Bilateral proptosis is common in
**Core Concept**
Bilateral proptosis refers to the forward displacement of both eyeballs, which can be caused by various conditions affecting the orbit. The underlying principle being tested involves the anatomical and pathological processes that lead to this symptom.
**Why the Correct Answer is Right**
The correct answer is related to conditions that cause an increase in the volume of the orbital contents, leading to protrusion of the eyeballs. One such condition is **Graves' disease**, an autoimmune disorder that causes thyroid hormone overproduction and can lead to inflammation and swelling of the tissues around the eye, including the eyelids, eye socket, and lacrimal gland.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect as it is not commonly associated with bilateral proptosis.
**Option B:** Incorrect as it does not typically cause bilateral proptosis.
**Option C:** Incorrect because, although it can cause proptosis, it is not the most common cause of bilateral proptosis.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that bilateral proptosis can be a sign of a systemic condition such as **Graves' disease**.
**Correct Answer:** D. Graves' disease