Fooling a Blood Test (Not in the way that you think)

November 13, 2012 10:11 PM

How can one simulate a medical condition that involves low potassium, low calcium, fewer electrolytes, and low blood pressure?

In the short story that I'm working on, the protagonist simulates a medical condition (involving the four telltale indicators above) using an overdose of over-the-counter vitamin supplements, so that when his blood is tested, it indicates abnormalities in those areas. Is this remotely plausible, or is it completely farfetched? If so, how long would it take and how would one go about it?

posted by wolfdreams01 to Health & Fitness (19 answers total)

Best answer: not vitamins, but consuming lots and lots and lots of water can push electrolyte levels very low.
posted by guybrush_threepwood at 10:16 PM on November 13, 2012

If you go with the hyponatremia route that guybrush_threepwood mentions, keep in mind that it is accompanied by cramps, impaired consciousness, weakness, and nausea. Also if you are trying to bring it on you would not only have to drink a ton of water but also not eat anything at all. Eating would provide electrolytes that would likely prevent one's body from entering that state.
posted by Scientist at 10:25 PM on November 13, 2012

In the short story that I'm working on, the protagonist simulates a medical condition (involving the four telltale indicators above) using an overdose of over-the-counter vitamin supplements, so that when his blood is tested, it indicates abnormalities in those areas.

He's trying to simulate a shortage by taking an overdose?
posted by empath at 10:28 PM on November 13, 2012 [2 favorites]

I was warned that overdose of Vitamin C could lead to calcium deficiency, but I don't know the time-scale required for what you're discussing.

And this isn't exactly going to be asymptomatic. It can also cause diarrhea, muscle cramps, kidney stones and I don't know what else. Your "remotely plausible" will need to include someone willing to make themself genuinely ill to fake another illness.

(Though the diarrhea will also help with the electrolytes.)
posted by RobotHero at 10:31 PM on November 13, 2012

Best answer: Lots of magnesium can create the effect of calcium deficiency (they work together, which is one of the reasons they're often sold in combination).

For the low potassium and electrolytes, lots of sweaty exercise paired with taking salt (vitamin tablets) and lots of water.
posted by DoubleLune at 10:44 PM on November 13, 2012

You can get all those things without too many other bad side effects with starvation. A two week water fast will do it. You definitely get low blood pressure and low electrolytes which include K and Ca. This is without almost any other adverse effects. However the blood test would also show ketosis as the body burns fat for energy.

Loop diuretics like furosemide could also work. Maybe take the standard dosage daily for a week?

Maybe natural/supplement diuretics are a possibility if you want supplements, though I don't know of any or how much it would take to equal to the medical type.
posted by kellybird at 10:47 PM on November 13, 2012 [1 favorite]

It sounds like one problem is that you've already decided how these abnormalities happened, even though you don't know if it could happen that way.

Another problem is your terminology. You say "low potassium, low calcium, and low electrolytes". This is actually only 2 different issues, not 3 - because potassium and calcium ARE electrolytes.

So that leaves us with the question: what could a person do that would cause a low potassium, low calcium, and low blood pressure? I'm not aware of any vitamin overdose that would cause these specific outcomes.

What I would suggest: have your character be taking over the counter diuretics (or maybe they're stealing diuretics from a family member, like a grandma with dementia? Maybe they're ordering prescription diuretics from the internet?). That could be a believable reason for low potassium and low blood pressure, and possibly even low calcium as well - especially if they're abusing prescription diuretics rather than just taking the milder OTC ones. Abuse of diuretics is a not uncommon problem, because many people do this for weight loss purposes.

(on preview, what kellybird said: I was also thinking of loop diuretics like furosemide)
posted by treehorn+bunny at 10:49 PM on November 13, 2012 [4 favorites]

Best answer: I think if it's OK that your protagonist looks ill, he could accomplish this within a short time, even a day or two, with a mega-dose of diuretics. The thing about loop diuretics is that as long as your kidneys are working, you'll just keep losing fluid until bad things happen if you take enough of them. People can put out liters and liters of fluid in a day or two if you hit them with big doses of Lasix - of course, if they didn't start with liters and liters of extra fluid in their bodies, this will leave them profoundly dehydrated and would be extremely dangerous - the resulting severe electrolyte abnormalities, most likely the very low potassium level that would result, would put them at high risk of heart arrhythmia.
posted by treehorn+bunny at 11:00 PM on November 13, 2012

I think the low blood pressure might be something your character can achieve via meditation/calming exercises. I can lower my already lowish bp a few points by actively calming myself. So you might want to consider that route for the bp part, which might make it easier to attack the other.
posted by maxwelton at 11:01 PM on November 13, 2012

Best answer: Remember also that low blood pressure and shock are best friends. In fact, 'psychogenic shock' is a fancy way of saying 'they got upset, their blood pressure dropped and they may have fainted'.

Also of note: nitroglycerin will cause your blood pressure to plummet (which is why it helps with angina) and is dangerously incompatible with viagra.

I am not a doctor and none of this is medical advice. Mostly these are things I picked up working on the rescue squad.

If the paramedics think you have overdosed on almost anything they are going to give you activated charcoal orally and run an IV to flush everything out. Activated charcoal isn't supposed to be an emetic, but I've seen it come back up a lot, staining everything black. It will also give you black stool.
posted by poe at 11:02 PM on November 13, 2012

I'm not going to say it's impossible, but I've never heard of someone who was able to consciously make themselves faint by trying to emotionally induce low blood pressure, i.e. psychogenic shock. By definition, that has to involve having a very strong emotion, which you can't really force. At most, I would expect, like max welton, that a person could only lower their BP a few points by just thinking about it.

Also, charcoal should not be given to any and all overdose victims. It's really rarely useful unless you know that the person just overdosed on something in the past 30 (to at maximum, 60) minutes, and even then it only works on certain substances. But it doesn't sound like in this story, the medical personnel are aware that the protagonist has overdosed.
posted by treehorn+bunny at 11:20 PM on November 13, 2012

I'm unclear about your plot - is the point supposed to be that the protagonist isn't really sick, he just faked a blood test? Because if so a possible problem is that if you had those blood test results you would be really sick, regardless of the cause. Low potassium in particular is not something you want to end up with. If you're not aiming for a Munchausen's/deliberate self harm vibe, you should pick different symptoms.
posted by Acheman at 12:50 AM on November 14, 2012

I mean, I have seen someone in hospital for what turned out to be 'simply' low electrolytes due to living in a hot country and having an inadequate diet. She was almost as ill as I've ever seen anyone, barely conscious, murmuring and glassy-eyed. It was horrifying.

To spell it out at length, many of the techniques suggested here (excessive water consumption, starvation, overdosing on diuretics) are dangerous specifically because they result in the symptoms you describe; that particular symptom constellation is life-threatening, regardless of its cause.
posted by Acheman at 12:58 AM on November 14, 2012 [2 favorites]

If you don't mind swapping out high blood pressure for low blood pressure, the syndrome of inappropriate mineralocorticoid excess from licorice consumption might get you where you need to be. The syndrome of inappropriate antidiuretic hormone, or SIADH, is much more common and matches your criteria better, but I'm not aware of any easily available over-the-counter compounds that would cause it.
posted by Protocols of the Elders of Sockpuppetry at 1:47 AM on November 14, 2012

Not eating for a couple of days would probably do the trick, especially if the protaganist excercised really hard the first day but not the day of their medical. However, decreasing blood pressure is still going to be tricky in that short a time frame. Depressant medications might be helpful.
posted by windykites at 6:07 AM on November 14, 2012

From a fiction-writing point of view, this seems like something where less detail is better.

If you say "These are the precise diagnostic criteria, these are how they're normally caused, these are the ways he faked it, here's an explanation for why it's possible to fake them that way...." then your readers are going to approach this like a Sherlock Holmes story (or an episode of House) and expect all the details to fit together flawlessly. And it sounds like that's not something you can make happen.

Much better to show Mr. Protagonist opening a mysterious parcel, quaffing some mysterious liquid from a mysterious vial, and going on to get the misdiagnosis he wants. If you don't explain the details, the reader will understand that those details aren't important, and will cheerfully disregard them.

The classic example here is the "midichlorians" debacle in the Star Wars prequels. When Jedi powers were unexplained, we all felt like "Whatever, he doesn't owe us an explanation, it's a work of fiction, let's just enjoy it." But as soon as he started trying to offer a canonical explanation, then we felt like "If he's going to do this at all it had better be really good" — and, sadly, it wasn't. He should just not have gone there and nobody would have minded. And I suspect the same might be true for you and the story you're writing.

(If you have to offer an explanation: claim Mr. Protagonist has found out about a little known exploitable bug or flaw in the equipment used for the diagnostic test. Do not provide any more details than that if you can help it. "He hacked the machine" is the modern realistic fiction author's equivalent of "A wizard did it.")
posted by nebulawindphone at 8:17 AM on November 14, 2012

The lowest blood pressure I've ever had was when I was dehydrated. the numbers were really shocking, and everyone was surprised I even made it to the clinic (45 over 55 range). If you used the loop diuretics mentioned above, low blood pressure would also be a likely symptom. When this happened, I was very weak, couldn't keep down anything (including fluids), and very ill. But I walked across campus without fainting. Not sure how long I could have kept that up, though.
posted by Kronur at 9:44 AM on November 14, 2012

Best answer: (A lot of detailed comment that doesn't need to exist on the internet about how to get close to this idea has been deleted by me. Here's the answer to your question)

(There are some borderline OTCs that will drop calcium and potassium levels, but there are no OTCs that drop BP significantly that I know of, although some can poke at it, but not enough in the following context.)

...

The things is, low calcium and potassium are easy, but when you say low electrolytes, the next most important electrolyte is sodium. The only normal-ish way to get hyponatremia (low sodium) is through dilution, and dilution requires an increase in volume, which would be directly followed by an increase in BP.

So, no, the scenario isn't realistic.
posted by 517 at 4:45 PM on November 14, 2012

I'd say this is possible, at least in theory (i.e. good enough for fiction), although not with supplements alone. But! The result would not be a "simulation" of a medical condition rather than a serious medical condition in itself. The abnormalities you mention aren't just signals or warning signs; the electrolytes in question are fundamental to, well, staying alive. In fact, he'd be making himself very ill in order to fake a particular condition.

Anyway, acute electrolyte imbalances and crashing blood pressure are something nutritionists sometimes see in e.g. patients with eating disorders, so we could start reverse engineering from there.

Does your character have time to starve himself for some time while losing a lot of of fluids? That would be a good start. If your story allows for him to fast until he's really weak, then rapidly ingest a large amount of glucose, the resulting refeeding syndrome could present with hypotension and life threatening biochemical abnormalities including hypophosphatemia, hypokalemia (low potassium) and sometimes also hypocalcaemia (low calcium).

If things need to happen faster, well, it won't be pretty. Combine acute fasting with extreme physical activity, severe perspiration, and a minimum intake of fluids (also to induce hypovolemic hyponatremia). To speed up hypocalcaemia your character could overdose with magnesium - I'd suggest a laxative containing magnesium as that would add to the effect of starvation. The resulting explosive diarrhea would also quickly set him on a fast course towards hypokalemia, and he could further enhance the overall effect with diuretics as well as heavy vomiting, for which he could use emetics. The internet tells me that an overdose of glycyrrhetinic acid extract may also lead to hypokalemia, so I guess that's one supplement he could take.

All of the above could already be contributing to an acute hypotension, but he could further add to the effect with the use of vasodilators.

Then add a sudden large intake of glucose to drive the electrolytes from the bloodstream into the cells, and lots of water to aggravate the hyponatremia. Voilà.

As to the emetics, diuretics and vasodilators: maybe not OTC where you live but probably available on the internet. Btw, your character would end up a delirious, sweating, shaky, exhausted mess with arrhythmia, muscle spasms etc. Also, he could die.
posted by sively at 7:06 AM on November 15, 2012