Características de la enfermedad cerebrovascular en un Servicio de Cuidados Intermedios Neurológicos, en Chile. Análisis de 459 pacientes consecutivos / Cerebrovascular disease in a Neurologic Intermediate Care Unit in Chile. Analysis of 459 consecutive patients

Background: Stroke is the second cause of mortality and the first cause of morbidity in Chile and worldwide. Nowadays there is a major interest in introducing new therapies applying evidence based medicine for these patients. Aim: To describe the clinical profile of patients attended after a stroke, to determine stroke subtypes and their risk factors. Material and methods: Retrospective review of clinical records of 459 patients (mean age 65±48 years, 238 female) that were admitted to our unit during a period of 37 months. Results: Sixty three percent of patients had an ischemic stroke, 14% had an hemorrhagic stroke, 15% had a transient ischemic attack, 2% had a cerebral venous thrombosis and 6% a subarachnoidal hemorrhage. The global mortality was 1%. Seventy percent of patients had a history of high blood pressure. Conclusions: The most common type of stroke is ischemic and high blood pressure is the main risk factor.

Falla auttonómica pura: Síndrome de Bradbury Eggleston / Pure autonomic failure. Bradbury Eggleston Syndrome: Case report

Pure Autonomic Failure is a progressive, adult onset, degenerative disorder of the autonomic nervous system characterized clinically by orthostatic hypotension, bladder, sexual and sudomotor dysfunction. Since there are no other associated somatic neurological deficits, this condition must be considered in the differential diagnosis of orthostatic hypotension. We report a 64 years old man with a history of seven years of autonomic dysfunction, with severe orthostatic hypotension, erectile and bladder dysfunction. Autonomic tests showed low circulating norepinephrine levels, sweating abnormalities with regional anhydrosis of the left side of the trunk and abnormal cardiovagal response, indicating generalized autonomic failure. Peripheral somatic neuropathies with autonomic involvement were excluded by normal electrophysiologic tests and the patient was diagnosed pure autonomic failure. Treatment with fludrocortisone and midodrine improved orthostatic tolerance.

[Cerebrovascular disease in a Neurologic Intermediate Care Unit in Chile. Analysis of 459 consecutive patients]. / Características de la enfermedad cerebrovascular en un Servicio de Cuidados Intermedios Neurológicos, en Chile. Análisis de 459 pacientes consecutivos.

BACKGROUND: Stroke is the second cause of mortality and the first cause of morbidity in Chile and worldwide. Nowadays there is a major interest in introducing new therapies applying evidence based medicine for these patients. AIM: To describe the clinical profile of patients attended after a stroke, to determine stroke subtypes and their risk factors. MATERIAL AND METHODS: Retrospective review of clinical records of 459 patients (mean age 65+/-48 years, 238 female) that were admitted to our unit during a period of 37 months. RESULTS: Sixty three percent of patients had an ischemic stroke, 14% had an hemorrhagic stroke, 15% had a transient ischemic attack, 2% had a cerebral venous thrombosis and 6% a subarachnoidal hemorrhage. The global mortality was 1%. Seventy percent of patients had a history of high blood pressure. CONCLUSIONS: The most common type of stroke is ischemic and high blood pressure is the main risk factor.

[Efficacy and secondary effects of chronic treatment with amiodarone]. / Eficacia y efectos secundarios del tratamiento crónico con amiodarona.

Long-term therapy with amiodarone has been associated with a high incidence of adverse side effects, that precludes its indication for common cardiac arrhythmias. We have prospectively studied 218 patients (pts), aged 32-87 years, under chronic amiodarone therapy that were followed for 2 years and evaluated for efficacy and adverse side effects. Previous amiodarone treatment ranged from 1 to 135 months. Cardiac arrhythmias were paroxysmal AF (PAF) in 120 pts, sustained VT (SVT) in 36 pts, paroxysmal supraventricular tachycardia (PSVT) in 21 pts, unsustained VT (UVT) in 18 pts and miscellaneous in 23 pts. Amiodarone doses ranged from 500 to 4200 mg per week. Amiodarone was effective in 65% of all patients. No difference was observed between efficacy and type of arrhythmia. Dermatologic toxicity was found in 36%, neurologic toxicity in 23%, thyroid toxicity in 13.4% and pulmonary fibrosis en 2.5% of pts. Amiodarone was discontinued routinely when pulmonary toxicity was present. We conclude that amiodarone therapy is effective in a wide spectrum of arrhythmias. Although drug therapy was associated with a high incidence of adverse side effects, these did not preclude continuation of treatment.

Triptofano y su uso en medicina / Medical uses of tryptophan

Ha habido importantes avances en el conocimiento del metabolismo del triptofano, la síntesis de serotonina y los receptores serotoninérgicos encefálicos. Se ha determinado la efectividad terapéutica del 5-hidroxitriptofano en la depresión, insomnio, dolor crónico, mioclonías, etc. Eso sí, ha surgido inquietud al establecerse, como efecto adverso del tratamiento con L-triptofano, la producción del síndrome de mialgia-eosinofilia con compromiso importante de las fuerzas debido a una polineuropatía

Encefalomiopatía mitocondrial, acidosis láctica y apariencia de accidentes vasculares cerebrales / Mitochondrial, lactic acidosis and features of cerebrovascular disorders

En una paciente de 12 años de edad, aparentemente sana hasta los 9 años, con epilepsia progresiva, deterioro mental, acidosis láctica y déficit neurológicos que simulaban accidentes cerebrovasculares, la biopsia muscular demostró fibras rojas desflecadas y acúmulos de mitocondrias anormales, confirmando el diagnóstico de encefalomiopatía mitocondrial. Conviene pensar en este grupo de enfermedades en pacientes escolares con cefalea periódica, epilepsia mioclónica que responde mal al tratamiento, hipoacusia sensorioneural y deterioro mental. Las manifestaciones musculares pueden ser frecuentemente tardías

[Mitochondrial encephalomyopathy, lactic acidosis and features of cerebrovascular disorders]. / Encefalomiopatía mitocondrial, acidosis láctica y apariencia de accidentes vasculares cerebrales.

A 12 year old girl with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke like episodes (MELAS) is reported. After a normal childhood, at 9 years of age she developed generalized and hemilateralized seizures. Posteriorly, these episodes became more frequent and were accompanied by headache, homonimous hemianopsia, ataxia, vomiting, photophobia, left hemiparesis, slurred speech and even convulsive status. Laboratory tests evidenced lactic acidosis, brain lucencies at CT Scan and ragged skeletal muscle fibers at muscle biopsy.

Intramuscular pH and endurance are abnormal in skeletal muscles from rats with experimental myotonia.

The relation between resistance to fatigue and intramuscular pH was studied in fast muscles (anterior tibialis and extensor digitorum longus) from rats treated with 2,4-dichlorophenoxyacetic acid (2,4-D) to induce myotonia. Fatiguability was studied in muscles indirectly stimulated at 30 Hz (330 ms/s; 1 train/s) for 2 min. The resistance to fatigue decreased significantly 1 h after drug treatment and remained low 24 h later. The intramuscular pH was lower than normal in resting muscles from 2,4-D-treated rats. After 2 min of stimulation the pH decreased in both control and drug-treated muscles. However, this decrement was reduced in the experimental muscles. The pH of control and of 2,4-D-treated muscles were similar after the stimulation period, but only the drug-treated muscles were fatigued. Therefore, a decrease in intramuscular pH would not be the cause of the observed decrease in muscle resistance to fatigue after 2,4-D treatment. The reduced endurance of drug-treated muscles could not be attributed to impaired neuromuscular transmission.

Changes in contralateral synaptic acetylcholinesterase following motor nerve section in rats.

We report here that denervation of rat extensor digitorum longus, soleus and diaphragm muscle results in an increase of a subset of asymmetric acetylcholinesterase (class II A-forms) in the contralateral muscle, within a few days. This observation is interesting because it suggests a specific regulation of one asymmetric enzyme fraction, which is solubilized only in the presence of chelating agents and is thought to reside in the basal lamina.

Glucocorticoid excess induces preferential depletion of myosin in denervated skeletal muscle fibers.

The combined effects of dexamethasone treatment (1 mg/Kg/day) plus denervation (DEX-DEN), were studied at 7, 13, and 28 days by microscopic, biochemical, and physiological techniques in plantaris and soleus muscles of adult rats. The results were compared with corresponding dexamethasone-treated (DEX) and denervated (DEN) muscles and appropriate controls. There was a significantly more marked atrophy of all fiber types in the DEX-DEN plantares at 7 and 13 days than in either DEX or DEN muscles. The degree of atrophy was greatest in type 2B fibers in DEX-DEN plantares. Electron microscopy revealed a severe preferential depletion of thick myofilaments in DEX-DEN plantares and solei but not in DEX or DEN muscles. The thick myofilament depletion in DEX-DEN muscles occurred in addition to a severe overall reduction of myofibrillar caliber. Gel electrophoresis showed a marked preferential decrease of myosin heavy chain in DEX-DEN plantares and solei, but not in either DEX or DEN muscles. Myosin light chains were also markedly reduced in DEX-DEN plantares and solei. In vitro physiological studies showed a marked reduction of the denervation-induced twitch potentiation in DEX-DEN solei. Maximal tetanic tension (20 Hz stimulation) per gram weight of muscle as well as the twitch-tetanus ratio was significantly reduced only in DEX-DEN solei in relation to controls. Myosin depletion in DEX-DEN muscles may be due to a severe preferential inhibition of its synthesis coupled with an accelerated catabolism.

Bilateral homonymous hemianopia with sparing of central vision after subdural hematoma.

A patient with bilateral homonymous hemianopia with preservation of the central vision, spatial disorientation and memory deficits secondary to bilateral occipital and mesial temporal infarctions, is presented. The cerebral damage followed a subdural hematoma with tentorial herniation and compression of both posterior cerebral arteries.

Calcium paradox in skeletal muscles: physiologic and microscopic observations.

Immersion of rat hemidiaphragms in Ca2+-free Krebs solution (KS) containing Ca2+ chelator in vitro leads to separation of basal lamina from the plasma membrane, as well as transient contracture and rapid loss of twitch response [calcium paradox (CP) phase 1]. Subsequent immersion in regular KS results in necrosis of muscle fibers accompanied by slowly increasing contracture (CP phase 2). This contracture could be prevented or reduced by using either Ca2+-free KS or calcium channel blockers, but not by dantrolene sodium, implying that after drastic reduction of extracellular and sarcolemmal Ca2+ during CP phase 1, the sarcolemma has lost its ability to control normal Ca2+ fluxes. Contracture did not develop at 21 degrees C. CP is a convenient model to study calcium-induced muscle cell death and the role of Ca2+ in maintaining sarcolemmal integrity.

Skeletal muscle endurance: the effect of increased availability of endogenous long-chain fatty acid fuel.

A possible role of intramuscularly derived fatty acid fuel on muscle endurance was investigated in curarized diaphragms of fasted rats. These showed significantly improved endurance during 60 min of intermittent stimulation at 20 Hz in vitro compared with diaphragms of fed control animals. The improved endurance appeared to be related to an increased availability and utilization of fatty acid fuel derived from greatly increased numbers of lipid globules in muscle fibers of fasted animals. The pH of muscles with improved endurance (fasted rats) was not different from that of muscles from fed controls at rest. After 60 min of intermittent stimulation, the muscle pH diminished to the same extent in both groups. Diaphragms of fasted rats that were refed 12 h before testing did not show improved endurance. Epinephrine in the bath abolished the improved endurance of diaphragms of fasted rats. Diaphragms of fasted guinea pigs did not show significantly improved endurance (despite abundant intracellular lipid globules), possibly because of a reduced intracellular carnitine.

Calcium-induced damage of skeletal muscle fibers is markedly reduced by calcium channel blockers.

Vascular perfusion of rat hind limbs with a Ca2+-free physiological solution containing ethylenediaminetetraacetate, when followed by a physiological solution with normal concentration of Ca2+, caused a marked rise of creatine kinase (CK) in the venous effluent. When calcium channel blockers were present in the perfusing solutions, no rise of CK occurred. On histological sampling of perfused muscles, CK rise was roughly correlated with muscle fiber damage of the appropriate muscles. Removal of calcium from the plasmalemma of muscle fibers appears to prevent closure of calcium channels, making the muscle fibers susceptible to a deleterious influx of extracellular calcium. This influx can be prevented by the presence of calcium channel blockers in the perfusates.

Increase of muscle peroxisomal enzymes and myotonia induced by nafenopin, a hypolipidemic drug.

The chronic administration of nafenopin, a hypolipidemic drug, induced an increase in catalase and acyl-CoA oxidase activities in various skeletal muscles, including the gracilis, diaphragm, soleus, and extensor digitorum longus. The magnitude of the increase was around 100% for both enzymes in each of the muscles studied in spite of the different basal level. These changes seem to be specific of the peroxisomal enzymes because acetylcholinesterase, which is not peroxisomal, did not follow the same pattern in all the muscles. Concomitant with the increase in muscle peroxisomal enzymes, the skeletal muscles presented an altered electromyogram with prolonged insertional activity, repetitive firing of action potentials, and myotonic runs characteristic of myotonia. Our results suggest a role for peroxisomes in the myotonic disorder.

Axonal transport dysfunction in dystrophia myotonica.

Axonal transport of acetylcholinesterase (AChE) was measured in the median and sural nerves of a subject who suffered from dystrophia myotonica and in a control subject. It was found that the basal activity of AChE was increased in myotonic nerves while its proximodistal transport was inhibited.