Annali italiani di medicina interna : organo ufficiale della Società italiana di medicina interna
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The clinical course of patients with cirrhosis of the liver is frequently complicated by progressive impairment of renal sodium handling leading to the formation of ascites. The occurrence of ascites is generally accompanied by the activation of several hormones and intrarenal autacoids and a complex derangement of systemic, portal and renal hemodynamics. The earliest "underfilling" theory of sodium retention proposes that ascites formation leads to hypovolemia and secondary sodium retention. ⋯ In patients with compensated cirrhosis, i.e. without ascites, compensatory events maintain blood volume despite vascular underfilling, and so these patients do not develop ascites. In patients with decompensated cirrhosis, vascular underfilling due to arterial vasodilation, together with a reduced oncotic pressure and a severe degree of portal hypertension, favours the development of ascites. Underfilling of the arterial circulation is at its maximum in functional renal failure and the hepatorenal syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)
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Respiratory function undergoes sleep-associated changes which in normal subjects leave it unaffected. However in some cases they may be more marked than usual or may be superimposed on a pre-existing disease, thus giving rise to sleep-related ventilation disorders. These include obstructive sleep apnea syndrome (OSAS), nocturnal desaturation events of chronic obstructive pulmonary disease (COPD) and restrictive syndromes, as well as nocturnal asthmatic attacks. ⋯ Nocturnal asthma is due to circadian changes in hormonal secretion (catecholamines, cortisol), as well as supine posture, reduced muco-ciliary clearance, gastro-esophageal reflux etc. Sleep itself plays some role through a depressed arousal reaction in slow wave sleep, resulting in more marked and prolonged attacks in this stage. Slow-release theophylline or beta-mimetic medications, as well as new chromones and antimuscarinic drugs are therapeutic alternatives.