Xerostomia is seen in all except –
**Core Concept**
Xerostomia, also known as dry mouth, is a condition characterized by reduced or absent saliva flow, often leading to oral discomfort, dental caries, and difficulty swallowing. It can result from various factors, including medications, systemic diseases, and radiation therapy.
**Why the Correct Answer is Right**
The correct answer is related to the common causes of xerostomia. Medications that inhibit the muscarinic receptors in the salivary glands can lead to xerostomia. Examples include anticholinergics, antihistamines, and certain antidepressants. Additionally, systemic diseases such as Sjögren's syndrome, diabetes mellitus, and hypothyroidism can cause xerostomia by affecting the salivary glands or the nervous system controlling saliva production.
**Why Each Wrong Option is Incorrect**
**Option A:**
This option is incorrect because it doesn't directly cause xerostomia. However, it might be related to another condition affecting the salivary glands.
**Option B:**
This option is incorrect because it's a condition that actually causes an increase in saliva production, not a decrease.
**Option C:**
This option is incorrect because it's a condition that affects the parotid glands, but it's not the primary cause of xerostomia.
**Option D:**
This option is incorrect because it's a condition that affects the lacrimal glands, causing dry eyes, not xerostomia.
**Clinical Pearl / High-Yield Fact**
A common exam trap is to confuse xerostomia with other dryness-related conditions, such as dry eyes (xerophthalmia) or hypovolemia (dry mouth due to decreased blood volume).
**Correct Answer:** D. Sicca syndrome (Sjögren's syndrome) is characterized by dry eyes, not xerostomia.