Poisons Assessment ASSESSMENT Assessment and diagnosis
of the poisoned patient Allister Vale Sally Bradberry
Abstract Assessment of an acutely poisoned patient involves the taking of an appropriate history, assessment of the level of consciousness, ventilation and circulation, a physical examination, and requesting appropriate toxi- cological and non-toxicological investigations. Diagnosis is based on the history, circumstantial evidence (if available), a cluster of common features (if present) and, occasionally, the results of biochemical or toxi- cological analyses.
Keywords diagnosis; examination; history; local toxicity; systemic toxicity; toxicological analyses
idiosyncratic manner to some agents (notably metoclopramide, and some phenothiazines and butyrophenones). In others, genetic predisposition may affect response (e.g. rate of metabo- lism of codeine to morphine). The speed with which features appear depends partly on the
route of exposure. It is greater with inhalation and injection than with dermal exposure and ingestion. Assessment of an acutely poisoned patient follows the estab- lished clinical method (Table 1)1:
immediate assessment of level of consciousness, ventila- tion and circulation;
history; examination;
appropriate toxicological and non-toxicological investigations.
Assessment of level of consciousness
The Glasgow Coma Scale (GCS) is the most commonly used method to assess the degree of impairment of consciousness.
A GCS score of 8 (not obeying commands, not speaking, not eye opening) should prompt careful respiratory assessment, particularly if the laryngeal (gag) reflex is lost. In poisoned
Toxicity and poisoning
The toxicity of a substance, and therefore the features of poisoning, can generally be predicted from:
the dose to which an individual has been exposed. The features of poisoning are classified as either local or
its physicochemical properties; its pharmacological/toxicological actions; the route of exposure;
systemic.
Local toxicity is confined to the site of contact of the substance with body surfaces. The route of exposure (eye, skin, respiratory or gastrointestinal tract) determines the anatomical location of the interaction; the physicochemical characteristics of the substance (solubility, volatility, pH) define its nature and extent.
Systemic toxicity depends on the fraction of the dose of the poison that is absorbed into the circulation; systemic toxicity is generally dose-related and may be organ-specific or involve several organs. While the pharmacological/toxicological effects of the poison are generally proportional to the amount that has been absorbed, the effects are modulated by variations between individuals. Some individuals react in a non-dose-dependent,
Allister Vale MD FRCP FRCPE FRCPG FFOM FAACT FBTS is Director of the National Poisons Information Service (Birmingham Unit) and the West Midlands Poisons Unit at City Hospital, Birmingham, UK. Competing interests: none declared.
Sally Bradberry BSc MD MRCP FAACT is Deputy Director of the National Poisons Information Service (Birmingham Unit) and West Midlands Poisons Unit at City Hospital, Birmingham, UK. Competing interests: none declared.
MEDICINE 40:2 40 Africa Health 48 Assessment and diagnosis of poisoned patients
Assessment of level of consciousness, ventilation and circulation C
C C C
What is the Glasgow Coma Score? Are laryngeal reflexes present? Is ventilatory insufficiency present? What are the pulse and blood pressure?
History C
Toxicological, medical, psychiatric and social
Circumstantial evidence C
Suicide note C Circumstances in which patient was found
Examination See Table 2
Diagnostic trial of antidotes C
C
Naloxone Flumazenil
Toxicological investigations C
Specific C Screening
Non-toxicological investigations C
C C C
Haematology Biochemistry ECG
Radiology Table 1 2011 Published by Elsevier Ltd. July 2012
patients, an initial GCS 8 has been claimed to be both a good2 and a poor predictor of the need for intubation,3 though it has
also been claimed that a GCS of 8 at any time during admission correlates well with the need for intubation.3 The AVPU (alert, responsive to verbal stimulation, responsive to painful stimula- tion, and unresponsive) responsiveness has also been employed and corresponds well to GCS scores when assessing level of consciousness in the poisoned patient.4
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68