Acquired nasolacrimal duct obstruction is a side effect of therapy of which of the following medication?
**Core Concept**
Acquired nasolacrimal duct obstruction is a condition where the nasolacrimal duct becomes blocked, preventing tears from draining out of the eye. This can be caused by various factors, including medications that alter the anatomy or function of the nasolacrimal duct.
**Why the Correct Answer is Right**
Topical corticosteroids, such as budesonide, are known to cause acquired nasolacrimal duct obstruction as a side effect. This is because long-term use of topical corticosteroids can lead to the thinning of the conjunctival and lacrimal sac mucosa, causing the nasolacrimal duct to become obstructed. The mechanism involves the suppression of the inflammatory response, which is necessary for maintaining the integrity of the mucosal lining of the nasolacrimal duct.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because beta-blockers, such as propranolol, are not commonly associated with nasolacrimal duct obstruction.
**Option B:** This option is incorrect because antihistamines, such as diphenhydramine, are not typically linked to nasolacrimal duct obstruction.
**Option C:** This option is incorrect because anticholinesterases, such as neostigmine, are not known to cause nasolacrimal duct obstruction.
**Clinical Pearl / High-Yield Fact**
Topical corticosteroids can cause a range of ocular side effects, including glaucoma, cataracts, and nasolacrimal duct obstruction. It is essential to use these medications judiciously and monitor patients for potential complications.
**Correct Answer:** C. Budesonide.