Chronic arsenic poisoning causes -a) Pure sensory neuropathyb) Pure motor neuropathyc) Mixed sensory and motor neuropathyd) Painful neuropathye) Hyperkeratosis of skin
**Core Concept**
Chronic arsenic poisoning is a condition caused by prolonged exposure to arsenic, leading to severe health consequences. It affects multiple organ systems, including the nervous system, skin, and cardiovascular system.
**Why the Correct Answer is Right**
Chronic arsenic poisoning is known to cause mixed sensory and motor neuropathy due to its toxic effects on the peripheral nerves. Arsenic interferes with the normal functioning of the Schwann cells, leading to demyelination and axonal degeneration. This results in symptoms such as numbness, tingling, and weakness in the hands and feet, as well as pain and loss of reflexes. The mixed sensory and motor neuropathy is a hallmark of chronic arsenic poisoning.
**Why Each Wrong Option is Incorrect**
* **Option A:** Pure sensory neuropathy is more commonly associated with conditions such as diabetes, vitamin B12 deficiency, and HIV, not chronic arsenic poisoning.
* **Option B:** Pure motor neuropathy is typically seen in conditions like amyotrophic lateral sclerosis (ALS) and is not a characteristic feature of chronic arsenic poisoning.
* **Option D:** Painful neuropathy is a feature of several conditions, including diabetes, chemotherapy-induced neuropathy, and HIV, but it is not the most specific or characteristic manifestation of chronic arsenic poisoning.
* **Option E:** Hyperkeratosis of the skin is indeed a feature of arsenic poisoning, but it is not the most direct consequence of chronic arsenic poisoning on the nervous system.
**Clinical Pearl / High-Yield Fact**
Remember the "ARSENIC" mnemonic to associate the symptoms of chronic arsenic poisoning: Arsenic causes mixed sensory and motor neuropathy, leading to pain, numbness, tingling, and weakness (Sensory and Motor neuropathy).
**Correct Answer: C. Mixed sensory and motor neuropathy**