A clinical approach to common electrolyte problems: 4. Hypomagnesemia.

Magnesium plays a critical role in many cell functions. Hypomagnesemia may occur because of decreased intake or absorption, internal redistribution or increased loss of this element through either renal or nonrenal routes. Manifestations of magnesium deficiency include alterations in calcium, phosphate and potassium homeostasis along with cardiac disorders such as malignant ventricular arrhythmias refractory to conventional therapy, enhanced sensitivity to digoxin and, possibly, coronary artery vasospasm and sudden death. Other features of magnesium deficiency include a host of neuromuscular and neuropsychiatric disorders. In this review we detail mechanisms that may lead to magnesium deficiency, summarize the clinical features of the deficiency and provide a clinical approach to the diagnosis and treatment of this electrolyte disorder.     

A clinical approach to common electrolyte problems. 1. Hyponatremia

The clinical approach to hyponatremia described in this paper involves identification of the hyponatremia as iso-osmolar (factitious), hyperosmolar (mediated by osmotically induced flux of water from cells) or hypo-osmolar. Hypo-osmolar hyponatremia results from decreased renal excretion of dilute urine. This may be caused by renal failure through decreased delivery of filtrate to or function of the ascending limb of the loop of Henle, where dilute urine is made, or through increased water reabsorption in the collecting duct, either independent of antidiuretic hormone or related to a physiologic, drug-induced or pathologic increase in the bioactivity of antidiuretic hormone. The treatment of hyponatremia must be individualized.     

A clinical approach to common electrolyte problems: 2. Potassium imbalances.

A clinical approach to potassium imbalances is presented. Hypokalemia is rarely due solely to a reduced intake of potassium; instead, it usually results from a potassium flux into the cells or increased loss of the element, at times combined with a decreased intake. The clinician must seek the cause of the intracellular flux or the source of the gastrointestinal or renal loss. The causes of gastrointestinal losses are generally self evident. Renal potassium wasting, though, generally results from increased mineralocorticoid activity, an increased rate of urinary flow or of sodium delivery to the distal nephron, or both, hypomagnesemia or a combination of these factors. Hyperkalemia may be factitious, but usually it is caused by a flux of potassium from the cells or a decrease in the renal loss of potassium, the latter being mediated by a reduction in renal function, mineralocorticoid activity, or the rate of urinary flow or sodium delivery, or both. In both hypokalemia and hyperkalemia, treatment must be guided by the specific clinical circumstances.     

A syndromic approach to common parasitic diseases

Standard textbooks discuss parasitic disease according to specific organisms. In contrast, patients with parasitic infections present to physicians with a variety of clinical manifestations that may involve any of several organ systems and that often mimic nonparasitic diseases. A syndromic approach to the clinical situation may help the physician in considering the most important parasitic agents. Many parasitic infections can be acquired in temperate climates. While often considered tropical or exotic, other parasitic diseases are now seen more frequently in developed countries because of immigration and increased world travel. In this review the clinical syndromes associated with common parasitic diseases in North America are discussed, with an emphasis on risk factors and diagnosis of specific infections.     

常见神经系统症状的影像学检查指南

头痛、一过性神经系统症状、轻微头部外伤后的症状以及颈部和腰背痛是全科医生和急诊室医生经常面对的问题。接诊医生常常不确定是否该行神经系统影像学检查。本文中，我们将讨论这些情况下可能最有帮助的影像学和检查的指征。表1总结了我们解决这类问题的思路。图1显示了头痛或轻微头部外伤病人的代表性影像的一系列情况，包括正常和异常的结果。图2显示了这里描述的临床情况下相关的异常影像学结果的各种例子。     

临床路径实施过程中常见问题探讨

对临床路径实施过程中常见问题进行了分析,对临床路径的实施要点进行阐述,提出在路径实施过程中的关键环节,包括充分调动医务人员参与的积极性、路径表单主题选择要恰当、路径文件格式定义要合理、要强调多学科共同参与、以及对变异的管理是路径管理的重点等。     

An approach to understanding and treating common foot problems in the diabetic population

The goal of this paper is to provide an overview of common foot problems seen in diabetic individuals. Initial therapeutic intervention such as debridement ofpre-ulcerative lesions may prevent limb-threatening ulcerations from occurring. It is also essential that an understanding of the foot deformity and imbalance responsible for the high ulcerating pressures be identified and addressed for long-term treatment of these patients. The nature of compensatory foot imbalance with recommended re-alignment and balance therapies to prevent pathologic foot compensation and principles of padding and specific off-loading techniques are highlighted. Evaluation and therapy of often neglected digital deformities and treatment of nail pathology are reviewed.     

A clinical approach to paediatric acid-base disorders

Acid-base disorders are common in pediatric patients. We present a simple methodology for assessing both simple and complex acid-base disorders that is applicable to patients of all ages, and focus specifically on the usefulness of this approach in the pediatric patient. The application of four simple rules in sequence will define even the most complicated acid-base disturbance. However, because acid-base disorders are manifestations of systemic disorders, the primary value of characterizing them is that each generates a unique differential diagnosis. For each of the cardinal acid base disorders, the common and clinically-relevant causes in pediatric patients are explored. Additional diagnostic tools (including the serum anion gap, the delta-delta, the alveolar-arterial gradient, urine anion gap, and urine chloride), certain easily-recalled mnemonics, and empiric rules of thumb are also useful in specific situations. The treatment of acid-base disturbances is also considered, though treatment is generally best directed at the underlying disorder.     

麻醉呼吸机使用中两个常见问题的分析

从机械原理和设计思想上对麻醉医师遇到的两个常见问题进行分析和探讨.