Hot Water
Want to know what easily available product in the drug store works like botulism? Why enemas were used to treat brain injuries?
This is the Pick Your Poison podcast. I’m your host Dr. JP and I’m here to share my passion for poisons in this interactive show. Will our patient survive this podcast? It’s up to you and the choices you make. Our episode today is called Hot Water. Want to know what easily available product in the drug store works like botulism? Why enemas were used to treat brain injuries? Listen to find out!
Today's episode starts with a text. You finally found time to catch up with a friend and are sitting down to chat over a cup of coffee at your favorite Yemeni coffee house. The proprietor hands you the mugs and as usual since you treated him in the Emergency Department, tries to insist it’s on the house. You thank him, but pay anyway, noting he looks well without green leaves in his teeth, hopefully still avoiding khat. You try to ignore the text, but glance at it, then read it and set your coffee mug down on the table with a thump.
“Something wrong?” Your friend asks.
“Ahh, not sure,” you say. “Sorry I need a minute.”
“Take your time,” she says wrapping her hands around the steaming cup of coffee.
It’s from your cousin, asking you to call immediately. She’s at the house of an elderly aunt. She picks up on the first ring, sounding frantic. The aunt isn’t directly related to you, but given family connections you see her once or twice a year at holiday parties.
Your cousin stopped by for a visit they’d planned in advance, but when she arrived at the house, no one answered, despite banging on the door and repeatedly ringing the doorbell. Fortunately, it was unlocked. Inside she found her aunt on the floor next to the bathtub, with no clothes on. Your cousin thought she was unconscious, though eventually her aunt opened her eyes and said your cousin's name. Your cousin called 911 and her aunt is on the way to the hospital. You apologize to your friend, tell her there's a family emergency and rush to the hospital.
This is a fictional case, so you guessed it you’re the doctor.
The patient is an 86-year-old woman, laying on the stretcher, minimally responsive. She withdrawals to pain, meaning she tries to move her arm as the nurse places an IV. She occasionally opens her eyes, but isn't talking. The nurse tells you vital signs, temperature is 96.8.6 Fahrenheit, or 36 C, heart rate is 48 bpm. Blood pressure is 85/60 and respiratory rate is eight, with a pulse ox of 95% on room air.
You do a physical exam. Her pupils are large, lungs clear to auscultation, heart rate is slow, but otherwise heart sounds are normal. Her abdomen is nontender. Her extremities are extremely weak. She can barely move even against gravity.
Your cousin has arrived and is now at the bedside. She spoke to her aunt a few days ago, the patient was her usual self. As far as your cousin knows, the patient has high blood pressure, diabetes, and high cholesterol. She’s occasionally confused or forgetful, but her mental status is generally pretty good, certainly well enough to live alone and manage her own affairs.
OK, so an altered mental status in an elderly person. The differential diagnosis here is just about any medical problem you can imagine. It's an extremely common chief complaint in the emergency department. Where do we start? We always start with basic labs, a urine specimen and a chest x-ray. This will give us some evidence for or against dehydration, urinary tract infection, pneumonia and other infectious causes. Also, the patient was found on the ground, so I’d definitely do a head CT. We don't know if she fell or hit her head, but an intracranial hemorrhage would certainly be on the list.
Often the history is all we have to go on. In this case, we do have some interesting vital signs to further direct workup. First, her temperature is low. This can go along with infection and sepsis, sometimes especially in older patients it can cause low, rather than high temperature. Though it could be simply explained by the fact she was lying on the bathroom floor without clothes on for an unknown amount of time. The nurses have already covered her in warm blankets. I’d wait an hour then recheck her temperature to see if it's anything concerning.
Altered mental status and a low respiratory rate. Could this be an opioid overdose? What? did I hear you say in an 85-year-old? Well first of all older patients can and do use illicit drugs. I'll never forget the patient who told me he used cocaine at his 90th birthday party. In addition, elderly patients can become confused, resulting in unintentional overdose by mixing up pills or accidentally taking extra doses after forgetting they already took todays dose. Maybe she was prescribed in opioid like Percocet or Vicodin for some reason and took too many. In addition, you always have to consider suicide and intentional ingestion.
Question number one is this an opioid overdose?
A. Yes
B. No
Answer: B no this is not an opioid overdose. Yes, to low respiratory rate and altered mental status, however, she has big pupils rather than small so we don’t have the third part of the triad, so doubtful.
Fortunately, your cousin brought all the medicines that she could find in the patient's bathroom and hands you a bag of pills. I love when family members have the presence of mind to do this. Sometimes if your hospital has a good electronic medical record, you may have an up-to-date list but you never know, so I love to get my hands on the prescription bottles themselves to see if I think medicines they have access play a role in the reason they're here.
You look through the bag, there’s a bunch of stuff, but overall not a huge amount for an older patient. The patient is taking a baby aspirin, 81 mg, a statin for high cholesterol. Lisinopril for high blood pressure, and glipizide, for diabetes. Could any of these medicines, in therapeutic does or overdose cause an altered mental status? If you tell me low temp, low blood pressure and low heart rate with altered mental status, I immediately think low blood sugar. Essentially it can cause a coma, which is where she’s headed if we don’t intervene. Glipizide causes low blood sugar. Not to mention, we’ve already discussed before, every patient with an altered mental status needs a fingerstick glucose.
The nurses, are as usual, one step ahead of you and say it’s 100mg/dL, normal. Chronic salicylism, or aspirin overdose can cause an altered mental status. Probably worth sending a level, but the vital signs and the story don’t really fit. Yes, if she fell and hit her head, it can contribute to bleeding. Statins cause muscle pain, but not much in acute overdose. We’ve discussed blood pressure medicines like b-blockers and calcium channel blockers causing low heart rate and blood pressure. But, lisinopril doesn’t cause low heart rate, and even in overdose, doesn’t cause much of a low BP. So I don’t think the answer is in this bag of medicines. Could this be one of the other antihypertensives? You cousin says there weren’t any other meds in the house. Calcium channel and b-blockers don’t cause altered mental status until you have complete cardiovascular collapse, so not a great fit here despite the vital signs.
The tech rips the EKG off the machine and hands it to you. You frown, it's a weird looking EKG, to use the medical terms. Her heart rate is low, ok, but it looks as if someone's taken both sides of the EKG and stretched it out. It's not a sine wave, like we've talked about before, all the elements supposed to be present are there, but they're all prolonged. The PR interval is prolonged, the QRS interval is prolonged, the QTC is prolonged.
What electrolyte disturbance can cause these EKG changes? Question 2.
A. sodium
B. Potassium.
C. Chloride
Answer: B. hypokalemia or low potassium definitely can cause EKG changes. We said it can stretch out the whole EKG until it it’s a sine wave or basically just a slow oscillation. Sodium and chloride disturbances don't typically have a big effect on the EKG.
Ok, I like this. Low potassium results in a slow heart rate and muscle weakness, that could cause a fall. You ask the nurse to run a quick bedside potassium test. Five minutes later, she tells you the potassium is normal. Hmmm.
The charge nurse pulls you into another room with a critical patient. After stabilizing him, you return to your desk to write some notes. Mostly, we hate notes, but sometimes I find it helps me work through a case. Typing the details, you think about the main components of her presentation, large pupils, muscle weakness, low blood pressure and heart rate, and an abnormal EKG. On the physical exam section, you realize you didn’t check something indicated here. You go back into the room and use your stethoscope to tap her knee, checking her reflexes. Nothing. You rap her knee several times, her leg doesn't move. You try her elbow, same thing. After a few more taps, you stop afraid you'll bruise her skin. She definitely has loss of deep tendon reflexes.
It's time to pick your poison. This case does fit with an electrolyte disturbance.
Question # ***. This is
A. High calcium
B. Low calcium
C. High magnesium
D. Low magnesium
Answer: C. Hypermagnesemia or high magnesium. This was a tough one, no shame if you got it wrong. Low calcium causes increased muscle tone and tetany. High calcium causes generalized weakness and fatigue, but not focal muscle changes. Low magnesium typically causes mild symptoms like generalized weakness, and muscle cramps, it doesn't cause EKG changes.
Hypermagnesemia and its signs and symptoms are easy to remember for many physicians. Because it's common? No it's rare. But anyone who rotated on OB/GYN has probably seen hypermagnesemia. Magnesium drips are used in patients with pre-term labor. During residency we rounded every 4 hours on patients on IV mag drips, checking mental status, muscle tone and reflexes. It’s not used as much as it used to be, but I’ll bet the obstetrics ward is still the most likely place to find someone with symptoms of high magnesium.
The nurse calls you back into the room. The patient has become less responsive. Her heart rate is now in the low 40s. And despite the IV fluids, her blood pressure has not improved. The nurse is most concerned, however, about the breathing as the patient’s respiratory rate is lower, now only 5-6 breaths per minute and her breathing more shallow. The pulse ox drifted down to 91%. She's not responsive at all. You tell your cousin her aunt will need to be intubated and put on a ventilator because her respiratory effort is no longer adequate. You tell her you want to check if the patient’s results are back first. They are, her HCT is normal, no intracranial hemorrhage. Her urine and chest x-ray are normal. There's no sign of infection on the lab work. Renal function is normal. As is Potassium and calcium.
And her magnesium level….
You stop and look at your screen again, assuming you misread it on the first glance. You were indeed right about hypermagnesemia, but the level isn’t just elevated. It's massively high. A normal level is around 1.7-2.2 mg/dL, or 0.75 to 0.95 mmol/L. Her level is 18 mg/dL, or 7.4 mmol/L. The diagnosis is confirmed. How did this happen? You put that question aside, she’s intubated so an answer is not likely forthcoming and we need to treat it.
First things first, I'd give IV fluids, as much as possible without causing volume overload, in her case several liters. She’s already gotten one liter. Since she doesn’t have a history of heart or renal failure, I’d give another 2 liters.
I’d also consider treatment with another electrolyte. Question number 3 Is it?
A. Folate
B. Potassium
C. Chloride
D. Calcium
Answer: The answer is D calcium.
We’ve discussed calcium before, it’s necessary for muscle contraction, including in your heart and blood vessels. Remember the other muscle we need for life? The diaphragm. There’s some evidence calcium administration helps in hypermagnesemia with respiratory failure, low blood pressure and arrythmias. I’d give her a few amps of calcium gluconate to see if we can avoid intubation and it might help her blood pressure.
There’s another treatment option I’d consider. Dialysis. It can remove magnesium from the blood stream. We’ve talked about weighing the risks and benefits before, it’s an invasive procedure that requires placement of a big catheter. In this case, I think it’s well worth the risk, especially if we are able to avoid intubation. I’d call nephrology stat.
After 3 amps of calcium gluconate, her respiratory rate is back to 8 with a pulse ox of 93%. Low, but adequately ventilating for now. Her blood pressure is 90s systolic. The nephrologist agrees with you and makes arrangements for emergent dialysis. The patient is admitted to the ICU.
We still don’t know what happened. Let’s talk about what happens with hypermagnesemia, then about what can cause it. By the end of my ob/gyn rotation in residency, I was really good at guessing patient’s magnesium levels. Why? Because toxicity really follows along with the level. A normal level as I said is 2 mg/dL. At levels of 5-8, patients feel sleepy and lethargic. They have hyporeflexia. Meaning if you tap the knee, you see a very weak response.
At 9 to 12 mg/dL, patients are very somnolent and difficult to arouse. They completely lose deep tendon reflexes. It's at these levels that you start to see EKG changes, including widening of the QRS and QTC. You see bradycardia, low heart rate, and hypotension, low blood pressure. Levels above 15 are truly life-threatening. Patients have complete heart block, respiratory failure, and dysrhythmias. Magnesium has been described as like anticalcium in the body. Calcium is required for muscles to contract, it’s also required for cardiac condition and contraction. Magnesium interferes with both. This is the reason giving calcium helps to treat it.
Also, high levels of magnesium result in decreased levels of acetylcholine in nerve terminals. Do you remember what two other classes of medicines reduce acetylcholine? Question 4. Is it?
A. Organophosphates like sarin and VX gas
B. Meds for dementia like rivastigmine and galantamine
C. Paralytics
D. Botulinum toxin
Answer: C and D. Essentially, at high doses magnesium is like botulism and paralytic agents, resulting in the same consequences, weakness and respiratory failure.
So what we really want to know is what causes high magnesium? Things like hyperthyroidism, diabetic ketoacidosis, for example, but only mild elevation. Same with lithium. It’s almost never clinically significant in these cases.
A massively elevated number like this, suggests one thing. Exposure to excess magnesium. An IV drip mishap, like the wrong concentration, if you’re on the obstetrics floor. Laxatives often contain magnesium. Magnesium citrate or oxide, magnesium enemas. We use these in medicine, typically they don’t cause toxicity, unless the patient has renal failure, because the kidney eliminates magnesium. There are case reports of magnesium laxatives used in patients with renal failure, causing toxicity. In serious bowel disease, like Chron’s or ulcerative colitis, sometimes to much Mag is absorbed, causing toxicity. Our patient doesn’t have renal failure or GI disease. None of this really fits.
After her aunt gets settled in the ICU, and started on dialysis, your cousin goes back to the house to search for more answers. You give her some suggestions as to what to look for. A few hours later your phone rings. She says, “I found something in the trash. Four boxes of Epsom salts.”
Ah ha. Very interesting. Epsom salts are usually magnesium sulfate and often 100% mag sulfate. Epsom salts are basically bath salts, though they don’t have colors or scents. They’ve been used medicinally for 100s of years to treat everything from hemorrhoids, to abscesses, to ingrown toenails and joint pain. I didn't know before this podcast that Epsom salts started in England in 1695, after discovery of a spring containing magnesium. The magnesium salts themselves were then sold as a medical product. You put them in the bath water, then soak supposedly getting relief. Do they work? There’s not much evidence they do, but hot water often helps all of the above. I often tell patients to do warm soaks, but using Epsom salts doesn’t add anything.
Did our patient soak too long? No magnesium probably isn’t absorbed through this skin, and if any does cross this barrier, it’s a minuscule amount.
I’d be worried she ate them. Why? Well, it's anybody's guess, but I've actually seen more cases of significant magnesium toxicity in my job is an ER doctor then I have as a toxicologist. I've had several patients who ate Epsom salts. Sometimes its dementia, other times someone mistakenly concludes its good for their health. Magnesium isn’t well absorbed in the GI tract, unless you have bowel disease as we discussed earlier. This is why mag citrate is generally safe to use as a laxative. But eating large enough quantities, does lead to absorption and toxicity.
Patients have developed magnesium toxicity via some strange routes. In one case report, a woman gargled with magnesium salts to treat halitosis or bad breath. She developed significant hypermagnesemia. Excessive use of mag enemas has resulted in toxicity. One thing to remember, is medicine absorption from the rectum is excellent, the reason we use suppositories for babies or patients who can't take things by mouth. There's a big venous plexus there, with a lot of blood vessels to absorb and distribute to the general circulation.
Patients have figured this out and some users of illicit drugs put them in the rectum. It's called amongst other things boofing or booty bumping. What I didn't know before this podcast was that magnesium slow drip enemas have actually been used to treat increased intracranial pressure, say from an intracranial hemorrhage. Apparently, someone decided a magnesium, slow drip enema might help dehydrate patients to reduce the pressure. You may not be surprised to hear these are no longer used.
Wrong doses of mag drips can happen in the hospital as I mentioned on the obstetric floor. There's one case in the medical literature of two men with alcohol use disorders for whom 2 g of magnesium was ordered, a very standard dose. But the medicine was diluted wrong, or not diluted correctly I should say, and they were given 20 g of magnesium. Tragically, fatal in one patient. The other patient had a cardiac arrest, but survived.
Back to our patient. She improves rapidly thanks to dialysis. The next day, she’s awake and alert, though still weak. Her magnesium level is down to 7mg/dL. She confirms your suspicion, saying she ate 4 boxes of Epsom salts over a few days. She read it could help joint pain, but didn’t read the box which said to add to bath water, not ingest it. She makes a full recovery and is able to go back to her home and live independently. This is a fictional case, as are all our cases, to protect the innocent. But it is based on real poisonings.
Last question in today’s podcast. Magnesium is essential for life, not just in humans, but because it’s found in?
A. Chlorophyll
B. Sea water
C. Volcanos
D. Earth’s crust
Follow the Twitter and Instagram feeds both @pickpoison1 for the answer. Remember, never try anything on this podcast at home or anywhere else.
Thanks for listening. It helps if you subscribe, leave reviews and/or tell your friends. Transcripts are available at pickpoison.com.
While I’m a real doctor this podcast is fictional, meant for entertainment and educational purposes, not medical advice. If you have a medical problem, please see your primary care practitioner. Until next time, take care and stay safe.