One hundred seventy-five patients, admitted to the Eating Disorder Unit of Florida Hospital, Altamonte, were evaluated for electrolyte disorders, with particular reference to hypomagnesemia. Careful physical examination conducted by an internist, three separate histories, an eating-disorder questionnaire, psychometric testing, and the Beck and Zung scales for rating depression were used. The symptoms reported in the medical literature associated with hypomagnesemia were evaluated by the patients blind for the presence of this condition, using an analogue scale. Following treatment, improvement in symptoms was noted. One hundred eating-disorder patients with normal magnesium levels were used as controls. The study demonstrated an incidence of hypomagnesemia of 25%. When the hypomagnesemic patients were compared to controls and electrolyte balance, eight symptoms statistically defined the hypomagnesemic group. These included muscular weakness, cramping of the extremities, restlessness, parasthesias, diminished concentration, cardiac arrythmias, hypertension, and diminished recent memory. Magnesium replacement over several weeks was usually necessary to correct the imbalance when replacement was by the oral route. Hypomagnesemia is an important and often overlooked electrolyte abnormality that occurs in eating-disorder patients. Consequently, it should be routinely evaluated in eating-disorder patients on admission to hospital.
