Annals of internal medicine
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Alzheimer disease is a complex neurodegenerative dementing illness. It has become a major public health problem because of its increasing prevalence, long duration, high cost of care, and lack of disease-modifying therapy. Over the past few years, however, remarkable advances have taken place in understanding both the genetic and molecular biology associated with the intracellular processing of amyloid and tau and the changes leading to the pathologic formation of extracellular amyloid plaques and the intraneuronal aggregation of hyperphosphorylated tau into neurofibrillary tangles. ⋯ Currently available cholinesterase inhibition therapy targets the cognitive symptoms. However, the goal of new therapies under development is halting the pathologic cascade and potentially reversing the course of the disease. If these new therapies are successful, they will represent a remarkable medical advance for patients and the families who care for them.
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Type 2 diabetes mellitus is associated with a heavy burden of suffering. Screening for diabetes is controversial. ⋯ The interventions that are most clearly beneficial during the preclinical phase are those that affect the risk for cardiovascular disease. The magnitude of additional benefit of initiating tight glycemic control during the preclinical phase is uncertain but probably small.
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The initial management of patients suspected of having community-acquired pneumonia is challenging because of the broad range of clinical presentations, potential life-threatening nature of the illness, and associated high costs of care. The initial testing strategies should accurately establish a diagnosis and prognosis in order to determine the optimal treatment strategy. The diagnosis is important in determining the need for antibiotic therapy, and the prognosis is important in determining the site of care. ⋯ Chest radiography is considered the gold standard for pneumonia diagnosis; however, we do not know its sensitivity and specificity, and we have limited data on the costs of false-positive and false-negative results. In the absence of empirical evidence, the decision to order a chest radiograph needs to rely on expert opinion in seeking strategies to optimize the balance between harms and benefits. Once community-acquired pneumonia is diagnosed, a combination of history, physical examination, and laboratory items can help estimate the short-term risk for death and, along with the patient's psychosocial characteristics, determine the appropriate site of treatment.
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Patients who sustain a cardiac arrest have a less than 20% chance of surviving to hospital discharge. Patients may request do-not-resuscitate (DNR) orders if they believe that their chances for a meaningful recovery after cardiopulmonary arrest are low. ⋯ Patients should be offered the option of consenting to CPR for "higher-success" situations, including a witnessed cardiopulmonary arrest in which the initial cardiac rhythm is ventricular tachycardia or fibrillation, cardiac arrest in the operating room, and cardiac arrest resulting from a readily identifiable iatrogenic cause. This new level of resuscitation could be called a "limited aggressive therapy" order.
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The term dysautonomia refers to a change in autonomic nervous system function that adversely affects health. The changes range from transient, occasional episodes of neurally mediated hypotension to progressive neurodegenerative diseases; from disorders in which altered autonomic function plays a primary pathophysiologic role to disorders in which it worsens an independent pathologic state; and from mechanistically straightforward to mysterious and controversial entities. In chronic autonomic failure (pure autonomic failure, multiple system atrophy, or autonomic failure in Parkinson disease), orthostatic hypotension reflects sympathetic neurocirculatory failure from sympathetic denervation or deranged reflexive regulation of sympathetic outflows. ⋯ In congestive heart failure, compensatory cardiac sympathetic activation may chronically worsen myocardial function, which rationalizes treatment with beta-adrenoceptor blockers. A high frequency of positive results on tilt-table testing has confirmed an association between the chronic fatigue syndrome and orthostatic intolerance; however, treatment with the salt-retaining steroid fludrocortisone, which is usually beneficial in primary chronic autonomic failure, does not seem to be beneficial in the chronic fatigue syndrome. Dysautonomias are an important subject in clinical neurocardiology.