Discussion Does anyone know why cyanide poisoning is so painful?

[littlelady774]

I was thinking about the inorganic salts Nitschke talks about (nitrite, cyanide and azide)
And was wondering what makes cyanide so painful, and if this pain is similar to nitrite poisoning/ Methemoglobinemia.
What is the difference?
Anybody have a science background wanna share?

 

[gingerplum]

I'm cribbing part of my response from an answer on Quora, because it explains with the "airplane analogy" I like to use, but does a better job of it:

SN is a relatively peaceful death because you experience hypoxia without the hypercapnic (CO2 retention) response that makes you panicky.

This is why hypoxia in aircraft is so dangerous - as the pilot (flying too high in an unpressurised cabin) slowly starts to become hypoxic, symptoms include feeling relaxed, cheerful, slightly "drunk" and (initially) just a little tired.

As the oxygen concentration in the blood falls further, more "happy feelings" and increasingly tired. The result usually being the pilot eventually passes out, dies and the aircraft eventually comes down when the fuel runs out.

This is what happened to Payne Stewart, the famous golfer.

Now, since cyanide cuts off the normal ability of red blood cells to utilize oxygen in a way that's similar to the mechanism of action of SN, I have no idea why so many deaths from cyanide poisoning are reported as horrific while SN is peaceful.

There's something different about the pathophysiological response and why the body goes into such horrible convulsions with cyanide, but I don't know what it is.

 

[littlelady774]

Thanks for responding @gingerplum.
Idk why cyanide is considered a lot more painful when the mechanism of action is similar to how SN would kill.

Cyanide interferes with cellular respiration and the cell's ability to use oxygen to produce ATP.

SN also results in the inability to deliver oxygen to tissues because the hemoglobin is converted to methemoglobin. (Wouldn't this be similar to carbon monoxide poisoning?)

I know the lactic acid content in cyanide poisoning is high because of the buildup of carbon dioxide within the cells.
Also oxygen cannot be utilized within the cells because cyanide ion won't allow it. ATP production becomes impossible.
Carbon dioxide and water build up within the cell and are released within the bloodstream causing acidosis.
This is the cause of the muscle cramps and pain

 

[gingerplum]

Thanks for responding @gingerplum.
Idk why cyanide is considered a lot more painful when the mechanism of action is similar to how SN would kill.

Cyanide interferes with cellular respiration and the cell's ability to use oxygen to produce ATP.

SN also results in the inability to deliver oxygen to tissues because the hemoglobin is converted to methemoglobin. (Wouldn't this be similar to carbon monoxide poisoning?)

I know the lactic acid content in cyanide poisoning is high because of the buildup of carbon dioxide within the cells.
Also oxygen cannot be utilized within the cells because cyanide ion won't allow it. ATP production becomes impossible.
Carbon dioxide and water build up within the cell and are released within the bloodstream causing acidosis.
This is the cause of the muscle cramps and pain

Girl, you totally outscienced me on that one. Seriously, you explained that better than most physicians could... I was waiting for you to break down the entire Krebs cycle into a schoolhouse rock jingle for me.

AP Biochem for the win ;)

 

[littlelady774]

Thanks
I'm still trying to figure out why cyanide poisoning is so painful compared to SN or carbon monoxide or inert gasses.
All result in hypoxia.. so idk

 

[Shewaitsforme]

Cyanide in small doses actually maintains healthy nerve activity but in large doses releases large amounts of adrenaline and increases muscle activity in the form of spasms. As there is a reduction in oxygen for cell metabolism the acidity rises this will be happening all over the body at the same time. All that Adrenaline, incresing acidity, 'air' suffocation, nerves firing off everywhere, not plesent at all.

 

[NotWhatIExpected]

Cyanide in small doses actually maintains healthy nerve activity but in large doses releases large amounts of adrenaline and increases muscle activity in the form of spasms. As there is a reduction in oxygen for cell metabolism the acidity rises this will be happening all over the body at the same time. All that Adrenaline, incresing acidity, 'air' suffocation, nerves firing off everywhere, not plesent at all.

You might be unconscious pretty fast though, and it's not necessarily guaranteed that muscle spasming is painful