Okay, let's tackle this question about anisocoria and the use of 1% pilocarpine. First, I need to recall what anisocoria is. It's when there's an unequal pupil size between the two eyes. The question is about determining the cause when the dilated pupil doesn't constrict after pilocarpine is applied.

The core concept here is understanding the pharmacologic response of different types of pupillary abnormalities. Pilocarpine is a cholinergic agonist that acts on the parasympathetic nervous system, stimulating the iris sphincter muscle. But in certain conditions, like a sympathetically mediated dilation (Horner's syndrome), the response might differ.

The correct answer is likely related to a pharmacologically dilated pupil. For example, if someone was given a mydriatic like atropine, the pilocarpine wouldn't reverse it because atropine blocks muscarinic receptors. But wait, pilocarpine is a parasympathomimetic, so if the pupil is dilated due to a sympathomimetic agent (like cocaine), the pilocarpine would still work because the sympathetic block is removed. Wait, no—maybe I'm mixing things up. Let me think again.

Wait, in Horner's syndrome, the pupil is constricted, not dilated. If the pupil is abnormally dilated and doesn't constrict with pilocarpine, it might indicate a pharmacologic cause. For instance, if the pupil is dilated due to a parasympathetic block (like atropine), then pilocarpine can't act because the muscarinic receptors are blocked. But if the dilation is due to a sympathetic denervation (Horner's), the pupil would be small, not large. So if the pupil is large and doesn't respond to pilocarpine, it's likely due to a pharmacologic block, such as atropine or anticholinergic agents.

So the options might include things like Horner's syndrome, Adie's tonic pupil, or pharmacologic dilation. The key is that 1% pilocarpine is used to differentiate between organic and pharmacologic causes. In pharmacologic dilation (e.g., from atropine), the pupil remains dilated because the drug blocks the muscarinic receptors. In Adie's, the pupil might constrict slowly. In Horner's, the pupil is small. So the correct answer would be pharmacologic dilation, like atropine.

Now, the incorrect options: Horner's is a constriction, not dilation. Adie's might show some response. Trauma could cause different reactions. So the answer is pharmacologic dilation.

**Core Concept**
Anisocoria with a non-reactive dilated pupil to 1% pilocarpine indicates **pharmacologic mydriasis**, typically caused by anticholinergic agents (e.g., atropine or scopolamine). Pilocarpine activates muscarinic receptors in the iris sphincter muscle to constrict the pupil, but this fails in anticholinergic toxicity due to receptor blockade.

**Why the Correct Answer is Right**
1% pilocarpine is used to distinguish pharmacologic dilation from organic causes (e.g., Adie’s tonic pupil or Horner’s syndrome). In pharmacologic

✓ Correct Answer: B. Pharmacological blockage