Weaknesses so review Flashcards
Discuss the antidotes of anti-cholinergic toxidromes
Physostigmine in case of atropine & antihistamines:
- It reverses the peripheral & central anticholinergic effects.
- It is indicated in severe cases.
- It should be given under cardiac monitoring & should not be given as a constant infusion for a long time.
- It is contraindicated with wide QRS complex, bradycardia, and bowel or bladder obstruction.
Sodium bicarbonate in case of TCAs is indicated for: Conduction defects, Arrhythmias, asthma and Metabolic acidosis.
- Mechanism: Alkalinization: promotes dissociation of the tricyclic antidepressant from sodium channels. Increased plasma sodium to helps to drive sodium through sodium channels.
- Dose: IV bolus dose, followed by continuous IV infusion with dextrose) to maintain alkalinization.
CNS manifestations of opioid poisoning
-The patient feels euphoria (sense of well being and relief of pains) due to depression of Sensory cortex followed by dysphoria (distress, anxiety and fear).
- Gradual deterioration of consciousness (drowsy, stupor then comatose) due to depression of Consciousness.
-Cyanosis due to depression of respiratory center.
- Circulatory collapse due to depression of vasomotor center.
-Vomiting due to stimulation of vomiting center.
-The pupils are constricted pin pointed pupil (ppp) and non- reactive due to stimulation of Pupillo-constrictor center.
Discuss the CVS, respiratory and gastrointestinal manifestations of opioid poisoning
CVS: slow full pulse due to vagal center stimulation
Respiratory: Non-cardiogenic pulmonary edema and slow deep respirations due to stimulation of vagal center
GIT: constipation and diminished bowel sounds
Discuss the treatment of Opioid poisoning
- Supportive measures: ABCs
- GIT decontamination: Gastric lavage Using cuffed endotracheal tube even if alert (rapid CNS depression), and Even in case of injected morphine (morphine is re-excreted in the stomach). Local charcoal also for adsorption
- Antidote:
-Atropine blocks vagal stimulation and increase HR.
-Naloxone (Narcan): reverses respiratory depression
-Nalmefene: new opioid antagonist
-Naltrexone: used in opioid addiction treatment - Symptomatic treatment
- Elimination of poison from blood: Hemodialysis is ineffective due to high volume of distribution
Discuss the treatment of sedative hypnotic toxidromes (CNS depressants) poisoning
- Supportive treatment: ABC.
- GIT decontamination: Emesis: not recommended since rapid neurologic deterioration is known to occur.
*Gastric Lavage: with cuffed endotracheal tube up to several hours after the overdose due to decreased GIT motility.
*Activated charcoal.
* MDAC: in phenobarbital toxicity only (enterohepatic circulation). - Elimination of the poison from blood:
* Forced alkaline diuresis: for long acting barbiturates only
* Hemodialysis and hemoperfusion have been successfully utilized in all types of barbiturate overdoses (most effective for long-acting barbiturates)
* Hemodialysis and hemoperfusion are ineffective in benzodiazepines
*Charcoal hemoperfusion is more effective than hemodialysis only in barbiturates. - Symptomatic treatment:
- Antidote: Flumazenil (Anexate) in benzodiazepines only:
*Action: Flumazenil is a competitive BZ receptor antagonist.
* Dose: IV, over 30 sec, may be repeated at 1-min. interval up to a maximum total dose of 3 mg.
Give the contraindications of flumazenil usage
o Hypersensitivity to flumazenil or BZ.
o Co-ingestions especially BZ+ drugs causing seizures,
o Chronic use of BZ as it may induce withdrawal syndromes,
o Patients given BZ for control of a potentially life-threatening condition as status epilepticus.
o History of convulsions.
o Head trauma (seizures may occur).
Factors affecting severity of corrosive
- Physical form: Solid/liquid.
- Concentration.
- Quantity.
- PH: pH <2 and >11 are more corrosive.
- Duration of contact
- Food: Presence or absence of food in stomach.
Complications (causes of death) in corrosive
1) Acute:
Airway obstruction Shock (due to pain)
Vomiting-
dehydration
GIT perforation.
2) Late:
- Stricture leading to cachexia.
3) Remote:
- Carcinoma of esophagus
It is CONTRAINDICATED to do the following in GIT corrosives
o Induced emesis: causes reintroduction of the caustic to the upper gastrointestinal tract and airway
o Activated charcoal:
■ It interferes with tissue evaluation by endoscopy.
■ Most caustics are not adsorbed to activated charcoal,
o Gastric lavage: carries the risk of perforation
o Neutralization and dilution:
■ It has the potential to form gas.
■ Generate an exothermic reaction leading to more tissue damage.
Compare between alkali and acid corrosives
A 21 year old female attempted suicide by drinking Dettol, following her final exams. The smell of phenol is prominent on her mouth
a) what is the causative substance?
b) Give the local clinical presentation
a) Carbolic acid (phenol)
b)
a)Stomach:
- Weak corrosive action:
Pain and vomiting which has characteristic phenolic smell. Superficial ulcers of gastric mucosa. - Local anesthetic action —>pain and vomiting disappear after short time.
- Coagulative necrosis-* thickening of gastric wall.
b)Skin:
white eschars with smell of phenol around the mouth or skin, which turns brown on exposure to air due to oxidation.
A 21 year old female attempted suicide by drinking Dettol, following her final exams. The smell of phenol is prominent on her mouth
c) Give the systemic clinical effect
a) Systemic effect:
a) CNS: stimulation followed by depression —> constricted pupil and
convulsions rapidly followed by coma.
b) CVS: myocardial depressant —►hypotension, tachycardia and
arrhythmias.
c) Kidney: Acute renal failure —> oliguria with albumin, blood and casts in urine passing to anuria. The urine turns green on exposure to air due to oxidation of the excretory products of phenol.
d)Acid Base imbalance:
* Respiratory alkalosis due to respiratory center stimulation.
* Metabolic acidosis follows due to uncompensated renal loss of base during stage of alkalosis because of renal damage.
e) Met-hemoglobinemia
A 21 year old female attempted suicide by drinking Dettol, following her final exams. The smell of phenol is prominent on her mouth
d) give the cause of death
e) why is phenol not commonly used in homocide?
d)
1- Early: respiratory failure due to respiratory center depression.
2- Late: renal failure.
e) has a very distinct smell
A 21 year old female attempted suicide by drinking Dettol, following her final exams. The smell of phenol is prominent on her mouth
-How would u treat this patient?
1) Supportive measures: ABCs
2) GIT decontamination:
* Emesis is not recommended due to rapid onset of coma and seizures (within half an hour for significant ingestion).
- Gastric lavage is indicated and essential due to: -
o Vomiting is temporary (local anesthetic action).
o Thickening of gastric wall (coagulative necrosis) and superficial ulcers (no expected perforation).
o Carbolic acid has a systemic effect so lavage is indicated to decrease absorption. - Local antidote is:
o Milk & egg white: as phenol will coagulate their protein
instead of stomach protein.
o Ethanol 10%: it dissolves phenol then rapidly removed by gastric lavage. - Eye decontamination: Flush exposed or irritated eyes with copious
amounts of water or saline for at least 15 minutes.
3) No specific antidotes.
4) Symptomatic: Treatment of renal failure, metabolic acidosis and seizures
