Serum creatine kinase activity in untreated primary hypothyroid children.

ABSTRACT

Objectives To determine association between primary hypothyroidism and serum creatine kinase (CK) activity in children. Design and Setting Prospective study of patients seen at university paediatric unit, Galle for a period of 4 years starting from January 1998. Method Primary hypothyroidism was confirmed by presence of elevated serum thyroid stimulating hormone and low thyroxine for age. All newly diagnosed patients with primary hypothyroidism were tested for serum CK activity. Levels were compared with serum CK activity in normal euthyroid children. Serum CK levels were repeated 6 weeks after starting thyroxine therapy. Results 19 children presented with primary hypothyroidism during study period. All had elevated serum CK levels. 2 patients showed clinical evidence of muscular hypertrophy. There were 7 neonates with congenital hypothyroidism. Conclusions: Elevated levels of CK activity were seen in all children with untreated primary hypothyroidism in this series. CK activity became normal 4-6 weeks after starting therapy. Hence elevated serum CK could be used as an indicator for diagnosis of untreated hypothyroidism or to assess adequacy of therapy in primary hypothyroidism.