[Advances in our knowledge of the causation and pathophysiology of reflex epilepsies]. / Avances en el conocimiento de la etiología y la fisiopatología de las epilepsias reflejas.

AIMS: In recent years our knowledge of the pathophysiology and aetiology of reflex seizures and epilepsies has advanced significantly due to the contributions made by modern functional neuroimaging and neurophysiology techniques, as well as the findings of research being conducted in molecular biology. The aim of our review is to summarise and integrate these contributions in order to describe the current state of our knowledge on the subject. DEVELOPMENT: The fundamental pathophysiological pattern is common to all types of reflex epilepsy and is based on the existence of a hyperexcitable cortical or subcortical neuronal area that can respond to a physiological stimulus in an exaggerated manner. This focal hyperexcitability may derive from a predisposing genetic substrate (idiopathic reflex epilepsy) or from a focal cortical lesion (lesional reflex epilepsy). Some genetic substrates have been reported in isolated families and there are many candidate genes, but we still do not know enough about the genetic base. The lesion-based aetiology is very heterogeneous, but disorders affecting cortical development are the lesions with the greatest capacity to cause reflex epilepsy. Clinical expression is conditioned by the topography of the lesion and not by the type of underlying lesion. CONCLUSIONS: Future characterisation of reflex epileptic seizures and syndromes must include a diagnosis centred around three axes, that is, topographic, lesional and genetic.

[Acute disseminated encephalomyelitis due to hymenoptera stings]. / Encefalomielitis aguda diseminada por picadura de himenóptero.

INTRODUCTION: Hymenoptera stings can give rise to a variety of conditions. The most common is a self-limiting local allergic reaction, but occasionally they may produce potentially serious systemic reactions. Neurological complications are rare, but very varied and of differing degrees of severity. Some such consequences are those of a demyelinating nature, which can affect the central and/or peripheral nervous system. Their exact pathogenesis remains unknown but an autoimmune mechanism has been suggested. CASE REPORT: We report the case of a 28-year-old female who had a clinical picture compatible with acute disseminated encephalomyelitis ten days after being stung several times by a bumblebee. The diagnosis was based on findings from magnetic resonance imaging and on the clinical-radiological course after a one-year follow-up. The patient was treated with massive doses of intravenous corticosteroids and immunoglobulins, which brought about partial recovery from the neurological deficit. CONCLUSIONS: Hymenoptera stings can produce demyelinating neurological complications, presumably related to the autoimmune system, which could benefit from treatment with immunomodulators such as corticosteroids, immunoglobulins or plasmapheresis.

Possible case of peripheral osmotic demyelination syndrome.

Central pontine myelinolysis (CPM) is an uncommon neurological syndrome that is usually related to the rapid restoration of a previous hyponatraemia. Although the most frequent location of CPM injury is the pons, it is now designated osmotic demyelination syndrome (ODS) because, as well as in the brainstem, these injuries can be observed in other parts of the central nervous system (CNS)-for example, the thalamus, subthalamic nucleus, external geniculate body, putamen, globus pallidum, internal capsule, white matter of cerebellum and the deep layers of the brain cortex. However, an exhaustive search of the literature (MEDLINE 1967-2007) has revealed no case report of peripheral nervous system (PNS) demyelination secondary to severe hyponatraemia.

[Trigeminal-autonomic cephalalgias: International Headache Society diagnostic criteria does not allow for a correct classification]. / Cefaleas trigeminoautonómicas: los criterios diagnósticos de la International Headache Society no permiten su clasificación correctamente.

INTRODUCTION: The International Classification of Headache Disorders only recognizes the following as trigeminal- autonomic cephalalgias (TAC): cluster headache, paroxysmal hemicrania and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) syndrome. Nevertheless, there are other types of TAC that still have not been incorporated into the International Classification of Headache Disorders although they have been before reported in the literature. We present the results of the analysis of a series of 94 cases of TAC. METHODS: We performed a retrospective study of 2,132 patient who attended a general neurology consultation due to headache between January 1997 and June 2006. Those patients with unilateral headache (orbital, supraorbital y/o temporal) accompanied of some ipsilateral autonomic sign were selected. We investigated the etiology of all cases and made a nosology classification according with two types of criteria: IHS (International Headache Society) strict criteria as well as other criteria (IHS plus) including migraine with ipsilateral autonomic signs and hemicrania continua, thus following Goabsby. RESULTS: A total of 94 cases of TAC (4.4% of all the headaches) were found, 89 of which had a primary etiology and 5 secondary etiology. Cluster headache was the most frequent TAC in our series (29%), independently of the criteria used. However, hemimigraine with ipsilateral autonomic signs had a similar frequency (28%) according to IHS plus criteria. CONCLUSIONS: a) In our series TAC have constituted an not very frequent entity, there being a subgroup of secondary cases among them, and b) the current International Classification of the Headache Disorders has some limitations as an instrument for the nosology classification of TAC.