General aspect of poisoning Flashcards
What is poisoning?
Exposure to poisons (Drugs, food, household products) that harm the body
What are the modes of poison exposure?
1) Ingestion
2) Inhalation (CO)
3) Topical exposure (Organophosphates)
4) Ocular exposure (drugs)
5) Envenomation (injection of snake venom into the body for ex)
6) Transplacental
What is the mortality rate of acute poisoning?
It is the most common medical emergency in young children with a mortality rate of <1% commonly you won’t find poisoning in adolescents you might suspect intended self-harm
How to prevent/minimize poison absorption?
1) Ipecac (enhances vomiting, but it’s not recommended anymore)
2) Gastric lavage (nasogastric tube that washes the medication, must be within the first hour of ingestion)
3) Activated charcoal (Helps in gut excretion, ineffective in pesticides, hydrocarbons, acid, alkali, alcohol, iron & lithium ingestion)
4) Cathartics (“accelerates defecation”, can cause electrolyte disturbance, severe dehydration, neuromuscular impairment, and coma)
5) Whole bowel irrigation used when the ingestion was >1hr ago (Golytely, “Polyethyleneglycol combined with electrolytes” PEG-ELS, given 0.5L/Hr for small children and 2L/hr for adolescents administering it for 4-6hours/until the effluent is clear, it is useful for iron, lithium, and sustained release drugs)
How do we enhance excretion?
1) Ion trapping, traps weak acids in the renal tubular fluid by alkalizing the urine (7-8 pH), it can help in Salicylate (Aspirin), phenobarbital, and tricyclic antidepressants elimination
2) Multiple-dose charcoal can cause bowel syndrome but it helps with the excretion of phenobarbital and theophylline poisoning
3) Hemodialysis: in case of alcohol intoxication, salicylate poisoning, & lithium overdose
What is the main difference between poisoning in adults and in children?
In adults, poisoning mostly occurs due to psychopharmacology drugs (sedatives, tranquilizers, and antidepressants) while in children it is mainly from households, plants, and personal care products.
What can you do if unexplained symptoms occur?
urinary drug screen
How to manage child poisoning?
1) Initial life support: Airway, Breathing, Circulation, Disability (ABCD)
2) Decontamination (skin wash with soapy water, eyer irrigate with0.9% NaCl, or decontaminating the GI tract)
3) Enhance the elimination
4) Antidotes
5) Supportive care
6) Prevention and education for children while psychiatric evaluation for adults
What are the general features in a medical history examination that suggest poisoning?
1) Acute onset
2) Age range 1-5
3) History of pica (ingestion of non-nutritional element) or exposure to a potential toxicant
4) Environmental stress (intentional poisoning)
5) involves multiple organ systems
6) Significant alteration in consciousness
7) puzzling clinical picture
8) Medications at home, used by other household members, particularly new medications
9) Visits from grandparents and other relatives.
10) Large family gatherings (e.g., holiday parties)
11) Moving to a new home
What are the strategies to decontaminate the GI?
1) Charcoal (most effective during the first hour of ingestion as it absorbs the drug into its surface, given 1g/kg)
2) Whole bowel irrigation (can also be valid after the toxin passes the bowel)
What are the toxins that are not adsorbed by activated charcoal?
1) Acids/alkalis
2) Alcohols
3) Metals and ionic compounds (iron, potassium, lithium) Hydrocarbons
When do we use the bowel irrigation method?
- Very rarely performed
- Polyethylene glycol (Golytely) –until effluent runs clear
1) Ingestion of a slow-release (potassium chloride) or extended-release substance (diltiazem/verapamil)
2) substance not bound to activated alcohol
3) Iron in high amounts (>60g/Kg of elemental iron was ingested)
- Presentation prior to symptom onset and
Ingestion is likely to result in significant toxicity despite supportive care or antidote therapy - Contradicted in patients with bowel obstruction, GI bleed, and perforation
What are some of the antidotal drugs available?
poisoning of (antidote):
1) Benzodiazepines (Flumazenil)
2) Opioids (Naloxone)
3) Paracetamol (N-acetyl cysteine)
4) Iron (Deferoxamine)
5) Cholinesterase inhibitors organophosphorus (Atropine & pralidoxime)
6) Carbon monoxide (oxygen)
7) Ethanol, Salicylates “aspirin”, oral hypoglycemics (Dextrose)
What is the antidote for Benzodiazepine poisoning?
Flumazenil
What is the antidote for Opioid poisoning?
Naloxone
What is the antidote for Paracetamol poisoning?
N acetyl cysteine
What is the antidote for Iron poisoning?
Deferoxamine
What is the antidote for Organophosphorus poisoning?
Atropine & pralidoxime
Dextrose is an antidote for which drug poisoning?
Ethanol, salicylates, oral hypoglycemics
Carbon monoxide poisoning, what to take?
oxygen
When do you suspect paracetamol poisoning?
- > 200 MG/KG
Delaying NAC treatment in patients with paracetamol poisoning can cause liver damage T/F?
True
What amount of iron must be ingested for toxicity to occur?
> 60mg/Kg in adults while 10-20mg/kg in children might be toxic
What are the symptoms of iron toxicity?
1) GIT irritation: nausea, vomiting abdominal pain diarrhea, hematemesis.
2) Fever
3) Latent phase (2) 4-12 hr
- patient appears to improve, metabolic acidosis imminent organ failure
4) Phase (3) 12-24hr severe metabolic acidosis, hypovolemic shock, hepatic failure
- NO NEED TO MEMORIZE
How to manage iron poisoning?
1) ABC
2) Supportive therapy (maintain adequate BP and electrolyte balance)
3) IVF 20ml/Kg
4) Potassium & glucose administration are necessary
5) Measure iron levels
6) Iron chelation (desferrioxamine)
What are the substances that can cause organophosphate poisoning? (no memorize plz)
1) Insecticides – Malathion, parathion, diazinon, fenthion, dichlorvos, chlorpyrifos, ethion
2) Nerve gases – Soman, sarin, tabun, VX
3) Ophthalmic agents – Echothiophate, isoflurophate
4) Anthelmintics – Trichlorfon
5) Herbicides – Tribufos (DEF), morphos
6) Industrial chemical (plasticizer) – Tricresyl phosphate
What is the mechanism by which organophosphate poisoning occurs?
Inhibition of carboxyl ester hydrolases, acetylcholinesterase (AChE), this enzyme normally degrades the neurotransmitter acetylcholine (ACh) into choline and acetic acid if inactivated ACh will accumulate in the NS resulting in the overstimulation of muscarinic and nicotinic receptors
What is the clinical presentation of organophosphate poisoning?
The signs of Muscarinic receptor overstimulation are:
SLUDGE and DUMBELS
salivation
lacrimation
urination
diarrhea
GI upset
emesis
diaphoresis and diarrhea
urination
miosis
bradycardia
bronchospasm & bronchorrhea
emesis; excess lacrimation
salivation
Nicotinic receptor overstimulation:
Fasciculation
Cramping
Weakness
Diaphragmatic faliure
How to treat organophosphate poisoning?
Medical therapy in organophosphate (OP) poisoning includes 1) atropine,
2) pralidoxime (2-PAM), and benzodiazepines (ex, diazepam)
- Remove all clothing from and gently cleanse patients suspected of organophosphate exposure with soap and water
- Irrigate the eyes of patients with ocular exposure using isotonic sodium chloride or lactated Ringer’s solution.
