Removal of poisons by extracorporeal means has been possible ever since Abel, Roundtree and Turner first attempted dialysis in 1913. Successful efforts at achieving these have been described since 1950s, initially with barbiturates and salicylates, and then progressively with a wide array of toxins, as expertise and knowledge expanded. Some modalities have become less popular (eg exchange transfusions, charcoal hemoperfusion) and others more so (continuous renal replacement therapy and hemodialysis).
The Extracorporeal TReatments In Poisoning workgroup (EXTRIP) was formed with a goal of providing guidance for clinicians providing care for patients with intoxications. It consists of experts from all over the world, from different specialties (internal medicine, emergency medicine, critical care, pediatrics, toxicology, clinical pharmacology and, needless to say, nephrology) and with support from many different professional organisations. The workgroup performs a systematic review of the literature to prepare their reports and guidelines. A key aspect, unlike other guidelines, is the lack of randomized clinical trials in this area - which is not surprising given the nature of clinical presentation of intoxications, and often the lack of equipoise in comparing extracorporeal treatment (ECTR) to a placebo or sham therapy. Hence, the literature supporting the guidelines is often based on case reports and series, as well as pharmacokinetic considerations. At the same time, the rarity of some of these cases means that an individual clinician may not be aware of the most uptodate evidence for the efficacy of ECTR. This is true especially given the complex interplay of history, clinical signs and symptoms, and toxin levels that have to be considered to decide if and when to act.
In this collaboration between UKidney and NephJC, we present a series of posts by the Nephrology Social Media Collective (NSMC) interns which summarize the EXTRIP guidance for common and important poisons.
Also check out the EXTRIP-powered toxicology primer on UKidney
Tricyclic acids (TCAs) have been in heavy use for clinical depression since the 1950s. Despite newer antidepressants, TCAs have a role in major depressive disorder, chronic and neuropathic pain, attention deficit hyperactivity disorder, cyclical vomiting, nocturnal enuresis, and obsessive-compulsive disorders.
Aspirin is one of the most widely used medications worldwide. It has mainly been prescribed as the antiplatelet drug of choice for patients with diverse arrays of vascular disease. Aspirin is still commonly prescribed for its analgesic properties as well. Due to aspirin’s widespread use, salicylate toxicity is an important clinical issue for practitioners.
Barbiturates remain an important cause of morbidity and mortality today. The barbiturate most frequently associated with self-poisoning is phenobarbital.
Thallium, colourless and odourless as a salt (Thallium sulphate) has been popularized by Agatha Christie and has even been used as a poison. In 2012, the EXTRIP group issued guidance on the use of extracorporeal treatment (ECTR) of thallium poisoning (Ghannoum et al cJASN 2012). The group conducted a thorough literature search that included abstracts and conference proceedings, but found the quality of evidence was poor, with only case reports and case series identified. Information from 74 patients (11 of whom died) was included to form the final recommendations which are well worth reading in full. The salient points of their recommendations are summarized below.
Methanol kills. If you regularly read the news you may have encountered this incident that happened in Sumatra to a young British woman. In fact, Wikipedia has a list (likely not exhaustive) of methanol poisoning incidents from around the world.
Can we love Metformin? Need we to fear it? Or perhaps we must give it Machiavelli’s ultimate accolade, and love and fear the drug with equal weight?
Why to love Metformin? It is endorsed in the US, UK and Europe as the initial drug treatment for adults with type 2 diabetes. It treats diabetes, does not cause weight gain, does not increase risk of hypoglycaemia, and might reduce heart attacks and strokes. One tablet costs about £0.20 ($0.29/€0.26) and the drug has been widely used for upwards of 60 years.
Lithium is a cation with small molecular mass of 7 Daltons. It does not bind to serum proteins and has a small volume of distribution of 0.7-0.9 L/kg. The half-life of lithium is 12-27 hours. It does not undergo any metabolism and is freely filtered in the glomerulus and excreted completely in the urine.
In 2014, about 2.2 million human exposures were reported to a poison control center in the United States. Many of these exposures led to visit in a healthcare facility. The exposures often require supportive care but when necessary extracorporeal treatments like intermittent hemodialysis (IHD), continuous renal replacement therapy (CRRT), hemoperfusion (HP), exchange transfusion, and extracorporeal membrane oxygenation (ECMO) may be required for the management of such exposures. The EXTRIP workgroup has produced a concise review that covers the history, technical aspects and utility of hemoperfusion.
Acetaminophen (APAP) belongs in every medicine cabinet. It’s a firm base to the analgesic ladder, and forms the foundation of analgesia for an array of indications from post-operative surgical pain to headache. Infants and seniors alike have benefited from its antipyretic properties, and it has more than earned its position in the WHO’s list of essential medicines.
The Extracorporeal Treatments in Poisoning (EXTRIP) workgroup was created to provide evidence-based clinical recommendations on the use of extracorporeal treatment (ECTR) in various poisonings. Here we will review their guidance in the case of anti-epileptic drug (AED) toxicities. We don’t see this too often as Nephrologists. However as these drugs are now in widespread use for many other indications such as neuropathic pain, bipolar disorder and migraine, AED toxicity may occur more frequently and we should familiarize ourselves with our role in its management. Being anti-epileptic drugs, neurological manifestations are common in intoxication, however differences in protein binding and volume of distribution make decisions about extracoporeal removal quite different for them
