Incidence of thyrotoxicosis in childhood: a national population based study in the UK and Ireland.

OBJECTIVE: To measure the UK and Ireland incidence of childhood (<15 years) thyrotoxicosis and to describe the presenting features.

CONTEXT: Incidence data on thyrotoxicosis in childhood are not available for the UK and Ireland. Recent studies have reported an apparent increase in cases in Europe.

DESIGN: A national prospective surveillance study for 12 months from September 2004, co-ordinated by The British Paediatric Surveillance Unit (BPSU).

PATIENTS AND MEASUREMENTS: All paediatricians across the UK and Ireland were requested monthly to report new cases. Details of presenting features were then obtained by questionnaire.

RESULTS: One hundred ten cases of acquired childhood thyrotoxicosis were identified in the UK and Ireland. The incidence of acquired thyrotoxicosis was 0.9 per 100,000 <15 years olds in the UK and Ireland, (95% CI: 0.8-1.1). Autoimmune thyrotoxicosis accounted for 96% of cases. There was an increasing incidence with age in each sex. Females have a significantly higher incidence than males in the 10- to 14-year age group. A variety of presenting symptoms were reported: weight loss (64%), fatigue/tiredness (54%), change in behaviour' (50%) and heat intolerance (47%). 4.5 % cases were asymptomatic. The commonest signs were goitre (78%) and tremor (58%). There were no cases of thyroid storm.

CONCLUSIONS: This national population survey defines the incidence of thyrotoxicosis in children in the UK and Ireland during 2004-2005, which was lower than expected in comparison with other European studies. The survey illustrates contemporary presenting characteristics of the disease.