Burn
Want to know what toxin causes excruciating pain and death in minutes? Has been treated with amputation? And when petroleum jelly (brand name Vaseline) is used to treat poisoning?
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 Burn. Want to know what toxin causes excruciating pain and death in minutes? Has been treated with amputation? And when petroleum jelly (brand name Vaseline) is used to treat poisoning? Listen to find out!
You're working in the emergency department when you hear shouts for help followed by the sound of someone racing down the hall with a stretcher. You excuse yourself from the bedside of a patient with the flu. Several staff members run out outside into the ambulance bay. Surprisingly, there are no ambulances. There is a beat-up pickup truck. The driver is leaning across, trying to push a man out of the passenger seat.
Question number 1. This scenario often means:
A. A cardiac arrest
B. A gunshot wound
C. A drug overdose
D. All of the above
Answer: D. It could be anything, however if you work in an urban emergency department, this scenario usually means a gunshot wound. Victims are pushed out of cars speeding away from the ambulance bay. Or the car and the patient are left as the driver runs away. This is a method, not recommended by myself, but nevertheless potentially effective, of getting the victim medical care while avoiding law-enforcement. I remember one morning as an intern after a long, busy night shift, exiting through the ambulance bay to see two separate cars cordoned off by the police into two separate crime scenes.
But, that's not what's happening here. There’s no blood. The passenger is unconscious and the driver isn’t trying to speed away, but pushing to help the nurse and the tech pulling from the other side to get him onto the stretcher. You meet them in the trauma bay.
The man is pale and unresponsive on the stretcher. Does he have a pulse? While palpating, with your fingers on his neck, you ask the tech to bring the driver in. The patient certainly won’t be able to give a history. Hopefully the driver can tell us what happened.
You feel a few weak thumps against your fingers. The pulse is present, though weak and thready, meaning he might not have it for much longer. The nurses cut off his clothes, hook him up to the monitor, and place two large bore IVs.
His vital signs are the following: temp 98.5 F or 36.9 C, heart rate 120 bpm, blood pressure is 80/40, respirations 20 and pulse ox is 97% on room air. Your quick physical exam reveals he’s completely unresponsive, even to pain, with normal pupils and an otherwise normal heart and lung exam. To treat the rapid heart rate and low blood pressure, you tell the nurses to start 2 L of normal saline. You order basic lab work, an EKG and a bedside chest x-ray.
With the immediate steps underway, you turn to the driver huddled in the back corner, asking how he knows the patient; he says they’re friends and work colleagues. You ask him to tell you what he knows. He says the patient is 32 years old and otherwise healthy. He was fine at work this morning without complaints. Just prior to arrival, they were transferring a compound from a larger bucket to a smaller bucket. One of the buckets slipped, splashing the patient from head to toe with the liquid. The driver grabbed a nearby hose and immediately washed the patient off with water. Despite this, the patient started screaming. A shiver runs through the driver as he recalls this. He didn't wait for an ambulance, but scooped up his friend into his truck and drove him here. About halfway through the 10-minute ride, the patient stopped screaming and lost consciousness.
Question #2. Are you and your staff safe? Or are you all about to become contaminated and poisoned?
A. True, it’s safe to continue
B. False, stop for decontamination
C. Who cares, the patient is critically ill?
Answer: A. First this is an important question. Think it’s callous or selfish when the patient is critically ill? If you, the nurses, and the rest of the staff become poisoned, there will be no one else to take care of the patient. That will not work in his favor, so regardless of his condition, we have to take a minute to think about decontamination. Most emergency departments have decontamination showers outside for potential chemical exposures. Do we need to take the patient back outside and shower him off?
Fortunately, here, I'd be reassured my staff is safe for two reasons. First the driver washed the patient off with a hose prior to arrival. Second the driver himself is not sick. Not only was he at the scene, he hosed off the patient, and helped him into and out of the truck. The driver says they were wearing rubber gloves and goggles, but otherwise regular work clothes.
It’s safe enough to proceed with medical care. You ask the driver what the toxic liquid was. Surely, he knows since they were using it at work.
Silence.
A glance at the monitor lets you know the patient’s blood pressure and heart rate are not responding to fluids. You ask the driver again what it was. After several more seconds, he admits he doesn't know.
Wait a minute, did I hear you say? That’s not realistic. Sadly, it’s not just realistic, but not uncommon, for a multitude of reasons we’ll come back to in a bit. Essentially we have a critically ill patient and absolutely no history. The first thing that comes to mind after someone is splashed with a liquid and starts screaming is an acid or base. I’m sure you’ve seen horrific images of victims of acid attacks. You ask the nurse to help you roll the patient to double check all of his skin, but he doesn’t have any burns, or even any irritation.
The tech rips off the EKG from the machine, and hands it to you. It’s a quick and easy screening test the reason you ordered it and you glance at it expecting it to be normal. You look at it, then look at it again to make sure you're reading it correctly. The QT segment is very prolonged. The QRS is starting to widen. Basically, it looks like someone has pulled both sides of the EKG and stretching it out.
Many medicines can cause this, we talked about a number of them in the past, but the patient didn’t suddenly have a side effect or take an overdose. Another cause is electrolyte disturbances, including potassium, magnesium, and calcium. Just as you finish this thought, the monitor starts beeping. You guessed it, he’s now in ventricular tachycardia, a lethal dysrhythmia. You check his pulse. This time, nothing.
The nurses have already placed defibrillation pads, clearly aware of which way this patient was headed. You change the defibrillator and administer a shock. His body jolts on the bed, but his rhythm doesn’t change. You start CPR and epinephrine.
While the nurses continue the advanced life support protocol, let’s consider potential occupational exposures causing cardiac arrest. This is a huge list, there are many, many toxins used in occupational settings, and of course any exposure that can happen at home can also happen at work. This isn’t an internal medicine podcast, so we don’t have hours to discuss the differential diagnosis, we have to work with what we have. Classic diagnosis we should consider include knockdown gases, like hydrogen sulfide, which we discussed in the Knockdown episode. Carbon monoxide exposure can occur in the workplace. The driver told us it was a liquid, and he in the same room is clearly fine, ruling out gases altogether.
Hydrocarbons, including benzene, are liquid and potentially lethal, but the scenario isn’t right for sudden sniffing death. Benzene causes a lot of toxicity, but mostly chronic as it causes leukemia. Cyanide, arsenic and nitroglycerin are liquids. Cyanide fits with rapid cardiovascular collapse, though I wouldn’t expect these EKG changes. And why the screaming?
Extremely rapid onset, severe pain, cardiac arrest and EKG changes suggestive of electrolyte disturbance bring to mind one compound: Hydrofluoric acid. Hydrofluoric acid burns, on the fingers especially, are not uncommon in the ED. Our patient doesn’t have a few burns on his fingers, this is clearly systemic toxicity. The very thought that this might be systemic hydrofluoric acid toxicity, to be honest strikes fear into my heart. No exaggeration.
But there's no time here for our feelings, we need to start treatment super stat. You ask the driver about hydrofluoric acid. He gives you a blank look. You tell him to contact his boss for more information.
Question #3. What is the treatment for hydrofluoric acid toxicity?
A. Calcium
B. Milk
C. Water
D. A base
The answer is A. Milk does nothing. Decontamination with water is correct to reduce exposure, but it doesn’t treat it. It would be great if we could neutralize acids with bases, like lye. But this doesn’t work in reality and you risk causing a other severe injuries from the base.
The treatment is calcium. How much? As much as you can administer, as quickly as you can give it. This might be the only time in medicine when I wouldn't worry about the dose of a drug. Generally, we have two forms of calcium, calcium chloride and calcium gluconate. Calcium chloride has three times the concentration of gluconate, however if given IV there is a risk of cardiac arrest. Therefore, we reserve it for patients already in cardiac arrest, or critically ill patients in danger of developing it. In low-risk patients, we use calcium gluconate as it's much safer.
The decision is easy in our patient. The code cart typically contains one or both, as we used to routinely give it during codes, though this has fallen out of favor. The cart has 5 amps of calcium chloride. You tell the nurse to push them all. I'd also call the pharmacy to tell them to send a lot more. After 5 amps of calcium chloride, this is a massive dose by the way, we typically don’t give more than one or two, the v. tach stops, and the patient regains a pulse.
Your own pulse slows down to a normal rate. The driver looks up from his phone. The boss texted back. The liquid is hydrofluoric acid. Confirming your worst suspicions and shooting your own pulse right back up. The pharmacist runs into the room, arms filled with amps of calcium. You also order several grams of magnesium. If you can get a quick bedside potassium level it would be useful here.
Let's take a step back to talk about what hydrofluoric acid does and why it's so lethal. Normally, when we talk about acids and bases, we’re talking about burns. Burns to the skin, like I mentioned earlier, or burns to the esophagus and GI tract after ingestion of a strong base like lye. The burns occur due to tissue destruction. Hydrofluoric acid can cause burns directly, but the main issue is fluoride toxicity. Side note – this is acute fluoride toxicity. It doesn’t occur from fluoride in the water, if you’ve seen this in the news lately, that debate is about chronic fluoride exposure. In acute exposures, fluoride binds to calcium, essentially bind up and removing calcium from the body. You can’t live without calcium, its necessary for muscle contraction. An of course, your heart is a muscle. It also binds to magnesium, thus the reason we gave mag. It also causes potassium disturbances, mostly high, though occasionally low levels.
HF for short, is used in many different industries. It’s used to etch glass a practice that actually started in 1670. It's used in the semiconductor industry, for electroplating, and in the petroleum industry to produce high octane fuels just to name a few. Industrial exposures are typically high HF concentrations. It’s available in lower concentrations for home use, typically 6 or 12% HF for rust removal and brick cleaning.
What we typically see in the ED, are local exposure with burns on the hand or fingers. A common scenario is someone cleaning bricks, then develops hand pain afterwards. HF is extremely permeable, penetrating deep into tissues. In this case, burns and pain are thought to be the results of precipitation of calcium fluoride. The patients often present with what’s called pain out of proportion. This means someone complains of intolerable, excruciating pain without any physical exam findings, because the burn starts deep inside.
Interestingly, you can guess the concentration from the time of onset. Exposure to high concentrations results in immediate toxicity as with our patient. Patients with extremity burns often don’t have pain for several hours after exposure, as symptoms are delayed with lower concentrations.
Back to systemic toxicity. It is fortunately, rare, but obviously lethal. It doesn't take much exposure to result in systemic toxicity. Shockingly if you get 100% HF on 2% of your body surface area, this is a lethal exposure. For reference, take a look at your hand, that’s approx. 1% of your body surface area. HF exposure can occur via any route including skin, eyes, inhalation and ingestion.
As I said, systemic toxicity results in essentially binding up all of the calcium and magnesium in the body and thereby causing ventricular fibrillation and cardiac arrest. Unfortunately, once this cascade starts, it can almost never be stopped.
There's no test for hydrofluoric acid. Quite frankly, patients with systemic exposure won't survive long enough for any test results. And those with local extremity burns will improve either way.
This is a question for the medical professionals. The patient continues to have an unresponsive mental status, and clearly needs to be intubated. What medicine would you avoid in this patient during intubation?
A. Succinylcholine
B. Ketamine
C. Rocuronium
D. Etomidate
Answer A. succinylcholine is contraindicated due to the risk of hyperkalemia.
The patient loses his pulse and is in v. tach again. You continue pushing amps of calcium. You intubate him, continue shocks and CPR.
This brings us to an area of medicine we, sadly, don’t know much about. CPR and advanced life support, is of course, what we do for everyone. It was designed for patients with cardiac arrest due to heart disease. It wasn’t designed for cardiac arrest from cancer, toxins or any other causes. And its extremely difficult to conduct research on these patients, due to issues of consent, inability to do randomized controlled trials, and rarity of cases.
Obviously, we’d throw everything in the book at this patient, but the bottom line here, electricity isn’t going to restart his heart if it doesn’t have any calcium to contract properly. Either the calcium and, maybe mag, is going to work or it isn’t.
While we wait, hoping for a miracle, let’s talk about treatment for other routes of exposure. Treating HF burns is one of my favorite things, its a lot less depressing and very rewarding. The treatment is a topical calcium gel. This exists in the US, but most hospitals don’t have it.
What do you do? Probably the only scenario in medicine I've mixed up my own concoction to treat a patient. Essentially you take calcium gluconate, the liquid IV form we discussed earlier and add it to petroleum jelly, called surgilube in the hospital and Vaseline at home. Every hospital has this for rectal thermometers, etc. You mix them together and apply the paste to the affected areas. With the fingers you can smear it all over and cover with a glove to really let it soak in. This helps with the tissue damage and treats the pain. So its really cool and the amazing part, topical application reduces pain better than IV pain meds like morphine. You can reapply every 30 minutes until the patient starts to feel better.
Another side note once you mix it, apply it immediately. I learned this the hard way while teaching an intern once. They had a lot of questions and by the time I answered them all, the calcium actually precipitated back out of the surge lube, leaving us with a weird powdery goop.
For inhalational exposures, you can give nebulized calcium gluconate. Nebulized is like an asthma breathing treatment. Its efficacy is not entirely clear, but since it has no side effects, I’d give it.
What about ingestion? Patients have ingested hydrochloric acid both intentionally to commit suicide and in several horrific pediatric cases unintentionally after it was left out or in a glass. These cases are almost universally lethal and require a difficult decision.
You could pass a nasogastric tube into the stomach to try to suck the HF out, essentially pumping the stomach. Given that this is incontrovertibly a life-threatening exposure, it might be a good idea. The flipside is blind placement of nasal gastric tubes is contraindicated if there's a risk of perforating the esophagus. Swallowing hydrochloric acid defiantly carries a risk of perforation. It’s a rock in a hard place. In addition, the procedure poses a real risk to you and your staff if you become exposed to the hydrochloric acid you’re sucking out. If you decide it’s worth the risk, PPE is a must. I'd also put calcium down the tube in the hopes of binding more of the fluoride.
One astonishing case reported successful treatment of a patient dying from HS exposure to one limb and reportedly survived after amputation of the limb. I had to share this with you, not because I recommend this approach, but because it’s quite a case. Other methods of calcium such as intra-arterial injection and Bier blocks have been used in the past, but are associated with significant morbidity and not generally recommended.
Back to our patient. Despite maximal therapy this time, he doesn't get a pulse back. You call the pharmacy for more calcium, again. They tell you you've used up all the calcium chloride in the hospital, so you switch to calcium gluconate. The pharmacist calls back saying this is about to run out as well.
At this point, the patient has been in cardiac arrest for 45 minutes. It’s medically futile and he’s almost certainly brain dead by now. You say the last words, traditional in a code, "anyone have any more ideas?" The team shakes their head. You pronounce the patient dead. The driver hasn’t moved, staring in shock.
This is a fictional case, as are all our cases, to protect the innocent however it is based on real cases. With significant exposure and systemic toxicity, the likelihood of survival is nearly zero.
The rapid action of HF here is not fictional at all. A terrible case in New York City occurred with two sanitation workers. As the arm of the trash truck came down to compact the load, liquid sprayed them. One died immediately, the other suffered extensive complications. Someone had thrown out a container with hydrofluoric acid into the regular trash. As the bags were compacted, the liquid shot out.
What can be done to prevent exposure in the workplace? Safety measures including corrosive proof suits, and scuba tanks work. Let's get back to the issue of why the driver didn’t know what they were using. Shouldn’t he have known? Yes, absolutely, but there are a number of issues related to dangerous, occupational exposures. Under OSHA rules, workers are supposed to know what they are working with, quite frankly in my experience this is often not the case. That’s problem number 1.
Number 2 is workers do know what they were exposed to, but are not forthcoming with the history. I’ve experienced this with workers with local burns cleaning bricks. Patients may not want to report an occupational injury for several reasons. Sometimes they’re undocumented, sometimes they’re paid under the table, worried about losing their job or they simply don’t want trouble for the boss or company.
An OSHA investigation into our patient’s workplace finds numerous hazards and violations. The company is shut down for the safety of the other workers, though 30 people, including the driver, lose their jobs.
The last question in the podcast is todays pop culture consult. HF was used to dissolve bodies in what movie or show?
A. Good Fellas
B. Breaking Bad
C. The Sopranos
D. Men in Black
Follow the Twitter and Instagram feeds both @pickpoison1 and you’ll see the answer when I post it. Remember, never try anything on this podcast at home or anywhere else.
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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. Thank you. Until next time, take care and stay safe.