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concept_intro_to_toxicology_patient [2025/05/12 06:28] – ↷ Links adapted because of a move operation jkohtsconcept_intro_to_toxicology_patient [2025/05/13 09:49] (current) – ↷ Links adapted because of a move operation 3.230.224.6
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 ===== - Approach to the Toxicology Patient ===== ===== - Approach to the Toxicology Patient =====
  
-Daly et al. (2006) [(16627846>[[https://pubmed.ncbi.nlm.nih.gov/16627846/|PMID: 16627846]]. Daly FF, Little M, Murray L. A risk assessment based approach to the management of acute poisoning. Emerg Med J. 2006;23(5):396-399. doi:10.1136/emj.2005.030312 {{ daly_2006_toxicological_risk_assessment2.pdf|PDF}})] provide a summary of factors that need to be considered when assessing and managing the toxicology patient.+Daly et al. (2006) [(16627846>[[https://pubmed.ncbi.nlm.nih.gov/16627846/|PMID: 16627846]]. Daly FF, Little M, Murray L. A risk assessment based approach to the management of acute poisoning. Emerg Med J. 2006;23(5):396-399. doi:10.1136/emj.2005.030312 {{ daly_2006_toxicological_risk_assessment.pdf |PDF}})] provide a summary of factors that need to be considered when assessing and managing the toxicology patient. Their described approach forms the common mnemonic '**R RSI DEAD**', some components of which are explored below. 
 + 
 +  * **R**esuscitation 
 +  * **R**isk assessment 
 +  * **S**upportive care and monitoring 
 +  * **I**nvestigations 
 +  * **D**econtamination 
 +  * **E**nhanced elimination 
 +  * **A**ntidotes 
 +  * **D**isposition
  
  
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 A thorough risk assessment is crucial in the approach to the toxicology patient and includes: A thorough risk assessment is crucial in the approach to the toxicology patient and includes:
  
-  * Agent/s taken+  * Agent(s) taken
   * Dose   * Dose
   * Time of ingestion   * Time of ingestion
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   * Clinical manifestations since the exposure   * Clinical manifestations since the exposure
   * Regular medications   * Regular medications
-  * Relevant co-morbidities - especially renal or liver disease which may affect drug clearance, cardiac, or respiratory disease which may increase toxicity for agents that cause cardiac or sedative effects and seizure history.+  * Relevant co-morbidities - especially: 
 +    * Renal or liver disease which may affect drug clearance. 
 +    * Cardiac or respiratory disease which may increase toxicity for agents that cause cardiac or sedative effects. 
 +    * Seizure history.
  
 If the exposure is a deliberate self-poisoning, a mental health risk assessment should also be undertaken. If the exposure is a deliberate self-poisoning, a mental health risk assessment should also be undertaken.
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 Examination should be focused on the expected toxicity given the risk assessment. In the patient where the risk assessment is unclear, examination for specific toxidromes may be helpful in determining likely agents involved in the poisoning. The below table summaries the examination findings of common toxidromes. Examination should be focused on the expected toxicity given the risk assessment. In the patient where the risk assessment is unclear, examination for specific toxidromes may be helpful in determining likely agents involved in the poisoning. The below table summaries the examination findings of common toxidromes.
  
-{{  :wikitox:toxidromes.png?direct&500  }}+{{  toxidromes.png?direct&500  }}
  
 Specific complications of poisoning should also be considered and sought on examination: Specific complications of poisoning should also be considered and sought on examination:
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 ===== - Investigations ===== ===== - Investigations =====
  
-The following investigations may be useful to perform:+The following investigations may be useful.
  
 +
 +**Laboratory tests**
   * **Blood gas**  analysis to assess gas exchange and metabolic disturbance particularly in patients with altered level of consciousness.   * **Blood gas**  analysis to assess gas exchange and metabolic disturbance particularly in patients with altered level of consciousness.
   * **Blood glucose **especially important in those with an altered level of consciousness.   * **Blood glucose **especially important in those with an altered level of consciousness.
-  * **Paracetamol concentration**  is often tested routinely when a patient is not alert enough to give a reliable risk assessment. 
-  * **ECG**  assessing for QT prolongation or evidence of sodium channel blockade. 
   * **Electrolytes, renal function, liver function tests**.   * **Electrolytes, renal function, liver function tests**.
   * **CK**  if rhabdomyolysis is suspected on risk assessment, particularly following long lie.   * **CK**  if rhabdomyolysis is suspected on risk assessment, particularly following long lie.
 +
 +**Toxicology tests**
 +  * **Paracetamol concentration**  is often tested routinely when a patient is not alert enough to give a reliable risk assessment.
   * Specific **drug concentrations**  (e.g. valproate, carbamazepine, lithium) may be helpful if results are available in a clinically useful timeframe.   * Specific **drug concentrations**  (e.g. valproate, carbamazepine, lithium) may be helpful if results are available in a clinically useful timeframe.
   * **Urinary drug screens**  have limited utility in a toxicology patient, they confirm the presence of some drug classes which are commonly misused, however false positives and negatives occur.   * **Urinary drug screens**  have limited utility in a toxicology patient, they confirm the presence of some drug classes which are commonly misused, however false positives and negatives occur.
-  * **CXR**  if evidence of aspiration 
-  * **Bedside echo**  in patients with haemodynamic instability to determine the contribution of negative inotropy versus vasodilation 
-  * **CT head**  if concerns for concurrent trauma or hypoxic brain injury 
-More in depth description of some investigations can be found in appropriate sections ([[:wikitox:arterial_blood_gases|Bloods Gases]] , [[:wikitox:ecg_changes|ECG]]) or in specific drug monographs. 
  
  
 +**Cardiac investigations**
 +  * **ECG**  assessing for QT prolongation or evidence of sodium channel blockade.
 +  * **Bedside echocardiography**  in patients with haemodynamic instability to determine the contribution of negative inotropy versus vasodilation.
  
-===== - Treatment =====+**Radiology studies** 
 +  * **CXR**  if evidence of aspiration. 
 +  * **CT head**  if concerns for concurrent trauma or hypoxic brain injury.
  
-==== - Resuscitation ====+More in depth description of some investigations can be found in appropriate sections ([[concept_blood_gas_analysis|Bloods Gas Analysis]] , [[concept_ecg_changes|ECG]]) or in specific drug monographs.
  
-Resuscitation should occur along standard lines with attention to a patient’s airway, breathing and ventilation. 
  
-Bedside echo may be helpful to delineate negative inotropy from vasodilation to better guide inotropic and vasopressor therapy. 
  
-Seizures if they occur should receive benzodiazepines in the first instance. Second line therapy is barbiturates.+===== - Treatment =====
  
-Hypoglycaemia should be corrected with glucose.+==== - Resuscitation ====
  
-Severe hyperthermia (> 39°C) should be corrected with cooling techniques.+Resuscitation should occur along standard lines such as the ABCDE approach.
  
-In the event of cardio-respiratory arrest advanced life support protocols should be provided. Prolonged resuscitation attempts are often advised as patients with poisonings are typically healthy before the exposure and the toxicity is likely to be reversible once peak toxicity has passed. Extracorporeal membrane oxygenation may have a role in refractory cardiac arrest due to poisoning and should be considered early where available.+**Airway and Breathing**\\ 
 +Certain drugs overdoses may cause a depressed level of consciousness. This can result in airway compromise, respiratory depression, hypoxemia, and hypercapnia. Airway adjuncts, oxygen therapies, or ventilation therapies may be required to correct these.
  
 +**Circulation**\\
 +Bedside echocardiography may be helpful to discriminate between negative inotropy from vasodilation as a cause of circulatory shock, to better guide inotropic and vasopressor therapy.
  
 +**Disability (Neurological Status)**\\
 +Hypoglycaemia should be corrected with glucose. Seizures, if they occur, should receive benzodiazepines in the first instance. Second line therapy is barbiturates. 
 +
 +**Exposure/Environmental**\\
 +Severe hyperthermia (>39°C) should be corrected with cooling techniques.
 +
 +**Cardio-respiratory arrest**\\
 +In the event of cardio-respiratory arrest, advanced life support protocols should be provided. Prolonged resuscitation attempts are often advised as patients with poisonings are typically healthy before the exposure and the toxicity is likely to be reversible once peak toxicity has passed. Extracorporeal membrane oxygenation may have a role in refractory cardiac arrest due to poisoning and should be considered early where available.
 ==== - Decontamination ==== ==== - Decontamination ====
  
-Decontamination refers to techniques that reduce the exposure to a drug or toxin by reducing absorption. \\ The use of decontamination methods should be based on a risk/benefit assessment. In those cases where the risk of toxicity is high decontamination should be given if the poisoning is amenable to it. Decontamination should always be a lower priority than resuscitation. \\ Methods of decontamination include:+Decontamination refers to techniques that reduce the exposure to a drug or toxin by reducing absorption. The use of decontamination methods should be based on a risk/benefit assessment. In those cases where the risk of toxicity is high decontamination should be given if the poisoning is amenable to it. Decontamination should always be a lower priority than resuscitation.  
 + 
 +Methods of decontamination include:
  
   * Activated charcoal   * Activated charcoal
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 Antidotes for poisonings have existed for thousands of years and the term refers to a wide range of substances that ameliorate poisonings. Broad mechanisms of action of antidotes include reducing absorption, restoring function, or treating effects of poisoning. Examples of antidotes used currently are supplied in the following table (click to enlarge). Antidotes for poisonings have existed for thousands of years and the term refers to a wide range of substances that ameliorate poisonings. Broad mechanisms of action of antidotes include reducing absorption, restoring function, or treating effects of poisoning. Examples of antidotes used currently are supplied in the following table (click to enlarge).
  
-{{  :wikitox:antidotes.png?direct&400  }}+{{  antidotes_list_buckley_2016.png?direct&400  }}
  
 ==== - Supportive Treatment ==== ==== - Supportive Treatment ====
  
-Good supportive care is the mainstay of managing the poisoned patient. It involves;+Good supportive care is the mainstay of managing the poisoned patient. It involves but is not limited to the following.
  
   * Maintaining hydration with IV fluids   * Maintaining hydration with IV fluids
   * Placing a urinary catheter if there is urinary retention   * Placing a urinary catheter if there is urinary retention
-  * Treating agitation with sedation (eg benzodiazepines)+  * Treating agitation with sedation (e.g. benzodiazepines)
   * Adequate thromboprophylaxis   * Adequate thromboprophylaxis
-  * Prevent of pressure areas+  * Prevent of pressure area damage
   * Treating nausea with antiemetics   * Treating nausea with antiemetics
  
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 Further Reading: Further Reading:
-  * [[https://pubmed.ncbi.nlm.nih.gov/25929508/|PMID: 25929508]]. Buckley NA, Whyte IM, Dawson AH, Isbister GK. A prospective cohort study of trends in self-poisoning, Newcastle, Australia, 1987-2012: plus ça change, plus c'est la même chose. Med J Aust. 2015;202(8):438-442. doi:10.5694/mja14.01116 {{ :buckley_2015_trends_self_poisoning.pdf |PDF}}+  * [[https://pubmed.ncbi.nlm.nih.gov/25929508/|PMID: 25929508]]. Buckley NA, Whyte IM, Dawson AH, Isbister GK. A prospective cohort study of trends in self-poisoning, Newcastle, Australia, 1987-2012: plus ça change, plus c'est la même chose. Med J Aust. 2015;202(8):438-442. doi:10.5694/mja14.01116 {{:buckley_2015_trends_self_poisoning.pdf|PDF}}
   * Assessment and Management of the Poisoned Patient Video Summary [[https://vimeo.com/428066691|Vimeo link]]   * Assessment and Management of the Poisoned Patient Video Summary [[https://vimeo.com/428066691|Vimeo link]]
-  * [[https://pubmed.ncbi.nlm.nih.gov/26816206/|PMID: 26816206]]. Buckley NA, Dawson AH, Juurlink DN, Isbister GK. Who gets antidotes? choosing the chosen few. Br J Clin Pharmacol. 2016;81(3):402-407. doi:10.1111/bcp.12894 {{ :buckley_2016_choosing_antidotes.pdf |PDF}} +  * [[https://pubmed.ncbi.nlm.nih.gov/26816206/|PMID: 26816206]]. Buckley NA, Dawson AH, Juurlink DN, Isbister GK. Who gets antidotes? choosing the chosen few. Br J Clin Pharmacol. 2016;81(3):402-407. doi:10.1111/bcp.12894 {{:buckley_2016_who_gets_antidotes.pdf|PDF}}
- +
  
 ~~REFNOTES~~ ~~REFNOTES~~