Biochemical role of selenium:
(1) glutathione peroxidase
(2) enzyme for converting T4 to T3 (type I iodothyronine 5'-deiodinase)
Clinical settings for selenium deficiency:
(1) deficiency in soil
(2) total parenteral nutrition without supplementation
(3) inflammatory bowel disease (Crohn's disease)
(4) chronic alcoholics
(5) HIV-positive patients
(6) protein malnutrition
(7) premature infants
(8) phenylketonuria and maple syrup urine disease (poor protein intake)
(9) dialysis
Clinical findings:
(1) cardiomyopathy (Keshan disease in China, peripartum cardiomyopathy in sub-Saharan Africa)
(2) muscle weakness
(3) osteoarthritis (Kashin-Beck disease)
It also has been implicated as contributory in endemic cretinism and Balkan nephropathy.
The presence of a clinical finding in a patient with an appropriate clinical setting should prompt measurement of a patient's selenium levels.
