Aquaretics and PCKD
One of the big stories at the ASN this year was the announcement of the results of the TEMPO trial which were simultaneously published in NEJM. It has been known for some time that ADH is implicated in…
Why Do Thiazides Decrease Polyuria in Diabetes Insipidus?
I was reviewing the treatment of diabetes insipidus the other day, and was reminded of the paradoxical effect of thiazide diuretics on urine output in diabetes insipidus. How does this work? The traditional thinking is that thiazide-induced blockade…
Water deprived
Recently in the clinic we were asked to review a patient with suspected diabetes inspidus. She had been taking lithium for more than 20 years for bipolar disorder that was very well controlled. During a routine medical examination,…
Take one glass of water, three times a day…
As mentioned previously by Nate, there is some evidence that lowering urine osmolarity below that of the serum can reduce the rate of growth of cysts in PCKD and thus preserve renal function. The rationale for this is…
Board question: Water-1 answer
This was an actual case I saw and thought it generated a multitude of interesting dilemmas. When I initially examined the patient she was in status epilepticus. This, by itself, mandated the immediate correction of her serum sodium….
Board question of the week: Water-1
A 40-year-old woman is rushed to ER for change in mental status. She has a history of multiple sclerosis and alcohol abuse. On arrival to ER, she exhibits 3 stereotyped, tonic-clonic seizure that resolve with ativan. The initial…
Diagnosing Reset Osmostat
The “reset osmostat” is a cause of hyponatremia, sometimes considered a variant of SIADH, in which the kidney retains its ability to appropriately concentrate and dilute the urine; however, the threshold for ADH secretion is reset downward. That…
Calculating Total Body Water
The easy way to calculate total body water is simply to multiply 0.6 times your weight in kilograms, since roughly 2/3 of your body weight is water. There are fancier (and more accurate) equation-based calculations used to determine…
Death by Soy Sauce?
Bizarre case of hypernatremia: a suicide attempt by a 73 year-old Japanese man in which the individual drank massive amounts of soy sauce. According to this 2006 Neurology paper by Machino et al, the patient presented with vomiting,…
Aquaporins and the Kidney
The discovery of aquaporins–the protein family of water channels which regulate water transport in the kidney and many other tissues–was considered significant enough to win the Nobel Prize in Chemistry for Peter Agre in 2003. The aquaporins…