A 25 year old young woman has recurrent episodes of headache and sweating. Her mother had renal calculi and died after having a neck mass. The physical examination reveals a thyroid nodule but no clinical sign of thyrotoxicosis. Before performing thyroid surgery, the surgeon should order –

**Core Concept**
The patient's symptoms and family history suggest a possibility of a familial syndrome that increases the risk of thyroid cancer. This requires a preoperative evaluation to assess the extent of thyroid cancer and guide surgical planning.

**Why the Correct Answer is Right**
The patient's symptoms of recurrent headache and sweating could be due to a pheochromocytoma, a type of neuroendocrine tumor that is often associated with multiple endocrine neoplasia (MEN) syndromes. The presence of a thyroid nodule and a family history of renal calculi (kidney stones) and a neck mass (possibly a thyroid cancer) suggests a possible diagnosis of MEN 2A or 2B syndrome. A preoperative evaluation with **24-hour urine catecholamine and metabolite measurement** is essential to diagnose and manage any potential pheochromocytoma before thyroid surgery.

**Why Each Wrong Option is Incorrect**
* **Option A:** Thyroid function tests (TFTs) are not directly relevant to the patient's symptoms and family history, which suggest a possible thyroid cancer or pheochromocytoma.
* **Option B:** A fine-needle aspiration biopsy (FNAB) of the thyroid nodule may not be sufficient to diagnose thyroid cancer, especially if it is associated with a pheochromocytoma.
* **Option C:** A chest X-ray may not be sufficient to assess the extent of thyroid cancer or pheochromocytoma, and may not be relevant to the patient's symptoms and family history.

**Clinical Pearl / High-Yield Fact**
It's essential to consider the possibility of a familial syndrome, such as MEN 2A or 2B, in patients with thyroid nodules and a family history of thyroid cancer or other endocrine tumors.

**Correct Answer:** D. 24-hour urine catecholamine and metabolite measurement

✓ Correct Answer: D. Serial 24 hours test for catecholamines, meta-nephrines and vanillylamandelic acid excretion