Category: Toxicology

LA – Toxicity

We are regularly doing blocks next to major vessels. So warn the patient of the symptoms, & keep them monitored(at least 15 min).

Symptoms of local anaesthetic toxicity

  • Circumoral and/or tongue numbness
  • Metallic taste
  • Lightheadedness/Dizziness
  • Visual/Auditory disturbances (blurred vision/tinnitus)
  • Confused/Drowsiness/Fitting
  • Arrhythmia
  • Cardio-Resp Arrest

Remember – Do basics WELL

Without Cardio-Resp Arrest

Use conventional therapies to treat:

  • Seizures
  • Hypotension
  • Bradycardia
  • Tachyarrhythmia (Lidocaine should not be used as an anti-arrhythmic therapy)

In Cardio-Resp Arrest

  • CPR – using standard protocols (Continue CPR throughout treatment with lipid emulsion)
  • Manage arrhythmias – using standard protocols
  • Consider the use of cardiopulmonary bypass if available
  • Recovery from LA-induced cardiac arrest may take >1 h
  • Lidocaine should not be used as an anti-arrhythmic therapy

PDF: Quick Reference Handbook – Guidelines for crises in anaesthesia

 

Concealed Illicit Drugs

Background

Those suspected of concealing illicit drugs often present near ports and borders however they can present to any ED or be brought in by the police.

Body Packers – Swallow large quantities of well packaged drugs to smuggle them into countries or institutions.  These are often well manufactured with a low risk of rupture but the potential for serious toxicity if rupture occurs.

Body Stuffers – Swallow small quantities of poorly packaged illicit substances often at the point of arrest to conceal them. These have a much high risk of package rupture but involve smaller quantities of substances.

 

Investigations

Authorisation for an intimate search or radiological investigation must come from an inspector or higher with written consent from the patient.

Intimate searches must be carried out by a police surgeon but require immediately available resuscitation facilities therefore may be conducted in the ED. ED physicians should not handle the drugs at any time.

AXR or low dose CT scanning can be used to detect concealed packages in Body Packers.

 

General Management

Try to obtain a history of what and how much has been concealed

Look for toxidromes suggestive of package leak – treat as per Toxbase

  • Cocaine: Tachycardia, hypertension, agitation, diaphoresis, dilated pupils, hyperpyrexia, seizures, chest pain, arrhythmias and paranoia.
  • Heroin: pinpoint pupils, respiratory depression, decreased mental state, decreased bowel sounds
  • Amphetamines : – Nausea, Vomiting, Dilated Pupils, Tachycardia, Hypertensions, Sweating, Convulsions and the development of non-cardiogenic pulmonary oedema

 

Toxicology screens (urinary/blood) should not be used to guide management or discharge decisions (Level 5 evidence).

 

Body Stuffers & Pushers should be observed for signs of toxicity for a minimum 8 hours, consider activated Charcoal

Body Packers with positive imaging who are asymptomatic can be discharged back to police custody for monitoring. Bowel preparation such as Cleanprep or movicol can be used.

 

Body Packers with signs of cocaine or amphetamine toxicity or signs of obstruction/ileus require urgent surgical intervention.

Body packers with signs of Heroin toxicity should be treated with Naloxone infusion as per toxbase guidelines

All patients transferred to police custody should receive a discharge letter, including
Suspected Internal Drug Traffickers.

 

Algorithms

 

 

 

Full RCEM Guide

Nitrous Oxide Induced Neurotoxicity

Nitrous Oxide  has been used clinically and recreationally since its discovery in 1772. Since then Nitrous Oxide induced neurotoxicity have been reported, and has been shown to be dose depaendant. With infrequent users unlikely to be at risk of neurotoxicity, while heavier and habitual used at risk of serious neurological conserquences.

With the increase in recreation use of “Whippits” we need to remember to take a detailed recreation drug history when seeing patients presenting to ED with neurological symptoms. As Nitrous Oxide induced neurotoxicity is treatable.

Presentations

Nitrous Oxide induced neurotoxicity can present as either spinal cord demyelination , peripheral neuropathy or a a combination of the two.

  • Demyelination of the dorsal columns of spinal cord 
    • Typically onset is subacute  (i.e. weeks), but acute onset has been reported in the literature
    • Typically symmetrical but can be unilateral
    • Signs
      • Pyramidal weakness – weak upper limb extensors, and lower limb flexors
      • Dorsal Column Sensory loss – Vibration, Proprioception, Fine touch
      • Sensory Ataxia – Incoordination due to loss of proprioception and weakness
    • Level – Most frequently cervical 4-6 levels, but can affect any.
  • Peripheral Neuropathy
    • Typically Symmetrical (but not always)
    • Sensory loss (often painful)
    • Distal Weakness
  • Optic Neuropathy  – has been reported and may present with visual disturbance.

Pathophysiology

Nitrous Oxide usage can render vitamin B12 inactive, which in-turn disrupts myelination, causing the demyelination of nerves.

Differentials

  • Deficiencies: B12, Folate, copper, zinc
  • Inflammatory: Guillian-Barre syndrome, MS, Neurosarcoidosis
  • Infection: HIV, Syphilis
  • Cancer
  • Vascular: Spinal cord ischaemia, vasculitis

Tests

  • Vitamin B12 level (often in normal range)
  • Homocysteine and Methylmalonic Acid Level (not available in ED)
  • MRI – contrast enhanced

Treatment

Start before Tests are back (i.e. on clinical suspicion)

  • IM Vitamine B12 1mg OD
  • PO Folic Acid 5mg OD

Follow-up

  • Discuss admission with Medical team as potential for SDEC management
  • Treat until clinical improvement(King’s Team noted the following)
    • Sometimes treat for 5-7days only
    • Often switch to alternate days IM Bit B12
    • Can teach to self administer
  • Further Testing
    • Homocysteine and Methylmalonic Acid levels – often improve quickly
    • MRI often lags clinical improvement endnote necessary to repeat
  • Majority Improve clinically – but futureabstinence is often challenging

 

References

Alcohol Withdrawl

Generally we DON’T admit patients acutely solely for “Detox”

However the following groups should be admitted [taken from trust guide]

  • Patients requiring admission for another reason – refer to appropriate specialty (e.g.  Head injury going to CDU, or Upper GI bleed going to medicine)
  • ALL patients with symptoms / signs of Wernicke’s – medicine
  • ALL patients with Delirium Tremens – medicine
  • ALL alcohol withdrawal fits if patient to remain abstinent – medicine
  • ALL alcohol related seizures with possible other trigger – medicnie
  • ALL decompensated alcoholic liver disease – medicine

If admitted to CDU – complete the PAT tool

Read more

Methaemoglobinaemia

Q: Why are Smurf’s Blue? 

A: Methaemoglobin (MetHb) of course!

– MetHb is produced by oxidisation of the Iron in Haemoglobin (Hb) from Fe2+ to Fe3+

– Fe3+ prevents Hb carrying oxygen (thus produces symptoms of hypoxia)

– Often due to chemical ingestion, but may also be genetic

– Treated with Methyl Blue & supportive measures

Read more

1. HAZMAT – First Contact

REMOVE – REMOVE – REMOVE

Remove Them..

At reception ask them to go outside to designated area and staff will be with them shortly. Inform Nurse in Charge!

Remove Clothes..

Use the disrobing card to get the patient to safely remove and bag up clothes. Do your best to maintain privacy. CARD HERE

Remove Substance..

If we have ample warning or the number of patients will be significant, it may be worth deploying the decontamination tent but remember setting this up is time consuming.