As I related in the previous post, last week my wife, son and I found ourselves in the emergency ward. Nicole lay paralyzed and on the verge of a heart attack. The blood work had just come back. It showed that her potassium levels had reached nearly twice normal level (a result of her kidneys being offline in stage-5 renal failure).
According to Wikipedia, once serum potassium reaches a certain level the body cells enter a difficult-to-understand biological state called depolarisation. As far as I can reckon, this means that once potassium gets too high in the blood, it reaches a tipping point and stops flowing into the cells. Without potassium entering the cells, nerves stop functioning and muscle tissue cannot contract.
“This leads to the impairment of neuromuscular, cardiac, and gastrointestinal organ systems,” says Wiki.
Gastrointesinal impairment may explain the increasing episodes of diarrhea Nicole had been suffering (especially at night) for the last few weeks. Strange that gut problems are not included on any symptom list for hyperkalemia (Latin for high potassium) that I’ve seen (such as the National Kidney Foundation’s).
Neuromuscular impairment explains why Nicole needed someone to help her walk into the dialysis clinic the last few sessions.
And Nicole’s slowing heart rate and sine wave pattern on the bleeping ECG above her stretcher gives her a potassium toxicity score of three out of three.
“Can we do dialysis now?” I asked the doctor. An hour ago Nicole had made the same request.
“Not enough time,” said the doctor. It could take 15 minutes just to get her set up and an hour before it would make a significant drop in potassium. “She could go into cardiac arrest at any moment.” Turning to Nicole he asked: “If you do, do you want us to try and restart your heart?”
“But to restart her heart you’d have to turn it off,” said our son.
“He means if her heart stops then they’ll try to get it going again,” I said.
“Oh,” said Jonah gleefully. “Defibrillator!”
That made everybody laugh. Nicole gave her consent. She didn’t want to leave her 11-year-old comedian.
“Alright, we have a special cocktail that will force the potassium into your cells,” said the doctor.
Nicole looked at me with a bit of dread. I shrugged my shoulders. What choice was there at this point? They were unwilling to do dialysis and we were far past the point of prevention.
We had actually suspected high potassium was behind her symptoms. Literally the night before we decided to take her off the two high-potassium foods (yams and split-peas) she had been eating in increasing quantities over the last few weeks.
Why on earth was she eating sweet potatoes and legumes? Didn’t we know that potassium-rich foods can lead to cardiac arrest in someone without kidney function? For example the Kidney Foundation of Canada says: “If the potassium level in your blood is too high or too low, it can affect your heartbeat. A very high level can cause the heart to stop beating.”
We were, of course, well aware of the policy to keep potassium intake around 2000 -3000mg per day while on dialysis. After all, it’s the kidneys job to remove unneeded potassium. Without kidney function Nicole is reliant principally on dialysis to excrete excess potassium. Since dialysis is only every other day, potassium builds up in between. Makes perfect sense except… it has never been proven.
An exhaustive University of New York analysis of existing studies came to the conclusion: “…the benefits of [limiting high-potassium foods] are entirely theoretical and not supported by rigorous randomized controlled trials…” says their review article in the Journal of Renal Nutrition. “…this approach is not evidence-based and may actually present harm to patients.”
For example, the BalanceWise Study found no correlation at all between the potassium that went into the mouth and what ended up in the blood. Patients who ate as low as 750mg per day of potassium had blood levels as high as a 6.2 mEq/L; while patients consuming over 3000mg per day were only 4.0 mEq/L.
(I wonder what kind of junk food diet would allow someone to consume only 750mg of potassium?)
In August, we presented these and many other studies in a letter to the nephrology department that overlooks the clinic Nicole uses. Her doctor responded by saying that he would present the letter I wrote at the next board meeting and have some medical students study it further.
From there we gradually started increasing Nicole’s intake potassium. We were particularly interested in seeing how she’d fair with more legumes in the diet (as they are associated with greater blood sugar control, intestinal health and longevity). By November her blood work was showing only a slightly elevated potassium level (5.1 mEq/L), despite her eating potatoes right before the blood work. Her heartrate had not increased or decreased.
The muscle weakness and diarrhea appeared so gradually that we hardly noticed its progression. Sadly we only suspected the connection between the extra beans and yams a day too late. Now here she was in the ER with a nurse trying to place an IV into the vein in her index finger.
The finger IV didn’t work, so they stopped the saline solution and used that IV to inject a mix of calcium, glucose and insulin into her blood. At the same time they had her inhale cortisol. Within minutes her heart rate went from the 50s to the 120s. She could move her fingers and toes, then her arms and legs.
“This won’t last,” said the doctor. “In a few hours the potassium will leave the cells and it will all start all over again.” He then explained how they were arranging an ambulance to rush her to University Hospital in London, Ontario for emergency dialysis treatment under the supervision of a nephrologist in the ER ward.
Next post, I share what happened next and explain why I think so many studies could not find any correlation between the potassium a kidney failure patient eats and what ends up in the blood. Regardless, for us, the connection between potassium intake and heart failure (for dialysis patients) is not merely theoretical anymore.
In the trenches with T1D & ESRD,
– John C. A. Manley
P.S. Rest assured, for anybody with normal (or even somewhat deteriorated) kidneys, potassium-rich foods like yams and legumes will not trigger the reaction it does for someone in end-stage kidney failure.
P.P.S. For a little known (yet epidemic cause of renal disease) check out: Does TMAO Cause Heart Attacks and Kidney Failure for Those with Type-1 Diabetes?