Clinical features and pathogenesis of thyrotoxicosis in adult Melanesians in Papua New Guinea.

OBJECTIVE

To investigate the cause of an apparent increase in the incidence of thyrotoxicosis in the Melanesian population of the coastal areas around Port Moresby, Papua New Guinea.

DESIGN

Consecutive patients attending the thyroid clinic at Port Moresby General Hospital were included in the study which collected clinical and immunogenetic data.

PATIENTS: One hundred and ninety-four patients with thyrotoxicosis were studied. The mean age was 31 years. The clinical features were typical for thyrotoxicosis apart from increased pigmentation, which occurred in the majority of patients and which reversed with treatment with antithyroid drugs and resolution of the thyrotoxicosis.

MEASUREMENTS: Antibodies to thyroid peroxidase, thyroglobulin and the thyrotropin receptor were present in 99%, 52% and 69% of patients, respectively, confirming that all cases were caused by autoimmune thyroid disease. Fine needle aspirations in 42 of 43 patients were consistent with Graves' disease.

CONCLUSIONS

The cause of this apparent sudden increase in Graves' disease in the coastal region around Port Moresby, an apparently iodine-replete area, remains unexplained.