Current opinion in pulmonary medicine
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Alveolar hypoventilation associated with neuromuscular disease can occur in acute and chronic forms. In the acute form, progressive weakness of respiratory muscles leads to rapid reduction in vital capacity followed by respiratory failure with hypoxemia and hypercarbia. Symptoms are those of acute respiratory failure, including dyspnea, tachypnea, and tachycardia. ⋯ For chronic but stable diseases such as old polio, quadriplegia, or kyposcoliosis, mechanical support of minute ventilation can reverse symptoms. For chronic and progressive disease such as muscular dystrophy and amyotrophic lateral sclerosis, mechanical support of minute ventilation provides only symptomatic relief and is usually associated with deterioration to the point of complete ventilator dependency for survival. For the chronic progressive forms of alveolar hypoventilation, there is currently a need for quality randomized controlled clinical trials to define physiologic indicators and appropriate timing for mechanical support of minute ventilation.
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The ventilatory drive is affected by several factors such as chemosensitivity, basal arterial oxygen or carbon dioxide tension, mechanical impedance, and respiratory muscle dysfunction. Blunted ventilatory drive or a decrease in the perception of dyspnea in bronchial asthma and chronic obstructive pulmonary disease (COPD) could lead to a decrease in the alarm reaction to dangerous situations such as severe airway obstruction, severe hypoxemia, or severe hypercapnia. ⋯ The ventilatory drive to chemical stimuli can be altered by a beta-2-agonist, oxygen administration; and lung volume reduction, and an increased dyspnea sensation may be improved by corticosteroid, chest wall vibration, or lung volume reduction. The ventilatory drive has been found to play a key role in determining the severity of asthma and COPD.
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Paracoccidioidomycosis is a systemic infection caused by the dimorphic fungus Paracoccidioides brasiliensis. It is commonly an endemic disease in Latin America, but several cases have been reported outside this area, particularly now in this time of world globalization. ⋯ The adult chronic manifestation of the disease is usually the result of reactivation of quiescent lesions with diffuse lung infiltrates, predominately of the interstitial pattern, with or without involvement of various other organs. The finding of this disease in a patient is an important step for the large differential diagnosis of the interstitial lung diseases group.
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Upper extremity deep-vein thrombosis has recently been recognized as being a more common and less benign disease than previously reported. It arises generally in the presence of recognizable risk factors, such as central venous catheters and cancer. However, as many as 20% of patients present with apparently spontaneous episodes. ⋯ Thrombolysis and surgical procedures may be indicated in selected cases. The prevention of this disease requires the institution of appropriate pharmacologic measures (i.e., low-dose unfractionated or low molecular weight heparin or low-dose warfarin) whenever an indwelling central venous catheter is indicated. This review suggests that upper extremity deep-vein thrombosis is at least as serious a disease entity as deep-vein thrombosis of the lower extremities.