Treatment of asymptomatic hyperuricemia is not necessary in most patients, unless perhaps they have very high levels of uric acid or are otherwise at risk of complications, such as those with a personal or strong family history of gout, urolithiasis, or uric acid nephropathy.
Obstructive sleep apnea (OSA) is the most common form of sleep-disordered breathing, affecting 5–15% of the population. It is characterized by intermittent episodes of partial or complete obstruction of the upper airway during sleep that disrupts normal ventilation and sleep architecture, and is typically associated with excessive daytime sleepiness, snoring, and witnessed apneas. Patients with obstructive sleep apnea present risk to the general public safety by causing 8-fold increase in vehicle accidents, and they may themselves also suffer from the physiologic consequences of OSA; these include hypertension, coronary artery disease, stroke, congestive heart failure, pulmonary hypertension, and cardiac arrhythmias. Of these possible cardiovascular consequences, the association between OSA and hypertension has been found to be the most convincing. Although the exact mechanism has not been understood, there is some evidence that OSA is associated with frequent apneas causing mechanical effects on intrathoracic pressure, cardiac function, and intermittent hypoxemia, which may in turn cause endothelial dysfunction and increase in sympathetic drive. Therapy with continuous positive airway pressure has been demonstrated to improve cardiopulmonary hemodynamics in patients with OSA and may reverse the endothelial cell dysfunction. Despite the availability of diagnostic measures and effective treatment, many patients with sleep-disordered breathing remain undiagnosed. Therefore, OSA continues to be a significant health risk both for affected individuals and for thegeneral public. Awareness and timely initiation of an effective treatment may prevent potential deleterious cardiovascular effects of OSA.
Pulmonary hypertension (PH) often complicates the course of patients with advanced lung disease, and it is associated with a worse prognosis. Per the recent classification of pulmonary hypertensive disorders, PH due to lung disease is considered as a separate category within a group of disorders that was previously referred to as "secondary" PH. Among the lung diseases associated with PH, the incidence and clinical course of PH is best known for patients with COPD. Per studies in patients with COPD and other lung disorders, it is evident that the pathophysiology and treatment of these disorders is generally distinct from that of pulmonary arterial hypertensive disorders. Changes in the pulmonary vasculature that accompany elevations in pulmonary vascular pressure are generally referred to as pulmonary vascular remodeling. Chronic hypoxia is well known to cause pulmonary vascular remodeling and PH, and it is the major mechanism implicated for the development of PH in patients with lung disease. Other mediators have also been implicated in the pathogenesis of PH in animal models and patients with PH, including patients with pulmonary diseases. General features of pulmonary vascular remodeling are discussed with particular emphasis on those changes that have been described in patients with lung diseases. Recent discoveries in these areas are also reviewed, and findings in pulmonary arterial hypertensive diseases are contrasted with those found in patients with PH due to lung diseases. Some of these discoveries have already led to new treatment strategies for patients with the most severe forms of PH. PH due to lung diseases shares some common pathophysiologic features with pulmonary arterial hypertension. Therefore, it is likely that these discoveries and new treatments will also be extended to benefit patients with PH due to lung disease.
Diffuse alveolar hemorrhage after hematopoietic stem cell transplantation is a frequently fatal complication with no standard therapy. Although significant changes in supportive and intensive care measures for patients undergoing hematopoietic stem cell transplantation have been made over the past decades, the impact of these changes on the incidence and outcome of patients with diffuse alveolar hemorrhage has not been examined. We analyzed 1228 patients who underwent allogeneic hematopoietic stem cell transplantation between 2008-2015 at the University of Minnesota to study the incidence, risk factors, and outcomes of diffuse alveolar hemorrhage. Diffuse alveolar hemorrhage developed in 5% of allogeneic hematopoietic stem cell transplant recipients, at a median of 30 days (range +3 to +168 days) after transplantation. The incidence of diffuse alveolar hemorrhage was significantly greater in recipients of umbilical cord blood than peripheral blood or bone marrow grafts (HR: 2.08, 95% CI: 1.16-3.74; P=0.01). In multivariate analysis, delayed neutrophil engraftment or primary graft failure was a risk factor for diffuse alveolar hemorrhage following peripheral blood or bone marrow hematopoietic stem cell transplants (HR: 5.51, 95% CI: 1.26-24; P=0.02) and delayed platelet engraftment was associated with significantly increased diffuse alveolar hemorrhage in umbilical cord blood transplant recipients (HR: 6.96, 95% CI: 2.39-20.29; P<0.05). Myeloablative regimens including total body irradiation were also risk factors for diffuse alveolar hemorrhage (HR: 1.8, 95% CI: 1.03-3.13, P=0.05) in both peripheral blood or bone marrow and umbilical cord blood hematopoietic stem cell transplants (HR: 1.87, 95% CI: 0.95-3.71). Patients with diffuse alveolar hemorrhage had an inferior 6-month treatment-related mortality (HR: 6.09, 95% CI: 4.33-8.56, P<0.01) and 2-year overall survival (HR: 4.16, 95% CI: 3.06-5.64; P<0.01) using either graft source. The etiology of diffuse alveolar hemorrhage is multifactorial, involving lung injury influenced by high-dose total body irradiation, graft source, and delayed engraftment or graft failure. The survival of patients with diffuse alveolar hemorrhage after hematopoietic stem cell transplantation remains poor. Clinical interventions or experimental studies (e.g., cell expansion for umbilical cord blood transplants or thrombopoietin use) that modulate these risk factors may limit the incidence and improve the outcomes of diffuse alveolar hemorrhage.
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