Questions for nephrologist (for phone convo 2/3/14)1. My blood sodium level has always been in the normal range, but my urine sodium level has been lower than normal (<30), including in our tests in August. What does this combination (normal blood sodium but low urine sodium) mean?
2. If my urine sodium hasn’t necessarily changed (since it was already low in August), why would the creatinine and GFR numbers have worsened in the intervening months, after getting better when I went off lithium? I’m eating fairly normally, and I've actually been drinking *less* water since I went off lithium in early July 2013.
3. If I am dehydrated because I’ve been drinking too much water compared to my sodium intake, should I be drinking less water or increasing my sodium intake? Or do you recommend some other course of action entirely?
4. Could diabetes inspidus be involved somehow? Back when I was taking lithium, it definitely seemed like I had it, but I don't know if it has gone away. I know my urine is still diluted, but my thirst has gradually declined in the months since the labs on August 8th.
5. What do we do now? Why have the numbers worsened? What can we do about it?
6. I think I should see a dietician once we understand what's going on. Can you refer me?
Lab Result Timeline (for phone convo with nephrologist 2/3/14)8/30/10: creatinine 1.19, eGFR 50, blood sodium 143
3/9/11: creatinine 1.25, eGFR 47, blood sodium 141
8/17/11: creatinine 1.24, eGFR 54, blood sodium 141
12/20/11: creatinine 1.26, eGFR 53, blood sodium 141
6/26/12: creatinine 1.23, eGFR 54, blood sodium 138
4/11/13: creatinine 1.53, eGFR 41, blood sodium 142
6/3/13: creatinine 1.41, eGFR 46, blood sodium 139
6/11/13: creatinine 1.65 (quite high), eGFR 38 (quite low), blood sodium 139 (normal)
* reduced lithium dosage *
6/21/13: creatinine 1.40, eGFR 46, blood sodium 138
* completely off lithium *
8/8/13: creatinine 1.33, eGFR 49, blood sodium 139, urine sodium <30 (low)
12/30/13: creatinine 1.57, eGFR 40, blood sodium 143
1/7/14: creatinine 1.60 (quite high), eGFR 39 (quite low), blood sodium 142 (normal)
1/15/14: urine creatinine 10.9 (low — what does this mean?), urine sodium <30 (low again)