Hyperthyroidism in people over 50 years of age in Senegal. Study of 31 cases observed over a 14-year period

Though common in elderly, with poor and masked symptomatology, hyperthyroidism has never been studied in people older than 50 years of age in African countries. Of the 300 cases of hyperthyroidism that were observed during this study, 31 belonged to this category. We analyzed the frequency of various parameters, demographic characteristics, motivation for consulting, thyrotoxic syndrome, non thyrotoxic signs, cardiac manifestations, hormonal and scintigraphic characteristics, etiology and etiologic factors, and treatment. The frequency of hyperthyroidism in this population was 10%. Housewives were more numerous, with 20 cases observed in the 31 patients. The main group (13/31) was of rural origin. Signs that predominantly led to consultation were weight loss (23/31), cervical tumor (17/31), and palpitations (12/31). Three major signs were associated with the thyrotoxic syndrome: weight loss (29 cases), tachycardia (27/31), and the existence of tremors in the extremities (22/31). Hormone assays showed that thyroxine (T4) was about 265 +/- 74 nmol/L and triiodothyronine (T3) about 6 +/- 2 nmol/L, at immunoradiometric assay; thyroid-stimulating hormone (TSH) was about 0.17 +/- 0.23 muIU/mL. Eye protrusion predominated in the nonthyrotoxic syndrome, with 25 cases in the 31 patients. Etiologic forms of the disease were composed of 25 Grave's disease, with 22 typical cases. Etiologic factors were various, however without any case of neoplasia. Cardiac complications included two cases of atrial fibrillation. No iatrogenic form of the disease was observed. Mean initial carbimazole dosage was about 34 +/- 8 mg/d. Of the 23 patients, 15 had a favourable outcome. In this series, the high number of housewives and the patients' rural origin were less characteristic of hyperthyroidism than the Grave's disease etiology. This might be due to the young age of this African population.