My four year old son had previous health problems until we bought a swimming pool. He spent a lot of time in it, got chilled, caught a cold, and, within a month weeks had full blown diabetes insipidus (DI). Head and body MRI’s show only a thickening of the pituitary stalk. Regardless of what I’ve been told, the DI came on very suddenly. He had no bedwetting, thirst or urinary problems until the diagnosis, and the pediatrician confirmed since my son’s his urine specific gravity was normal four months previously.

Are there any additional tests that can be performed? Do I play the “wait and see” game, relying on only MRIs once a year? Do I wait until another hormone is destroyed? It does seem to me that his problems started with the pool. Could it be the chemicals? Was it from his cold that developed into an infection? Could he still have an infection? Should I take him to a major center for further evaluation?

First of all, it seems clear that the MRIs were done after showing that your son did not have the rather more common nephrogenic diabetes insipidus and that he was sensitive to vasopressin analogs like DDAVP. There have been two recent reviews of 79 and 39 children respectively with this problem which show first of all that somewhere between 30% and 65% of cases are idiopathic. The most common definable cause was some form of intracranial tumor; but, in your son’s case, the MRI shows no evidence of this nor of head trauma. Langerhans cell histiocytosis was the next most common cause.

Coming more precisely to your questions, it seems very unlikely indeed that any chemicals in the swimming pool brought this about. Less than 5% were linked to an infection which might have precipitated the very very rare autoimmune cause.”Thickening of the pituitary stalk’ on MRI was seen in about 40% but did not offer any clue to a more precise diagnosis.

It does seem appropriate to monitor anterior pituitary hormones such as growth hormone and TSH, not only because replacement therapy may be both simple and beneficial, but because progressive change could be an indication to pursue a diagnosis of histiocytosis more aggressively. In most instances though, there seems to be no additional endocrine disturbance. In general policy has been to treat the DI and to repeat the MRI annually with an expectation that time will show improvement.

Your son seems to be in very competent hands and I do not think it would be helpful to take him elsewhere.

DOB

[Editor’s comment: Diabetes Insipidus (DI) is a different disorder than diabetes mellitus, which is the main focus of this website. For previous discussions of DI at Children with Diabetes, see Diabetes Insipidus.

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