Mercury Toxicity Mimicking Pheochromocytoma

Mercury intoxication can cause hypertension in children and mimic pheochromocytoma. We present an 8-year-old girl who presented with night sweats, intractable myalgias, hypertension, and tachycardia. Her electrocardiogram showed sinus tachycardia, and her echocardiogram was normal. Her electrolytes, creatinine, and urinalysis were normal. A thyroid function panel showed normal TSH with slightly elevated free T4. Computed tomography of the chest, abdomen, and pelvis was negative. She was discharged with antihypertensives but did not show significant improvement in her symptoms. Further workup showed normal renin levels and elevated 24-hour urinary norepinephrine, epinephrine, metanephrines, and normetanephrines. Pheochromocytoma was suspected. On readmission and additional questioning, we learned that the patient was prescribed Ayurevedic supplements, which she had been taking for 3 months. These were discontinued 2 weeks prior to presentation when the patient first became symptomatic. Her blood and urine mercury levels were elevated. She was started on oral chelation therapy with succimer. Her hypertension was treated with doxazosin. One week after the initiation of therapy, her symptoms improved, and she was normotensive. Mercury toxicity produces a state of catecholamine excess resembling pheochromocytoma. Any diagnostic evaluation for suspected pheochromocytoma in a child should include testing and inquiry about possible sources of mercury.