RESUMO
Portal hypertension is the leading cause of morbidity and mortality in liver cirrhosis. Complications of portal hypertension in cirrhotic patients include esophageal and gastric varices, portal hypertensive gastropathy, ascites, hepatorenal syndrome, hepatopulmonary syndrome and portopulmonary hypertension. The hepatic venous pressure gradient should be at least 10 mmHg for esophageal varices to appear, and more than 12 mmHg for acute esophageal variceal bleeding. This article reviews the pathophysiology responsible for portal hypertension and its complications, and the treatments used for esophageal varices in the setting of primary and secondary prophylaxis and during active bleeding.
Assuntos
Varizes Esofágicas e Gástricas/etiologia , Varizes Esofágicas e Gástricas/prevenção & controle , Varizes Esofágicas e Gástricas/fisiopatologia , Hipertensão Portal/complicações , Hipertensão Portal/fisiopatologia , Cirrose Hepática/complicações , Cirrose Hepática/fisiopatologia , Varizes Esofágicas e Gástricas/diagnóstico , Humanos , Hipertensão Portal/diagnóstico , Cirrose Hepática/diagnóstico , Prevenção Primária , Prevenção SecundáriaRESUMO
OBJECTIVES: To assess whether head-up tilt-induced hyperventilation is seen more often in patients with chronic fatigue syndrome (CFS), fibromyalgia, dizziness, or neurally mediated syncope (NMS) as compared to healthy subjects or those with familial Mediterranean fever (FMF). PATIENTS AND METHODS: A total of 585 patients were assessed with a 10-minute supine, 30-minute head-up tilt test combined with capnography. Experimental groups included CFS (n = 90), non-CFS fatigue (n = 50), fibromyalgia (n = 70), nonspecific dizziness (n = 75), and NMS (n =160); control groups were FMF (n = 90) and healthy (n = 50). Hypocapnia, the objective measure of hyperventilation, was diagnosed when end-tidal pressure of CO2 (PETCO2) less than 30 mm Hg was recorded consecutively for 10 minutes or longer. When tilting was discontinued because of syncope, one PETCO2 measurement of 25 or less was accepted as hyperventilation. RESULTS: Hypocapnia was diagnosed on tilt test in 9% to 27% of patients with fibromyalgia, CFS, dizziness, and NMS versus 0% to 2% of control subjects. Three patterns of hypocapnia were recognized: supine hypocapnia (n = 14), sustained hypocapnia on tilt (n = 76), and mixed hypotensive-hypocapnic events (n = 80). Hypocapnia associated with postural tachycardia syndrome (POTS) occurred in 8 of 41 patients. CONCLUSIONS: Hyperventilation appears to be the major abnormal response to postural challenge in sustained hypocapnia but possibly merely an epiphenomenon in hypotensive-hypocapnic events. Our study does not support an essential role for hypocapnia in NMS or in postural symptoms associated with POTS. Because unrecognized hypocapnia is common in CFS, fibromyalgia, and nonspecific dizziness, capnography should be a part of the evaluation of patients with such conditions.