He Ohtahara syndrome (OS) Is a type of epilepsy characterized by spasms, epileptic seizures resistant to therapeutic approaches, and severe psychomotor retardation (Ortega-Moreno et al., 2014).
This type of epilepsy is characterized by being one of the most precocious, appearing during the first months of life, being also one of the least common (López, Varela and Marca, 2013).
At the etiological level, this pathology may be caused by various events, including hemorrhages, strokes, asphyxia or structural alterations at the cerebral level. However, in over 60% of cases, a specific cause can not be identified (Aviña Fierro and Hernández Aviña, 2007).
As for the diagnosis, in the presence of convulsive crisis And clinical suspicion of epilepsy , Various diagnostic tests such as Computed axial tomography (TAC) or the Electroencephalography (EEG) (Palencia and LLanes, 1989).
On the other hand, in terms of treatment, the different approaches do not usually have positive results, usually doses of Vitamin B1 , valproic acid , Vigabatrin , Ketogenic diet , etc. (López, Varela and Marca, 2013).
Generally, children with Ohtahara syndrome usually have a poor medical prognosis, dying in a short period of time. However, there are cases in which they survive, progressing towards West syndrome (Aviña Fierro and Hernández Aviña, 2007).
Characteristics of the Ohtahara syndrome
The Ohtahara syndrome is a type of epileptic encephalopathy, of varied origin and dependent on age, presenting its first clinical manifestations in the prenatal period (Pozo Alonso, Pozo Lauzán and Pozo Alonso, 2003).
Epilepsy is a type of neurological pathology that affects fundamentally the Central Nervous System (Mayo Clinic, 2015). In most cases, it is a disease with a chronic course characterized by the development of seizures or epileptic seizures (Fernández-Suárez, et al., 2015).
These events, resulting from abnormal brain activity, are characterized by periods of unusual sensations and behaviors, muscle spasms, behavior, even by loss of consciousness (Mayo Clinic, 2015).
In addition, epilepsy is considered one of the most frequent neurological disorders worldwide (Medina, 2015). About 50 million people suffer from epilepsy worldwide (World Health Organization, 2016); however, Ohtahara syndrome or childhood epileptic encephalopathy is a disease with a low prevalence in the general population.
In the case of this pathology, the term encephalopathy is specifically used to refer to various disorders that alter the functioning and Brain structure (National Institute of Neurological Disorders and Stroke, 2010).
Some authors, such as Aviña Fierro and Herández Aviña (2007), define epileptic encephalopathy as a set of severe convulsive paroxysmal syndromes that usually begin their clinical course in the first moments of life or during early childhood and have to progress to epilepsy Intractable condition that quickly courses 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 (Yelin, Alfonso and Papazian, 1999).
Similarly, Clark in 1987, through the analysis of 11 cases, confirmed the characteristics of this disease and called it Ohtahara syndrome (Aviña Fierro and Hernández Aviña, 2007).
In this way, the West syndrome Was defined through the following characteristics (Yelin, Alfonso and Papazian, 1999):
- Beginning of convulsive events in early childhood.
- Tonic-spasmodic convulsions.
- Seizures refractory to the therapeutic approach.
- Generalized delay of psychomotor development.
- Unpromising medical forecast.
- Clinical evolution to West syndrome
- Diverse etiology
Finally, it was not until 2001, when the International League Against Epilepsy included Ohtahara syndrome as a specific medical entity classified as epileptic encephalopathies occurring in the pediatric age (Aviña Fierro and Hernández Aviña, 2007).
About us
Epilepsy is one of the most frequent neurological pathologies, approximately 50 million people affected worldwide (World Health Organization, 2016).
Specifically, several studies have estimated its prevalence in approximately 4-10 cases per 1,000 inhabitants (Fernández-Suárez, et al., 2015).
Ohtahara syndrome is a rare type of epilepsy in the general population, and there are few published cases in the clinical reports, with a higher proportion of cases in the female population (Yelin, Alfonso and Papazian, 1999).
Therefore, from the epidemiological point of view, the Ohtahara syndrome is considered a Rare disease , Its prevalence has been estimated to be around 0.2-4% of all childhood epilepsies (Pavone, Spalice, Polizzi, Parisi and Ruggieri, 2012).
Signs and symptoms
The fundamental characteristic of Ohtahara syndrome is the presentation of seizures or epileptic seizures. Typically, seizures are tonic-like, but myoclonic seizures are also common (International League Against Epilepsy, 2016).
In general, the symptoms of epileptic seizures vary depending on the specific etiologic cause and the individual clinical course, since while some people seem to be absent for a few seconds, others have strong muscular jerks.
Specifically, depending on the structural expansion and source of epileptic discharge, epileptic events can be classified as generalized and focal (Mayo Clinic, 2015).
In the case of Ohtahara syndrome, seizures are usually generalized, ie, abnormal neuronal discharge affects all or most of the brain areas (Mayo Clinic, 2015).
Although there are different types of generalized seizures (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 an abnormally increased muscle tone, that is, significant muscle stiffness, especially in the extremities and in the back. The muscular alteration in many cases causes the fall of the person affected.
- Myoclonic seizures : In this case, epileptic seizures are characterized by the presence of strong muscular jerks, in legs and arms.
In addition, this cardinal symptom is characterized by its intractable nature, in most cases, the classic pharmacological and surgical approaches employed in the treatment of epilepsy, do not usually work in Ohtahara syndrome.
How is the clinical course?
As for the beginning of the clinical manifestations of the Ohtahara syndrome, epileptic seizures and seizures usually begin to manifest in the early stages of life (Aviña Fierro and Hernández Aviña, 2007).
Specifically, tonic-myoclonic seizures usually begin to manifest in the first three months of life. However, in some early cases, it is evident in just 10 days after birth (Aviña Fierro and Hernández Aviña, 2007).
After a birth with no incidences and normal development during the first moments of life, the crises have to present in an acute and sudden form (Palencia and Llanes, 1989).
Thus, these tonic-myoclonic events usually have a duration of approximately 10 seconds and may also occur during the sleep phase or during the day in the waking state (Lopez, Varea and Marca, 2013).
Usually, due to medical complications and the development of severe neurological (structural and functional) involvement, the clinical course of Ohtahara syndrome has to evolve to a poor to poor medical prognosis (Beald, Cherian and Moshe, 2012).
Most people with Ohtahara syndrome die during the early part of childhood, but in other cases, this medical condition evolves into West syndrome (Beald, Cherian and Moshe, 2012).
What are the clinical repercussions of seizures in Ohtahara syndrome?
Children suffering from Ohtahara syndrome have generalized underdevelopment of the cerebral hemispheres, a product of events and epileptic discharges (National Institute of Neurological Disorders and Stroke, 2015).
Consequently, a large number of those affected will show a significant delay in psychomotor development, especially in the acquisition of new abilities and motor skills in early childhood (National Institute of Neurological Disorders and Stroke, 2015).
In addition, when this medical entity evolves towards the West syndrome, the symptoms mentioned above can be added some of the following:
- Childhood spasms : Body shaking characterized by total flexion, limb stiffness and lumbar arches (National Institute of Neurological Disorders and Stroke, 2015).
- Hipsarrhythmia : This event is defined as a pattern of cerebral electrical discharge of absolute disorder, characterized by discharges of slow waves, tips and acute waves with a total absence of hemispheric synchronization (Clínica de la Universidad de Navarra, 2015)
- Regression of motor skills : Besides there is a marked difficulty to acquire some skills related to muscle coordination or control of voluntary movements, in many cases may appear the loss of the ability to smile, Hold the head, stand erect or sit Andalusian Association of Epilepsy, 2016).
Muscular paralysis : It is possible the development of Diplegia, quadriplegia or tetraplegia .
- Microcephaly : Development of a reduced cranial perimeter compared to individuals of the same age group and sex.
Causes
The etiology of epileptic encephalopathies, such as the Ohtahara syndrome, is very diverse (Lopez, Varea and Marca, 2013).
However, some of the more common ones include the presence or development of structural alterations in the Central Nervous System (CNS), pathologies of metabolic character or genetic alterations (Lopez, Varea and Marca, 2013).
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 (Beald, Cherian and Moshe, 2012).
Diagnosis
At present 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, besides the study of the symptoms and the characteristics of the seizures and crises, some complementary tests can be used as the magnetic resonance , Electroencephalography, computerized tomography, neuropsychological examination, or genetic study (National Institute of Neurological Disorders and Stroke, 2015).
Treatment
The treatment used in Ohtahara syndrome is based mainly on the combination of various drugs used in other types of epileptic pathologies (Aviña Fierro and Hernández Aviña, 2007).
Thus, some of the approaches employ: phenobarbital, valproic acid, clonazepan, midazolan, vigabatrin, topiramate, among others (Aviña Fierro and Hernández Aviña, 2007).
In addition, other interventions related to steroid therapy, surgery, diet therapy or the treatment of metabolic disorders (Epilepy Foundation, 2016) may also be tried.
However, most of these do not have a beneficial effect in controlling seizures and progression of pathology. Over time, seizures become recurrent and are accompanied by severe impairment of physical and cognitive development (National Institute of Neurological Disorders and Stroke, 2015).
References
- Avian Fierro, J., & Hernández Aviña, D. (2007). Early childhood epileptic encephalopathy. Description of a case of Otahtah syndrome. Rev Mex Pdiatr, 109-112.
- Beal, J., Cherian, K., & Moshe, S. (2012). Early-Onset Epileptic Encephalopathies: Othara Syndrome and Early Myoclonic Encephalopathy. Peadiatric Neurology, 317-323.
- EF. (2016). Ohtahara Syndrome. Obtained from Epilepsy Foundation.
- ILAE. (2016). OHTAHARA SYNDROME. Obtained from International League Against Epilepsy.
- López, I., Varela, X., & Marca, S. (2013). Epileptic Syndromes in Children and Adolescents. Rev. Med. Clin. Condes, 915-927.
- NIH. (2015). Ohtahara Syndrome. Retrieved from the National Institute of Neurological Disorders and Stroke.
- Ortega-Moreno, L., Giráldez, B., Verdú, A., García-Campos, O., Sánchez-Martín, G., Serratosa, J., & Guerrero-López, R. (2015). New mutation in the gene STXBP1 in a patient with non-lesional Ohtahara syndrome. Rev Neurol.
- Palencia, R., & LLanes, P. (1989). Early childhood epileptic encephalopathy (Ohtahara syndrome). Bol Pediatr, 69-71.
- Pavone, P., Spalice, A., Polizzi, A., Parisi, P., & Ruggieri, M. (2012). Ohtahara syndrome with emphasis on recent genetic discovery. Brain & Development, 459-468.
- Yelin, K., Alfonso, I., & Papazian, O. (1999). Ohtahara syndrome. Rev Neurol, 340-342.