Which of the following forms radiopaque stones:
**Core Concept**
Calcium oxalate stones are the most common type of kidney stones, and they are radiopaque, meaning they can be visualized on X-rays. This is due to the presence of calcium in the stone, which absorbs X-rays and makes the stone visible.
**Why the Correct Answer is Right**
Calcium oxalate stones form when there is an imbalance of calcium and oxalate in the urine, leading to the precipitation of calcium oxalate crystals. This can occur due to various factors such as excess oxalate production, low urine volume, or abnormalities in calcium metabolism. The presence of calcium in the stone makes it radiopaque, allowing it to be detected on X-rays.
**Why Each Wrong Option is Incorrect**
**Option A:** Uric acid stones are radiolucent, meaning they do not absorb X-rays and are not visible on plain X-rays.
**Option B:** Cystine stones are also radiolucent and are typically detected using other imaging modalities such as CT scans or ultrasound.
**Option C:** Struvite stones are composed of magnesium ammonium phosphate and are often associated with urinary tract infections. They are radiopaque, but this option is not the correct answer as we are specifically looking for calcium oxalate stones.
**Clinical Pearl / High-Yield Fact**
It's essential to note that while calcium oxalate stones are radiopaque, uric acid stones are radiolucent and may not be visible on plain X-rays, making CT scans or other imaging modalities necessary for diagnosis.
**Correct Answer: C. Calcium oxalate stones are radiopaque.**