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 :
Answer is D (Serial 24 hours test for catecholamines, metanephrines and vanillylamandelic acid excretion) : Theochromocytoma, must be excluded by measurement of urinary catecholamines levels in all cases before embarking upon thyroid surgery to avoid the potential hazards. of this condition' - Bailey Essays employed for diagnosis of pheochromocytoma include those for: Vanillyl mandelic acid (VMA) Metanephrines Free catecholamines The patient in question is a case of inherited Men II a syndromes The presence of 'headache and sweating' in a patient with thyroid nodule warrants prompt investigation for a possible pheochromocytoma as pa of MEN II syndrome, more so in a patient with a positive family history (as suggested by presence of renal calculi and thyroid nodule in mother). Pheochromocytoma secrete large amounts of catecholamines, the secretion of which is fuher increased during surgery. This may result in large swings in blood pressure and arrhythmias, and increases the risk of surgical moality. Stable a adrenergic blockage is essential before embarking on thyroid surgery.
Measurement of thyroid hormones
Serial determinations of serum calcium, phosphorus protein and alkaline phosphatase
24-hours urine test for 5 hydroxyindoleacetic acid excretion.
Serial 24 hours test for catecholamines, metanephrines and vanillylamandelic acid excretion.