Saturday, August 17, 2019

Reversible acute kidney disease in a ultrarunner



Reversible Kidney Damage in a 100 mile runner.


At the 2018 Western States 100 mile race we encountered a runner who presented to the medical aid station at mile 70.   The runner was on his goal pace but had been noticing that the color of his urine had changed from clear to “copper colored.”   He denied any severe muscle pain and was running well.  This urine color began changing around mile 30 and then fluctuated for a while before getting worse between mile 65-70.  He also had not had any nausea or vomiting during the race.   He had taken some non-steroidal anti-inflammatories around mile 62  for foot and ankle pain he had for about 40 miles.  .   He was well ahead of the cutoff at the aid station.

Because of his symptoms, we elected to do an I-stat on a venous sample.  

Results showed:  

Sodium 135  (138-146)
Potassium 6.2  (3.5-4.9)
Chloride 98 (98-109)
CO2 27 (24-29)
Bun 58  (8-26) 
Creatinine 2.2  (0.6-1.3)
Glucose 127  (70-105)

After consultation with the race director, we discussed the risks of him continuing and warning signs.   He was instructed to back off his pace a bit, hydrate and not take any more anti-inflammatories.    He was also instructed to recheck in at the medical tent at the finish for re-evaluation.

 He “fast-walked” with some mild running from mile 70-95.   At mile 95 he started running again with no problems.  Upon finishing, we performed another i-stat.

Post race results showed

Sodium 134
Potassium 4.8
Chloride 100
CO2 23
BUN 44
Creatinine 1.6
Glucose 123

This is the first time we have seen a runner with acute renal injury as documented by i-stat testing continue with a race and show improvement in renal function while continuing with the race.    The treatment plan of increasing hydration, backing off of exertion and avoiding NSAIDS allowed him to finish while his renal function improved.   Despite the elevated BUN/Cr levels, the runner was looking good and didn’t seem in any medical distress.

Teaching points:
1) Runners with mild renal failure can continue to safely run a race given proper instructions
2) Having an i-stat available  did give us the ability to more accurately determine the extent of the runners kidney injury
3) In cases where there are no clear guidelines, having an honest discussion with  athletes of the risk/benefits of continuing the race can help the runner meet their goals.  In this case, we were fortunate that the runner was honest with the medical staff and trusted our advice.  In return, we also wanted to do what we could to help the runner continue so they could achieve a race finish.

2 comments:

  1. Martin D. Hoffman, MDAugust 18, 2019 at 12:11 PM

    Thanks for your report. It raises a few questions.
    1. Why were you not concerned about the hyponatremia? The initial serum sodium was evidently 3 mmol/L below your lower limit of normal. We know that additional hydration in a mildly hyponatremic athlete could worsen the hyponatremia (as evident from your second serum sodium value) and induce symptoms.
    2. Why were you so concerned about acute kidney injury? The serum creatinine and BUN values of this runner are not that unusual for this race, there is rarely need for intervention for acute kidney injury in ultramarathons, and the evidence suggests that these insults in which the “injury” criteria is met are not cumulative (Hoffman & Weiss. Clin J Sports Med 2015).
    3. Why was the race director consulted rather than the medical director, who is a nephrologist and has published on this topic?

    The combination of exercise-associated hyponatremia and rhabdomyolysis is not uncommon. We reported on a cluster of five such cases from the 2009 Western States Endurance Run (Bruso et al. Wild Environ Med 2010). There is a likely relationship between these two conditions, though it is not clear which is the chicken and which is the egg. The simultaneous presentation of exercise-associated hyponatremia and rhabdomyolysis creates a treatment paradox since the treatments are contradictory. But when one condition is likely to be benign, I think that the focus should be on the one that is less likely to be.

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  2. Good questions:

    1) We weren't worried about hyponatremia as the runner had no signs/symptoms of hyponatremia. He denied any dizziness, lightheadedness, bloating, headache, or nausea. While his sodium levels were low and he was urinating regularly and didn't feel like he was having any issues with fluid retention. His renal function and potassium levels were more concerning to us than his sodium.

    If we didn’t have the iStat, he looked good enough that I would have probably given him the same directors (slow down, cut out the NSAIDs and hydrate). I'm not sure what at what BUN/CR level that I would have advised him to stop but I’m glad we had Dr. Weiss was available to consult.

    In looking at your 2016 paper and counting dots, you only had about 12/627 samples with creatinine levels higher than 2.2 and that was at the finish line. So while this is seen, with only 2% of runners having acute renal injury this severe, we were concerned. We were also concerned as he still had 30 miles to go and we didn’t want his renal function to get worse. FWIW there were two other runners at 2018 WS100 that ended up on dialysis and neither of them talked to medical staff during the race or as the post race medical tent from my understanding. I understand the concerns about hyponatremia but we’re also equally concerned about runners needing dialysis.

    2)We were concerned about acute kidney injury because of the color of his urine and that he had taken non-steroidal anti-inflammatories. Again, clinically he had no severe muscle aches and he was moving well so we didn't think he had severe rhabdo. Frankly he was considering dropping out of the race as he was concerned about his urine color, doing damage to kidneys and didn’t want to end up in acute renal failure needing dialysis . If it were any other race other than WS100, he would have dropped out, but he wanted to make sure it was safe to continue. Using the iStat which gave us some reassurance that he was safe to continue. Again, I’m not sure where I would have cut him off but I think if we saw a creatinine above 3.5, we likely would have had a different discussion with him.

    3) That was a typo and it should have said medical director. I did talk with Bob Weiss and it was very reassuring talking to him about this case!

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