Hyperammonaemia and associated factors in unprovoked convulsive seizures: A cross-sectional study

Acute Valproate-Induced Encephalopathy in Status Epilepticus: A Registry-Based Assessment

BACKGROUND

Valproate-induced encephalopathy (VIE) affects between 0.1% and 2.5% of patients under long-term epilepsy treatment. Its frequency and characteristics in adults with status epilepticus (SE) is, however, unknown.

OBJECTIVE

The aim of this study was to characterize the frequency and the clinico-biological characteristics of VIE in adult SE patients.

METHODS

We reviewed all patients included in our institutional SE registry who were treated for an SE episode between November 2021 and February 2023 and identified 39 patients who received valproate for their SE treatment. Acute VIE was defined by worsening of consciousness having led to the discontinuation of valproate, and improvement of consciousness within 96 hours after discontinuation of valproate during acute hospital treatment.

RESULTS

Patients had a mean valproate intravenous loading dose of 34.5 mg/kg and a mean maintenance dose of 15.3 mg/kg/d (1078 mg/d). Four out of 29 patients with measured ammonium had hyperammonemia. We identified four (10%) patients fulfilling acute VIE criteria. Median time from administration of valproate to the occurrence of VIE, and to resolution of VIE after cessation of valproate treatment, was 2 days for each. Three of the four VIE patients had no associated hyperammonemia. Patients who developed VIE more frequently had a history of liver disease (p = 0.023), and tended to be younger, but other clinical variables did not differ significantly from patients without VIE, including valproate loading or maintenance doses, SE cause, duration or severity, other concomitant antiseizure medications (none received topiramate, phenobarbital, or primidone).

CONCLUSION

Pending larger studies, VIE in SE seems relatively frequent and difficult to foresee; clinical alertness to symptoms is mandatory, even without hyperammonemia, and valproate withdrawal should be considered in suspected cases.

Predicting the Onset of Acute Encephalopathy With Biphasic Seizures and Late Reduced Diffusion by Using Early Laboratory Data

Background: Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) often causes various neurological sequelae, necessitating early and objective differentiation of AESD from a febrile seizure (FS). Therefore, we developed a scoring system that predicts AESD onset using only early laboratory data. Methods: We selected patients with AESD or FS admitted to the Tottori University Hospital between November 2005 and September 2020 and collected laboratory data from onset to discharge in patients with FS and from onset to the second neurological events in patients with AESD. Results: We identified 18 patients with AESD and 181 patients with FS. In comparison with patients with FS, patients with AESD showed statistically significant increases in ammonia (NH3), blood sugar (BS), and serum creatinine (Cr) levels, and the white blood cell (WBC) count, and a significant decrease in pH at <3 h from onset. We set the cut-off values and adjusted the weight of each of these parameters based on data obtained <3 h from onset and proposed a scoring system for predicting AESD. This system showed 91% sensitivity and 94% specificity for distinguishing AESD from FS. These accuracies were only slightly improved by the addition of information related to consciousness and seizure duration (sensitivity, 91%; specificity, 96%). Conclusion: NH3, BS, and Cr levels, WBC count, and pH were significantly different between patients with AESD and patients with FS at <3 h from seizure onset. This scoring system using these data may enable the prediction of AESD onset for patients under sedation or without precise clinical information.

Hyperammonemia in Patients With Status Epilepticus Treated With or Without Valproic Acid

BACKGROUND

Hyperammonemia is a common side effect of valproic acid (VPA) and can occur after generalized seizures, but the clinical significance is unclear. The aim of this study was to better understand the clinical practice and utility of ammonia testing in status epilepticus (SE) treated with or without VPA.

METHODS

Charts of adult patients with SE from St. Mary's Hospital Intensive Care Units (ICUs) (Mayo Clinic, Rochester, MN) from 2011 to 2016 were reviewed. Clinical factors were compared between patients who had ammonia checked versus those who did not, and those with normal ammonia versus hyperammonemia (>50 µg/dL). Charts were reviewed to determine if hyperammonemia changed clinical management and if it was felt to be symptomatic.

RESULTS

There were 304 patients identified: 94 received VPA, 142 had ammonia checked and receiving VPA was associated with ammonia testing (P<0.001). Hyperammonemia was identified in 32 and associated with younger age, being in a non-neurological intensive care unit, and liver disease, but was not statistically associated with VPA. Only one patient had valproate-induced hyperammonemic encephalopathy; however, many patients received treatment for hyperammonemia such as lactulose, levocarnitine, or VPA dose reductions.

CONCLUSIONS

This study demonstrated variability in ammonia testing and management changes in SE but does not support the routine monitoring of ammonia levels and showed that hyperammonemic encephalopathy was rare in this clinical setting.

Status epilepticus severity score as a predictor for the length of stay at hospital for acute-phase treatment in convulsive status epilepticus

To date, hospital length of stay (LOS) determinants for convulsive status epilepticus's (CSE) acute-phase treatment have not been sufficiently investigated, as opposed to those for status epilepticus's (SE) outcome predictors, such as status epilepticus severity score (STESS). Here, we aimed at assessing the significance of STESS in the LOS in patients with CSE. We retrospectively reviewed consecutive adult patients with CSE who were transported to the emergency department of our urban tertiary care hospital in Tokyo, Japan. The study period was from August 2010 to September 2015. The primary endpoint was the LOS of patients with CSE who were directly discharged after acute-phase treatment, and survival analysis for LOS until discharge was conducted. As a result, among 132 eligible patients with CSE admitted to our hospital, 96 (72.7%) were directly discharged with a median LOS of 10 days (IQR: 4-19 days). CSE patients with severe seizures, represented by higher STESS (≥3), had a significantly longer LOS after adjustments with multiple covariates (p = 0.016, in restricted mean survival time analysis). Additionally, prediction for the binomial longer/shorter LOS achieved better performance when STESS was incorporated into the prediction model. Our findings indicate that STESS can also be used as a rough predictor of longer LOS at index admission of patients with CSE.

Acute metabolic effects of tonic-clonic seizures

OBJECTIVE

Tonic-clonic seizures (TCS) lead to metabolic stress and changes in related blood markers. Such markers may indicate harmful conditions but can also help to identify TCS as a cause of transient loss of consciousness. In this study, we hypothesized that the alterations of circulating markers of metabolic stress depend on the clinical features of TCS.

METHODS

Ninety-one adults undergoing video-EEG monitoring participated in this prospective study. Electrolytes, renal parameters, creatine kinase (CK), prolactin (PRL), lactate, ammonia, glucose, and other parameters were measured at inclusion and different time points after TCS.

RESULTS

A total of 39 TCS were recorded in 32 patients (six generalized onset tonic-clonic seizures in 6 and 33 focal to bilateral tonic-clonic seizures in 26 patients). Shortly after TCS, mean lactate, ammonia, and PRL levels were significantly increased 8.7-fold, 2.6-fold, and 5.1-fold, respectively, with levels of more than twofold above the upper limits of the normal (ULN) in 90%, 71%, and 70% of the TCS and returned to baseline levels within 2 hours. Only postictal lactate levels were significantly correlated with the total duration of the tonic-clonic phase. In contrast, CK elevations above the ULN were found in three TCS (~10%) only with a peak after 48 hours. Immediately after the TCS, hyperphosphatemia occurred in one third of the patients, whereas hypophosphatemia was observed in one third 2 hours later. TCS led to subtle but significant alterations of other electrolytes, creatinine, and uric acid, whereas glucose levels were moderately increased.

SIGNIFICANCE

Lactate is a robust metabolic marker of TCS with elevations found in ~90% of cases within 30 minutes after seizure termination, whereas ammonia rises in ~ 70%, similarly to PRL. Phosphate levels show an early increase and a decrease 2 hours after TCS in a third of patients. CK elevations are rare after video-EEG-documented TCS, challenging its value as a diagnostic marker.

Postictal syndrome: The forgotten continent. An overview of the clinical, biochemical and imaging features

Postictal syndrome (PIS) encompasses the clinical, biological, electroencephalographic (EEG) and magnetic resonance imaging (MRI) signs that follow the termination of a seizure. These signs occur as soon as the epileptic discharge ends, but might remain for a substantially long period of time, making them amenable to clinical observation. As a direct consequence, neurologists and intensivists are more frequently attending patients with PIS than during their seizure. Moreover, careful PIS documentation may help physicians to diagnose epileptic seizure from other non-epileptic disorders. Careful analysis of PIS could also be helpful to better characterize the seizure (seizure subtypes, and to some extent, the localization and/or lateralization of the seizure). This article aims to review the main clinical, biological, EEG and MRI components of PIS, discuss differential diagnoses and propose a general clinical attitude, based on the acronym "WAITTT": W for "Watch", to monitor and investigate PIS in order to provide relevant information on seizure, AIT for "Avoid Inappropriate Treatment", to underscore the risk carrying out unnecessary drug injections and intensive care procedures in the setting of a self-limited symptomatology, and TT for "Take Time", to keep in mind that time remains the clinician's best ally for treating patients with PIS.

Elevated circulating TGFβ1 during acute liver failure activates TGFβR2 on cortical neurons and exacerbates neuroinflammation and hepatic encephalopathy in mice

BACKGROUND

Acute liver failure resulting from drug-induced liver injury can lead to the development of neurological complications called hepatic encephalopathy (HE). Hepatic transforming growth factor beta 1 (TGFβ1) is upregulated due to liver failure in mice and inhibiting circulating TGFβ reduced HE progression. However, the specific contributions of TGFβ1 on brain cell populations and neuroinflammation during HE are not known. Therefore, the aim of this study was to characterize hepatic and brain TGFβ1 signaling during acute liver failure and its contribution to HE progression using a combination of pharmacological and genetic approaches.

METHODS

C57Bl/6 or neuron-specific transforming growth factor beta receptor 2 (TGFβR2) null mice (TGFβR2^ΔNeu) were treated with azoxymethane (AOM) to induce acute liver failure and HE. The activity of circulating TGFβ1 was inhibited in C57Bl/6 mice via injection of a neutralizing antibody against TGFβ1 (anti-TGFβ1) prior to AOM injection. In all mouse treatment groups, liver damage, neuroinflammation, and neurological deficits were assessed. Inflammatory signaling between neurons and microglia were investigated in in vitro studies through the use of pharmacological inhibitors of TGFβ1 signaling in HT-22 and EOC-20 cells.

RESULTS

TGFβ1 was expressed and upregulated in the liver following AOM injection. Pharmacological inhibition of TGFβ1 after AOM injection attenuated neurological decline, microglia activation, and neuroinflammation with no significant changes in liver damage. TGFβR2^ΔNeu mice administered AOM showed no effect on liver pathology but significantly reduced neurological decline compared to control mice. Microglia activation and neuroinflammation were attenuated in mice with pharmacological inhibition of TGFβ1 or in TGFβR2^ΔNeu mice. TGFβ1 increased chemokine ligand 2 (CCL2) and decreased C-X3-C motif ligand 1 (CX3CL1) expression in HT-22 cells and reduced interleukin-1 beta (IL-1ß) expression, tumor necrosis factor alpha (TNFα) expression, and phagocytosis activity in EOC-20 cells.

CONCLUSION

Increased circulating TGFβ1 following acute liver failure results in activation of neuronal TGFβR2 signaling, driving neuroinflammation and neurological decline during AOM-induced HE.

Old Stroke as an Independent Risk Etiology for Todd's Paralysis

BACKGROUND

Todd's paralysis (TP) is a well-known postictal paresis in which patients present with transient weakness in their limb(s) after seizures. Although recognized as a stroke mimic in clinical practice, the pathophysiological mechanism and clinical features of TP remain unknown. Furthermore, its diagnosis can be erroneous in neurological emergency practice. We aimed to illustrate the clinical features and identify factors associated with TP.

METHODS

This single-center, retrospective observational study included consecutive adult patients who presented with convulsive seizure and were referred to an urban tertiary care emergency department between August 2010 and April 2016. The diagnosis of TP was set as the primary outcome measure. Clinical and laboratory variables were evaluated.

RESULTS

Of 1381 eligible convulsive seizures in 1187 patients, TP was observed in 89 seizures (6.4%) in 75 patients. Patients with TP were significantly older, more likely to have convulsive status epilepticus, and had a longer duration of convulsion than patients without TP. TP was found in 19.7% (39 of 198) of convulsive seizures with remote etiologies including those due to old stroke. These etiologies were identified as independent significant risk factors for TP compared with seizures with cryptogenic etiology. The positive likelihood ratio of TP seizures was 11.2 for remote seizure etiologies.

CONCLUSIONS

Our results indicated that the diagnosis of TP highly suggests premorbid or comorbid structural lesions in the central nervous system, including old stroke. This consideration in seizure etiology may help in reducing the risk of misdiagnosis of acute stroke in emergency settings and further antiepileptic treatment.