Evidencias en la prevención de trombosis venosas profundas en pacientes con ictus isquémicos / Evidence of the preventionof deep vein thrombosisin patientswith ischaemic ictus

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[Cerebral ischemia in Rendu-Osler-Weber disease]. / Isquemia cerebral en la enfermedad de Rendu-Osler-Weber.

Neurologic manifestations occur in 8-12% of the patients with Rendu-Osler-Weber disease or hereditary hemorrhagic telangiectasia (HHT), principally infectious and hemorrhagic and, less frequently, ischemic ones. More than a half of these neurologic complications are associated with pulmonary arterio-venous malformations (PAVM). The diagnosis of HHT is based on the presence of telangiectases, hemorrhagic events and a family history with an autosomal dominant pattern. We report a case of a patient diagnosed as having HHT with transient ischemic attacks and a PAVM, which was occluded by the use of embolotherapy. Cerebral ischemia in HHT is related to the existence of a PAVM and results from three mechanisms: 1) secondary poliglobulia and hyperviscosity because of the hypoxemia due to a right-left shunt; 2) communication between the airway and the pulmonary circulation during cough access, which produces gas embolism and hemoptysis; 3) and, finally, paradoxical embolism trough the PAVM, the same mechanism proposed to the infectious neurologic manifestations of the disease. When the diagnosis of HHT is suspected, early search and treatment of PAVM, with embolotherapy or surgery, are necessary in order to avoid respiratory problems (hemoptysis, exertional dyspnea, cianosis, clubbing) and neurologic complications.

Isquemia cerebral en la enfermedad de Rendu-Osler-Weber / Cerebral ischemia in Rendu-Osler-Weber disease

Un 8-12 por ciento de los pacientes con enfermedad de Rendu-Osler-Weber o telangiectasia hemorrágica hereditaria presenta manifestaciones neurológicas, sobre todo, hemorrágicas e infecciosas y, de forma menos frecuente, isquémicas. De ellos, más de la mitad asocian la presencia de malformaciones arteriovenosas pulmonares. El diagnóstico de la enfermedad se basa en la existencia de telangiectasias, fenómenos hemorrágicos y un patrón hereditario autosómico dominante. Se describe el caso clínico de un paciente, diagnosticado previamente de telangiectasia hemorrágica hereditaria, con accidentes isquémicos transitorios y una malformación arteriovenosa pulmonar que fue tratada mediante embolización. La isquemia cerebral en la telangiectasia hemorrágica hereditaria está relacionada con la presencia de una malformación arteriovenosa pulmonar y puede deberse a tres mecanismos: a) hiperviscosidad por poliglobulia secundaria a la hipoxemia provocada por la formación de un cortocircuito derecha-izquierda; b) comunicación de la vía aérea y la circulación pulmonar durante accesos de tos, lo que ocasiona una embolia gaseosa habitualmente acompañada de hemoptisis, y, por último, c) embolia paradójica a través de la malformación arteriovenosa pulmonar, que es, asimismo, el origen de las complicaciones neurológicas infecciosas de la enfermedad. En los pacientes con telangiectasia hemorrágica hereditaria debe investigarse la presencia de malformaciones arteriovenosas pulmonares y llevar a cabo de forma precoz su tratamiento, ya sea intravascular o quirúrgico, con el fin de evitar tanto problemas respiratorios (hemoptisis, disnea de esfuerzo, cianosis o acropaquías) como las posibles manifestaciones neurológicas. (AU)

[Segmental arteriographic anomalies in migranous cerebral infarct]. / Anomalías arteriográficas segmentarias en el infarto cerebral migrañoso.

A migranous cerebral infarct (ICM) has the appearance of an ischaemic cerebral lesion which occurs during a migraine crisis and is shown by neuroimaging techniques to be in the corresponding vascular area. Four young patients are described. They fulfilled the clinical and neuroimaging criteria for compatibility with ICM and the protocol for the aetiological study of stroke was normal. Angiography ruled out other causes of ischaemia (dissection, fibromuscular dysplasia, etc.) and showed segmental images of 'vasculitis appearance' similar to these described in Call's syndrome, in 'benign intracranial angiopathy' and in other intracranial vasculopathies or criteria of 'reversible segmental cerebral vasoconstriction'. The pathogenic significance, as with migraine, is still unknown.

[Lateral sinus thrombosis in the first three months of pregnancy]. / Trombosis del seno lateral durante el primer trimestre del embarazo.

Thrombosis of the cerebral venous sinuses is characterized by clinical pleomorphism and variable pathogenesis. Although there is a relationship with pregnancy and especially with the puerperium, occurrence during the first trimester of pregnancy is unusual and this may effect the diagnosis and treatment. We describe the case of a 33 years-old patient with lateral sinus thrombosis in the first trimester of pregnancy. This was diagnosed and followed-up by magnetic resonance. Investigations as to its aetiology were inconclusive and it followed a benign course without anticoagulation. Thrombosis of the venous sinuses has been found empirically to be related to states of deficiency of S protein, hypercoagulability, anaemia and deshydration during pregnancy, to having previously taken contraceptive pills. Behçet's disease, other coagulopathies, central or systemic vasculitis, collagen disorders, septic and neoplastic disorders and a large number of cases of unknown aetiology. In our patient neurological deterioration secondary to a venous infarct or intraparenchymatous haemorrhage was not seen. There was full recovery and complete spontaneous canalization of the sinus, as shown on posterior cranial angiography. The controversial decision to use heparin in thrombosis of the cerebral venous sinuses should probably depend on the possible risks and benefits in each individual case, taking into account the clinical findings, aetiology and topography of the thrombosed sinus.

[The spectrum of prion pathology broadens: fatal familial insomnia]. / El espectro de la patología prion se amplía: el insomnio familiar fatal.

INTRODUCTION: The small group of prion diseases, caused by accumulation in the brain of an abnormal protein characterized by its aggregation and relative resistance to proteases (the PrPSc) in man is comprised of Creutzfeldt-Jacob disease (CJE), the Gerstmann-Straussler-Scheinker syndrome, kuru and the newest addition which is fatal familial insomnia (FFI). DEVELOPMENT: FFI is a hereditary condition with dominant autosomal transmission, characterized clinically by progressive insomnia, dysautonomy, changes in the circadian rhythm of hormone secretion, motor signs and slight to moderate deterioration of cognition. The usual age of onset is between 40 and 60 years, and the course of the illness lasts between 7 and 18 months. The histopathological changes, involving neurone loss and reactive gliosis, particularly affect the anteroventral and dorsomedial thalamic nuclei. These lesions lead to insomnia and to autonomic and endocrine disorders. To a lesser extent and degree, lesions are seen in other thalamic nuclei, the cerebral cortex, inferior olives and the cerebellum. FFI and some families with CJE have the same mutation of the codon 178 of the protein prion gene (gene PRNP) with substitution of aspartic acid by asparagine. Polymorphism of codon 129, which codifies methionine or valine determines the development of the clinical and neuropathological phenotype of FFI or CJE respectively. CONCLUSIONS: The description of FFI and the detection of PrPSe in familial cases of diffuse subcortical gliosis has indicated the possibility that there may be other familial or non-familial neurodegenerative diseases caused by prions.

[Kinematic deterministic chaos of fluids and fractal geometry in the carotid system]. / Caos determinista, cinemática de fluidos y geometría fractal en el sistema carotídeo.

INTRODUCTION: Atherosclerosis is a generalized vascular disorder which tends to be localized to specific arterial territories. At the bifurcation of the carotid artery there is a marked predisposition to form plaques of atheroma on the postero-external wall. This tendency is due to the kinematics of fluids and their particular morphological characteristics which are unique in the vascular system. The carotid tree is a physical, non-lineal or in 'non-equilibrium', dynamic system which depends on the fluctuating contribution of energy from the cardiac cycle. It has fractal geometry which follows the Law of Biology of maximum efficiency with a minimum of effort. DEVELOPMENT: The complexity of the relationship between the haemo-rheological and anatomical factors, and the periodic oscillation of flow does not permit use of simple models and classical determinist equations to describe idealized systems of continuous movement and Newtonian fluids. On the contrary, since we are considering a complex dissipative dynamic system. It has marked intrinsic operational freedom adapting its responses to external disturbances well, thus determining vasculo-cerebral autoregulation. The theories of Determinist Chaos and of the Science of Complexity imply the existence of emerging properties which exceed those of the individual elements in the dynamic systems in non-equilibrium, which tend to function in the 'frontier of chaos' at the critical points of phase transition. The carotid tree has non-linear properties, appearance of order and fractal 'sibisemejanza'. Pseudo-chaotic vortices appear--in regions of phase transition between laminar flow and turbulence--with the emergence of a 'strange attractor' near to the postero-external wall of the bulb. CONCLUSIONS: The anatomical and kinematic complexity of the system, together with the irreversibility of the second Law of Thermodynamics, lead to a long-term tendency towards the appearance of a region of stagnant flow with increased Entropy in the territory of the strange attractor which determines--as an inevitable long-term outcome--the tendency to the appearance of atherosclerosis at this particular point.