ALCOHOLISM
Hypomagnesemia occurs frequently in patients with
alcoholism, either in the presence or in the absence of
delirium tremens or cirrhosis.93'120'169'176 Because of its
known sedative effects magnesium sulfate was used
empirically to treat delirium tremens.l i l a The discovery
of hypomagnesemia in patients with chronic alcoholism
and delirium tremens,93'120 coupled with the similarity of
signs and symptoms of delirium tremens. and
magnesium deficiency in animals, led to the hypothesis
that delirium tremens is the direct result of magnesium
deficiency.112'113
Much of the research carried out on human magnesium metabolism over the past decade was stimulated
by these observations. In man the delineation of the
clinical syndrome associated with hypomagnesemia has
been a direct outgrowth of these early reports. Although
the serum concentration of magnes ium is reduced in
many patients with delirium tremens, this finding has
not been universally true. The response of some of these
patients to parenteral magnesium has appeared to be
beneficial, but controlled studies of the use of
magnesium in the treatment of delirium tremens have
not conclusively demonstrated a specific therapeutic
effect.96'172'173 Moreover, hypomagnesemia frequently
occurs in alcoholics in the absence of delirium tremens.
In a survey of all patients requiring hospitalization for
alcoholism irrespective of its severity, hypomagnesemia
occurred in 25 per cent whereas delirium tremens
developed in only a few patients.172 No clinical
differences between the alcoholic patients with
hypomagnesemia and those without were observed. The
lack of correlation of hypomagnesemia in the alcoholic
population with a neurologic syndrome — either tetany
or delirium tremens — has also been pointed out.174
The serum concentrations of magnesium in some
*From the Biophysics Research Laboratory, Department of Biological
Chemistry, Harvard Medical School, and the Division of Medical Biology,
Department of Medicine, Peter Bent Brigham Hospital, Boston (address
reprint requests to Dr. Wacker at the Department of Medicine, Peter Bent
Brigham Hospital, Boston, Mass. 02115).
Original work contained in this review was supported by a venture
grant from The Nutrit ion Foundation, Incorporated, and by a grant-in-aid
(HE-07297) from the National Institutes of Health, Public Health
Service, United States Department of Health, Education, and Welfare.
patients with alcoholic cirrhosis are reduced.118'11S Attempts
have been made to correlate the extent of the decrease
with the severity of the liver disease However, the
occurrence of hypomagnesemia ir alcoholics lacking
physical or chemical evidence oi impaired hepatic
function suggests that the disturb ance in magnesium
metabolism in patients wit: alcoholism is not necessarily
related to impairec liver function.
One of the primary mechanisms for magnesiurr
depletion in alcoholism may be the direct effect o
alcohol on renal excretion of magnesium.172'177-171
Magnesium diuresis occurs without appreciable change
in renal blood flow or glomerular filtratior of
magnesium and is independent of the alcohol induced
water diuresis. Two mechanisms have beer proposed:
alcohol affects a tubular mechanism es sential for the
resorption of magnesium; or, alcoho increases the
production of metabolic intermediate (such as lactate)
with some potential for bindini magnesium as they are
excreted by the kidney. A present no experimental
evidence is available ti support either of these
hypotheses. It should b pointed out, however, that
alcohol did not increasi magnesium excretion in
several normal persons whi were depleted of
magnesium experimentally.31
Other factors that can account for excessive mag
nesium loss in alcoholics include vomiting am diarrhea,
which are common in the alcoholic popu lation,
hyperhydrosis,82 particularly in patients witl delirium
tremens, and hyperaldosteronism in cirrhot ic patients
who have ascites. Inadequate intake c magnesium
alone would not in all probability ac count for the
depletion, since marked renal consei vation
mechanisms are operative, restricting mag nesium losses
to 1 to 2 mEq per day when diet solely deficient in
magnesium are consumed.27'31
DISEASES OF THE KIDNEY
Ionized magnesium is available for glomeruh
filtration. The tubules reabsorb the major portion (
filtered magnesium "by processes operating no mally at
or near saturation."180 Whether tubular st cretion plays
a part in regulating magnesium home( stasis in man is
still in question.181 Animal studie using the stop-flow
technic demonstrated acth