A 68 y.o. woman was trapped in the basement during a house fire. She was treated for cyanide poisoning but remained acidotic.
this is a CT of her abdomen. What do you see?
Our patient had no burns but considerable soot on her skin and in her airway. She was given a cyanokit by EMS. The image shown depicts ischemic bowel with pneumatosis and bowel wall thickening.
On arrival Her CO level was low at 3.1 ( repeated at 25)and she had persistent acidosis. (venous pH was 6.9 and lactate 18.8). Blood pressure was initially 231/121. She gradually developed hypotension in the ICU requriting pressors but presumably the initial persistent severe acidosis was partly related to cyanide poisoning and contributed to the bowel ischemia. She underwent emergency surgery but the entire bowel was found to be nonviable and comfort care was initiated. She died within one day.
CN will block cytochrome oxidase in all mitochondria leading to an end of aerobic metabolism. Death results in minutes unless an antidote is given. Cyanide poisoning is noted in approximately 35% of fire victims and is generated from burning plastics, rugs and wood .
cyanide will kill in minutes except for Rasputin who had a witnessed cyanide ingestion and did not die. He had to be shot in the chest and then in the head and thrown into a river.
Hydroxocobalamin binds with cyanide forming cyanocobalamin, which is B12. This is excreted in the urine Whether or not CN is present, the urine turns purple.
A French publication reported a potential relationship between hydroxocobalamin administration and acute mesenteric ischemia which has not been found in other studies therefore hydroxocobalamin is currently the recommended treatment for cyanide poisoning. Hydroxocobalamin has also been used for septic shock, vasoplegia after liver transplantation and in hypotension after cardiac bypass. ( this is thought to work because it scavenges nitrous oxide and inhibits guanylate cyclase)
Two other antidotes for cyanide were used in the past. Amyl nitrate and sodium nitrite oxidize hemoglobin to methemoglobin which then scavenges cyanide. It does limit oxygen carrying capacity so the methemoglobin must be changed back to hemoglobin with methylene blue. Thiosulfate can also be used to convert CN to thiocyanate but works slowly. It’s advantage is that our body uses the same mechanism to detoxify the CN we eat every day. This enzyme is called rhodenase and has evolved in humans over millennia.
The antidotes for cyanide
FUN FACTS
Agatha Christie, the most successful novelist of all time, was a certified apothecary assistant in WWI and WWII. She had extensive knowledge of poisons and used them in many of her novels. Sparkling Cyanide is her novel about cyanide poisoning.
The word cyanide comes from the Greek meaning dark blue referring to the sky. The chemical poison is referred to as “blue”( even though HCN is colorless) because it describes the color of of oxidized ferrous ferrocyanate commonly used in pigment. It was the first modern synthetic pigment and is used for blueprints, and paints.
Cyanide is found in many foods seeds, bitter almonds and stone fruits. It is found in Madagascar bamboo and can only be eaten by the golden lemur which has developed a tolerance to cyanide.