Bright red venous blood and an odor of bitter almonds are characteristic of poisoning by which agent?

Bright red venous blood and an odor of bitter almonds are characteristic of poisoning by which agent?

• A. Arsenic
• B. Lead
• C. Mercury
• D. Cyanide

Answer: (D)

Cyanide poisoning is suggested here. It blocks cytochrome c oxidase in mitochondria, stopping oxidative phosphorylation. Tissues can’t use oxygen even when it’s present, so venous blood stays highly oxygenated and appears bright red—hence the red venous blood finding. The bitter almond odor comes from hydrogen cyanide and is a classic clue, though not everyone can detect it. Other toxins like arsenic, lead, or mercury produce different signs and don’t typically cause this combination of bright red blood and almond odor.

Cyanide poisoning is suggested here. It blocks cytochrome c oxidase in mitochondria, stopping oxidative phosphorylation. Tissues can’t use oxygen even when it’s present, so venous blood stays highly oxygenated and appears bright red—hence the red venous blood finding. The bitter almond odor comes from hydrogen cyanide and is a classic clue, though not everyone can detect it. Other toxins like arsenic, lead, or mercury produce different signs and don’t typically cause this combination of bright red blood and almond odor.