The infectious protein or prion (PrPSC) is a transmissible and replicable polypeptide, which arises from an abnormal folding of the PrP protein, by unknown mechanisms and without changes in the primary sequence of its amino acids. Its new spatial disposition arises from the substitution of its alpha helices by beta bands, which increase its structural stability, avoiding its complete proteolysis, resulting in a residual accumulation of prions. These prions induce the misfolding of normal PrP protein, generating their exponential increase, leading to a disturbance of neuronal homeostasis which results in the development of the fatal spongiform encephalopathy of the Creutzfeldt-Jakob disease (CJD). This is the most prevalent human prion disease, and 90% of cases are sporadic, suggesting the endogenous genesis of prions. There are different types of prions, identified based on the genetic variance of codon 129 amino acids of the prion protein. Meteonin (M) and Valine (V)), associated with the result of their enzymatic proteolysis, define prions type 1 (21 kDa) and type 2 (19 kDa). The Classical form of CJD produced by MM1 prion occurs in 70% of the cases. The Cerebellar form originated by the VV2 prion occurs in 15% of cases, the form with Kuru plates, associated with the prion MV2 occurs in 5%, and the Vacuolar, related to the MM2 prion occurs in 4%. CJD is always characterized by behavioral, motor, cognitive, and vision alterations and by findings in magnetic resonance imaging, electroencephalogram and cerebrospinal fluid that define each clinical and neuropathological form.

Pneumococcal meningitis produces several inflammatory disorders in susceptible subjects. A worsening of meningitis can occur on the fourth day of evolution in relation with the withdrawal of steroids. Other complications include the development of inflammatory signs in the post-acute stage of infection associated with disseminated vasculitis of the cerebral blood vessels and, even later, an autoimmune chronic meningitis. All these inflammatory complications are well controlled with the use of steroids. We report a 53-year-old woman with pneumococcal meningitis that had a good response to treatment with antibiotics and steroids. On the four day, after the steroids were discontinued, she complained of headache, became confused, and had an abnormal cerebrospinal fluid (CSF), report CT angiography showed signs of arteritis. She improved when the steroids were re-started. She was discharged in good condition but after slow tapering of the steroids over a four-month period she had a relapse of all her symptoms and had a gait disturbance. On readmission, she had an inflammatory CSF, there were no signs of infection and the cerebral MRI showed meningeal thickening with ventricular space enlargement. She improved again with steroids and she is now well on high-dose steroids but deteriorates each time the steroids are stopped. She experienced both acute and sub-acute inflammatory responses and finally developed a chronic meningitis responsive, and is dependent on steroids.

Background: Lymphotropic Virus Type I (HTLV-I) causes Tropical Spastic Paraparesis (PET) in 3% of infected patients; in whom have been described exceptionally associated a central vestibular syndrome and cerebellar atrophy. Those alterations of CNS are predominating in women. Purpose: To present a new case of the exceptional form of spastic paraparesis and cerebellar atrophy. To suggest a pathogenic interpretation of female predominance in this pathology Patient: A 20-year-old woman of small size, infected with HTLV-I during lactation. Approximately at 15 years of age he started a progressive ataxo-spastic syndrome, later cognitive damage and cerebellar atrophy were added. Upon admission, high viral load and high levels of Tax protein, leukemoid lymphocytes and Sicca syndrome were observed. Conclusion: PET is an axonopathy of the central motor pathway, originated by a chronic disturbance of axoplasmic transport, attributable to the action of elevated levels of Tax protein in the CNS. In addition axons of the oval center (cognitive impairment) or the cerebellar vermis (central vestibular syndrome) are occasionally damaged. Although PET mainly affects 3: 1 women, this prevalence increases in accordance with the increase of neurological damage. The apparent greater vulnerability of the CNS in women would be due to the higher concentration of Tax in the CNS of them, originated in the adverse relationship between body weight and absolute amount of Tax, which was evident in our patient, who gave the key to this hypothesis.

Resumen Antecedentes: El virus linfotrópico T tipo I (HTLV-I) origina la paraparesia espástica tropical (PET) en el 3% de los infectados, afectando predominante mujeres. Excepcionalmente la PET puede asociar un síndrome vestibular central y atrofia cerebelosa. Propósito: Presentar un nuevo y excepcional caso de paraparesia espástica y atrofia cerebelosa. Sugerir una interpretación patogénica del predominio femenino en esta patología Paciente: Mujer de 20 años de talla baja y menuda, infectada con HTLV-I durante la lactancia. Aproximadamente a los 15 años inició un síndrome ataxo-espástico progresivo, con grave alteración de la marcha, posteriormente agregó daño cognitivo y atrofia cerebelosa en la RM. Se constató a su ingreso una elevada carga viral y altos niveles de proteína Tax. Fue tratada con 4 mg betametasona diarios durante 10 días, que mejoraron la marcha. Conclusión: La PET es una axonopatía de la vía motora central, originada por la crónica perturbación del transporte axoplásmico, atribuible a la presencia de elevados niveles de la proteína Tax del virus. Circunstancialmente este aumento de Tax logra dañar axones del centro oval (deterioro cognitivo) o del vermis cerebeloso (síndrome vestibular central). La PET afecta mayoritariamente a mujeres 3:1, prevalencia que hace aparecer a las mujeres con una mayor vulnerabilidad en su SNC. Sin embargo, esta aparente minusvalía, sería debida a un aumento en la concentración de Tax en el SNC de ellas, causado por la adversa relación entre peso corporal y cantidad absoluta de Tax, que fue evidente en nuestra paciente, quien dio la clave para esta hipótesis.

Giant cell arteritis is the most common vasculitis in patients aged over 50 years. We report an 89-year-old woman with significant weight loss and persistent frontal-occipital headaches lasting two months. The neurological examination at admission identified a decrease in visual acuity of the left eye, paralysis of the third cranial nerve of the right eye and alterations of body motility without objective signs of damage of the motor or sensitive pathways. Magnetic resonance imaging showed changes of the temporal artery wall and in both vertebral arteries, as well as bilateral cerebellar and occipital ischemic lesions. The Doppler ultrasound of the temporal arteries was compatible with Giant cell arteritis. Treatment with steroids was started. While receiving oral prednisone, the patient suffered new infarcts of the posterior territory, documented with a CAT scan.

Background: Cerebral ptosis is understood as the bilateral paralysis of eyelid elevation linked to a stroke or hemorrhage of the middle cerebral artery (MCA). It is a transient condition, independent of the evolution of the lesion. Aim: To analyze six patients with the condition. Patients and Methods: Report of five women and one male aged 42 to 72 years. Results: All suffered an infarction or hemorrhage in the territory of the middle cerebral artery of the non-dominant hemisphere and developed a bilateral palpebral ptosis. The recovery started after the fourth day. At the tenth day, eye opening was effortless and did not require frontal help, despite the persistence of hemiplegia. Conclusions: Cerebral ptosis is a mimetic dysfunction of a specific non-injured area of the cerebral cortex, originated from a nearby parenchymal damage such as the middle cerebral artery of the same hemisphere. Cerebral ptosis expresses the inhibition of the voluntary eyelid elevation center, of prefrontal location in the non-dominant hemisphere.

Intrathecal chemotherapy may be complicated with the development of myelopathies or toxic radiculopathies. This myeloradicular involvement, of toxic character, is unpredictable, since these patients have repeatedly received Intrathecal chemotherapy with the same drugs without apparent injury. The toxic effect should be mainly attributed to Cytarabine and not to methotrexate, since the central nervous system lacks Cytidine deaminase, the enzyme that degrades Cytarabine. We report two patients, an 18-year-old woman and a 16 years old male, who received systemic and intrathecal chemotherapy (methotrexate, cytarabine) for the treatment of an acute lymphoblastic leukemia and developed, in relation to this procedure, a spinal subacute combined degeneration. They had a proprioceptive and motor alteration of the lower extremities and neuroimaging showed selective rear and side spinal cord hyper intensity produced by central axonopathy. Two weeks later the woman developed a quadriplegia and the young man a flaccid paraplegia due to added root involvement.

Upgaze or sustained elevation of the eyes, is an alteration of ocular motility initially described in hypoxic coma. We report a 65-year-old woman admitted with hypotension and alteration of sensorium due to the ingestion of 9.5 g of Bupropion. She presented two seizures of short duration, without epileptic activity on the EEG. She had a persistent asynchronous myoclonus in extremities, tachycardia and prolonged Q-t. She suffered a cardiac arrest caused by asystole, which recovered quickly in five minutes. At that moment, upgaze appeared, associated with a persistent ocular opening, which persisted for days, but finally disappeared, without remission of coma. A magnetic resonance imaging done at the eighth day, showed hyperintensity of the oval center and corpus callosum which disappeared in a new imaging study done 30 days later, where images of hypoxia in the basal nuclei and cortex appeared. The patient died forty seven days after admission. Up-gaze is an ominous oculomotor alteration linked to an important but incomplete damage in the cerebral cortex, a condition that perverts some sequences of the ocular opening, reversing the Bell phenomenon and producing eyelid retraction.

Background: Patients with Glioblastoma multiforme (GBM) have a five years survival of less than 5%, but the response to chemotherapy with alkylating agents can vary depending on the methylation status of O6-methylguanine-DNA-methyltransferase (MGMT). Genetic testing has limitations for routine use, while immunohistochemistry (IHC) offers a fast and affordable technique but with heterogeneous results in the literature. Aim: To evaluate MGMT expression by IHC in tumor tissue of Chilean patients with GBM. Material and Methods: Tumor samples of 29 patients with a pathological diagnosis of GBM were studied. We performed IHC staining and manual analysis of positive and negative cells for MGMT expression. A cut-off of at least 10% of cells expressing MGMT was used. Demographic and clinical features of patients were obtained from clinical records. Results: The median number of cells counted per case was 692 (interquartile range [IQR] 492-928). Fifteen cases (52%) were positive for MGMT expression. Median overall survival was 5.3 months (IQR 3.4-12-8). The effect of MGMT expression on the therapeutic response was not studied since only 3 patients received chemotherapy. Conclusions: Our results are similar to international reports, but we were not able to determine the association between MGMT expression and therapeutic response.

Eyelid retraction, has received limited attention and it has passively been interpreted as the result of an overactive levator palpebrae superioris muscle secondary to midbrain injury. However, eyelid retractions can occur in other neurological diseases, not directly related with the midbrain. We report three patients who developed eyelid retraction. One patient had a bilateral eyelid retraction, related with Creutzfeldt-Jakob disease (CJD). Another patient had a unilateral right eyelid retraction associated with a thalamic-mesencephalic infarct. The third patient had a bilateral pontine infarction on magnetic resonance imaging. In the patient with CJD, eyelid retraction did not subside. Among patients with infarctions, the retraction persisted after focal symptoms had subsided, showing an evolution that was apparently independent of the basic process. The analysis of these patients allows us to conclude that the pathogenesis of eyelid retraction includes supranuclear mechanisms in both the development and maintenance of the phenomenon. Unilateral or bilateral eyelid retraction does not alter the normal function of eyelid, which ever had normal close eye blink. In these reported cases, a hyperactivity of levator palpebrae superioris muscle was clinically ruled out.

Liquefied hydrocarbon gas, such as propane is considered safe. However there are reports that voluntary exposure to liquefied gas at least could originate hallucinatory states. We report a 20 years old woman who was found in a coma with extensor muscle hypertonia, brisk tendon reflexes and extensor plantar (Babinski) responses after being exposed to propane gas. The brain magnetic resonance imaging (MRI) showed lesions in both hippocampi and white matter in the oval center. The patient had a normal oxygen saturation of 98%, a carboxyhemoglobin of 1.6% and a metabolic acidosis with a pH of 7.01 with an anion gap of 16 mEq/l. This pattern suggested that it was a consequence of the intermediary metabolism of isopropanol. The recovery of the patient was slow and four months later she still had lesions on MRI and limitations in her cognitive sphere, memory and executive functions. Thus, liquefied gas exposure can cause a toxic encephalopathy with a persistent damage of the central nervous system.

Posterior reversible encephalopathy (PRES) is a condition characterized by T2 and FLAIR hyperintensities in magnetic resonance imaging (MRI) studies, localized preferentially in the occipital-parietal white matter regions. Pathological MRI images located in midbrain, pons, medulla and spinal cord, that could be asymptomatic, were recently included in this entity. These images are interpreted as vasogenic edema, which is caused by arterial hypertension or eclampsia, neurotoxicity related to immunosuppressive agents or chemotherapy, among other causes. We report a 25 years old asymptomatic male with AIDS, with normal blood pressure who after initiating highly active antiretroviral therapy (HAART) reported vertigo. The MRI showed a central pontine T2 hyperintensity with diffusion restriction, which was interpreted as a central pontine myelinolysis (CPM), but the lack of motor symptoms made improbable a real demyelination of the pons. The follow-up MRI revealed complete regression of the images. To our knowledge, this case could be the second report of a reversible leucopathy of the pons in a patient with AIDS, were the MRI images also simulated a CPM. This report extends the knowledge around the variability of the pathogenic interpretation of CPM images and their association with HAART.

The prevalence of drug-associated toxic encephalopathy is unknown, but it is an uncommon condition. Toxic leukoencephalopathy was described associated with heroin consumption, it has been less commonly described with the use of cocaine and there are no reports of its association with consumption pasta base of cocaine (PBC). We report two females aged 31 years and a male aged 19 years, consumers of PBC who developed a fatal toxic leukoencephalopathy. They initiated their disease with severe and persistent headache, sequential focal neurologic deficits and a progressive impairment of consciousness that culminated with their death. Laboratory parameters such as blood count, cerebrospinal fluid analyses or infectious biological indices were normal. MRI showed multifocal lesions in brain white matter of both hemispheres confirming the leukoencephalopathy. There was no response to the use of methylprednisolone.

The Meningitis-Retention Syndrome associates aseptic meningitis and neurogenic bladder, with a vesical dysfunction that outlasts meningitis widely. Urodynamic assessment shows a detrusor palsy with normal function of the external sphincter. We report a 24-year-old male admitted for headache, fever, myalgias and acute urinary retention, which was diagnosed as a urinary tract infection. Worsening of symptoms and slight meningeal signs prompted for a lumbar puncture that yielded a cerebrospinal fluid with 94 lymphocytes, in which etiological evaluation was inconclusive. Meningeal syndrome and myalgia subsided by the fifth day, while urinary retention persisted. A magnetic resonance imaging of the brain and spinal cord done at the fifth day, showed high intensity signals in basal ganglia and central spinal cord, not altered by contrast. These images disappeared in the imaging control performed two months later. Bladder dysfunction lasted at least until the second month of follow up.

Background: Nocardiosis is caused by several strains of Nocardia, Gram-positive bacteria that infects humans and animals likewise. They develop a systemic infection of pulmonary or cutaneous origin that can spread to the Central Nervous System. It frequently affects immunosupresed patients, in which parvosymptomatic cerebral abscess has been described, visible in magnetic resonance imaging but without focal symptoms. Patients and Methods: We want to communicate two women with renal transplant in immunosupresor treatment who were admitted to our hospital for acute pulmonar disease, during which patient A presented a convulsive episode and patient B headache and stupor, after which CT and MR were obtained. In both cases multiple cerebral abscesses were found, of different sizes and location, with no clinical manifestations. Nocardia diagnosis was made in patient A by biopsy from a cutaneous mycetoma and in patient B after surgery of a cerebellar abscess. In both cases antimicrobial treatment was initiated with good response, but had to be interrupted due to adverse effects. This reactivated the infection, which had a complicated course and finally lead to the death of both patients. Conclusions: The fact that several cases of parvosymtomatic cerebral Nocardiosis in immunosupresed patients have been published suggest that cellular immunosupresion is key in the development of cerebral infections by Nocardia. It probably allows the access and multiplication of the bacteria inside the encephalon without an immediate clinical response. The development of symptoms is probably related to a late alteration of the blood-brain barrier rather than to the slow progression of Nocardia disease.

Antecedentes: La nocardiosis es originada por distintas cepas de Nocardia, bacterias Gram positivas que afecta a humanos y animales. Pueden producir infecciones sistémicas de ingreso cutáneo o pulmonar, que llegan a comprometer el Sistema Nervioso Central. Se afectan especialmente pacientes inmunosuprimidos que pueden desarrollar abscesos cerebrales, visibles en la Resonancia Magnética (RM), pero que no expresan síntomas de las lesiones focales o son parvosintomáticos. Pacientes y Método: Queremos comunicar dos mujeres con trasplante renal en tratamiento inmunosupresor, que desarrollaron cuadros pulmonares agudos que obligaron a su hospitalización, en cuyo contexto la paciente (A) presentó una convulsión y la (B) cefalea y compromiso de conciencia, que obligaron a una RM de cerebro. En ambos casos se encontraron múltiples abscesos cerebrales de distinta ubicación y tamaño que no habían dado síntomas focales. La nocardiosis se identificó en la paciente (A) con la biopsia de un micetoma cutáneo y en la (B) con la resolución quirúrgica de un absceso cerebeloso. En ambas se inició tratamiento específico con adecuada respuesta. Sin embargo, las reacciones adversas a la antibioterapia obligaron a suspenderla. Esta suspensión reactivó la infección que complicó y llevó al fallecimiento de las pacientes. Conclusiones: La publicación de varios casos de nocardiosis cerebral parvosintomática en pacientes inmunosuprimidos sugiere que para las infecciones cerebrales por Nocardia la pérdida de la inmunidad celular resulta muy significativa, porque permitiría el ingreso y proliferación de la bacteria al interior del SNC sin generar respuestas clínicas inmediatas. La aparición de síntomas se relacionaría con una tardía alteración de la barrera hematoencefálica, más que con el lento proceso lesional de la Nocardia. Lo que condicionaría su diagnóstico oportuno.