URINARY MAGNESIUM EXCRETION IN STEADY-STATE SICKLE-CELL-ANEMIA

Previous reports indicate that individuals with sickle cell anaemia ma y be magnesium deficient. The role of renal excretion of magnesium in the pathogenesis of this low magnesium status was investigated in 25 p atients with sickle cell anaemia (sicklers) in the steady state and in 25 age- and sex-matched controls with haemoglobin genotype AA. The cl earance, excretion fraction and excretion rates of magnesium were enha nced in the sicklers. These patients also had significantly lower eryt hrocyte and plasma magnesium concentrations than the controls. However expressed, urinary magnesium showed a significant positive correlatio n with plasma magnesium and a weak negative correlation with erythrocy te magnesium. Furthermore, a significant negative correlation was obse rved between erythrocyte and plasma magnesium in the sicklers. These r esults suggest that urinary disposal of magnesium in rates and amounts inappropriate to the body stores of the cation may be one of the mech anisms accounting for hypomagnesaemia and low erythrocyte magnesium co ntent in patients with sickle cell anaemia.