7439 Mercury toxicity presenting as Pheochromocytoma

Abstract Disclosure: A. Ansar: None. K. McNerney: None. B.A. Marshall: None. Background: Mercury intoxication is a rare cause of hypertension in children and can mimic other endocrinopathies such as pheochromocytoma. Mercury affects catecholamine metabolism and can cause elevated catecholamine levels, thereby incorrectly suggesting a catecholamine-secreting tumor. Clinical Case: An 8-year-old girl presented to the ED with progressive night sweats, intractable migratory myalgias, hypertension and tachycardia. Patient was in her usual state of health until 2 weeks before presentation when she started to have worsening intermittent pains in her chest, arms, back, and knees. She also experienced restlessness and inability to sleep. On presentation she was hypertensive, with blood pressure of 146/116 mm Hg while calm, heart rate 125 bpm, afebrile. She was anxious, irritable, and seemed uncomfortable. Her skin was dry and rough with a scaly eczematous rash on the arms and legs. She had persistently elevated blood pressure in upper and lower extremities, unremarkable echocardiogram and electrocardiogram, and a normal result on fundoscopic examination. Her initial electrolytes, creatinine, and urinalysis were all normal and remained so on serial evaluations. Urine drug screen was negative. Thyroid function panel showed normal TSH with slightly elevated Free T4 2.28 ng/dL (0.9-1.7), but a normal Free T3 3.9 pg/mL (2.0-4.4) and Free T4 by equilibrium dialysis 1.8 ng/dL (0.8 - 2.0). CT of the chest, abdomen and pelvis was negative and did not show any lesions. Plasma renin activity was 4.6 ng/mL/hour, supine, (<2.0) and plasma aldosterone level < 4.0 ng/dL (< 40 supine) were normal. 24-hour urinary norepinephrine was 90 μg/24h (13-65), epinephrine 37 μg/24h (0.2-10), urine metanephrines 195 μg/24h (18-144), urine normetanephrines 305 μg/24h (29-145), all elevated. Further history taking revealed that patient was taking Ayurvedic supplements prepared by hand by medicinal personnel in India for 3 months prior to presentation. These were stopped 2 weeks prior to her presentation, when she first became symptomatic. Her blood mercury level was 11 ng/mL (n <9), and urinary mercury excretion 67 μg/24 hours (n<10), both obtained 3 weeks after stopping supplementation. She was started on oral chelation therapy with succimer 10 mg/kg/day. Her hypertension was controlled with doxazosin. One week after initiation of therapy, her symptoms improved, and she became normotensive. Her acrodynia and irritability resolved. Urine metanephrine levels will be repeated at upcoming clinic follow up. Conclusion: Mercury toxicity should be considered in the differential of pheochromocytoma to avoid extensive diagnostic testing and morbidity associated with it. Lead, mercury, and arsenic have been detected in traditionally prepared Ayurvedic supplements. A careful history of intake of supplements can be important in cases with unusual symptomatology. Presentation: 6/3/2024