A 72 farmer present in hospital with pin point pupil & increased secretions. The diagnosis is
**Core Concept**
Opioid-induced miosis and increased secretions are due to the activation of mu-opioid receptors in the parasympathetic nervous system, particularly in the Edinger-Westphal nucleus and the lacrimal gland.
**Why the Correct Answer is Right**
The patient's symptoms are consistent with opioid overdose, which is a common cause of pinpoint pupils (miosis) and increased secretions in the setting of substance abuse. Mu-opioid receptors in the parasympathetic nervous system are responsible for this effect, leading to the characteristic symptoms of opioid toxicity. The Edinger-Westphal nucleus, which is part of the oculomotor nerve complex, plays a key role in the parasympathetic control of the eye and is also involved in the regulation of pupil size.
**Why Each Wrong Option is Incorrect**
**Option A:** This is not a plausible diagnosis for the symptoms described. While certain medications and substances can cause pupil constriction, the combination of pinpoint pupils and increased secretions is highly suggestive of opioid overdose.
**Option B:** This option is incorrect because it does not account for the patient's increased secretions, which are a hallmark of opioid toxicity.
**Option C:** This option is incorrect because it does not provide a plausible explanation for the patient's symptoms.
**Clinical Pearl / High-Yield Fact**
In cases of suspected opioid overdose, it is essential to consider the possibility of pinworm (Enterobius vermicularis) infection, which can also cause increased secretions and pinpoint pupils due to the release of histamine and other mediators.
**Correct Answer: D. Opioid overdose.**