P4.40: Severe hypothyroidism and metabolic encephalopathy in a child receiving long-term home parenteral nutrition without selenium

Abstract

Introduction: Selenium is essential in the protection against oxidative stress, for optimum immune response and for thyroid hormone biosynthesis and metabolism. We describe a case of chronic selenium deficiency with severe hypothyroidism and metabolic encephalopathy in a child with ultra-short bowel syndrome receiving long-term home parenteral nutrition (PN) without selenium supplementation. Methods: The patient is a 4-year-old girl, born prematurely at 26 weeks of gestation, birth weight 670g. At the 13th day of life she was diagnosed with necrotizing enterocolitis and required exploratory laparotomy. There was necrosis of the small bowel and need of extensive resection, with 3 cm of small bowel and half of colon remaining. After the surgery, she was started on exclusive PN containing a fixed dose of multi-trace element solution but lacking selenium, probably due to drug shortage. After a one-year hospitalization, she was discharged and continued to receive PN at home. At 3 years old she presented with converging strabismus and regression of motor development. Initially she had inability to ambulate, which worsened until she couldn’t walk, sit and talk. At that time, she was diagnosed with decompensated hypothyroidism, requiring T3 and T4 replacement therapy. Results: At the age of 3 years 8 months, she was referred to our intestinal rehabilitation center for investigation. On examination she had an edematous face, muscle weakness, irritability and depigmented hair. Plasma selenium levels were undetectable. The diagnosis of encephalopathy and myxedema secondary to severe selenium deficiency was made. Intravenous selenium repletion therapy was initiated (4 µg/kg/day), followed by 2 µg/kg/day as maintenance and, as selenium plasma levels normalized, the need of T3 replacement was reduced until it was discontinued and maintenance treatment with levothyroxine isolated was initiated. She was discharged from hospital to home care four months later at the age of 4. After selenium levels restored to normal, neurological signs improved progressively and growing hair was repigmented. She continues to receive physio, speech and occupational therapy and she is progressing well. Conclusion: Chronic selenium deficiency caused severe hypothyroidism and metabolic encephalopathy in a child receiving exclusive long-term home PN without selenium. Patients on long-term PN need selenium supplementation to avoid serious clinical manifestations of deficiency.