I enjoyed and learned from many medical toxicology papers in 2022. I am including two important ones every EP should read—having the resources to talk to nephrologists about poisonings and understanding the toxicity of abortifacients—but I added one at the end that is a fun read that even comes with visual aids about birds. Yes, birds! Yes, toxicology. Yes, birds and toxicology!
The Role of the Nephrologist in Management of Poisoning and Intoxication: Core Curriculum 2022
Mullins ME, Kraut JA
Am J Kidney Dis.
Hemodialysis has several potential roles in exposures to or overdose from various poisons: removal of the poison itself, correction of acid-base or electrolyte imbalance, and compensation for renal insufficiency. Classic poisons for which hemodialysis may be indicated include toxic alcohols, salicylates, acetaminophen, lithium, and metformin.
Nephrologists learn the indications for hemodialysis in these cases, but they don't often see poisoned patients and are not completely aware of the nuances of when to use (or not use) extracorporeal treatments in such situations.
This article by a medical toxicologist and a nephrologist is an excellent review of the basic principles nephrologists should know in treating poisonings, and it is a great resource to have on hand when discussing these cases with renal specialists.
I remember a case years ago of a patient with altered mental status, respiratory distress with pulmonary infiltrates, and a salicylate level of 60 mg/dL. The nephrology service initially suggested that we administer sodium bicarbonate to alkalinize the urine and then they would follow up in the morning.
This was unacceptable for several reasons, and the consultant agreed to immediate dialysis only after a lengthy discussion. Things probably would have gone much more quickly if I had this reference that points out what the nephrology literature itself has to say about the matter.
One small carp: The authors discuss several criteria for hemodialysis in cases of lithium toxicity based on serum lithium levels. They fail to stress the important point that lithium takes some time to distribute after ingestion and that levels obtained less than six hours after the last dose may be artificially high and not require dialysis if other markers of toxicity are not present. Nonetheless, this is an excellent paper to read and file away.
Toxicity of Abortifacients: A Review for Physicians in the Post Roe Era
Mazir-Amirshahi M, Ye P
Am J Emerg Med.
Several months ago, I reviewed the toxicity of herbal and over-the-counter products sometimes used in attempts to induce abortions; those included pennyroyal, blue cohosh, black cohosh, mugwort, rue, and quinine. (EMN. 2022;444: http://bit.ly/3KK9JGQ.) It seems reasonable to expect that we will see more cases of exposure to and overdose from these agents following the U.S. Supreme Court decision that overturned Roe v. Wade.
This useful article reviews the toxicity of legal prescription drugs that have been used to induce medical abortions. Mifepristone is a progesterone receptor antagonist that increases uterine contractility. The uterine lining during pregnancy is maintained by the actions of progesterone, and mifepristone causes sloughing of the decidua. It also enhances the abortion-inducing effects of prostaglandins on the uterus, which is why it is often given in conjunction with misoprostol.
Significant adverse effects can include vaginal bleeding, abdominal pain, and fever. Because it is metabolized by the CYP3A4 enzyme, mifepristone can interact with many other medications. Treating adverse effects from mifepristone includes good supportive care with blood transfusion when necessary. Rh immune globulin may be indicated if a pregnant woman is Rh negative. Patients taking long-term steroids or those with adrenal sufficiency may develop adrenal crisis after receiving mifepristone and require treatment with fluids and steroids.
One other important point. As this paper points out, “[M]ifepristone does not treat ectopic pregnancy and should not be administered if an ectopic is confirmed or suspected.” Because of this, mifepristone is contraindicated in pregnant patients with IUDs.
Misoprostol is a prostaglandin E1 analogue initially developed to treat gastric ulcers. It also increases uterine contractions and has been used alone or in combination with mifepristone to facilitate medical abortions. Gastrointestinal adverse effects include nausea, vomiting, and diarrhea. Pelvic pain and vaginal bleeding can be severe and sometimes lead to hemorrhagic shock.
Misoprostol is a teratogen, primarily affecting the development of fetal limbs and the central nervous system. It can also cause Moebius syndrome, which affects the formation of the cranial nerves, most often VI and VII, resulting in facial paralysis and impaired ocular movement.
If misoprostol has been applied intravaginally, decontamination with vaginal irrigation may be indicated. Because the drug is teratogenic, women who receive it in an attempt to induce medical abortion should be followed closely to confirm that the abortion has been completed.
Methotrexate toxicity is discussed in this review but too complex to cover here. Fortunately, it is not often used for medical abortions at present because protocols using misoprostol with or without mifepristone are safe and more effective.
Avian Toxins and Poisoning Mechanisms
Yeung KA, Chai PR, et al.
J Med Toxicol.
This fascinating paper reviews several species of birds known to contain poisonous compounds in their feathers or secretions. Their names have a poetic ring: pitohui, Ifrita kowaldi, spur-winged goose, North American ruffed grouse (pictured), and European hoopoes, among others. The authors discuss toxic mechanisms, clinical presentations, and adaptions that make the birds themselves impervious to the toxins they carry. This is an entertaining read complete with pictures of the birds and 75 references.
Dr. Gussowis a voluntary attending physician at the John H. Stroger Hospital of Cook County in Chicago, an assistant professor of emergency medicine at Rush Medical College, a consultant to the Illinois Poison Center, and a lecturer in emergency medicine at the University of Illinois Medical Center in Chicago. Read his blog atwww.thepoisonreview.com, follow him on Twitter@poisonreview, and read his past columns athttp://bit.ly/EMN-ToxRounds.