Should We Be Using the Poisoning Severity Score?

Evan S. Schwarz, Kathryn T. Kopec, Timothy J. Wiegand, Paul M. Wax, Jeffrey Brent

Despite the existence of a number of severity-of-illness classifications for other areas of medicine, toxicology research lacks a well-accepted method for assessing the severity of poisoning. The Poisoning Severity Score (PSS) was developed in the 1990s in Europe as a scoring system for poisonings reported to a poison center in order to describe a patient's most severe symptomatology. We reviewed the literature to describe how the PSS is utilized and describe its limitations. We searched the medical literature in all languages using PUBMED, EMBASE, and SCOPUS from inception through August 2013 using predefined search terms. Out of 204 eligible publications, 40 met our criteria for inclusion in this review. There has been a paucity of published studies from North America that used the PSS. In some cases,  the PSS was misapplied or modified from standard scoring, making a bottom line appraisal of the validity or reliability of the original version of the instrument challenging. The PSS has several subjective criteria, is time consuming to score, and is likely to be of little use with some types of poisonings, limiting its clinical utility. The PSS was developed as a tool to document encounters with poisoned patients. However, it is used infrequently and, when applied, has been misused or modified from its original form. In its current form, it has limited clinical utility and likely cannot be broadly applied to many exposures due to their unique clinical circumstances. With better global collaboration among medical toxicologists, it is possible that a modified score could be developed for use clinically or as a research instrument.