Fear conditioning as a pathogenic mechanism in the postural tachycardia syndrome.

Despite its increasing recognition and extensive research, there is no unifying hypothesis on the pathophysiology of the postural tachycardia syndrome. In this cross-sectional study, we examined the role of fear conditioning and its association with tachycardia and cerebral hypoperfusion on standing in 28 patients with postural tachycardia syndrome (31 ± 12 years old, 25 females) and 21 matched controls. We found that patients had higher somatic vigilance (P = 0.0167) and more anxiety (P < 0.0001). They also had a more pronounced anticipatory tachycardia right before assuming the upright position in a tilt-table test (P = 0.015), a physiological indicator of fear conditioning to orthostasis. While standing, patients had faster heart rate (P < 0.001), higher plasma catecholamine levels (P = 0.020), lower end-tidal CO2 (P = 0.005) and reduced middle cerebral artery blood flow velocity (P = 0.002). Multi-linear logistic regression modelling showed that both epinephrine secretion and excessive somatic vigilance predicted the magnitude of the tachycardia and the hyperventilation. These findings suggest that the postural tachycardia syndrome is a functional disorder in which standing may acquire a frightful quality, so that even when experienced alone it may elicit a fearful conditioned response. Heightened somatic anxiety is associated with and may predispose to a fear-conditioned hyperadrenergic state when standing. Our results have therapeutic implications.

Comprehensive Perioperative Approach to Complex Spine Deformity Management.

OBJECTIVE: Study perioperative strategies for optimizing neuroprotection in complex spine deformity correction surgery. METHODS: We report the case of a patient with severe lumbar dextroscoliosis, thoracolumbar junction hyperkyphosis with a 40-degree Cobb angle levoconvex scoliosis who underwent spinal deformity correction with loss of neuromonitoring during surgery. We performed a literature review on perioperative management of complex spine deformity. RESULTS: A 50-year-old man presented with lumbar pain and right L4 radiculopathy. Surgical intervention for deformity correction and decompression was indicated with T4-L4 posterior instrumentation L2/L3 and L3/L4 transforaminal lumbar interbody fusion. Surgery was aborted due to the loss of neuromonitoring. Postsurgery, the patient had left sensory deficit and the neurocritical care team clinically suspected and deduced the anatomic location of the spinal cord compression. Magnetic resonance imaging confirmed a T10-T11 hyperintensity suggestive of cord ischemia due to osteophyte compressing the spinal cord. The patient underwent a second corrective surgery with no intraoperative events and has no long-term neurological sequela. CONCLUSIONS: This case illustrates that a comprehensive perioperative approach and individualized risk factor assessment is useful in complex spine deformity surgery. Further research is needed to determine how this individualized comprehensive approach can lead to intraoperative and postoperative countermeasures that improved spine surgery outcomes. LEVEL OF EVIDENCE: Level V.

Colistin neurotoxicity mimicking Guillain-Barré syndrome in a patient with cystic fibrosis: case report and review.

Guillain-Barré syndrome (GBS) is an immune-mediated polyneuropathy, which is characterized by areflexia and ascending paresthesia which can progress to a respiratory failure. Certain conditions, such as vasculitis and heavy metal and drug toxicity, may have misleadingly similar clinical presentation to GBS. We describe a case of a patient with cystic fibrosis and intravenous colistin-induced neurotoxicity mimicking GBS. The patient had used inhaled colistin on five occasions with no adverse effects, however, developed symptoms on the second day of intravenous treatment. Overlapping findings between immune-mediated polyneuropathy and drug-induced neurotoxicity include limb paresthesia and decreased reflexes. Perioral tingling, however, is a common presentation of colistin-induced neurotoxicity, and therefore, is an important differentiating factor. Early diagnosis prevents further neurologic decline, extensive unnecessary workup and potentially harmful incorrect management.

Uremic neuropathy: an overview of the current literature.

INTRODUCTION: Peripheral neuropathy is a disorder that affects the cell body, axon or myelin of motor or peripheral sensory neurons and occurs in 60-100% of patients who are submitted to dialysis due to chronic kidney disease. Uremic neuropathy (UN) is attributed to the accumulation of organic waste, evident in patients with reduced glomerular filtration rate. OBJECTIVES: This review aims to make clinical characteristics of uremic neuropathy evident enabling early diagnosis and treatment. METHODS: This is a literature review of articles published on PubMed over the last 10 years using "Uremic Neuropathy" as "Title/Abstract". RESULTS: A total of nine articles that met the inclusion criteria were included. UN is a distal symmetric sensorimotor polyneuropathy that occurs due to the accumulation of uremic toxins associated with an oxidative stress-related free radical activity. Hyperkalemia is thought to play an important role in its pathophysiology. Diagnosis depends on nerve conduction studies, and treatment includes dialysis or renal transplant. CONCLUSION: Clinical presentations of UN are broad and non-specific; nonetheless, it is important to detect early changes in order to avoid its progression. The earlier UN is diagnosed and treated, the more successful are the clinical outcomes.

Uremic neuropathy: an overview of the current literature.

INTRODUCTION: Peripheral neuropathy is a disorder that affects the cell body, axon or myelin of motor or peripheral sensory neurons and occurs in 60-100% of patients who are submitted to dialysis due to chronic kidney disease. Uremic neuropathy is attributed to the accumulation of organic waste, evident in patients with reduced glomerular filtration rate. OBJECTIVES: This review aims to make clinical characteristics of uremic neuropathy evident enabling early diagnosis and treatment. METHODS: This is a literature review of articles published on PubMed over the last 10 years using "Uremic Neuropathy" as "Title/Abstract". RESULTS: A total of nine articles that met the inclusion criteria were included. UN is a distal symmetric sensorimotor polyneuropathy that occurs due to the accumulation of uremic toxins associated with an oxidative stress-related free radical activity. Hyperkalemia is thought to play an important role in its pathophysiology. Diagnosis depends on nerve conduction studies, and treatment includes dialysis or renal transplant. CONCLUSION: Clinical presentations of UN are broad and non-specific; nonetheless, it is important to detect early changes in order to avoid its progression. The earlier UN is diagnosed and treated, the more successful are the clinical outcomes.

Uremic neuropathy: an overview of the current literature

SUMMARY INTRODUCTION: Peripheral neuropathy is a disorder that affects the cell body, axon or myelin of motor or peripheral sensory neurons and occurs in 60-100% of patients who are submitted to dialysis due to chronic kidney disease. Uremic neuropathy is attributed to the accumulation of organic waste, evident in patients with reduced glomerular filtration rate. Objectives: This review aims to make clinical characteristics of uremic neuropathy evident enabling early diagnosis and treatment. Methods: This is a literature review of articles published on PubMed over the last 10 years using "Uremic Neuropathy" as "Title/Abstract". Results: A total of nine articles that met the inclusion criteria were included. UN is a distal symmetric sensorimotor polyneuropathy that occurs due to the accumulation of uremic toxins associated with an oxidative stress-related free radical activity. Hyperkalemia is thought to play an important role in its pathophysiology. Diagnosis depends on nerve conduction studies, and treatment includes dialysis or renal transplant. Conclusion: Clinical presentations of UN are broad and non-specific; nonetheless, it is important to detect early changes in order to avoid its progression. The earlier UN is diagnosed and treated, the more successful are the clinical outcomes.

RESUMO INTRODUÇÃO: A neuropatia periférica (NU) é um distúrbio que afeta o corpo celular, o axônio ou a mielina do motor ou neurônios sensoriais periféricos e ocorre em 60%-100% dos pacientes que são submetidos à diálise por doença renal crônica. A neuropatia urêmica é atribuída à acumulação de resíduos orgânicos, evidente em pacientes com taxa de filtração glomerular reduzida. Objetivo: O objetivo desta revisão é fazer com que as características clínicas da neuropatia urêmica sejam evidenciadas, permitindo o diagnóstico e tratamento precoce. Método: Esta é uma revisão da literatura de artigos publicados no PubMed nos últimos dez anos usando "Neuropatia Urêmica" como "Título/Resumo". Resultados: No total, foram incluídos nove artigos que atendem aos critérios de inclusão. A NU é uma polineuropatia sensório-motora simétrica distal que ocorre devido ao acúmulo de toxinas urêmicas associadas à atividade de radicais livres relacionados ao estresse oxidativo. A hipercalemia tem um papel importante na sua fisiopatologia. O diagnóstico depende de estudos de condução nervosa e o tratamento inclui diálise ou transplante renal. Conclusão: As apresentações clínicas das NU são amplas e não específicas; no entanto, é importante detectar mudanças iniciais para evitar sua progressão. Quanto mais precoce for a detecção e tratamento da NU, melhor será o resultado clínico.

Time trend and regional variability of mortality rate due to ovarian cancer in Brazil: a 15-year analysis.

Introduction: Ovarian cancer (OC) is the most lethal gynecological tumor. In Brazil, there are important regional differences regarding mortality rates for the same cancer type. Objectives: To analyze the progression of OC mortality rates in Brazil and its regions, in age groups over 50 years, between 2000 and 2015. Methods: Ecological longitudinal study carried out using secondary data from DATASUS (Brazil's public health system database) regarding deaths due to OC in women living in Brazil between 2000 and 2015. We calculated gross and adjusted mortality, estimated the impact of death of OC and proportional mortality rate of all cancer types in women between the age of 50 and 79 years. Results: There were 34.335 deaths due to OC in women in the referred age interval, with a 9% increase in mortality adjusted for age, a 0.05% (P = 0.012) trend and a 24.67% increase in the proportional mortality due to all causes with a 0.02% (P < 0.001) trend. There were statistically significant increases in mortality rates due to OC in the age groups of 50-54 (28,4%, P < 0,05) and 75-79 years (25,1%, P < 0,05). Conclusion: Although there are oscillations in mortality rates of OC in Brazil and its regions over the period studied, this parameter has remained relatively stable.

Medical Student Oncology Congress: Designed and Implemented by Brazilian Medical Students.

Oncology is an essential field of medicine; however, its teaching is occasionally underemphasized and uncoordinated during medical school. An alternative method of providing additional oncological information to medical students is through extracurricular activities, such as congresses and medical student associations. The aim of this paper is to describe a Medical Student Oncology Congress entirely designed and organized by medical students. Three medical students from oncology study and research groups identified the gap in oncology training at universities and decided to organize a congress for students. They selected representatives from 26 universities in Brazil for onsite registration and created a website for online registration and promotion of the congress. To determine the topics of the lectures, they searched the medical literature for the most commonly occurring cancers in adults and children. Extrapolating the academic content of oncology, they organized lectures by non-governmental organizations (NGOs), talks on career guidance and research in this field as well as a role-playing workshop to train future doctors on how to deliver news to patients. There were a total of 609 attendees, with 590 students from 26 different universities in Brazil. Approximately 82% were medical students, and among the participants there were also 15 medical educators. A total of 80.75% of the participants were extremely satisfied with the congress, and 99.17% would recommend it to a colleague. Most of the overall cost of the congress, 96%, was covered by registration fees. There was a 6% positive net balance, which was donated to the NGOs participating in the congress. This successful experience proves that it is possible to have a congress fully designed, organized and managed by students. It demonstrates how students can be active participants in their own education, as opposed to a classic approach through which only professors are responsible for instruction.