Lecture 13 Acute Poisoning

Question 1

BNF guidance

1. Who should be admitted to hospital?
2. Who do you contact if you are unsure about management or degree of risk?
3. What should accompany the patient to hospital?
4. What requires urgent attention?
5. What blood pressure abnormality is common?

Answer 1

1. Patients who have features of poisoning, patients who have taken poisons with delayed effects
2. TOXIBASE or UK national poisons information service
3. A note of all relevant information including if the patient has already been treated and with what. Identity of the poison and size of the dose.
4. The patient’s respiration
   (most poisons that reduce consciousness also depress respiration)
5. Hypotension and so raise foot of bed and administer saline or colloid.

Question 2

List the types of poisoning

Answer 2

• Accidental/ Non-accidental
• Contaminant poisoning
• Non-accidental poisoning as a form of child abuse
• Deliberate malicious poisoning
• Deliberate self poisoning
• Recurrent deliberate self poisoning

Question 3

1. Who presents with accidental poisoning?
2. Toxicity?
3. What substances are usually involved?
4. Steps taken afterwards?

Answer 3

1. Often those at the extremes of age - children/elderly
2. Often low toxicity
3. Wide spectrum of diseases - TOXBASE, NPIS (ask someone to take a photo of what a child has taken so it can be identified)
4. Assess the circumstances of the incident for both opportunity and prevention

Question 4

1. What is the cause of contaminant poisoning?
2. Who is affected?
3. What are the means of spread of poison?

Answer 4

1. Accidental/terrorist
2. Those in a localised area
3. Water or air supply.
   - Heavy metals (old pipes or fish)
   - Organophosphates
   - Radioactive

e.g. Sarin gas

Question 5

Describe deliberate malicious poisoning.

Answer 5

• Rare
• Often missed
• Requires opportunity, access to lethal substances and a psychopath

Question 6

1. Who usually presents with deliberate self-poisoning?
2. Toxicity?
3. What are the risk factors?

Answer 6

1. Adolescents and adults who may have had similar previous episodes, and for whom a psychiatric/psychosocial/personality disorder has already been identified. The person may have triggers.
2. Wide variety in toxicity - CAUTION
3. • Male
     - Older age group
     - Mental/physical illness
     - Social isolation
     - Unemployment
     - Alcoholism
     - Premediated planning
     - Family history of suicide

Question 7

1. Who is involved in the multidisciplinary approach?

2. Why is this effective?

Answer 7

1. Nursing care (mainstay), medical team, medical toxicologist (TOXBASE/NPIS), psychiatric liaison service.
2. Proven to provide best care, efficient use of resources and reduced length of stay

Question 8

List 5 steps of management:

Answer 8

• ABCDE - resuscitation
• Symptomatic treatment
• Reduced absorption
• Increased elimination
• Consider specific antidotes/ trial of an antidote

Question 9

In a medical emergency what do you do?

Answer 9

1. Initial impression
2. ABCDE and MOVE approach
3. History
4. Only progress to full clerk-in once the patient is fully stabilised

Question 10

AIRWAY

1. Why might a poisoned patient’s airway be at high risk?
2. Describe key points of assessing the patient’s airway.

Answer 10

1. Poisons generally activate the vomiting centre and reduce consciousness so there is a high risk of aspiration.
2. • pen torch examination
     - low threshold for intubation
     - caution with the neck
     - may need airway adjunct
     - oxygen unless paraquat (oxygen free radical species that concentrates in the lung)
     - anti-emetics/ NG tube

Question 11

BREATHING

1. Comment on the respiratory rate of someone who has been poisoned
2. What might a high respiratory rate indicate?

Answer 11

1. Low respiratory rate common. Caused by opiates, alcohol and benzodiazepines
2. High respiratory rate may indicate a metabolic acidosis or aspiration pneumonitis

Question 12

CIRCULATION

1. What blood pressure problem is common?
2. What is the intervention/ monitoring?

Answer 12

1. Hypotension is common
2. IV access, bloods and fluids.
   Pulse and BP monitoring and ECG and cardiac monitoring (dysarrhythmias)

Question 13

DISABILITY

Main points:

Answer 13

• Decreased GCS common
• Pupil size may be a useful clue
• Must check glucose
• Do not give activated charcoal if drowsy
• No poison will cause asymmetrical signs!

Question 14

EXPOSURE

1. What do you need to be aware of?
2. What is a common exposure issue?

Answer 14

1. Previous self harm or abuse
Concurrent head injury 
Skin/ Mucosal lesions
Coagulopathy
2. Hypothermia is very common

Question 15

NEVER FORGET

Answer 15

Because a patient is drunk or intoxicated does not mean they have no other pathology

esp when drunk and low capacity to feel pain

Question 16

History- what is important?

Answer 16

• Adults vs children
• Corroborative history
• Ambulance crew
• What?
• When?
• How much?

Question 17

How is the patient monitored?

Answer 17

Using the National Early Warning Score

For most poisons patient’s score decreases over time EXCEPT TRICYCLIC ANTIDEPRESSANTS which cause the three Cs:

• Cardiac arrhythmias
• Convulsions
• Coma

Question 18

What are the common clinical clues of poisoning on the skin and the eyes?

Answer 18

SKIN:

• Cherry red (CO)
• Blisters (Barbituates)
• Needle tracks (opiate abuse)
• Burns esp mouth (caustics, corrosives)

PUPILS:

• Small (opiates, organophosphates, barbituates)
• Large (amphetamine, cocaine, TCA, atropine)
• Nystagmus (phenytoin, carbamazepine, barbituates)

Question 19

1. What drugs cause behavioural disturbance?

2. What drugs cause seizures in OD?

Answer 19

1. -Anticholinerics
   - Solvents
   - Hallucinogens
2. -TCAs
   - Phenothiazines
   - Mefenamic Acid
   - Theophyllines
   - Salicylates

Question 20

What are the 7 common toxic syndromes?

Answer 20

1. Excess sedative / excess stimulant
2. Sympathomimetic syndrome
3. Opiates cause Narcosis
4. Salicysm - aspirin OD (ear ringin, abdominal pain, shallow and fast breathing)
5. Anticholinergic syndrome = PS system switched off and large pupils and full palpable bladder
6. Cholinergic syndrome - vomiting, crying, defacating and peeing
7. Serotonin syndrome - muscle rigidity and hyperthermia. In patients on SSRIs taking tramodol.

Question 21

What investigations do you do?

Answer 21

Blood investigations:

• U&E, glucose, plasma osmolality
• Arterial blood gases (osmolar and anion gap from above)
• Paracetamol levels (+/- alcohol)
• Coagulation screen (liver)

Urine:
- Toxicology screen

Question 22

What specific tests are done?

Answer 22

• Salicylates/ Alcohol
• Digoxin
• Theophylline
• Methanol
• Ethylene glycol
• Lithium
• TCAs
• Barbituates
• Benzodiazepines
• Paraquat

Question 23

What do abnormal results indicate?

Answer 23

Hypoglycaemia:

• Insulin, oral hypoglycaemics
• Ethanol

Hypokalaemia

• Salbutamol
• Theophylline
• Salicylates

Hyperkalaemia

• Tissue necrosis/ digoxin/ renal failure
• ACE inhibitors

Prolonged QT
- Warfarin, paracetamol, mushrooms

Metabolic acidosis
- Salicylates/ Ethanol/ Methanol/ TCAs

Increased plasma osmolality
- Ethanol/ methanol/ Ethylene glycol

Question 24

Give 6 methods of symptomatic treatment:

Answer 24

(1) Rewarming/ cooling
(2) Anticonvulsant therapy, diazepam, phenytoin, ventilation
(3) Anti-emetic therapy
(4) Correction of fluid and electrolyte imbalance and hypoglycaemia
(5) Raising/ lowering blood pressure
(6) Pain relief

Question 25

When should you consider a gastric lavage?

Answer 25

- If life-threatening amounts have been taken within the last 1-2 hours However no clinical experimental evidence of efficacy. In some patients it may increase absorption and morbidity.

Question 26

What 4 drugs benefit from repeated activated charcoal? When does this need to be given?

Answer 26

(1) Carbamazepine (2) Theophylline (3) Phenobarbital (4) Quinine Within 1-2 hours consumption

Question 27

Which 4 drugs benefit from haemodialysis

Answer 27

(1) Salicylate (2) Lithium (3) Methanol/ Ethylene glycol (4) Barbituates

Question 28

For which drugs do you increase elimination by alkalisation of the urine?

Answer 28

(1) Salicylates (2) TCAs (3) Phenoxyacetate herbicides

Question 29

What are the antidotes for these poisons? ``` Paracetamol Opioids TCAs Warfarin Benzodiazepines Carbon monoxide Digoxin B blockers ```

Answer 29

``` N-acetylcysteine Naloxone Sodium Bicarbonate Vitamin K Flumazenil Oxygen Antidigoxin Antibodies Atropine (glucagon) ```

Question 30

1. What are the features of opioid poisoning? 2. What do you give? And how? 3. In what period of time do you see a response? 4. What is the issue in addicts ?

Answer 30

1. Sedation, respiratory depression, hypotension, pin-point pupils 2. A specific competitive antagonist at opiate receptor called naloxone. Give as 0.8-2.0 mg IV for adults repeated until effect seen. If opiate poisoning is suspected may be given as a therapeutic trial before proceeding to endotracheal intubation. Has a shorter duration than many opiates and therefore repeated doses or infusion may be necessary 3. Usually a very rapid response 4. May precipitate withdraw

Question 31

List some common pitfalls in acute poisoning treatment?

Answer 31

- Underestimating the psychosocial risk (see risk factors for deliberate poisoning) - Underestimating toxin risk especially for TCAs - Miscalculating N-acetylcycsteine regime and causing an anaphylactoid reaction

Question 32

LEGAL HIGHS 1. What is mephedrone? 2. What else is it called? 3. What are the reported adverse effects?

Answer 32

1. Synthetic stimulant similar euphoria as MDMA (ecstasy) 2. 4-MMC, MM-Cat, Meow Meow, plant food, bubbles 3. -Nose-bleeds - Vomiting - Tachycardia - Headaches - Chest pain - Anxiety attacks - Hallucinations STAY UP TO DATE ON LEGAL HIGHS