Treatment of choice of cyanide poisoning is:
The correct answer is likely to be something that provides an alternative pathway. Sodium thiosulfate is often used because it helps convert cyanide into thiocyanate, which is excreted. But wait, there's also hydroxocobalamin, which binds cyanide directly. Oh, and maybe sodium nitrite is part of the treatment as well, since it causes methemoglobin formation, which can bind cyanide. But the question is about the treatment of choice. I think hydroxocobalamin is now considered the first-line because it's more effective and safer than nitrite-based treatments. Let me confirm that.
So, hydroxocobalamin works by binding cyanide to form cyanocobalamin (vitamin B12), which is then excreted. Sodium thiosulfate is still used, but maybe in combination. The options might include hydroxocobalamin as the correct answer. Let me check the options again. The user didn't list them, but common distractors would be things like sodium nitrite, activated charcoal, or perhaps something else like amyl nitrite.
Wait, sodium nitrite is part of the old treatment protocol where it induces methemoglobinemia, which binds some cyanide. But it's not as effective as hydroxocobalamin. Also, there's a risk of hypotension with nitrite. So the treatment of choice is hydroxocobalamin. Therefore, the correct answer is hydroxocobalamin. The other options like sodium nitrite are outdated or incorrect. Activated charcoal isn't effective for cyanide. Amyl nitrite is used in some cases but is less preferred now. Sodium thiosulfate is an adjunct. So the explanation should highlight hydroxocobalamin's mechanism and why it's preferred over others.
**Core Concept**
Cyanide poisoning disrupts cellular respiration by inhibiting cytochrome c oxidase in the mitochondrial electron transport chain. Treatment must rapidly bind or detoxify cyanide to restore oxygen utilization.
**Why the Correct Answer is Right**
Hydroxocobalamin is the first-line treatment for cyanide poisoning. It binds cyanide to form cyanocobalamin (vitamin B12), which is excreted via the kidneys. This mechanism is effective, safe, and does not require specific antidote kits (unlike sodium nitrite), making it the preferred choice in modern guidelines.
**Why Each Wrong Option is Incorrect**
**Option A:** Sodium nitrite induces methemoglobinemia, sequestering some cyanide but causing hypotension and requiring careful monitoring. It is outdated compared to hydroxocobalamin.
**Option B:** Sodium thiosulfate is an adjunct, enhancing cyanide detoxification by sulfite oxidase pathways but insufficient as monotherapy.
**Option C:** Amyl nitrite is an older, less effective inhaled agent with inconsistent absorption and limited use in modern practice.
**Clinical Pearl /