Newsletters

POSTED: January 18th, 2019
POSTED IN: EM Pulse - The Official Newsletter of MOCEP, Resources, September/October 2018, Toxicology,

Written by Evan Schwarz, MD, FACEP, FACMT

In early October, letters containing ricin were sent to the President, Secretary of Defense, and FBI Director. They were traced back to a former seaman in the Navy. Fortunately, no one was hurt. From reports in the media, the letters actually contained a castor bean concoction (whatever that exactly means), which ricin comes from, and not actually ricin. But wait, doesn’t castor oil come from castor beans? And hasn’t castor oil been used to treat constipation for a long time? So why is that not harmful but ricin is so dangerous?

Ricin does come from castor beans, as does castor oil. However, it’s how it is extracted that is the key. When oil is extracted from the beans, it does not contain ricin so it is safe for human consumption. While it is a laxative, and ricin causes diarrhea, castor oil does not rely on any toxicity from ricin for its therapeutic effects. Ricin is made from the waste material left over after processing the beans to obtain the oil. That’s why if a small child just swallows a bean whole, they won’t get sick as the ricin remains inside the bean. However if they chew the bean, that is potentially a different story, although still unlikely to cause significant toxicity unless they chew multiple beans.

Fortunately even though ricin is incredibly toxic and from my understanding not too hard to make, it doesn’t weaponize well. This is in comparison to biologics such as botulinum, sarin, and anthrax, to name a few, that are more potent, and in some cases, easier to weaponize. This is good news as the castor plant is an ornamental plant that grows well in multiple settings. It’s an important crop as it is used both as a laxative and in motor oil. As such, the beans are rather easy to find. But as previously mentioned, it doesn’t weaponize well so its use as a weapon is limited. It can be aerosolized and ingested but those in general aren’t great delivery mechanisms. Plenty of kids chew the beans and do okay as ricin isn’t well absorbed from the GI tract, at least from chewed up beans. Toxicity from aerosolizing ricin in an envelope is also not a great delivery mechanism as opposed to if it were in a mist. Small granules could theoretically be released when handling a letter containing ricin powder but would be unlikely to cause toxicity. Now injection, that is a very effective mechanism. As little as 500 micrograms of injected ricin is lethal. Injection would be an inefficient mechanism to harm a large amount of people but is very effective as an assassination tool. The Bulgarian novelist and dissident Georgi Markov was murdered using an umbrella gun that injected a pellet containing ricin and he died a few days later.

Ricin is a glycoprotein and inhibits ribosomes thereby inhibiting protein synthesis which is how it causes its toxic, and potentially lethal, effects. In general, ricin causes nausea, vomiting, and diarrhea. Symptoms generally start within a few hours and progress quickly with death occurring within a few days from the exposure. It can look a lot like sepsis as the patient develops a leukocytosis, hypotension, and multiorgan failure. Inhalation can disrupt the alveolar-capillary permeability and cause airway necrosis and a lung injury. Significant ingestion can also cause a gastrointestinal hemorrhage. Ricin is not absorbed dermally so just touching ricin, such as from an envelope, would not cause significant toxicity, although it can still cause erythema and pain. There is no antidote and treatment is supportive, which includes aggressive fluid resuscitation, vasopressors, and pulmonary support as needed. Additionally depending on the mechanism of exposure, aggressive decontamination can also be considered.