Hyperthyroidism in a population with Down syndrome (DS).
BACKGROUND
Thyroid disorders are frequent in patients with Down syndrome (DS). It is well-known that the prevalence of hypothyroidism is high but data on hyperthyroidism are scarce.


OBJECTIVE
To assess the prevalence, aetiology, clinical characteristics, evolution and treatment of hyperthyroidism in a population with DS attending a specialized medical centre.


METHODS
Data were gathered by systematic review of 1832 medical records from the Catalan DS Foundation, in Spain, registered between January 1991 and February 2006. Patients with the diagnosis of hyperthyroidism were identified and data on clinical features, physical examination, laboratory and imaging tests, treatment and evolution were collected.


RESULTS
Twelve patients with hyperthyroidism were recorded (6.5 cases/1000 patients with DS). There were 5 males and 7 females, with a mean age at diagnosis of 16.8 years. The most common presenting symptoms were decreased heat tolerance, sweating, increased irritability and weight loss. All patients had diffuse goitre at physical examination and two patients presented with exophthalmia. Clinical diagnosis was confirmed biochemically. Thyroid-stimulating immunoglobulin levels were raised (mean 128.1 U/l) and imaging tests confirmed the diagnosis of Graves' disease in all cases. Patients started treatment with carbimazole at diagnosis and after a mean period of 40 months without clinical remission, they required definitive therapy with radioactive iodine. Subjects developed hypothyroidism after radio-iodine therapy and replacement therapy with levothyroxine was necessary.


CONCLUSIONS
Hyperthyroidism is more prevalent in patients with DS than in the general population and has no gender predominance. It is caused mainly by Graves' disease. Anti-thyroid drugs were not effective in achieving remission and radioactive iodine as a definitive treatment was required in all cases.
Goday-Arno
Alberto
A
Endocrinology and Diabetes Unit, Hospital Universitari del Mar, Universitat Autonoma de Barcelona, Barcelona, Spain. agoday@imas.imim.es
Cerda-Esteva
Mariaina
M
Flores-Le-Roux
Juana Antonia
JA
Chillaron-Jordan
Juan José
JJ
Corretger
Josep Maria
JM
Cano-Pérez
Juan Francisco
JF
D000293:Adolescent; D000328:Adult; D013956:Antithyroid Agents / Q000627:therapeutic use; D002231:Carbimazole / Q000627:therapeutic use; D002648:Child; D004314:Down Syndrome / Q000150:complications*; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000150:complications* / Q000188:drug therapy / Q000453:epidemiology; D018828:Immunoglobulins, Thyroid-Stimulating / Q000097:blood; D008297:Male; D013030:Spain / Q000453:epidemiology; D055815:Young Adult
D013956:Antithyroid Agents; D018828:Immunoglobulins, Thyroid-Stimulating; D002231:Carbimazole