Bitten
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!
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 Bitten. What antidote has caused more deaths than the toxin itself? Want to know what type of bite has been mistaken for appendicitis? Listen to find out!
Today’s episode starts in the emergency department. You hear commotion and shouting from room 1. Inside, several nurses and techs are trying to get a small boy undressed. His parents are shouting, “Do something, he needs help.” You’re tempted to walk past and let your colleague handle this one, but instead you enter and ask what’s happening.
The parents instead start shouting at you to do something. You try to calm them down, to get a history, so you can potentially intervene. The patient, 5-years-old, is lying on the stretcher, crying and grimacing in pain. His knees are drawn up to his chest.
After much difficulty, you manage to obtain the following information. The patient was fine until three hours ago. He told his mother he his arm hurt, the said he felt sick and threw up. The pain progressed, becoming severe and encompassing his entire body. He has no other symptoms including constipation or diarrhea. He has no fever, no past medical history and doesn’t take any medicines.
The nurses are having difficulty getting him undressed because he doesn’t want them to move his limbs. The parents want his clothes left on. They refuse to allow a gown until he’s given pain medicine. The patient screams out every few seconds and is crying nonstop. You agree, hoping this will expedite the patient’s care, he’s obviously unwell and prolonged arguing with the parents isn’t in the patient’s best interest.
The nurses do manage to get vital signs as follows: Temperature in 98.5 or 36.9 Celsius, heart rate 130 bpm, respiratory rate is 40 breaths per minute, blood pressure is 140/80.
You do a limited physical exam, over his clothes. He's sweating profusely, diaphoretic in medical terms. He’s crying and won’t answer questions, so that’s all you can gather about his mental status. His lungs are clear though he's breathing rapidly. His heart rate is also rapid, but otherwise normal. His abdomen feels hard and rigid. A rigid abdomen is often caused by peritonitis, infection inside the abdomen, a ruptured appendix for example. He doesn’t have focal tenderness in one area, but rather pain all over. The muscles in his extremities are twitching.
The nurse places an IV, you order a dose of morphine, nausea medicine and IV fluids. What now? Clearly, we need labs and a CT scan of his abdomen to look for a source of infection. Is this appendicitis? The rigid abdomen suggests intraabdominal pathology, yes. Patients with peritonitis don’t want to move, because that makes the pain worse, possibility explaining why he won’t move. You might’ve had appendicitis yourself or seen a family member with it. Were they twitching? No. Something isn’t right.
Question #1 What electrolyte causes muscle spasms?
A. Calcium
B. Potassium
C. Magnesium
D. Sodium
Answer: A. High calcium causes muscle spasms and tetany. Both high and low potassium
cause weakness, as does high magnesium. Sodium has minimal extremity muscle effects. Hypercalcemia can cause constipation and thus abdominal pain, but not to this degree.
His lab results, including his calcium are normal. There's no evidence of infection. A urine specimen is normal. His CT scan is also normal. Hmmm. What’s going on with this kid? You go back into the room. He’s no longer crying after two doses of morphine, but he still looks very uncomfortable. He’s still grimacing and sweating. His jaw is clenched tight. Is this resus sardonicus, the facial changes we discussed with strychnine in the Culinary Catastrophe episode? His mouth is clenched shut, rather than pulled back into a dreadful smile, so no. You didn’t give the parents any morphine, but they’ve calmed down as well. The nurse has managed to get him into a gown.
Why is this so important? I’ve found shingles, ticks, cellulitis and other infections, blood clots, fractures and even a dislocation once in an intoxicated patient after undressing and thoroughly examining my patients. You pull up the gown, noting his abdomen looks as rigid as it felt. You check his back to make sure there’s no rash, infection or other finding, then give his skin a quick check. On the back of his left wrist is a red mark, in a swollen circle. At first glance, it looks like an insect bite. On closer inspection, it’s white in the center, called central pallor or central clearing. In the middle, two puncture wounds.
Question 2. This is the classic description of what kind of sting or bite?
A. Bee
B. Rattlesnake
C. Black widow spider
D. Brown recluse spider
Answer: this is a black widow bite. Good thing we got him undressed and did a through physical examination. Otherwise, we’d still be in the dark, without a clue. This is the classic description of the bite, but what about the rest of the symptoms? Can a black widow cause this? Yes. In fact, clinically, I’d give more weight to these symptoms in making the diagnosis than I would the bite itself. More on this in a minute.
You ask the parents about spiders and black widows. Mom looks baffled. Dad says he saw one in the yard a few weeks ago.
What now? Question #3.
A. Obtain confirmatory testing
B. Supportive care
C. Suck out the venom
D. Administer the antidote
Answer: D. Administer the antidote. Though if you said supportive care, that answer is also ok. We have black widow spider antivenom and I’d give it to this patient, though there is some controversy about it. More on this, too, in a minute.
You order a dose, one vial, and are relieved the pharmacy has it. Not every hospital carries it. Black widow bites aren’t uncommon, most patients are fine with mild symptoms and don’t require antidotal treatment.
Unlike snake bites, the dose is always one vial. It’s enough to neutralize the venom from one spider. This is also the reason children are more affected than adults. The amount of venom injected by the spider is much more potent in a child who weighs a few pounds or kilos, than an adult who weighs many pounds or kilos.
One hour after administration, the child is almost completely recovered. He’s no longer having muscle twitching, his abdominal pain resolved. He still complains of pain in his left arm, but that too is improving. He has a guilty look on his face every time someone mentions a spider, but hasn’t been forthcoming about what happened.
Widow spiders are found on every continent except Antarctica. In North America, we have the classic black widow Latrodectus mactans. The spiders are usually found in woodpiles, outhouses, and rubbish piles and aren’t typically aggressive towards humans.
Black widow bites are painful, systemic symptoms develop over several hours from mild pain, to severe envenomation including whole body pain and spasms, sweating, high blood pressure, rapid heart rate and breathing, severe abdominal pain, priapism, myocardial infarction, seizures, hallucinations and psychosis.
No deaths are reported from black widows. Three deaths are reported from other Latrodectus species. Two in Madagascar, one from cardiovascular failure and the other gangrene of the foot. A third death in Greece was attributed to myocarditis, inflammation of the heart muscle.
What does black widow venom do? It’s a mixture of toxic compounds meant to paralyze prey. The main culprit in human toxicity is alpha- latrotoxin. Remember I said hypercalcemia causes muscle spasms and tetany? alpha- latrotoxin works by increasing calcium concentrations inside the cell, causing, muscle twitching, spasms and tetany. In the face, this is called facies latrodectismica.
The antivenom is horse-derived antibody that binds alpha- latrotoxin. It works, reducing symptom duration from 22 hours to 9. Onset is a rapid as thirty minutes, with most symptoms resolving 1-3 hours after administration. It also reduces the need for hospital admission. Why is it controversial? Two patients have died from anaphylactic shock due to the antidote. As I just said, no patients have ever died from a black widow bite, thus the controversy.
Both deaths were tragic, but also unusual cases. One patient with a history of asthma and allergies was given undiluted antivenom as a push, rather than a standard dilution given as a slow infusion. She suffered anaphylactic shock, unusually complicated by a collapsed lung and died. A second patient, also with asthma, developed anaphylactic shock and cardiac arrest. These tragic cases, and again, no deaths from black widows, led to caution for many years. However, the antivenin has since been used, safely, in hundreds of patients. It isn’t recommended for patients with mild symptoms, local symptoms only, or those with asthma.
Research is being done into a new antidote, a lab manufactured antibody, presumably with a reduced risk of anaphylaxis.
What about brown widows, Latrodectus geometricus? These aren’t native to the US, but are spreading now to many states. They have equally potent venom as black widows. However, their bites are usually less problematic as they inject a smaller amount of venom. Black widows are declining in many areas. Why? Interestingly, due in part to the fact that brown widows hunt black widows.
I want to share two historical cases with you. The first is from 1900. A San Franciso construction worker was bitten and after developing extreme pain, he was treated with potassium, permanganate, cocaine and morphine. Convinced he was dying, the patient treated himself with whiskey. After severe, ongoing symptoms, physicians injected him with strychnine and whiskey. Patient died 14 hours after the bite, likely killed by the treatment, rather than the spider.
Interestingly, there was controversy at this time as to whether black widows were actually venomous to humans. The second historical case definitively proved the answer to this question.
On Nov 12, 1933, a physician named Alan Walker Blair conducted an experiment on himself. In his lab at the University of Alabama school of medicine, he allowed a black widow to envenomate him and recorded exactly what happened.
Twenty minutes after the bite his entire arm began to hurt, progressing to neck pain, chest pain and abdominal pain. Several hours later he was taken to the VA hospital due to the severity of his abdominal pain. He then developed difficulty speaking and was unable to stand up. Early the next morning, afraid he’d go insane, he was treated with morphine. His condition improved 36 hours after the bite.
The initial plan was a second bite to see if immunity developed, lessening the effects. He said, “I was presented with the opportunity of deciding this point, but lack the courage to submit myself to a possible repetition of first experience.”
Back to our patient. He admits to his parents he found the black widow while playing in the yard, put it on his arm and poked it with a stick until it bit him. Why? He was hoping to turn into Spider man. Fortunately, he recovers uneventfully, unfortunately he doesn’t develop any super powers.
This is a fictional case, as are all our cases, but based on the real case of several brothers in Boliva who apparently all wanted to become Spiderman.
Today I’m here with answers to a burning question. We’ve talked about bites, but what happens when you inject a black widow spider? Basically, the same thing. How do we know? Someone did this, crushed up a spider, mixed it with water and injected it, apparently hoping to get high. Don’t take my word for it, check out the letter in the annals of emergency medicine. One of the many reasons we EM doctors are so hard to shock.
Last question in today’s podcast. The red hourglass marking on spiders has been shown to protect against attacks from which of the following?
A. Birds
B. Humans
C. Male black widows
D. Wasps
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.