In my experience ( in a hospital), this seem almost always , accompanied
by low
Magnesium and Calcium  or either. However, if mother is allowed to breastfeed
her baby as she should, this seem to alleviate the problem.
    Last night there was a case where a 2 days old baby displayed signs of
jitteriness. The doctor ordered heelstick glucose levels every three hours!
some results were borderline and some were low. Of course the dreaded formula
was also
ordered too . It did,nt help. I had to really insist that the nurse who was
taking care of the baby, call the doctor and convince the doctor to order
Mag. and Cal. levels instead of continuing to stick the baby,s heel. Sure
enough, the Calcium level was very low and the Magnesium borderline,
        As mentioned before these three important seem to work together when
normal, and against each other if  something else is going on.
          Of course I stand corrected if I am wrong. Dr. Newman ( I met you
in Orlando
 in January)  please correct me if I am wrong.