Although β-lactams are considered to have a safe therapeutic profile, neurotoxicity has been reported. The aim of this study was to assess the association between β-lactam concentrations and neurological alterations in septic ICU patients.

METHODS

Retrospective study on all ICU patients who were treated with meropenem (MEM), piperacillin-tazobactam (TZP) or ceftazidime/cefepime (CEF) and in whom at least one β-lactam trough concentration (C min) was determined. Drug levels were measured using high-performance liquid chromatography; C min was normalized to the clinical breakpoint of Pseudomonas aeruginosa (as determined by EUCAST) for each drug (C min/MIC). Changes in neurological status were evaluated using changes in the neurological sequential organ failure assessment score (ΔnSOFA) using the formula: ΔnSOFA = nSOFA(day of TDM) - nSOFA(ICU admission). Worsening neurological status (NWS) was defined as a ΔnSOFA ≥ 1 for an nSOFA on admission of 0-2.

RESULTS

We collected 262 C min in 199 patients (130 MEM, 85 TZP, 47 CEF). Median APACHE II score and GCS on admission were 17 and 15, respectively. Overall ICU mortality was 27 %. There were no differences in the occurrence of NWS between antibiotics (39% for MEM, 32% for TZP and 35% for CEF). The occurrence of NWS increased with increasing C min/MIC ranges (P = 0.008); this correlation was found for TZP (P = 0.05) and MEM (P = 0.01), but not for CEF. C min/MIC was an independent predictive factor for NWS (OR 1.12 [1.04-1.20]).

CONCLUSION

We found a correlation between high β-lactam trough concentrations and increased occurrence of neurological deterioration in septic ICU patients. Although our data cannot determine causality, monitoring of β-lactam levels should be considered when deterioration of neurological status occurs during critical illness.

[Recurrent episodes of brushite nephrolithiasis revealing primary hyperparathyroidism]

INTRODUCTION

Nephrolithiasis is a frequent disease observed in 1 to 20 % of the general population. This disease predominates in male patients (2:1) and is characterized by a high rate of recurrences (about 50 %).

CASE REPORT

We report the case of a 45-year old male patient who experienced during about ten years recurrent bilateral renal colic episodes due to brushite lithiasis. These stones were treated with multiple extracorporeal shock wave lithotripsy sessions. A pyeloureteral junction syndrome predisposing to bulky stones formation has been put in evidence and required a pyeloplasty. After more than ten years of disease activity, a biochemical screening diagnosed primary hyperparathyroidism (PHPT). Radiological assessment identified a parathyroid gland adenoma. Successful surgical removal of this lesion was followed by resolution of the symptomatic kidney stones formation.

DISCUSSION

PHPT is associated with kidney stones in about 20 % of the patients. Hypercalciuria is the main risk factor of stones formation but other predisposing factors are also probably involved. Patients carrying a polymorphism located in the coding sequence of the calcium-sensing receptor gene or in the regulatory region of this gene seem to experience an increased occurrence of urinary lithiasis.

CONCLUSION

The present case stresses the importance of a metabolic assessment in all patients with recurrent nephrolithiasis, especially in case of bilateral episodes.

Written production in a case of locked-in syndrome with bilateral corticopontic degeneration

Patients in locked-in syndrome show normal or near normal mental abilities that contrast with the limited motor capacity that hinders voluntary communication. However, eye movements and blinking are usually preserved and can be used to establish a communication system. We report an exceptional case of locked-in syndrome. The aetiology was basilar thrombosis consecutive to a cervical manipulation. In addition, brain MRI performed 23 years later showed a ventral pontine stroke with bilateral corticopontic degeneration. In this study the patient was able to produce written output using a chin-controlled Morse system decoded by a computer. A detailed linguistic analysis of text written over 20 years by the patient was carried out. The data demonstrate that improvements in language performance can be observed even in patients with brain lesions in areas associated with high-level cognitive processes. The data show a decrease of typing, grammatical and lexical errors over time, use of less frequent words, and an increase of more complex linguistic structures. This paper adds to previous findings confirming the value of daily practice and rehabilitation to enhance quality of life in this group of patients.

[Contribution of clinical biology in the etiological exploration and follow-up of urolithiasis]

Urolithiasis is a frequent pathology with a constantly increasing prevalence in industrial countries. The relapse frequency is around 50 % with a risk of complications. The laboratory input is essential in the determination of the etiology and in the therapeutic monitoring. The morphoconstitutional analysis of the stone is the most important element. It comprises the examination of the stone with binocular loupes and the simultaneous analysis of its crystalline composition. This can be done by different techniques but infrared spectrophotometry is the most powerful. The chemical analysis should be definitely proscribed. The analysis of crystalluria includes the search, the identification and the counting of crystals in fresh morning urines. It is useful for the diagnosis and for the patient follow-up. Finally, the biochemical analyses in urine and serum, in first line or on the basis of the stone composition, are an important part of the etiological exploration and therapeutic monitoring.

Lesions of the ovary with T1-hypersignal

Pelvic magnetic resonance imaging (MRI) has been used successfully to diagnose ovarian masses that cannot be adequately evaluated using pelvic ultrasound. T1 hyperintensity is a common finding in an ovarian mass and has important diagnostic implications. The aims of this review are to list the substances that may produce high signal intensity on T1-weighted MRI, to explain the physical basis for causes of the high T1 signal intensity, and to describe common and uncommon T1 hyperintense ovarian lesions. The morphological findings, the imaging features of the additional sequences, and clinical variables can help in the differential diagnosis, and in some cases, enable a specific diagnosis, leading to appropriate management of the patient.

β-lactam antibiotic concentrations during continuous renal replacement therapy

Introduction

The use of standard doses of β-lactam antibiotics during continuous renal replacement therapy (CRRT) may result in inadequate serum concentrations. The aim of this study was to evaluate the adequacy of unadjusted drug regimens (i.e., similar to those used in patients with normal renal function) in patients treated with CRRT and the influence of CRRT intensity on drug clearance.

Methods

We reviewed data from 50 consecutive adult patients admitted to our Department of Intensive Care in whom routine therapeutic drug monitoring (TDM) of broad-spectrum β-lactam antibiotics (ceftazidime or cefepime, CEF; piperacillin/tazobactam; TZP; meropenem, MEM) was performed using unadjusted β-lactam antibiotics regimens (CEF = 2 g q8h; TZP = 4 g q6h; MEM = 1 g q8h). Serum drug concentrations were measured twice during the elimination phase by high-performance liquid chromatography (HPLC-UV). We considered therapy was adequate when serum drug concentrations were between 4 and 8 times the minimal inhibitory concentration (MIC) of Pseudomonas aeruginosa during optimal periods of time for each drug (≥70% for CEF; ≥ 50% for TZP; ≥ 40% for MEM). Therapy was considered as early (ET) or late (LT) phase if TDM was performed within 48 hours of antibiotic initiation or later on, respectively.

Results

We collected 73 serum samples from 50 patients (age 58 ± 13 years; Acute Physiology and Chronic Health Evaluation II (APACHE II) score on admission 21 (17–25)), 35 during ET and 38 during LT. Drug concentrations were above 4 times the MIC in 63 (90%), but above 8 times the MIC in 39 (53%) samples. The proportions of patients with adequate drug concentrations during ET and LT were quite similar. We found a weak but significant correlation between β-lactam antibiotics clearance and CRRT intensity.

Conclusions

In septic patients undergoing CRRT, doses of β-lactam antibiotics similar to those given to patients with normal renal function achieved drug levels above the target threshold in 90% of samples. Nevertheless, 53% of samples were associated with very high drug levels and daily drug regimens may need to be adapted accordingly.

Can changes in renal function predict variations in β-lactam concentrations in septic patients?

This study investigated whether variations in creatinine clearance (CLCr) are correlated with changes in β-lactam concentrations or pharmacokinetics in septic patients. Data for 56 adult patients admitted to the ICU in whom routine therapeutic drug monitoring (TDM) of broad-spectrum β-lactams (ceftazidime, cefepime, piperacillin or meropenem) was performed were reviewed. Patients were included if they had at least two TDM during their ICU stay for the same antibiotic and were not concomitantly treated with any extracorporeal replacement therapy. Serum drug concentrations were measured by HPLC-UV. Antibiotic pharmacokinetics were calculated using a one-compartment model and the percentage of time spent above four times the MIC (%T>4×MIC) for Pseudomonas aeruginosa and the antibiotic clearance (ATB-CL) were obtained. CLCr was measured on the same day as the TDM using 24-h urine collection. The %T>4×MIC and ATB-CL were significantly correlated with CLCr at the first (r=-0.41, P=0.002; r=0.56, P<0.001, respectively) and second (r=-0.61, P<0.001; r=0.63, P<0.001, respectively) TDM. However, changes in ATB-CL were only weakly correlated with changes in CLCr (r=0.34, P=0.01). The proportion of patients with insufficient β-lactam concentrations at the first and second TDM were 39% and 30%, respectively, and increased proportionally to CLCr. Although CLCr was significantly correlated with concentrations and clearance of broad-spectrum β-lactams, changes in CLCr did not reliably predict variations in drug pharmacokinetics/pharmacodynamics. Routine TDM should be considered to adapt β-lactam doses in this setting.

[Giant ameloblastoma of the mandible]

INTRODUCTION

Giant ameloblastomas are more common in developing countries. They raise a serious problem of management. We present the case of one of the largest ameloblastoma ever reported.

CASE REPORT

A 48-year-old Congolese female patient was referred for mandibular swelling having begun 23 years before and now inducing severe functional disorders. A cephalic CT scan revealed a multicystic mass, 30×18×10cm in size, with a typical "soap bubble" presentation, and with thinned and inflated cortical bone. The treatment was sub-total segmental mandibulectomy with immediate reconstruction using a fibular free flap, modeled on the sampling site by four ostectomies. The pathological examination confirmed the diagnosis of a benign follicular and plexiform ameloblastoma. The excess of soft tissue was treated with a right commissuroplasty on the 15th postoperative day. There was no complication.

DISCUSSION

Radical treatment followed by immediate reconstruction using a free flap is the treatment of choice for giant mandibular ameloblastomas, when considering immediate functional and esthetic benefits. This is a prime concern for patients with a difficult access to health care and for whom long-term follow-up is not feasible.

Time course of iron metabolism in critically ill patients

BACKGROUND

Altered iron metabolism plays a central role in the development of anaemia in critically ill patients but the time course of iron status in septic and non-septic critically ill patients has not been well defined.

METHODS

Prospective study in a 34-bed medico-surgical ICU. The complete blood count, iron, ferritin, transferrin, and transferrin receptor concentrations, transferrin saturation and C-reactive protein (CRP) concentrations were measured on days 1, 3 and 5 of the ICU stay in 95 consecutive ICU patients (33 with sepsis and 62 without).

RESULTS

Despite an identical complete blood count on day 1, septic patients had significantly lower iron concentrations (21 [13-34] vs 50[28-75] microg/dL, p<0.001), transferrin concentrations (169[121-215] vs 214[173-247] mg/dL; p=0.003), and transferrin saturation (11[7-15] vs 19[11-25]%; p= 0.004), and higher ferritin concentrations (432[184-773] vs 204[78-354] ng/mL; p=0.002) than non-septic patients. These alterations were associated with a lower reticulocyte count (42[29-61] vs 58[48-77] x 10(3)/mm3; p=0.028). On day 1, CRP concentrations, which were higher in septic than in non-septic patients (20.0[13.5-27.5] vs 2.3[0.7-5.9] mg/dL; p<0.001), were directly correlated with ferritin concentrations (rho=0.55, p<0.001) and inversely correlated with transferrin concentrations (rho=-0.49, p=0.0001) and transferrin saturation (rho=-0.49, p=0.0001). After 3 days, iron and transferrin concentrations were identical in septic and non-septic patients. Iron metabolism remained altered in both populations until the 5th day.

CONCLUSIONS

Iron status is rapidly altered in critically ill patients, especially in septic patients. These alterations persist during the course of the disease and are associated with decreased erythropoiesis.

Reliability of longitudinal brain volume loss measurements between 2 sites in patients with multiple sclerosis: comparison of 7 quantification techniques

BACKGROUND AND PURPOSE

Brain volume loss is currently a MR imaging marker of neurodegeneration in MS. Available quantification algorithms perform either direct (segmentation-based techniques) or indirect (registration-based techniques) measurements. Because there is no reference standard technique, the assessment of their accuracy and reliability remains a difficult goal. Therefore, the purpose of this work was to assess the robustness of 7 different postprocessing algorithms applied to images acquired from different MR imaging systems.

MATERIALS AND METHODS

Nine patients with MS were followed longitudinally over 1 year (3 time points) on two 1.5T MR imaging systems. Brain volume change measures were assessed using 7 segmentation algorithms: a segmentation-classification algorithm, FreeSurfer, BBSI, KN-BSI, SIENA, SIENAX, and JI algorithm.

RESULTS

Intersite variability showed that segmentation-based techniques and SIENAX provided large and heterogeneous values of brain volume changes. A Bland-Altman analysis showed a mean difference of 1.8%, 0.07%, and 0.79% between the 2 sites, and a wide length agreement interval of 11.66%, 7.92%, and 11.94% for the segmentation-classification algorithm, FreeSurfer, and SIENAX, respectively. In contrast, registration-based algorithms showed better reproducibility, with a low mean difference of 0.45% for BBSI, KN-BSI and JI, and a mean length agreement interval of 1.55%. If SIENA obtained a lower mean difference of 0.12%, its agreement interval of 3.29% was wider.

CONCLUSIONS

If brain atrophy estimation remains an open issue, future investigations of the accuracy and reliability of the brain volume quantification algorithms are needed to measure the slow and small brain volume changes occurring in MS.