Poisoning

1
Poisoning

• Helen Mollard
• ST4 Emergency Medicine

2
Introduction

• Diagnosis
• Management
• Specific poisoning case based
• Suicide risk
• Mental Health Act Mental Capacity Act

3
Diagnosis Clinical Patterns

• Reduced GCS, dilated pupils, divergent squint,
  tachycardia, extensor plantars
• Tricyclic antidepressants
• Reduced GCS, hypotension, decreased resps,
  hypotonia
• Barbiturates, benzodiazepines, TCAs
• Reduced GCS, pinpoint pupils, decreased resps
• Opiates
• Agitated, tremor, dilated pupils, tachycardia
• Amphetamines, Ecstasy, Cocaine, SSRIs

4
Management

• ABCs!!
• Ix BM, ECG, ABG, UEs, Levels
• Specific antidotes
• Supportive care
• - protect airway - ?ETT
• - BP fluid, inotropes
• - arrhythmias treat cause
• - convulsions - ?lorazepam
• - hyperpyrexia paracetamol, dantrolene

5
Will they pump his stomach

• Gastric lavage
• No evidence decreases mortality
• Used if life threatening amount lt1hr and if has
  cough reflex or ETT in situ.

6
Charcoal

• Give if lt1hr
• Can decrease absorption
• Decreases half life of some substances
• Dont use if substances bind to it iron,
  lithium, ethanol, methanol
• Occasionally needed in repeated doses

7
Case Study 1

• 17 year old girl attends 6.5 hours after taking
  24 paracetamol tablets.
• Describe your initial management?
• ABC
• Take blood paracetamol levels

8
Case Study 1

• Would you start parvolex immediately?
• No
• Would start if results not back by 8hrs.
• lt8rs await levels
• 8-15hrs start parvolex, take levels and treat
  accordingly
• 15-24hrs start parvolex, take levels, creat,
  INR. If normal at 24hrs stop treatment
• gt24hrs start parvolex, take levels, UE,
  INR,ABG. Seek expert advice

9
Case Study 1

• What factors would make you high risk?
• Malnutrition reduced glutathione stores
• Enzyme inducers anticonvulsants, rifampicin, St
  Johns wort
• Alcohol
• Liver disease
• How does N acetylcysteine work?
• Increases availability of hepatic glutathione
  which inactivates the toxic metabolite N
  acetyl-parabenzoquinonemine

10
Case Study 1

• The levels are back and above the treatment line.
  You start parvolex. What would you do if she
  developed itching and a rash?
• Stop infusion, IV piriton, restart at slower rate
• Are there any alternatives to parvolex?
• Methionine PO, less effective if gt8hrs and if
  charcoal used.
• What blood tests have the best prognostic value
  if it is a late presentation?
• PT, pH, Creatinine

11
Case Study 2

• A 40 year old woman presents 2 hours after taking
  10 aspirin tablets.
• (aspirin contains 300mg acetylsalicylic acid)

12
Case Study 2

• What clinical features can occur with salicylate
  poisoning?
• General hyperpyrexia, dehydration, tinnitus,
  deafness, sweating
• Resp hyperventilation
• GI GI haemorrhage
• CNS confusion, coma, seizures
• Derm eyelid petechiae

13
Case Study 2

• What is you initial management and what
  investigations need doing?
• ABC
• Levels, UE,BM, ABG, CK
• Is charcoal required?
• Yes useful even if later presentation as
  absorption is erratic.
• May need repeated doses if salicylate level is
  increasing

14
Case study 2

• An ABG shows pH 7.60, pO2 16.2, pCO2 1.9, b ex
  2.
• What does this show?
• Respiratory alkalosis
• Explain the acid-base effects of salicylates.
• Initially resp alkalosis secondary to
  hyperventilation. Then metabolic acidosis mixed
  picture.
• If purely metabolic acidosis severe poisoning.

15
Case Study 2

• Her salicylate level is 300mg/l.How would you
  manage her?
• Mild poisoning PO fluids, Repeat levels 4-6hrs
• No use for Dome normogram erratic absorption.
• How would you manage moderate poisoning?
• gt450mg/l
• Alkalinize urine 1.26 sodium bicarbonate.

16
Case Study 2

• Works by alkalinizing blood limits salicylate
  that crosses blood/brain barrier.
• Alkalinizing urine limits reabsorption of
  salicylate at renal tubules.
• Urine pH from 5 8 x1000 greater excretion.
• What features suggest severe poisoning and how
  would you manage it?
• CNS features, renal failure, persistent acidosis,
  Level gt700mg/l.
• haemodialysis

17
Case Study 3

• A 75 year old man is found collapsed at home. He
  has angina, hypertension and hypercholesterolaemia
  . He has been low in mood recently since his wife
  was diagnosed with cancer.
• On examination
• A clear
• B RR 12, sats 95 air, Chest clear
• C p42, BP 86/44. HS normal
• D GCS E3,V3,M5 11/15.

18
Case Study 3

• Describe your initial management
• A/B oxygen
• C iv access, iv fluids.
• BM, ECG, ABG, Bloods
• You are worried he may have taken an OD. What
  type of drug do you think he has taken?
• Beta blocker, Ca channel antagonist

19
Case Study 3

• This is his ECG. What features are present and
  what are the typical features with this type of
  poisoning?
• Bradycardia
• Long QRS, 1st degree block, RBBB, ST / T
  abnormalities.
• Sotalol blocks K long QT VT torsades de
  pointes.
• He wakes up and confirms he has taken an OD of
  his tablets.

20
Case Study 3

• Describe how you would manage him?
• Iv fluids, iv atropine (often ineffective)
• Glucagon 2-10mg initially, can cause profound
  vomiting, may need infusion.
• Increases cAMP activates Ca channels
  increases pulse and contractility.
• If initial treatment is unsuccessful what other
  measures can you use to manage his hypotension
  and bradycardia.
• Isoprenaline, Dobutamine, Pacing (often increases
  pulse but not BP due to decreased contractility),
  intra aortic balloon pump.

21
Case Study 4

• 43 yr old woman presents drowsy. She has a hx of
  depression and has previously been an inpt under
  psychiatric care.
• A patent.
• B RR12, sats 99 air, Chest clear
• C p124, BP 98/60, HS normal
• D GCS E3, V4, M5 12/15.
• Pupils dilated bilaterally.

22
Case Study 4

• What is your initial management and
  investigations. What type of drug do you suspect
  she may have taken?
• Oxygen, iv access, iv fluids
• ECG, ABG
• Tricyclic antidepressants
• What features may be present on her ECG?
• Sinus tachy, QRS widening (PR prolongation,
  ventricular arrhythmias)

23
Case Study 4

• This is her ABG. What does it show?
• pH 7.14, pO2 11.0, pCO2 3.6, B ex 8
• Metabolic acidosis.
• What treatment is required and what are the
  indications for this?
• Sodium bicarbonate 8.4
• Indications Metabolic acidosis
• QRS gt 0.1 sec
• Hypotension systolic lt90
• Arrhythmias

24
Case Study 4

• How does it work?
• Increases Na conduction through myocardial Na
  channels which are blocked by TCAs
• Increases plasma protein binding of TCAs less
  available.
• How would you treat her hypotension?
• Sodium bicarbonate, iv fluids, inotropes
  noradrenaline, glucagon improves myocadial
  contractility.

25
Case Study 5

• A 26yr old known IVDU is found collapsed in the
  street.
• A snoring
• B RR6, sats 94 on 100 O2, chest clear,
  decreased resp effort.
• C p72, BP 100/64, no iv access possible.
• D GCS E1,V1,M1
• pinpoint pupils bilaterally

26
Case Study 5

• Describe your initial management?
• A airway NP / Guedel.
• B 100 oxygen, consider BAMV if resp effort
  decreases.
• C unable to obtain access.
• Call anaesthetic / ITU help.
• IM naloxone 0.8mg
• Dose 0.4-0.8mg initially up to 10mg. If no
  response to 10mg unlikely to respond.

27
Case Study 5

• After initial treatment the pt then wakes up
  and pulls off monitoring. After security are
  called he calms down and gradually becomes more
  drowsy. How would you manage him?
• Repeated dose of naloxone, naloxone infusion.
• How long do you need to observe him for?
• Observe 4-6hrs post last dose.
• Naloxone short duration 40-75mins.

28
Case Study 5

• What symptoms suggest opiod withdrawal?
• Anxiety, hyperventilation, dilated pupils,
  nausea, vomiting, diarrhoea, abdo cramps,
  yawning, runny nose, lacrimation.

29
Case Study 6

• A 60yr old man attends the ED after British Gas
  have condemned his boiler. He is concerned he may
  have CO poisoning.

30
Case Study 6

• What features might he exhibit?
• Headache, malaise, NV, flulike, confusion, SOB.
• Severe coma, hypotension, convulsions,
  pulmonary oedema, MI, cerebral oedema, gait
  probs, peripheral neuropathy.
• What is you initial management?
• 100 oxygen, ABG to measure COHb
• COHb up to 8 in smokers
• Poor predictor of toxicity and pt outcome

31
Case Study 6

• Describe the pathophysiology of CO poisoning?
• Binds directly to haemoproteins.
• Causes left shift of oxygen dissociation curve.
• Binds to Hb x 240 more avidly than oxygen makes
  Hb unavaliable for oxygen transport.
• Binds to myoglobin non-functioning - ?
  Decreases output.

32
Case Study 6

• What other management options are available for
  CO poisoning? What are the indications for this
  and what are the potential risks?
• 100 oxygen dissociation of CO from
  haemoproteins depends on concentration of oxygen.
• Elimination halflife
• air 4hrs
• 100 oxygen 1hr
• O2 3atmos 23 mins.

33
Case Study 6

• Hyperbaric oxygen therapy.
• Use if COHb gt20, cardiac / neuro features, coma,
  pregnant.
• No def evidence of HBO reducing neuropsycholgical
  sequelae.
• Risks transfer, barotrauma, hyperoxic seizures,
  managing a sick pt in difficult enviroment.

34
Case Study 7

• A 19yr old boy is brought into the ED 0230 sun
  am. He is agitated.
• A shouting abuse.
• B RR42, sats 100 air, Chest clear.
• C p144, BP 184/122.

35
Case Study 7

• What substances do you suspect he may have taken?
• Amphetamines, Cocaine, GHB, Alcohol
• What other parts of the exam are important?
• Temp malignant hyperpyrexia.
• GCS - ?further airway management.
• Pupils often dilated.

36
Case Study 7

• Describe your initial management. What
  investigations are required and why?
• 100 oxygen, iv access and fluids.
• Bloods UE decreased Na cerebral oedema. ?
  Due to polydipsia, SIADH
• Gluc hypoglycaemia.
• Clotting coagulopathy.
• CK rhabdomyolysis due to increased muscle
  contraction.
• ECG arrythymias, MI

37
Case Study 7

• What further managment options might you
  consider?
• Iv benzodiazepines decreases agitation and
  decreased muscle contraction decreased temp.
• If temp gt40C dantrolene 1mg/kg iv
• If increased BP - ?nifedipine.

38
Case Study 7

• Give 4 life threatening complications of cocaine
  use?
• MI 6 cocaine users with chest pain had MI.
• Cerebral haemorrhage
• Rhabdomyolysis renal failure.
• Aortic dissection.
• Bowel ischaemia / infarction sec to
  vasoconstriction.

39
Case Study 7

• Describe you management of a 30yr man presenting
  with chest pain after using cocaine?
• 100 oxygen, buccal, aspirin, GTN infusion.
• Iv lorazepam
• ECG If ST elevation discuss with cardiology.
• Avoid beta blockers vasoconstriction.

40
Case Study 7

• This is his ECG. What does it show? How would you
  manage him now?
• As above.
• Discuss with cardiology. ?PCI

41
Assessment of suicide risk SAD PERSONS score

• Sex male 1
• Age lt19 or gt45 1
• Depression/hopelessness 2
• Prev attempt / psychiatric hx 1
• Etanol excessive use 1
• Rational thinking loss 2
• Separated / widowed /divorced 1
• Organised / serious attempt 2
• No social support 1
• Stated further attempt 1

• lt6 low risk
• 6-8 mental health referral
• gt8 likely admission
• As with all scoring systems use with care and
  clinical judgement.

42
Capacity

• to understand the information relevant to the
  decision
• to retain that information
• to use or weigh that information as part of the
  process of making the decision
• to communicate the decision (whether by talking,
  using sign language or any other means).

43
Mental Capacity Act 2005

• Came into force April 2007.
• A person must be assumed to have capacity unless
  it is established that they lack capacity.
• A person is not to be treated as unable to make
  a decision unless all practicable steps to help
  him to do so have been taken without success.
• A person is not to be treated as unable to make
  a decision merely because he makes an unwise
  decision.

44
Mental Capacity Act 2005

• An act done, or decision made, under this Act for
  or on behalf of a person who lacks capacity must
  be done, or made, in his best interests.
• Before the act is done, or the decision is made,
  regard must be had to whether the purpose for
  which it is needed can be as effectively achieved
  in a way that is less restrictive of the persons
  rights and freedom of action

45
Mental Health Act 2007

• Amends Mental Health Act 1983 and Mental Capacity
  Act 2005.
• Act of Parliament of UK only applies to England
  and Wales.
• Implemented 3rd Nov 2008.
• Who can be detained?

46
Mental Health Act 2007

• a) he is suffering from mental disorder of a
  nature or degree which warrants the detention of
  the patient in a hospital for assessment (or for
  assessment followed by medical treatment) for at
  least a limited period and(b) he ought to be so
  detained in the interests of his own health or
  safety or with a view to the protection of other
  persons." (s2(2))