A patient presented with headache and flushing. He has a family history of his relative having died of a thyroid tumour. The investigation that would be required for this patient would be -

Ans is "C" i.e. measurement of catecholamine This patient is having MEN syndrome more specifically MEN type 2, which includes. Medullary carcinoma of thyroid and Pheochromocytoma Headache and flushing are manifestation of pheochromocytoma which can be diagnosed by measuring catecholamine level in urine or blood.