Global polyuria
Global polyuria is the continuous overproduction of urine that is not only limited to sleep hours. Global polyuria occurs in response to increased fluid intake and is defined as urine outputs of greater than 40 mL/kg/24 hours. The common causes of global polyuria are primary thirst disorders such as diabetes mellitus and diabetes insipidus (DI). Urination imbalance may lead to polydipsia or excessive thirst to prevent circulatory collapse. Central diabetes insipidus is caused by low levels of Vasopressin (also called antidiuretic hormone (ADH), arginine vasopressin (AVP) or argipressin). ADH is produced in the hypothalamus and stored in and released from the posterior pituitary gland. ADH increases water absorption in the collecting duct systems of kidney nephrons, subsequently decreasing urine production. ADH regulate hydration levels in the body. that helps regulates water levels. In nephrogenic DI, the kidneys do not respond properly to the normal amount of ADH.Diagnosis of DI can be made by an overnight water deprivation test. This test requires the patient to eliminate fluid intake for a fixed period of time, usually around 8–12 hours. If the first morning void is not highly concentrated, the patient is diagnosed with DI. Central DI usually can be treated with a synthetic replacement of ADH, called desmopressin. Desmopressin is taken to control thirst and frequent urination. Although there is no substitute for nephrogenic DI, it may be treated with careful regulation of fluid intake.
Scott syndrome is a rare congenital bleeding disorder that is due to a defect in a platelet mechanism required for blood coagulation.Normally when a vascular injury occurs, platelets are activated and phosphatidylserine (PS) in the inner leaflet of the platelet membrane is transported to the outer leaflet of the platelet membrane, where it provides a binding site for plasma protein complexes that are  involved in the conversion of prothrombin to thrombin, such as factor VIIIa-IXa (tenase) and factor Va-Xa (prothrombinase).In Scott syndrome, the mechanism for translocating PS to the platelet membrane is defective, resulting in impaired thrombin formation. A similar defect in PS translocation has also been demonstrated in Scott syndrome red blood cells and Epstein–Barr virus transformed lymphocytes, suggesting that the defect in Scott syndrome reflects a mutation in a stem cell that affects multiple hematological lineages.The basis for the defect in PS translocation is, at present, unknown. A candidate protein, scramblase, that may be involved in this process appears to be normal in Scott syndrome platelets. Other possible defects in PS translocation, reported in some patients, require further study. The initially reported patient with Scott Syndrome has been found to have a mutation at a splice-acceptor site of the gene encoding anoctamin 6 (ANO6, transmembrane protein 16F, TMEM16F). At present, the only treatment for episodes of bleeding is the transfusion of normal platelets. References
Further reading
Heemskerk JWM, Bevers EM, Lindhout T. Platelet activation and blood coagulation, Thromb Haem 2002; 88:186–194
Martinez MC, Martin S, Toti F, Fressinaud E, Dachary-Prigent J, Meyer D, et al.