This is a copy of a note I sent to Robin Musial regarding a question she had
about a patient with hypomagnesemia and nipple vasospasm. I thought there
might be general interest.

I checked a few texts and spoke with a very good endocrinologist about the
question.  It would probably be best to have her physician do a more indepth
review of the literature.

Hypomagnesemia (low serum magnesium levels)  is often equated with magnesium
depletion.  However serum magnesium (Mg) concentration, even if free Mg ion
is measured, may not reflect the status of intracellular or bone mass Mg
stores.

Mg depletion usually results from inadequate intake plus impairment of renal
or gut absorption.  It has been described in association with prolonged
parenteral feeding, usually in combination with loss of body fluids via
gastric suction or diarrhea, lactation (increased requirement of Mg) and
conditions of abnormal renal conservation of Mg (hypersecretion of
aldosterone, ADH, thyroid hormone, hypercalcemia, diabetic acidosis and
diuretic therapy).

The disorders associated with Mg deficiency are complex and are usually
accompanied by multiple metabolic and nutritional disturbances. Experimental
depletion in human volunteers has produced anorexia, nausea, vomiting,
lethargy, weakness, personality change, tetany, tremor and muscle
fasciculations.

How does this relate to nipple vasospasm?  There might be some indication
that hypomagnesemia can be related to increased vascular tone.   The
endocrinologist said that some patients with leg cramps due to
atherosclerotic disease of the leg arteries are sometimes helped by calcium
and magnesium.  This is not a muscle effect but rather a vascular effect.
HYPERmagnesemia can also decrease the tone of the entire vascular bed so
perhaps by extension hypomagnesemia can increase vascular tone.

The recommended intake of magnesium is 200 mg per day for the average adult
female and you add an additional 65 mg for lactation.  The endocrinologist
thought that this patient might take a similar amount of Mg for one week,
perhaps along with a little calcium and see if this helps.  If not, it is
unlikely to be the cause of the vasospasm.  I haven't tried this in any of
my patients as none have had any liklihood of Mg depletion.

In summary, hypomagnesemia is not common in an otherwise healthy patient and
hypomagnesemia is difficult to diagnose through serum levels. There is no
evidence that ties hypomagnesemia to nipple vasospasm but there is a
possibility that there is a relationship.

Shirley Gross
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M. Shirley Gross M.D.,C.M., C.C.F.P., I.B.C.L.C.
Director, Edmonton Breastfeeding Clinic
Edmonton, Alberta, Canada
E mail at  <  [log in to unmask]  >
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