Schilddrüsenparameter bei häufig in der tierärztlichen Praxis vorgestellten Landschildkrötenspezies

Thyroid parameters in tortoises and turtles frequently presented at
the veterinary practise The present study is concerned with the
examination of thyroid parameters in those tortoisespecies
frequently presented at the veterinary practise. 338 tortoises and
turtles were examined over a period of one year. The examinations
included case history, clinical examinations, diagnosis and
determination of fT3, fT4, T3, and T4 levels by way of
electrochemiluminescence immunoassay and sonographic examinations
of the thyroid gland with determination of the thyroid size by
measuring. One of the first steps was to determine the thyroid
hormone concentrations of fT3, fT4, T3, T4 in 103 healthy tortoises
and turtles. Subsequently the levels were examined for dependencies
regarding species, age, sex, and season. This revealed
significantly higher fT4- and T4-concentrations in turtles compared
to tortoises. A diagnostical dependence regarding age, sex, and
season could not be detected. Accordingly a reference range,
defined as 95% percentile interval, was established for those
tortoises frequently presented at the veterinary practise (Testudo
hermanni, Testudo graeca, Testudo marginata, Agrionemys
horsfieldii). In a second step the fT3, fT4, T3, and T4
concentrations of 235 ill tortoises were determined. The animals
were divided according to manner and severity of their illness into
three groups (slightly ill animals, profoundly ill animals, and
animals under medication by Allopurinol). Significant differences
were revealed in the thyroid hormone concentrations of healthy
compared to profoundly ill animals. The main parameter for
diagnostic use, it became, is apparently fT3. There is evidence
suggesting an increase of this parameter in excess of the reference
range indicates that the animals suffer from a severe illness with
possibly fatal consequences. This test has a high specificity and a
comparatively low sensitivity. At the same time the thyroid glands
of 338 tortoises were examined sonographically. Position, shape,
echogenicity and echotexture were described. The maximum diameter
of the thyroid gland was established and put in relation to the
body weight. Dependencies between the size of the thyroid and the
state of health or illness on the one hand and the concentration of
thyroid hormones on the other hand were checked. This showed that
animals under medication by Allopurinol frequently feature bigger
thyroid glands than healthy animals. A correlation between thyroid
hormone concentration and thyroid-size could not be proven. The
results of this study are compared to evidence from to literary
references and the diagnostical applicability is discussed.