Tuesday, December 27, 2011

Hypokalemia mystery


I’m a generally healthy 23 year old female who is having some problems with hypokalemia.

For the past 10 months I have been having trouble keeping my potassium at a normal level (above 3.5). Five times I have ended up in the ED or hospitalized for IV replacement after levels around 2.7
Other times I have caught it earlier around 3.1 and was able to get it back up after ED visits for some oral replacement.

After a the first few times this happened my doctor put me on a high potassium diet, and when it continued to happen I was put on 10meq of potassium daily and then when that didn’t work either it was increased to 20meq daily, however I am still having trouble keeping my potassium at normal level at times.

Most of the time my potassium is around 3.4-3.7, but randomly it will begin to drop and drop quickly to the 2.7. When it gets to around 3.0 I start to get really nauseated, shaky and generally feel like crap, when it gets down to the 2.7 I have usually started vomiting which only makes it drop lower (I do not vomit before it initially starts to plunge though so the low levels isn’t caused by vomiting).
I am normal weight, generally healthy, and my blood pressure always lower, 90/60 ( I know that there is one thing that can cause the low potassium levels but my doctors do not think I have it because it is associated with high blood pressure).

I really want to know why this is happening because when it happens I feel like crap, the IV potassium replacement is not any fun (many of my veins are shot from all the potassium infusions, once they had to use my foot) and I always feel horrible for days afterwards.

Since being on the high potassium diet and 20meq of potassium daily I have had less of these episodes, but they are still happening.

Gender: Female
How old are you?: 23
How long has this been going on?: More than a month
Check all symptoms you are currently experiencing: None
Describe associated symptoms not listed above: During these episodes I first feel weak, leg cramps, nauseated then I get shaky, and begin to have muscle contractions in my hands and finally begin to vomit.

What have you done so far to remedy this condition? Please include tests and relevant studies here.

Potassium is generally normal (3.4-3.7) with these occasional drops to 2.7-3.1

Magnesium is always normal.

Thyroid is normal.

Abdominal/Pelvic CT is normal.

Only thing that works once it gets really low (2.7) is a few days in the hospital getting IV potassium infusions.
Please list any chronic medical problems and also list any prior surgery (lacerations don't count!): Hemicrania Continua: treated with an occipital nerve stimulator implant

Neurocardiogenic Syncope: Loop recorder implant and explant surgeries.

Inappropriate Sinus Tachycardia

3 EP studies

Check all conditions present in your immediate family... :

Asthma / Lung Problems
Cardiac Disease
Please list any medications you are currently taking (and dosage if known) :: Bisoprolol 10mg 1x a day (for inappropriate sinus tachycardia)

Zoloft 100mg 1z a day (for neurocardiogenic syncope)

Multi-vitamin 1x a day

Potassium 20 meq 1x a day

Vitamin D 50,000IU 2x a week (vitamin D level one month ago was 13)

Ambien CR 12.5mg 1x day

When was your last menstrual cycle?: 1 week ago
Are you currently using or do you have a history of tobacco use?: No
Are you currently using or do you have a history of illegal drug use?: No
Please describe your alcohol consumption :: Occasionally

So that we can serve you best, please try to tell us your top three things you wish to be addressed in our response. You will likely get more than you ask for, but we wish to understand your priorities.

Why does my potassium level drop like this?

My doctors seem to have given up on finding a cause for this and are just treating as it happens, should I be pressing for answers or should I just accept that this is what my body does?

Any additional tests I should ask my doctor for?


Well, as an Emergency Doctor I see disorders of potassium all the time. But it is rare indeed for me to see someone like yourself.... someone in pretty good health, with persistent, unexplained hypokalemia. And make no mistake.... this is serious business. Hypokalemia in the extreme is terribly dangerous, and you say the only way for you to get repleted and feel well is to have IV runs of potassium. This is going to my contribution here and I'm going to let my good Internal Medicine docs go a little more in depth... It is, after all, what they do. ER docs are shallow, Internal Medicine docs are deep. I am making a bit of a joke but an ER doc knows a little about a lot, and the Internist knows a lot about a little (if you consider all of adult medicine a little.... but I digress). 

Disorders of potassium can be disorders of absorption, excretion, or intake. The strange fact about your case is that you do not seem to properly absorb the oral potassium. So I wonder if you have an absorption problem. In the ER if someone is low on potassium then the quickest way to get them back to where they need to be is to give the potassium orally, usually mixed in a liquid. 

The other likely cause would be a problem in the kidney itself, something called 'renal tubular acidosis', and a problem with the kidney's ability to hold onto potassium would also make sense in your case.
So with hope my Internal Medicine colleagues ride to my rescue here, I am concerned about your intestinal absorption of potassium since the oral supplementation does not seem to work AND also concerned this may be a kidney problem. If you have not been referred to a nephrologist then that would be a good next step.

None of the medicines you are on are potassium-wasters but just so you know, people who take certain diuretic pills off label... often to lose weight, can stay very low on potassium. People who self induce vomiting or take laxatives can have this problem too. And, finally, if you live on black licorice then that may honestly be the culprit. 

Please feel free to ask questions in the comment section and I will stand by for more insightful commentary from my fellow docs. 




Anonymous said...

Oh and I forgot to mention that I have never taken any diuretics and I don't drink any caffeine either.... Thought I should mention that because doctors in the past have thought that might be the cause.

Anonymous said...

Thanks for the response. The only medications I take are the ones listed and no self induced vomiting or laxatives either and I've never had black licorice.

I have seen a nephrologist though, I was referred to see one after a urologist had a negative work-up for persistent blood in urine. She said that it was most likely IgA Nephropathy but wasn't too concerned because I'm not passing any protein in my urine. She was a bit interested in my problem with the potassium levels but never said that it could be my kidneys causing that problem. Maybe I should go back?

One intersting thing I found in your link was that it mentioned a connection between hyperglycemia and hypokalemia... and I have had some slightly elevated blood glucose readings, which is just something my corrent doctor is rechecking in 3 months because my A1C was fine... but now I wonder if I'm having these increases in my blood glucose because of the hypokalemia.

I don't think I ever had the potassium level in my urine measured, and that seems like are good next step in finding out what is causing this.

DOC2 said...

The illustrious MD STAT ER DOC 1 gives him/herself too little credit. The answer provided to you is very thoughtful. It seems that you have exhausted all of the possibilities among the "usual suspects" that we look for when it comes to hypokalemia.

Maybe your problem is not a kidney-centered issue (a nephrogenic issue). [However, your urine SHOULD be examined for the levels of potassium in it to see if the kidneys are conserving or ridding the body of potassium.] Maybe it is an adrenergic issue. The adrenal gland is responsible for doing a few important things. One of those is producing the body's own epinephrine and norepinephrine (aka adrenaline and noradrenaline). You certainly have other symptoms of "adrenergic" activity including "inappropriate sinus tachycardia". Increases in epinephrine and norepinephrine can cause potassium to leave the plasma and enter into the cells which makes the number you see on the blood tests lower. (Most of the body's potassium supply lives in the cells and the plasma potassium level is only the tip of the potassium "iceberg".)Has the incidence of hypokalemia abated (even a little) since starting bisoprolol? You said that the CT of the abdomen and pelvis was normal. So, no adrenal masses or hyperfunctioning nodules, etc. You can check the urine for the presence of elevated levels of epi and norepi, but I think that you would have been MUCH more symptomatic with tachycardia AND elevations in blood pressure. Are you taking cold medicines or decongestants?

In my office practice, I had a patient taking as much as 60meq of potassium chloride elixer twice per day in order to keep her potassium levels at norm. (no kidding) So, know that you aren't alone out there. She had an absorption problem. Were you taking pills of potassium or liquid elixer?

An increase in insulin may cause hypokalemia. It is good that you are being monitored for diabetes. Type 2 diabetes has as a hallmark of a necessary increase in your own insulin production. This is due to increasing resistance at the cellular level to your own insulin. Your body tries to make up for the difference by increasing its insulin output. Perhaps you should get your insulin levels checked? That might be helpful.

Do you have loose stools or diarrhea regularly?

Do you have any odd cravings?

Do you drink alot (alcoholic or nonalcoholic)?

Just wanted to inject some thoughts. I'm not at my sharpest at the present as I have spent the last week tackling an INCREDIBLY DIFFICULT hospital duty. So, let me know what you have to say about my questions above, and I will try to clear the cobwebs tomorrow and answer your question afresh.

Thanks for your interesting question!

-Doc 2

MDSTAT_ER_DOC_1 said...

The following is from this link....  http://goo.gl/JJX2C
Causes of potassium loss from the kidney:
Diuretic medications (water pills) like HCTZ or Lasix
Elevated corticosteroid levels, either from medication like prednisone or from Cushing's Syndrome
Elevated levels of aldosterone, a hormone that can increase with renal artery stenosis or adrenal tumors
Renal tubular acidosis
Low body magnesium levels
Urine electrolyte studies would be helpful in zeroing in on your problem. It seems your doctors have done a good job so far in ruling the most common things out, but there IS a reason for this and there is more to be done. Going back to the nephrologist would be a good idea asking specifically if this could be a problem with renal tubular acidosis or the other possibilities mentioned above.
Many thanks for your question, and I hope we have been helpful. If so, please tell your friends to come by and give us a try.

Anonymous said...

In response to your questions:
I am not currently taking any cold medicines or decongestants but during the spring/early summer I take Nasacort Aq for seasonal allergies.

My potassium supplements are in the pill form, I have a lot of trouble taking any kind of liquid medicine the taste is usually too much for me and I almost always end of vomiting.

I have been on the bisoprolol for 2.5 years now. Though when my potassium drops low I get some wicked palpations and usually have such a high heart rate that the ED docs generally don't leave my side until they can get it down some, usually with IV metroprolol.

I don't have loose stools or diarrhea regularly.

As for odd cravings not so much, just the occasional craving for chocolate or something salty.

I try to drink a lot of water daily (it's supposed to help with the neurocardiogenic syncope). I don't drink much alcohol (never really cared too much for the taste nor the empty calories) so I only drink on special occasions so it's usually only 1 drink (usually wine) every few months.

I did do some reading on renal tubular acidosis last night and am beginning to make some connections, I think. I pass a lot of calcium oxalate crystals in my urine and on a CT of spine (done after a bad syncopal episode) the radiologist made a incidental note of "small stones in minor calyces of the kidneys" I also know that for sure at least one time I was in the ED for the potassium replacement I was midly acidotic. I also read that type 2 RTA can be caused by vitamin D deficiency. It seems like some stuff fits for RTA.

Thanks so much, I really appreciate all of the help.

MDSTAT_ER_DOC_1 said...

Well I hope we have pointed you in a helpful direction. Keep tuned in and feel free to ad on here as you figure out with your doctors what is going on to cause your hypokalemia. Hope you get a good solution soon!

space doc said...

SPACE DOC Checking in after Christmas in D.C.

After all the good advice you have received I would like to add a couple of things you could ask your primary doctor or your nephrologist

A couple of rare phenomena: Bartter's and/or Liddle
syndromes which can be associated with hypokalemia (low potassium)

It's wonderful that you keep persuing any and all of the avenues to figure out the causes and potential treatments for this potassium problem

Good Luck and please keep us posted on your pursuit.

All our best.
Space Doc