Hazardous Hike
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 the Hazardous Hike. Want to know what phrase strikes fear into the hearts of toxicologists? What was in the state poison Athens used for capital punishment? How people become sick after eating quail? Listen to find out!
A 24-year-old man presents to the emergency department complaining of weakness and dizziness. He was hiking, just prior to arrival, when the symptoms began. He felt so weak, he required help from his friend to get back to the beginning of the trail. He didn’t fall or injure himself and they’d gone only a mile or two, (less than 3 kilometers) through a meadow and in the forest before they turned back.
He notes the weather was hot and humid, 100F (37.8C). He wonders if he’s dehydrated, though he hadn’t hiked far and was drinking plenty of water. He denies medical problems, medicines, over-the-counter meds and supplements, as well as tobacco. alcohol and drugs. He’s not suicidal.
His vital signs are: temperature 98.5F, or 37 C, heart rate 95 beats per minute, respiratory rate 24 breaths per minute, and pulse ox 93% on room air. His blood pressure is 125/70. Essentially, he’s breathing a little fast, and his oxygen, while within normal limits, is on the low side, especially for a fit person. On physical exam, his pupils are normal, as are his lungs and heart. He’s able to move all extremities, but seems overall a bit weak. Like the strength of a 90-year-old not a fit, healthy young man. The weakness is generalized, not focal, meaning all limbs, not unilateral like a stoke.
In summary, we have an otherwise healthy patient with nonspecific complaints and nonspecific physical exam findings. Not a lot to work with. Dizziness is the least favorite complaint of every EM physician. Why? It can mean anything from I don’t feel good and have a cold, to I’m having a lethal arrythmia and might drop dead at any moment. Frustratingly for both patients and physicians, the ED evaluation is often unrevealing.
Dehydration is one easy answer for dizziness. Do you think he’s dehydrated? Maybe, but I’m not convinced. Certainly hiking in extreme conditions can result in serious injury and death, but I’m sure many of you have hiked a mile or two in hot weather without requiring an ED visit afterward.
So what should we do? Hook him up to the monitor, check labs, including electrolytes, and an EKG. I’d start here, watch his clinical status, watch the monitor and wait for the results. I’d also order IV fluids. If, in fact, he’s dehydrated, he’ll feel better shortly.
Normally, I’d pause to talk about the differential diagnosis. Right now it includes everything, so instead of wasting time, let’s keep moving. After you see a few more patients, his labs come back, all normal. His EKG is normal, including the QRS and QTC intervals.
The nurse says, “I think something’s wrong with your guy, the hiker.” When you ask what, he says, “I don’t know. Something’s just not right.” Never dismiss the nurse who thinks something’s wrong, go directly to the bedside.
The patient’s heart rate is now elevated to 115 beats per minutes, despite getting the IV fluid you ordered. His respiratory rate has also gone up to 30 breaths per minute, despite this, his oxygen saturation is down to 90% on room air. Something definitely isn’t right. You re-examine him; his muscles are weak. He can barely lift them against gravity, off the bed. It’s all 4 extremities and worse in the legs than the arms. Putting this together, what do we have? Flaccid paralysis. What’s wrong with his breathing you ask? Using the Socratic method of teaching we love in medicine, let me ask you a question instead. What kills you in flaccid paralysis? Question 1.
A. Heart failure
B. Arrythmia
C. Respiratory arrest
D. Kidney failure
Answer: C respiratory failure from diaphragmic paralysis. The diaphragm is a muscle. If it’s paralyzed you can’t breathe.
This is very bad news for our patient. That said, we now have enough to generate a useful differential diagnosis and figure out what’s happening. What causes flaccid paralysis? Polio for one, a disease we shouldn’t even be talking about because it was almost eradicated. But it wasn’t and it’s back. Guillian-barre syndrome, myasthenia gravis, myelitis.
This isn’t a neurology podcast; it’s a toxicology podcast so let’s get right to it. We’ve talked a lot about heavy metals causing neuropathy. This isn’t thallium poisoning, he doesn’t have pain, much less excruciating agony. Could it be lead or arsenic poisoning? Maybe, but not likely in the absence of gastrointestinal symptoms. Plus the onset is too fast. He was hiking an hour ago. The timeline for heavy metal neuropathy is days rather then hours generally.
What about a snakebite? Elapid bites cause paralysis. They can be painless, but the snakes latch on, so I think he’d have noticed. Black widow envenomation occasionally causes muscle weakness, but not in the absence of other symptoms including severe pain and muscle fasciculations. Tick paralysis would fit here. I’d check every inch of his body including his hair. If you don’t see one, we can exclude it because the symptoms resolve immediately after you remove the tick.
Paralytic shellfish poisoning and tetrodotoxin fit with his symptoms, but it’s doubtful he’d be exposed to either on a hike. Same with botulism. High magnesium and things causing low potassium cause paralysis, but his electrolytes are normal.
How about curare, poisoning from a blow dart? I love this, its almost perfect. Indigenous people in the Amazon used the plant to poison blow dart tips for hunting. Some of the modern drugs we use for paralysis in anesthesia are derived from curare. However, it works very quickly in seconds to minutes and I don’t think he was hit by a blow dart on the hike.
The patient’s friend arrives and says three words that strike fear into the heart of toxicologists. “He was foraging.”
Uh oh.
Hold that thought. The patient’s respiratory rate increases, his oxygen drops. Watching his chest rise you note minimal excursion, meaning despite breathing rapidly it isn’t moving much. A sign of impending respiratory failure because his diaphragm isn’t working. What’s the treatment for this? You guessed it, intubation. You put him on the ventilator and send him to the ICU, which at this point must be packed with toxicology patients, given the number we’ve admitted there recently.
With that managed, we can focus on the new information. He wasn’t just hiking, but foraging. Why does it strike fear into my heart? It’s very easy to misidentify plants, resulting in poisoning. Most commonly, people unintentionally poison themselves with mushrooms. But it’s far from the only possibility. People trying to consume berries, ramps, leeks, potatoes, carrots and parsnips, just to name a few, have poisoned themselves. Don’t believe me? Increases in the popularity of foraging and bumper mushroom crops from damp weather, have been shown to increase calls about mushroom toxicity to poison centers. Both photo ID apps and books can lead you astray. Quick aside, Disturbingly, AI generated foraging books are on sale with concern for potentially dangerous mistakes. Beware.
Putting together plants and paralysis, a few things come to mind. First jequirity peas, also called rosary peas, and grasspeas in a family called Lathyrus cause lathyrism. They cause a lot of symptoms including paralysis when eaten. These are well known to be poisonous, but have been consumed in times of famine for example as depicted in a Goya print entitled Grasias a la almort, or “thanks to the grasspea”. Typically lathyrism occurs with repeated exposure, not after one or two bites.
Tobacco is another great thought here. Exposures cause paralysis and respiratory failure. If he did eat a tobacco plant for some reason, he’d probably have to eat a large amount. Maybe he was vaping on the hike, but again, he’d have to have eaten the vaping cartridge or several cartridges. While I love tobacco to explain his symptoms, it’s not the most likely exposure on a hike.
The friend pulls out two brown paper bags from his backpack with their finds. The first bag contains 10 mushrooms, all brown. One of my friends recently asked me to identify morel mushrooms from her back yard to let her know if they were real rather than false morels and therefore safe to eat. I told her as a toxicologist, not a mycologist, I’m more useful after you eat the mushroom then before. Patients often want us to ID what they’ve eaten. You need a professional to make the determination with certainty. I don’t know what kind of mushrooms these are, I do know this isn’t mushroom poisoning
Different types of mushrooms cause different symptoms. The one we worry most about are amanitas, so called death caps. These cause liver failure, so no our patient didn’t eat an amanita. Other mushrooms cause nausea and vomiting, seizures, anticholinergic toxicity and hallucinations. Again, not consistent with our patient’s symptoms.
The second bag contains parsnips. Basically, white carrots if you haven’t seen one. Ever heard of anyone getting parsnip poising? No not from the real ones. Wild parsnips are another story. Why because they can be mistaken for another plant. Time to pick your poison. Question 2. What did our patient eat?
A. Poison hemlock
B. Water hemlock
C. Foxglove
D. Jimson weed
Answer: This is a tough question. It’s poison hemlock. Foxglove contains digoxin, causing lethal arrythmias. Jimsonweed causes anticholinergic toxicity, listen to the Mad as a Hatter episode for more. Water hemlock causes seizures.
Our patient ingested poison hemlock, mistaking the poisonous roots for wild parsnips. Let me clear up the confusion. Conium maculatum is called poison hemlock, giving our patient the classic symptoms of paralysis. Water hemlock cicuta maculata is a different plant causing seizures.
Poison hemlock is a tall plant white flowers and a green stem with purple splotches. It’s a weed, originally imported from Europe as an ornamental garden plant. Apparently, it smells like mouse urine, though I’m not sure how many people that description helps. The stem, flower, leaves and root are all toxic. It has been mistaken for parsnips, wild carrots, anise seeds, and parsley. It’s often mistaken for edible Queen Anne’s lace. How do you distinguish them? The purple splotches on the stem. My advice – don’t try.
The main toxic compound is coniine. What does it do? Actually, it’s like nicotine. It binds to and blocks nicotine receptors in the neuromuscular junction. The muscle can’t contract and the patient develops flaccid paralysis. It’s very poisonous to livestock, causing paralysis and death in cows, pigs and sheep.
What’s the treatment for this? Supportive care, there’s no antidote. It’s definitely lethal, but with treatment, specifically mechanical ventilation, most patients have a good prognosis. The toxin doesn’t last long, patients receiving timely medical care recover by the next day.
There are some very interesting reports in the literature around unusual routes of exposure. One patient injected a liquid preparation of poison hemlock. I don’t know if he made ir or bought it somehow. He had cardiac arrest and prolonged encephalopathy for weeks.
Another interesting route of exposure is via quails. I could do a whole podcast on poisoning after eating quail, called conturnism, described in the Bible and recognized since ancient times. In 1991, in Italy, 17 patients became sick after eating songbirds. It’s believed, though not definitively proven, the birds ate hemlock which then poisoned the patients who ate the birds. Six patients in the series were paralyzed and 11 had muscle weakness. Four died.
Question 3. True or False, you can safely transplant the organs of someone with hemlock poisoning.
A. True
B. False
Answer: True. The liver, kidney and pancreas of a 14-year-old-girl who died of hemlock toxicity were successfully transplanted. None of the recipients showed any signs of poisoning.
Question 4. Who famously died of hemlock poisoning?
A. Alexander the Great
B. Aristotle
C. Socrates
D. Julious Cesar
Answer: Socrates. Poison hemlock was part of the Athenian state poison used for capital punishment. Hemlock was mixed with wine, sometimes opium from poppies. Socrates was convicted of impiety and corrupting Athenian youth and sentenced to death in 399 BCE. Plato wrote a description of his death, describing the following. The physician-poisoner, not a job description that should exist, told Socrates to walk until he felt difficulty, a common practice to speed up circulation of the poison. Socrates developed numbness and tingling in his legs, then deadening of his body traveling up from the feet. Toxicologists, and others, debate if the drink was really poison hemlock, but I think the description is fairly convincing.
Like many other natural poisons, hemlock was used in medicine to treat things like herpes, arthritis, gout, and cancer. Even St. Anthony’s fire, according to one source I read. Interesting to imagine treating ergot poisoning with hemlock poisoning.
Question 5. what disease was hemlock used to treat in medieval Europe?
A. Rabies
B. Syphilis
C. The plague
D. Smallpox
Answer: rabies. Hemlock mixed with wine and fennel was used to treat rabies. Partial credit if you said syphilis, I’m sure we could find that someone, somewhere did use it since every other potential therapeutic was tried. In fact, hemlock was listed in the British Pharmaceutical Codex all the way until 1938.
Back to our patient. The next day, his breathing returns to normal, he’s extubated. You go to see him. He’s awake with no sequala. He swears off foraging in the future, though you notice the brown paper bag with mushrooms is still in his friend’s backpack. This is a fictional case, as are all our cases, to protect the innocent. But it is based on real poisonings.
I want to share this poem by Nicander of Colophon from an illustrated manuscript on plant toxicity from the 2nd century BCE. “Take note of the noxious draught which is hemlock, for this drink assuredly loses disaster upon the head bringing the darkness of night: the eyes roll, and men roam the streets with tottering steps and crawling upon their hands; a terrible choking blocks the lower throat and the narrow passage of the windpipe; the extremities grow cold; and in the limbs the stout arteries are contracted; for a short while the victim draws breath like one swooning, and his spirit beholds Hades”. A vivid and accurate description of hemlock toxicity.
Last question in today’s podcast. In which TV series does a character die of hemlock poisoning?
a. Breaking Bad
b. Walking dead
c. The Sopranos
d. Gray’s anatomy
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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