>Does any one know the precise mechanism (with a reference if
>possible) as to how hypercalcaemia causes nausea and vomiting?
The brainstem's vomition centre receives signals from four centres. Of
these, the bilateral chemoreceptor trigger zone (CTZ), which sits on the
floor of the fourth ventricle, is directly responsible for the sensing of
chemical abnormalities in the blood, e.g. hypercalcaemia, hypoxia,
ketoacids, drugs, etc., and sending excitatory signals to the vomition
centre. Many anti-emetics work by acting on the CTZ.
The gut also sends potent signals to the vomition centre, so it's possible
that hypercalcaemia may indirectly, via the mechanism that you mentioned,
cause emesis.
(N.B. The other two centres that send signals to the vomition centre are
the cortex and the vestibular centres, leaving room for the senses from the
activities of the medical team dealing with the hypercalcaemia to make the
patient sick.)
I think a good (old) physiology textbook should give you all the information.
Best wishes,
Reza Morovat
Clinical Biochemist
Institute of Neurology
London
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