Pyridoxine-dependent epilepsy initially responsive to phenobarbital

PYRIDOXINE-dependent epilepsy (PDE): An observational study of neonatal cases on the role of pyridoxine in patients treated with standard anti-seizure medications

BACKGROUND

The main objective of this study was to evaluate the neurological consequences of delayed pyridoxine administration in patients diagnosed with Pyridoxin Dependent Epilepsies (PDE).

MATERIALS AND METHODS

We reviewed 29 articles, comprising 52 genetically diagnosed PDE cases, ensuring data homogeneity. Three additional cases were included from the General Pediatric Operative Unit of San Marco Hospital. Data collection considered factors like age at the first seizure's onset, EEG reports, genetic analyses, and more. Based on the response to first-line antiseizure medications, patients were categorized into four distinct groups. Follow-up evaluations employed various scales to ascertain neurological, cognitive, and psychomotor developments.

RESULTS

Our study includes 55 patients (28 males and 27 females), among whom 15 were excluded for the lack of follow-up data. 21 patients were categorized as "Responder with Relapse", 11 as "Resistant", 6 as "Pyridoxine First Approach", and 2 as "Responders". The neurological outcome revealed 37,5 % with no neurological effects, 37,5 % showed complications in two developmental areas, 15 % in one, and 10 % in all areas. The statistical analysis highlighted a positive correlation between the time elapsed from the administration of pyridoxine after the first seizure and worse neurological outcomes. On the other hand, a significant association was found between an extended latency period (that is, the time that elapsed between the onset of the first seizure and its recurrence) and worse neurological outcomes in patients who received an unfavorable score on the neurological evaluation noted in a subsequent follow-up.

CONCLUSIONS

The study highlights the importance of early recognition and intervention in PDE. Existing medical protocols frequently overlook the timely diagnosis of PDE. Immediate administration of pyridoxine, guided by a swift diagnosis in the presence of typical symptoms, might improve long-term neurological outcomes, and further studies should evaluate the outcome of PDE neonates promptly treated with Pyridoxine.

Clinical and genetic features in pyridoxine-dependent epilepsy: a Chinese cohort study

AIM

To characterize the clinical and genetic characteristics of a large cohort of patients with pyridoxine-dependent epilepsy (PDE).

METHOD

We retrospectively collected clinical and genetic information of 33 (15 males, 18 females; mean [SD] age 4y 11mo [2y 5mo]; 1y 3mo-10y 4mo) patients with PDE from 31 unrelated families at a single centre.

RESULTS

There were many types of seizures, with focal seizures in 32 cases. Dravet syndrome was suspected clinically in two patients. Electroencephalogram (EEG) was normal in seven patients at the initial stage and then in 17 patients during pyridoxine maintenance therapy. Genetic studies revealed 26 kinds of variants in ALDH7A1 and four in PLPBP with 18 variants unreported previously, and 48 ALDH7A1 variants were located in exon 11, 12, 14, and 17 or intron 9 and 11. In addition, three patients carried different exons deletion. Among these, seizures could be controlled for several years in one patient by levetiracetam monotherapy. Another patient remained seizure free for up to 7 months without therapy. All patients received oral pyridoxine treatment, with only one case (with exon 8-13 deletion) showing poor control.

INTERPRETATION

This study illustrates the range of clinical presentations and genetic causes in PDE, as well as responsiveness to antiepileptic drugs. A relationship between EEG and pyridoxine therapy could be seen in many cases. Seizure control was seen in all with pyridoxine monotherapy except for one patient.

WHAT THIS PAPER ADDS

There is a parallel relationship between electroencephalogram and pyridoxine therapy in many patients. Patients with pyridoxine-dependent epilepsy may respond well to low-dose pyridoxine.

Inborn Errors of Metabolism in Pediatric Epilepsy

Patients with refractory epilepsy from inborn errors of metabolism typically present as neonates. Direct supplementation with the deficient vitamin or cofactor is recommended, and case series report both efficacy and safety data of these agents. Some conditions may also occur together, necessitating multiple treatments. Despite effective and early treatment, patients are at heightened risk for neurological sequela. The literature on seizures related to metabolic deficiencies for pediatric patients is limited but has some guidance on appropriate dosing and monitoring for agents to target specific deficiencies, which may help with narrowing antiepileptic therapies, reducing side effects, and improving neurodevelopmental outcomes and quality of life. The focus of this review is to discuss the pharmacotherapy, including the most updated published efficacy and safety data, involved in treating refractory epilepsy as a result of metabolic errors.

[Combined therapy of cerebrovascular disorders with neuroprotectors]

Safety of drugs is one of the priorities of modern medicine. The goal of pharmacological treatment is a search for effective and safety drugs as well as a study of possibilities of combined using of the drugs with opposite effects. Basing on the possible therapeutic interactions, 2-ethyl-6-methyl-3-hydroxypyridine succinate can be recommended as a basic medication for patients with cerebrovascular diseases to normalize the energy metabolism of brain cells. The complex use of cholinergic drugs with different neuroprotective effects is effective from the first hours after admission. Cholinergic drugs (citicoline or choline alfoscerate) as the drugs of the first choice should be justified taking into consideration dysfunction of the brain system activation. Patient's age, the level of consciousness, somatic pathology, previous strokes, cognitive impairment are predictors of treatment efficacy.

Pyridoxine-Dependent Epilepsy: An Expanding Clinical Spectrum

BACKGROUND

Pyridoxine-dependent epilepsy is a rare autosomal recessive epileptic encephalopathy caused by antiquitin (ALDH7A1) deficiency. In spite of adequate seizure control, 75% of patients suffer intellectual developmental disability. Antiquitin deficiency affects lysine catabolism resulting in accumulation of α-aminoadipic semialdehyde/pyrroline 6' carboxylate and pipecolic acid. Beside neonatal refractory epileptic encephalopathy, numerous neurological manifestations and metabolic/biochemical findings have been reported.

METHODS AND RESULTS

We present a phenotypic spectrum of antiquitin deficiency based on a literature review (2006 to 2015) of reports (n = 49) describing the clinical presentation of confirmed patients (n > 200) and a further six patient vignettes. Possible presentations include perinatal asphyxia; neonatal withdrawal syndrome; sepsis; enterocolitis; hypoglycemia; neuroimaging abnormalities (corpus callosum and cerebellar abnormalities, hemorrhage, white matter lesions); biochemical abnormalities (lactic acidosis, electrolyte disturbances, neurotransmitter abnormalities); and seizure response to pyridoxine, pyridoxal-phosphate, and folinic acid dietary interventions.

DISCUSSION

The phenotypic spectrum of pyridoxine-dependent epilepsy is wide, including a myriad of neurological and systemic symptoms. Its hallmark feature is refractory seizures during the first year of life. Given its amenability to treatment with lysine-lowering strategies in addition to pyridoxine supplementation for optimal seizure control and developmental outcomes, early diagnosis of pyridoxine-dependent epilepsy is essential. All infants presenting with unexplained seizures should be screened for antiquitin deficiency by determination of α-aminoadipic semialdehyde/pyrroline 6' carboxylate (in urine, plasma or cerebrospinal fluid) and ALDH7A1 molecular analysis.

Case Report: Intravenous and Oral Pyridoxine Trial for Diagnosis of Pyridoxine-Dependent Epilepsy

Pyridoxine-dependent epilepsy is a rare, autosomal recessive, treatable cause of neonatal seizures. Genetic testing can confirm mutations in the ALDH7A1 gene, which encodes antiquitin. To avoid delays in initiating treatment while awaiting confirmatory genetic testing, it is recommended that all neonates with unexplained seizures should receive trial of intravenous (IV) pyridoxine to assess for responsiveness. However, oral pyridoxine is not commonly continued in the absence of the typical EEG changes. Two cases are presented that highlight the potential inadequacy of this single-step approach. One neonate ultimately diagnosed with pyridoxine-dependent seizures had no EEG changes after administration of IV pyridoxine. In contrast, another neonate who did not have this diagnosis had profound EEG changes after pyridoxine administration. We present 2 cases that highlight the difficulties in using initial EEG response to IV pyridoxine in establishing a diagnosis of pyridoxine-dependent seizures in the neonate. Given the availability of biochemical markers and gene testing, we suggest that oral pyridoxine treatment should be continued until biochemical and/or genetic testing has confirmed the presence or absence of pyridoxine-dependent epilepsy.

Fetal onset ventriculomegaly and subependymal cysts in a pyridoxine dependent epilepsy patient

Pyridoxine dependent epilepsy (PDE) is caused by mutations in the ALDH7A1 gene encoding α-aminoadipic semialdehyde dehydrogenase. The classic clinical presentation is neonatal seizures responsive only to pyridoxine therapy. White matter abnormalities, corpus callosum agenesis or hypoplasia, megacisterna magna, cortical dysplasia, neuronal heterotopias, intracerebral hemorrhage, and hydrocephalus in neuroimaging have been reported in patients with PDE. We report a new patient with asymmetric progressive ventriculomegaly noted on fetal sonography at 22 weeks' gestation. Postnatal brain sonography on day 1 and MRI on day 5 confirmed bilateral asymmetric ventriculomegaly caused by bilateral subependymal cysts. Intractable seizures at age 7 days initially responded to phenobarbital. Markedly elevated urinary α-aminoadipic acid semialdehyde levels and compound heterozygous mutations in the ALDH7A1 gene (c.446C>A/c.919C>T) confirmed the diagnosis of PDE caused by ALDH7A1 genetic defect. Despite the presence of structural brain malformations and subependymal cysts, PDE should always be included in the differential diagnosis of neonatal seizures that are refractory to treatment with antiepileptic drugs.

A Rare Case of Pyridoxine-dependent Seizures in Infancy

Pyridoxine-dependent seizures is a rare cause of recurrent seizures in neonatal period and resistant to most of the antiepileptic medications, but respond to administration of pyridoxine. We report a male infant who had neonatal seizures which were initially responsive to anticonvulsants and later became unresponsive and presented at 45 days of life with seizures. These seizures were not responding to any anticonvulsant but responded to pyridoxine. After discharge parents inadvertently stopped pyridoxine and the infant presented with seizures once again. These seizures were promptly controlled with readministration of pyridoxine confirming the diagnosis of pyridoxine-dependant seizures.

Biomarkers aiding diagnosis of atypical presentation of pyridoxine-dependent epilepsy

A 2-year-old girl from a consanguineous marriage was evaluated for refractory seizures that had presented at birth. Since her presentation, she had been treated with pyridoxine and antiepileptic medications. Because she did not manifest the expected clinical response, pyridoxine was discontinued, which led to an increase in clinical events. Cerebrospinal fluid neurotransmitter metabolite chromatography and an assay of serum biomarkers, including pipecolic acid and α-aminoadipic semialdehyde, confirmed the diagnosis of pyridoxine-dependent epilepsy, and genetic testing identified a homozygous mutation in our patient, and in a first cousin with epilepsy. The reintroduction of pyridoxine and addition of folinic acid eventually led to control of her seizures. Early testing of biomarkers may prevent delays in diagnosing pyridoxine-dependent epilepsy. We recommend that all patients presenting with cryptogenic seizures before age 18 months undergo this evaluation.

Efficacy of pyridoxine in early-onset idiopathic intractable seizures in children

OBJECTIVE

To identify pyridoxine responsive seizures among children with early onset intractable seizures, and to identify pyridoxine-dependency as a subset in this group.

METHODS

Patients with neonatal onset idiopathic, intractable seizures were identified over a 6-month period and subjected to a 'pyridoxine trial', at the Pediatric Neurology Clinic of a tertiary-care teaching hospital in New Delhi, India. This consisted of an intravenous infusion of 100 mg of pyridoxine over 10-min with a simultaneous EEG monitoring. This procedure was carried out in the EEG laboratory with all appropriate precautions (including availability of resuscitation equipment and trained personnel). Continuous EEG monitoring was done throughout the infusion and till 20 min later, to look for correction of EEG abnormalities. All patients were then prescribed oral pyridoxine, 10-15 mg/kg/day divided TDS for 6 weeks, in addition to their current anticonvulsant therapy. Patients were reviewed every 15 days regarding compliance and change in seizure frequency. A reduction in seizure frequency by 50% of the baseline was considered as 'response' (significant change), meriting further continuation of pyridoxine therapy. In patients who remained seizure free on pyridoxine therapy, previous anti-epileptics were gradually tapered one by one.

RESULTS

621 children with active epilepsy were seen at the PNC, of which 48 had early-onset, medical intractable epilepsy, and 21 children (13 males and 8 females), aged between 11 month and 38 month were enrolled. The median age at onset of seizure was 5.1 months. The major seizure type was focal in 3 and generalized in 18 (including infantile spasm in 11). No patient had normalization of EEG during the 'trial'. Two patients (9.5%) had a response during the 2 weeks of oral treatment and oral therapy was continued. No toxicity or side-effects of pyridoxine were observed in these two patients over a follow-up of more than 18 months.

CONCLUSIONS

Pyridoxine responsive seizures contribute a significant proportion to early-onset idiopathic intractable epilepsy in childhood. Routine use of pyridoxine in the management of early onset resistant seizures would go a long way in identifying these patients early.

New treatment paradigms in neonatal metabolic epilepsies

Neonatal seizures represent a major challenge among the epilepsies vis-à-vis seizure classification, electroclinical correlation, inherent excitability of neocortex, ontogenic characteristics of neurotransmitter receptors, and responsiveness to standard antiepileptic drugs. Each of these factors renders neonatal seizures more difficult to treat, and therapy has been a vexing area for recent advances in this seizure category. Conversely, specific metabolic disorders have very special therapeutic considerations in the clinical setting of neonatal seizures which require a high index of clinical suspicion and rapid intervention for a successful outcome. The prototype is pyridoxine dependency, although pyridoxal 5'-phosphate dependency is a recently recognized but treatable neonatal epilepsy that deserves earmarked distinction. Clinicians must remain vigilant for these possibilities, including atypical cases where apparent seizure-free intervals may occur. Folinic acid-dependent seizures are allelic with pyridoxine dependency. Serine-dependent seizures and glucose transporter deficiency may present with neonatal seizures and have specific therapy. A vital potassium channel regulated by serum ATP/ADP ratios in the pancreas and brain may be mutated with a resultant neuroendocrinopathy characterized by development delay, epilepsy, and neonatal diabetes (DEND). This requires oral hypoglycaemic therapy, and not insulin, for neurological responsiveness. The startle syndrome of hyperekplexia, which mimics neonatal epilepsy, has been associated with laryngospasm and sudden death but is treated with benzodiazepines.