Question
The Autopsy findings of a case of poisoning caused by inhalation of fumes for a few minutes in a person working in gold mining is represented in the picture below .Mechanism of action for poisoning is ?
A. Inhibition of acetylcholine
B. Irreversible inhibition of selenoenzymes
C. Inhibits protein syntheisis.
D. Blocks Cytochrome enzyme P- 450.
Show Answer
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Correct Answer » D Explanation |
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Ans:D. Blocks Cytochrome enzyme P- 450.
The poisoning case shown in the picture above represents HCN poisoning as lividity shown is bright red(pinkish red) staining.
HCN poisoning
- Acute hydrogen cyanide poisoning can result from inhalation of fumes from burning polymer products that use nitrile in their production, such as polyurethane, or vinyl.
- Cyanides are used in many industries and thus are available to potential poisoners.
- The main industries that use cyanides are:Mining of gold and Silver,Electroplating industry,pesticide industry
- Cyanide poisoning is a form of histotoxic hypoxia because the cells of an organism are unable to create ATP, primarily through the inhibition of the mitochondrial enzyme cytochrome c oxidase.
Autopsy Findings
- Hypostasis is said to be brick-red, due to excess oxyhaemoglobin (because the tissue are prevented from using oxygen) and to the presence of cyanmethaemoglobin.
- There may be a smell of cyanide about the body, and a distinct odor of bitter almonds about the viscera especially in the skull cavity and the brain.
- Internally the tissues may also be bright pink caused by the oxyhaemoglobin that cannot be utilized by the tissues – which is probably more common than the presence of cyanmethaemoglobin.
- The stomach lining may be badly damaged and can present a blackened, eroded surface, by altered blood staining the stripped mucosa.The oesophagus may be damage, especially the mucosa of the lower third.
| CO poisoning | Cyanide poisoning | |
| Effect on ability of RBCs to transfer Oxygen | Yes,it impairs | No |
| Effect on mitochondria | Effect not as much as Cyanide poisoning | Complete and sustained blockade of cellular respiration inducing severe lactic acidosis |
| Type of Hypoxia | Hypemic hypoxia is caused by the reduction of the oxygen carrying capacity of the blood. | Histotoxic hypoxia because the cells of an organism are unable to create ATP, primarily through the inhibition of the mitochondrial enzyme cytochrome c oxidase. |
| Amount of exposure required | Requires hours of exposure | Occurs within seconds or minutes of exposure |
| Post-mortem lividity Colour | Cherry red | Pinkish red |
| Treatment | Oxygen | Oxygen with Antidote like amyl nitrite,intravenous sodium nitrite, intravenous sodium thiosulfate and Hydroxocobalamin |
