The Ohtahara syndrome, Also known as early childhood epileptic encephalopathy, it is a type of epilepsy characterized by spasms, seizures resistant to therapeutic approaches, and severe psychomotor retardation. This type of epilepsy is characterized by being one of the earliest, appearing during the first months of life, and is also one of the least common.
At the etiological level, this pathology can be caused by various events, including hemorrhages, heart attacks, asphyxia or structural alterations at the brain level. However, in more than 60% of cases a specific cause cannot be identified.
Regarding the diagnosis, in the presence of seizures and the clinical suspicion of epilepsy, various diagnostic tests are usually used, such as computerized axial tomography (CT) or electroencephalography (EEG).
On the other hand, in terms of treatment, the different approaches do not usually have positive results, doses of vitamin B1, valproic acid, vigabatrin, ketogenic diet, etc. are usually used..
Generally, children with Ohtahara syndrome tend to have a poor medical prognosis, dying in a short period of time. However, there are cases in which they survive, progressing to West syndrome..
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Ohtahara syndrome is a type of epileptic encephalopathy, of varied origin and dependent on age, presenting its first clinical manifestations in the prenatal period.
Epilepsy is a type of neurological pathology that mainly affects the central nervous system. In most cases, it is a disease with a chronic course characterized by the development of seizures or epileptic seizures..
These events, the result of abnormal brain activity, are characterized by periods of unusual sensations and behaviors, muscle spasms, behavior, even loss of consciousness..
Furthermore, epilepsy is considered to be one of the most common neurological disorders worldwide. About 50 million people suffer from epilepsy worldwide, however, Ohtahara syndrome or childhood epileptic encephalopathy, is a disease with low prevalence in the general population.
In the case of this pathology, the term encephalopathy is used specifically to refer to various disorders that alter brain function and structure.
Some authors, such as Aviña Fierro and Herández Aviña, define epileptic encephalopathy as a set of severe paroxysmal seizure syndromes that usually begin their clinical course in the first moments of life or during early childhood and that tend to progress towards intractable epilepsy that develops quickly towards the death of the affected person.
Thus, in 1976, Ohtahara and his work group described a type of epileptic encephalopathy with an early onset and related to other syndromes such as Lennox-Gastaut and West syndrome..
Similarly, Clark in 1987 through the analysis of 11 cases, confirmed the characteristics of this disease and called it Ohtahara syndrome. In this way, West syndrome was defined through the following characteristics:
Finally, it was not until 2001 when the International League Against Epilepsy included Ohtahara syndrome as a specific medical entity, classified within the epileptic encephalopathies that occur in children..
Epilepsy is one of the most frequent neurological pathologies, approximately 50 million people affected worldwide (World Health Organization, 2016). Specifically, various studies have estimated its prevalence at approximately 4-10 cases per 1,000 inhabitants..
Ohtahara syndrome is a rare type of epilepsy in the general population, in addition there are few cases published in clinical reports, with a higher proportion of cases in the female population.
Therefore, from the epidemiological point of view, Ohtahara syndrome is considered a rare disease, its prevalence has been estimated at around 0.2-4% of all childhood epilepsies.
The fundamental characteristic of Ohtahara syndrome is the presentation of seizures or epileptic seizures. Normally the seizures are tonic, however, myoclonic ones are also frequent.
In general, the symptoms of epileptic seizures vary depending on the specific etiological cause and the individual clinical course, since while in some people they seem to be absent for a few seconds, others present strong muscle jerks.
Specifically, depending on the structural expansion and the source focus of the epileptic discharge, epileptic events can be classified as generalized and focal..
In the case of Ohtahara syndrome, the seizures are usually generalized, that is, the abnormal neuronal discharge affects all or a good part of the brain areas.
Although there are different types of generalized seizures (absence seizures, tonic, atonic, clonic, myclonic and tonic-clonic seizures), the most frequent in Ohtahara syndrome are tonic and myclonic:
- Tonic seizures: In this case, epileptic seizures are characterized by the development of abnormally increased muscle tone, that is, significant muscle stiffness, especially in the extremities and the back. Muscle alteration in many cases causes the affected person to fall.
- Myoclonic seizures: in this case, epileptic seizures are characterized by the presence of strong muscle jerks, in the legs and arms.
In addition, this cardinal symptom is characterized by its intractable nature, in most cases, the classical pharmacological and surgical approaches used in the treatment of epilepsy do not usually work in Ohtahara syndrome..
Regarding the beginning of the clinical manifestations of Ohtahara syndrome, epileptic seizures and seizures usually begin to manifest in the early stages of life.
Specifically, tonic-myoclonic seizures usually begin to appear in the first three months of life, however, in some early cases, it is already evident in just 10 days after birth.
After an uneventful birth and normal development during the first moments of life, seizures tend to appear acutely and suddenly.
Thus, these tonic-myoclonic events usually last approximately 10 seconds and, in addition, can occur during the sleep phase or during the day in a waking state..
Normally, due to medical complications and the development of a serious neurological affectation (structure and functional), the clinical course of Ohtahara syndrome tends to evolve to a poor to poor medical prognosis..
Most people with Ohtahara syndrome die in early childhood, however, in other cases, this medical condition evolves into West syndrome..
Children with Ohtahara syndrome present a generalized underdevelopment of the cerebral hemispheres, as a result of epileptic events and discharges.
As a consequence of this, many of those affected will show a significant delay in psychomotor development, especially accentuated in the acquisition of new capacities and motor skills during early childhood..
In addition, when this medical entity evolves into West syndrome, some of the following may be added to the aforementioned symptoms:
- Infantile spasms: body jerks characterized by total flexion, stiffness in the limbs and arching of the lumbar area.
- Hypsarrhythmia: This event is defined as a completely disorderly cerebral electric discharge pattern, characterized by discharges of slow waves, spikes and sharp waves with a total absence of hemispheric synchronization.
- Regression of motor skills: in addition to there being a marked difficulty in acquiring some skills related to muscular coordination or the control of voluntary movements, on many occasions there may be a loss of the ability to smile, hold the head, stand upright or sit.
- Muscle paralysis: the development of diplegia, quadriplegia or tetraplegia is possible.
- Microcephaly: development of a reduced head circumference compared to individuals of the same age group and sex.
The etiology of epileptic encephalopathies, such as Ohtahara syndrome, is very diverse.
However, some of the most common include the presence or development of structural alterations in the central nervous system (CNS), metabolic pathologies or genetic alterations..
In the case of genetic abnormalities, examination of some cases has shown the presence of a mutation in the STXBP1 gene associated with the clinical course of this pathology.
Currently there is no specific test or test that indicates its presence unequivocally, therefore, the diagnostic protocol followed in Ohtahara syndrome is similar to that of other types of epileptic disorders.
In the clinic, in addition to the study of the symptoms and the characteristics of the seizures and convulsions, some complementary tests such as magnetic resonance, electroencephalography, computerized tomography, neuropsychological examination or genetic study can be used..
The treatment used in Ohtahara syndrome is based mainly on the combination of various drugs used in other types of epileptic pathologies.
Thus, some of the approaches use: phenobarbital, valproic acid, clonazepan, midazolan, vigabatrin, topiramate, among others..
In addition, other types of interventions related to steroid therapy, surgery, dietary therapy or the treatment of metabolic disorders are also being tested..
However, most of these do not have a beneficial effect in controlling seizures and disease progression. Over time, seizures become recurrent and are accompanied by a serious impairment of physical and cognitive development.
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