Thrombosis in particular organ veins.

Renal vein thrombosis in early infancy is a complication of dehydration and prolonged hypotension. The onset is usually acute and the most common clinical signs are uni- or bilateral frank masses, hematuria, proteinuria and thrombocytopenia. In most cases, with conservative management, the late outcome is favorable. In the adult, renal vein thrombosis is often a silent complication of the nephrotic syndrome, the hypercoagulability of which may be an important factor in the pathogenesis of the thrombosis. Clinically, the presentation of a sudden complete occlusion is that of severe abdominal and lumbar pain with hematuria and loss of function of the kidney that suffers hemorrhagic infarction. Physical examination often reveals an enlarged kidney. With gradual occlusion, renal function is preserved. The initial diagnostic approach is with ultrasound studies and computed tomography; definitive diagnosis is established by renal venography or by selective renal arteriography. In general, a conservative approach including the use of anticoagulant treatment is preferred to surgical intervention. Priapism is a persistent painful penile erection due to ischemic or non-ischemic causes; therapeutic intracavernosal injection of papaverine is becoming the most common cause. In early and mild stages, aspiration of blood from the corpora cavernosa supplemented with intracavernosal irrigation with alpha-stimulating agents is the procedure of first choice; in late and severe ischemia, a shunt procedure may become necessary. Hepatic vein thrombosis occurs in association with a number of conditions considered predisposing factors including the use of oral contraceptives. The clinical picture may be that of an acute illness with abdominal pain, hepatomegaly, ascites and hepatic failure as well as early death. More often, the onset is insidious with slowly developing ascites and wasting. For the diagnosis, hepatic scintigraphy may be helpful but, at present, ultrasonography, computed tomography and magnetic resonance scanning are procedures of choice. There is, as yet, no adequate treatment. A fatal outcome may be prevented by surgical decompression of the congested liver and, in recent years, liver transplantation has been employed. Portal vein thrombosis, in children, is usually considered a complication of umbilical sepsis or a result of a congenital abnormality of the portal vein. In adults, the most frequent causes are hepatic cirrhosis and neoplasia. Clinically, there may be a sudden appearance of ascites with resolution in a symptom-free interval until the onset of other features of portal hypertension occur. Currently, ultrasound real-time imaging supplemented with Doppler capability, computed tomography and magnetic resonance scanning provide the necessary diagnostic information. Variceal hemorrhage is often the first major complication requiring treatment.(ABSTRACT TRUNCATED AT 400 WORDS)