A Study of Induced Hyponatremia in the Prevention and Treatment of Sickle-Cell Crisis

Because the formation of sickle cells is dependent on the intracellular concentration of deoxyhemoglobin S, we investigated the possibility of altering or preventing sickle-cell crises by reducing serum sodium so as to cause red cells to swell. In three patients with sickle-cell anemia who had been disabled by recurrent painful crises, sustained dilutional hyponatremia was induced by 1-desamino-8-D-arginine vasopressin (DDAVP) in combination with a high fluid intake. Mean corpuscular hemoglobin concentration fell, and the degree of sickling at low partial oxygen pressure was reduced, as determined by morphologic criteria and by increased oxygen affinity of blood. Chronic hyponatremia (serum sodium, 120 to 125 mmol per liter) reduced the frequency of painful crises, whereas acutely induced hyponatremia abbreviated the duration of crises. These results, although preliminary, are encouraging enough to warrant further study of the safety and effectiveness of induced hyponatremia in the prevention and treatment of sickle-cell crises. (N Engl J Med. 1980; 303:1138–43.) THE recurrent, painful crises of sickle-cell anemia, which are the major cause of morbidity in this disease, result from what has been termed “a vicious cycle of erythrostasis.” ¹ In the hypoxic environment of the capillary bed, hemoglobin S is deoxygenated and cells may sickle. Resistance to blood flow is thereby increased, passage of red cells through capillaries is further delayed, and more deoxygenation and sickling ensue. The tendency of cells to sickle depends on a number of factors, particularly the concentration of intracellular hemoglobin.^{2 3 4} Perillie and Epstein, ⁵ in their study of the cause of the renal concentrating defect in sickle-cell.