Triphasic diabetes insipidus

4966 3
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.

3 comments

  1. It depends on the osmolality of the Gatorade (reportedly 330mosmol/kg). If you lose free water (i.e. solute free water) which is what happens with DI(failure to insert aquaporin channels into the distal tubule in central DI), your serum osmolality will rise above the average/normal serum osmolality of 285-295mosmol/kg. When you replace that free water loss your serum osmolality will trend towards the osmolality of the fluid you are replacing it with (i.e. 330mosmol/kg if you use Gatorade). Therefore if the osmolality of Gatorade is higher than serum osmolality the serum osmolality will rise. This will make you thirsty and if high enough may become life-threatening. This of course assumes all solute is absorbed across the GI tract and into the intravascular space. It would be better to replace the DI induced volume loss with fluid of similar or lower osmolality than the osmolality of the urine you are passing. The exception to this would be if you had significant solute (likely primarily sodium) loss from other sources such as sweat as may occur with a marathon runner in the heat and is why you might need to drink a hyperosmolar solution such as Gatorade. The converse occurs if you use large volumes of a fluid with an osmolality lower than serum osmolality (primarily low sodium). In this instance you risk inducing hyponatremia (and hypo-osmolality). However if you consumed reasonable volumes of a hypo-osmolar solution such as tap water other nutritional intake from things like a packet of salty chips are likely to provide sufficient sodium to account for any mis-match – this is what happens daily for most people with normal kidney function and the ability to access and consume water.

  2. 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…

  3. 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?

Leave a Reply