Irreversible Cerebellar Atrophy as a Complication of Short-Term Phenytoin Exposure: Clinical Improvement Following Discontinuation of the Culprit

Molecularly imprinted polymer-based extended-gate field-effect transistor chemosensors for selective determination of antiepileptic drug

Ultrathin molecularly imprinted polymer (MIP) films were deposited on the surfaces of ZnO nanorods (ZNRs) and nanosheets (ZNSs) by electropolymerization to afford extended-gate field-effect transistor sensors for detecting phenytoin (PHT) in plasma. Molecular imprinting efficiency was optimized by controlling the contents of functional monomers and the template in the precursor solution. PHT sensing was performed in plasma solutions with various concentrations by monitoring the drain current as a function of drain voltage under an applied gate voltage of 1.5 V. The reliability and reproducibility of the fabricated sensors were evaluated through a solution treatment process for complete PHT removal and PHT adsorption-removal cycling, while selectivity was examined by analyzing responses to chemicals with structures analogous to that of PHT. Compared with the ZNS/extracted-MIP sensor and sensors with non-imprinted polymer (NIP) films, the ZNR/extracted-MIP sensor showed superior responses to PHT-containing plasma due to selective PHT adsorption, achieving an imprinting factor of 4.23, detection limit of 12.9 ng/mL, quantitation limit of 53.0 ng/mL, and selectivity coefficients of 3-4 (against tramadol) and ~ 5 (against diphenhydramine). Therefore, we believe that the MIP-based ZNR sensing platform is promising for the practical detection of PHT and other drugs and evaluation of their proper dosages.

The Phenytoin Ataxia Enigma Unveiled ''A Case Report''

Background: Phenytoin (PHT) has been approved for the treatment of epilepsy. It belongs to the category of medications with a limited therapeutic window and requires therapeutic drug monitoring (TDM). PTH has been observed to induce a variety of Adverse drug reactions (ADRs) including ataxia, dystonia, nystagmus, dyskinesia, etc. Phenytoin-induced ataxia is an uncommonly observed ADR of Phenytoin whose reports are extremely limited. Case: Herein, we present a case report of a 16-year-old Asian patient with a past history of epilepsy that was admitted to a tertiary care hospital due to the development of ataxia, giddiness, and vomiting when taking Phenytoin in addition to Oxcarbazepine, Clobazam, and Levetiracetam to treat seizures. On admission, Magnetic resonance imaging (MRI) findings revealed bilateral variable cerebrospinal fluid (CSF) lesions in the parieto-occipital region of the periventricular area (periventricular leukomalacia). Additionally, serum Phenytoin levels were observed to be in the toxic range (40 μg/mL) due to which physicians confirmed the ADR to be due to Phenytoin toxicity. Thus, the Phenytoin drug was discontinued in the patient gradually and he was continued on clobazam, oxcarbazepine, and brivaracetam which led to reversal of the ADR in the patient. Conclusion: In this case, ataxia resulted from Phenytoin overdose, as confirmed by MRI and serum tests suggesting that TDM of Phenytoin is essential to prevent ADRs. Given the scarcity of ataxia cases caused by Phenytoin, awareness is lacking within the scientific community. Our aim is to provide insights to promote better monitoring and patient-centered treatment outcomes for epileptic patients.

Incidence and Characteristics of Cerebellar Atrophy/Volume Loss in Children with Confirmed Diagnosis of Tuberous Sclerosis Complex

Objectives: The goal of our study was to determine the incidence of cerebellar atrophy, assess the imaging findings in the posterior fossa and determine the incidence of hippocampal sclerosis in a cohort of pediatric patients with confirmed tuberous sclerosis complex (TSC). Material and methods: MRI studies of 98 TSC pediatric patients (mean age 7.67 years) were evaluated for cerebellar atrophy, cerebral/cerebellar tubers, white matter lesions, subependymal nodules, subependymal giant cell astrocytomas, ventriculomegaly, and hippocampal sclerosis. Clinical charts were revisited for clinical symptoms suggesting cerebellar involvement, for seizures and treatment for seizures, behavioral disorders and autism. Results: Cerebral tubers were present in 97/98 cases. In total, 97/98 had subependymal nodules, 15/98 had SEGA, 8/98 had ventriculomegaly and 4/98 had hippocampal sclerosis. Cerebellar tubers were found in 8/98 patients (8.2%), whereas cerebellar atrophy was described in 38/98 cases (38.8%). In 37/38 patients, cerebellar volume loss was mild and diffuse, and only one case presented with left hemi-atrophy. Briefly, 32/38 presented with seizures and were treated with anti-seizure drugs. In total, 8/38 (21%) presented with behavioral disorders, 10/38 had autism and 2/38 presented with seizures and behavioral disorders and autism. Conclusions: Several studies have demonstrated cerebellar involvement in patients with TSC. Cerebellar tubers differ in shape compared with cerebral tubers and are associated with cerebellar volume loss. Cerebellar atrophy may be focal and diffuse and one of the primary cerebellar manifestations of TSC, especially if a TSC2 mutation is present. Cerebellar degeneration may, however, also be secondary/acquired due to cellular damage resulting from seizure activity, the effects of anti-seizure drugs and anoxic-ischemic injury from severe seizure activity/status epilepticus. Further, prospective studies are required to identify and establish the pathogenic mechanism of cerebellar atrophy in patients with TSC.

Anything but Little: a Pictorial Review on Anatomy and Pathology of the Cerebellum

Despite its small size the cerebellum is an anatomically complex and functionally important part of the brain. Traditionally the cerebellum is viewed as a motor control structure entirely devoted to motor control and learning, but recent functional magnetic resonance imaging (fMRI) studies demonstrated significant involvement of the cerebellum in higher order cognitive functions. The anatomical complexity of the cerebellum is reflected by the several nomenclature systems that exist for the description of cerebellar anatomy. The cerebellum can be affected by a variety of pathological processes, including congenital, infectious and inflammatory, neoplastic, vascular, degenerative and toxic metabolic diseases. The purpose of this pictorial review is to (1) provide a general overview of cerebellar anatomy and function, (2) demonstrate normal cerebellar anatomy on imaging studies, and (3) illustrate both common as well as rare pathological conditions affecting the cerebellum.

The Impact of Epilepsy on Complication Rates After Total Joint Arthroplasty: A Propensity Score-Matched Cohort Study

BACKGROUND

It is unclear how epilepsy may affect total joint arthroplasty outcomes. The purpose of this study is to analyze the impact of epilepsy on prosthesis-related complications following primary total hip arthroplasty (THA) and total knee arthroplasty (TKA).

METHODS

A retrospective cohort study was conducted using a national database. Patients who have epilepsy underwent a primary THA (n = 6,981) and TKA (n = 4,987) and were matched 1:4 (THA, n = 27,924; TKA, n = 19,948). Rates of low-energy falls and prosthesis-related complications within 2 years postoperatively were compared for patients who did and did not have epilepsy with multivariable logistic regression.

RESULTS

After primary TKA, patients who have epilepsy exhibited significantly higher rates of aseptic revision (4.3% versus 3.5%, odds ratio [OR] 1.21, P = .017) and revision for prosthetic joint infection (1.8% versus 1.3%, OR 1.29, P = .041). THA patients who have epilepsy exhibited significantly higher rates of prosthetic dislocation (3.2% versus 1.9%, OR 1.54, P < .001), periprosthetic fracture (2.2% versus 0.8%, OR 2.39, P < .001), and aseptic loosening (1.7% versus 1.1%, OR 1.40, P = .002). Rates of low-energy falls within 2 years after TKA (14.1% versus 6.4%, OR 2.19, P < .001) and THA (33.6% versus 7.5%, OR 5.95, P < .001) were also significantly higher for patients who have epilepsy.

CONCLUSION

Epilepsy was associated with significantly higher rates of falls (P < .001) and prosthesis-related complications after primary THA (P < .05) and TKA (P < .05). Precautions should be implemented in this population during intraoperative and perioperative decision-making to reduce complication risk.

LEVEL OF EVIDENCE

Level III.

Long-Term Effects of Antiseizure Medications

Most patients with epilepsy will benefit from seizure control with one of an array of chronic antiseizure medications. Knowledge of the potential long-term effects of these medications is critical to prevent adverse consequences on overall health. Antiseizure medications vary in their capacities to affect the brain and peripheral nerves, hormones, bone mineralization, cardiovascular risk, renal health, hepatic, hematological, and dermatological systems. Understanding of pathophysiology and population risk has evolved, although most of the data available are still on older generation antiseizure medications such as phenytoin, carbamazepine, and valproic acid. The enzyme-inducing properties of some antiseizure medications make their effects on cardiovascular risk and bone health detrimental. Few clear guidelines exist for monitoring long-term effects of medication therapy for epilepsy. When selecting an antiseizure medication, consideration should be given to the individual patient's risks of adverse consequences on other organ systems. During monitoring of patients on chronic therapy, screening tools such as metabolic panels and bone density measurements can help stratify risk and guide management.

Movement disorders associated with antiseizure medications: A systematic review

New-onset movement disorders have been frequently reported in association with the use of antiseizure medications (ASMs). The frequency of specific motor manifestations and the spectrum of their semiology for various ASMs have not been well characterized. We carried out a systematic review of literature and conducted a search on CINAHL, Cochrane Library, EMBASE, MEDLINE, PsycINFO, and Scopus from inception to April 2021. We compiled the data for all currently available ASMs using the conventional terminology of movement disorders. Among 5123 manuscripts identified by the search, 437 met the inclusion criteria. The largest number of reports of abnormal movements were in association with phenobarbital, valproic acid, lacosamide, and perampanel, and predominantly included tremor and ataxia. The majority of attempted interventions for all agents were discontinuation of the offending drug or dose reduction which led to the resolution of symptoms in most patients. Familiarity with the movement disorder phenomenology previously encountered in relation with specific ASMs facilitates early recognition of adverse effects and timely institution of targeted interventions.