Group 12 Flashcards
(18 cards)
What is cyanide’s mechanism of toxicity?
Binds to cytochrome c oxidase (Fe³⁺), inhibiting oxidative phosphorylation → histotoxic hypoxia (ATP depletion despite oxygen).
List three clinical manifestations of cyanide poisoning.
- Dyspnea, headache, dizziness.
- Confusion, coma, seizures.
- Lactic acidosis, respiratory failure.
What is the adult dose of hydroxocobalamin for cyanide poisoning?
5 g IV over 15 minutes; may repeat once (total 10 g) if needed.
What are unique adverse effects of hydroxocobalamin?
Red discoloration of skin, mucous membranes, and urine; transient hypertension.
Why is hydroxocobalamin preferred in smoke inhalation victims?
Unlike nitrites, it does not worsen oxygen-carrying capacity (safe with carbon monoxide poisoning).
What is the pediatric dosing for hydroxocobalamin?
70 mg/kg IV (up to 5 g) over 15 minutes; repeat based on response.
What is amyl nitrite’s role in cyanide poisoning?
Acts as a bridge therapy by inducing methemoglobin, which binds cyanide to form cyanmethemoglobin.
What is the dosing regimen for amyl nitrite?
0.3 mL per inhalation every minute for 30 seconds until IV antidotes (e.g., sodium nitrite) are given.
Name three contraindications for amyl nitrite.
- Severe anemia.
- Glaucoma.
- Recent head trauma/cerebral hemorrhage.
What complications arise from amyl nitrite use?
Methaemoglobinaemia, syncope, cyanosis, hemolytic anemia (in G6PD deficiency).
What are key components of the traditional cyanide antidote kit?
Sodium nitrite (induces methemoglobin) and sodium thiosulfate (converts cyanide to thiocyanate).
Why is the traditional kit contraindicated in G6PD deficiency?
Risk of hemolysis and exacerbated methemoglobinemia.
What is a relative contraindication for the traditional kit?
Smoke inhalation with suspected carbon monoxide poisoning (nitrites worsen hypoxia).
How does Cyanokit differ from the traditional antidote kit?
- Cyanokit: Uses hydroxocobalamin (no methemoglobin induction; safer in CO poisoning).
- Traditional kit: Uses sodium nitrite/thiosulfate (risk of methemoglobinemia).
Which antidote is first-line for pediatric cyanide poisoning?
Hydroxocobalamin (safer profile; avoids nitrite-induced methemoglobinemia).
What lab finding confirms cyanide poisoning?
Elevated lactic acid (due to anaerobic glycolysis).
What is the role of sodium thiosulfate in cyanide detoxification?
Converts cyanide to thiocyanate, which is excreted renally.
What vital sign must be monitored during amyl nitrite use?
Blood pressure (risk of hypotension).
