Cerebral and cerebellar pseudoatrophy associated with valproic acid. Report of three pediatric cases

INTRODUCTION

Cerebral and cerebellar pseudoatrophy is a rare adverse effect of valproic acid (VPA) that we need to be aware of, due to its diagnostic and therapeutic implications.

CASE REPORT

We report three cases of children between 5 and 9 years old, with epilepsy and previous normal brain magnetic resonance imaging, who were taking the drug at correct doses. Pseudoatrophy manifests subacutely with symptoms and images of cerebral and/or cerebellar atrophy, reversible after drug withdrawal.

DISCUSSION AND CONCLUSIONS

This is a type of VPA-related encephalopathy, different from dose-dependent toxic encephalopathy, hyperammonaemic encephalopathy or encephalopathy related to liver failure. In children, it causes cognitive, motor, mood and behavioral deterioration, and may be accompanied by epileptic decompensation. Withdrawing the drug leads to complete clinical-radiological recovery, and reducing the dose leads to improvement.

[Paediatric status epilepticus]

INTRODUCTION

Status epilepticus is defined as the situation resulting from the failure of the mechanisms responsible for terminating an epileptic seizure. In 2015, an operational concept was adopted internationally in which two times are identified: a first time, at which treatment must begin (five minutes for convulsive status, 10-15 minutes for focal and non-convulsive status); and a second time, after which there is considered to be a high risk of subsequent sequelae (30 minutes in the case of the convulsive). It occurs in 3-42/100,000 children per year, who are refractory or super-refractory in 10-40% of cases.

DEVELOPMENT

This article will review the different therapeutic options for status, from early treatment at home to the different first-line (benzodiazepines), second-line (phenobarbital, valproic acid, phenytoin, levetiracetam and lacosamide) or third-line treatments, which include both pharmacological (anaesthetics, propofol, ketamine, lidocaine, topiramate, brivaracetam or perampanel) and non-pharmacological (ketogenic diet, immunomodulatory treatments or epilepsy surgery) therapies.

CONCLUSIONS

Early identification and treatment of a prolonged crisis are essential to prevent progression to status. Although with fewer sequelae than in adults, status epilepticus in children represents a cause of mortality of up to 3-5%, while 25% of them will develop subsequent epilepsy, as well as a considerable percentage of neurological sequelae.

[Variability of the clinical expression of KCNB1 encephalopathy]

INTRODUCTION

The KCNB1 gene encodes a voltage-dependent potassium channel that regulates transmembrane currents in pyramidal neurons. Heterozygous variants have recently been associated with early-onset epileptic encephalopathies and intellectual disability, but their clinical characterisation has not yet been fully defined.

AIM

To describe the clinical spectrum associated with variants of KCNB1 in paediatric patients.

PATIENTS AND METHODS

Retrospective study of four patients from three families with KCNB1 encephalopathy, including an analysis of the clinical and electroencephalographic features of epilepsy, associated neurological manifestations and neurodevelopmental pattern.

RESULTS

In two of them, the mutation in KCNB1 was de novo; the other two, who were sisters, inherited the variant from a parent with germline mosaicism. All had mild-to-moderate intellectual disability, two patients had autistic spectrum disorder and two had attention deficit hyperactivity disorder. Only case 2 displayed alterations in the MRI brain scan: progressive cortical atrophy. Three of them developed epilepsy (cases 1-3). Case 1: onset at 9.5 months with West syndrome that was well controlled with vigabatrine and zonisamide. Case 2: onset at 13 months with West syndrome, evolutionary development of polymorphic seizures (atonic, hypermotor, dysautonomic and tonic) that were refractory to 10 antiepileptic drugs and corticosteroids. Accompanied by a movement disorder characterised by ataxia, dyskinesias and tremor. Case 3: onset at 14.5 years with atonic seizures, multifocal EEG pattern and adequate control with levetiracetam.

CONCLUSIONS

KCNB1 encephalopathy has a heterogeneous natural history, mainly with respect to epilepsy, ranging from patients with refractory epilepsy to patients without any epileptic seizures. All had neurodevelopmental disorders, such as intellectual disability or autism spectrum disorder, independent of epilepsy.