Monday, March 23, 2009

Triphasic diabetes insipidus

In central diabetes insipidus induced by cerebral trauma or following neurosurgery, there is a "triphasic" presentation which may occur. Briefly, the patient begins with a tendency towards hypernatremia, then develops a tendency towards hyponatremia, and finally ends with a chronic tendency towards hypernatremia. The three phases are described below:

  1. First Phase: due to ischemia or direct trauma to the vasopressin-secreting neurons of the hypothalamus, there is an initial polyuric phase that lasts for about 4-5 days in which there is a fall in urine osmalality and, if the patient loses too much free water, hypernatremia ensues.
  2. Second Phase: in the second phase, there is a transient SIADH occurring as a result of leakage of vasopressin from damaged posterior pituitary tissue and severed axons. This typically occurs around days 5-6 post-event and the tendency to hyponatremia may be exacerbated by the administration of free water given in response to the First Phase.
  3. Third Phase: after all the ADH from damaged neurons has leaked out, individuals may or may not enter the third phase, a chronic diabetes insipidus. This does not happen in all individuals as over 80-90% death of all vasopressin-secreting neurons must be destroyed in order for central D.I. to occur.


Jake said...

I'm trying to find the answer to a question and am hoping posting it here might help:

I was diagnosed with DI in 1997 after experiencing head trauma. I recall being told by my endocrinologist at the time that Gator-Aid and similar drinks were, counter-intuitively, bad for someone with me because I had DI.

After avoiding those drinks for 13 years and regularly explaining to people "I can't drink it, I don't know exactly why but a doctor said it's bad for me" I decided to do some research online.

Failing to find any references to Gator-Aid, Smart Water or any other electrolyte-enhanced drinks being bad for someone with DI-- in fact finding a few references that imply the opposite-- I'm starting to wonder if maybe the endocrinologist was referring only to that specific period (during which I was undergoing DI-related tests).

My question: As someone with DI, are Gator-Aid, Smart Water and other electrolyte-rich drinks good for me, bad for me, neither or both?

Anonymous said...

In my experience, patients beyond early childhood with DI can drink pretty much whatever they want--you will be exquisitely sensitive to hypernatremia, and drink a ton to correct. If your sodium is running high, you'll prefer water to anything else and likely pass on the gatorade. Otherwise, go ahead and drink it...