Fatal dose of arsenic in adults:
**Core Concept**
Arsenic is a highly toxic heavy metal that can cause severe poisoning, leading to multi-organ failure and death. The fatal dose of arsenic in adults is a critical parameter in forensic medicine and toxicology.
**Why the Correct Answer is Right**
The fatal dose of arsenic in adults is approximately 1-2 grams, depending on the route of exposure and individual susceptibility. Arsenic acts by inhibiting cellular respiration and disrupting mitochondrial function, leading to ATP depletion and cellular necrosis. Ingestion of arsenic compounds, such as arsenic trioxide or arsenic pentoxide, can lead to rapid absorption and distribution to various organs, including the liver, kidneys, and central nervous system.
**Why Each Wrong Option is Incorrect**
**Option A:** Arsenic is not typically considered a lethal dose at 0.1 grams, as this amount may cause mild to moderate symptoms but is unlikely to be fatal.
**Option B:** While arsenic is indeed highly toxic, the stated dose of 5 grams is excessively high and would likely cause rapid death, but it's not the commonly accepted fatal dose.
**Option C:** The dose of 0.01 grams is far below the lethal threshold and would likely not cause significant harm.
**Clinical Pearl / High-Yield Fact**
It's essential to note that arsenic poisoning can be difficult to diagnose, as the symptoms may resemble those of other conditions. However, a high index of suspicion, supported by laboratory analysis of hair, nails, or urine samples, can aid in diagnosis.
**Correct Answer: C. 0.5-1.5 grams.**