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Endocrinology 2018
Journal of Clinical and Molecular Endocrinology
ISSN: 2572-5432
Page 35
August 09-10, 2018
Madrid, Spain
11
th
International Conference on
Endocrinology and
Diabetology
Background:
In hyperthyroidism, physicianmust have information
that whether this hyperthyroidism is caused due to excess iodine
or not, as this fact dramatically affects on the prognosis and
management of subsequent therapy. The diagnostic methods
which are nowadays widely used like, serum TSH level, fT4,
fT3 and USG of thyroid gland, do not answer to the question of
what is the pathogenesis of hyperthyroidism in terms of iodine
induction. Thyroid scintigraphy or scan with technetium (
99m
Tc)
allows assessing only in non-iodine induced hyperthyroidism by
diffused uptake. Thyroid scintigraphy, in case of iodine induced
hyperthyroidism, will not allow visualizing thyroid gland due to
blocked function of iodine trapping (Wolff-Chaikoff effect). This
blockade can occur not only due to Wolff-Chaikoff effect, but also
some elements like, bromide and corvalol etc. Patients might
not remember about these elements, which particularly reduce
the value of DD in hyperthyroidism with thyroid scintigraphy. In
accentuation, the only method, which allows diagnosing the
thyroid function disorder, is the thyroid density imaging with
computed tomography, so called Hounsfield unit (HU). This
thyroid density is directly proportional to the concentration of
intrathyroidal stable iodine. Based on literature data, the following
variations of the thyroid density in HU are proposed for all regions
of Russia, reflecting the euthyroid state is from 85 to 140 HU.
When there is iodine-induced impairment of thyroid function,
thyroid density in HU is more than 140. In primary hypothyroidism
(thyroid hormones are not synthesized) or in diffuse toxic goiter
(lack of fixation of thyroid hormone in colloid due to pathological
secretion) thyroid density in HU is less than 85 HU.
Aim:
To demonstrate the necessity of application of thyroid
density imaging with computed tomography (CT) for differential
diagnosis between iodine-induced hyperthyroidism and non
iodine-induced hyperthyroidism.
Materials and methods:
Three women with 59, 58, 64-years-old
presented for evaluation of tachycardia, nervousness, moderate
sweating, weight loss, tremors in the extremities. A 59- year-old
woman did not have contact with an excess iodine or bromide. A
58-year-old woman, 18 months ago, had finished treatment with
amiodarone. A 64-year-old woman, since a week has been using
eye drop (Corvalol) by ophthalmologist’s prescription. All patients
were examined clinically and laboratory with determination of
hormones – serum TSH and fr.T4, USG of thyroid gland, thyroid
scintigraphy with capture index of
99m
Tc (the ratio of the intensity
of radiation (IR) from
99m
Tc from the zone of interest over the
thyroid gland to the IR of the zone of interest over the background
on the neck), thyroid density imaging with CT in HU.
Results:
The patient’s (59-year-old) clinical and laboratorical
values- serum TSH 0.02mU/l (normal value 0.4-4.2 mU/l); fr.T4
64 pmol/l (normal value 9-19 pmol/l); volume of thyroid gland 19
cm3 (normal value till 18 for women); capture index with
99m
Tc
40 (normal value 2-7); thyroid density in HU 70 (normal value
85-140 HU). The patient’s (58-year-old) clinical and laboratorical
values- serum TSH 0.05mU/l (normal value 0.4-4.2 mU/l); fr.T4
21 pmol/l (normal value 9-19 pmol/l); volume of thyroid gland 12
cm3 (normal value till 18 for women); capture index with
99m
Tc
1.3 (normal value 2-7); thyroid density in HU 150 (normal value
85-140 HU). The patient’s (64-year-old) clinical and laboratorical
values- serum TSH 0.28mU/l (normal value 0.4-4.2 mU/l); fr.T4
20 pmol/l (normal value 9-19 pmol/l); volume of thyroid gland 19
cm3 (normal value till 18 for women); capture index with
99m
Tc
1.5(normal value 2-7); thyroid density in HU 80 (normal value 85-
140 HU).
Conclusion:
Among these three patients, increased capture index
of
99m
Tc in thyroid scintigraphy is observed only in one patient
(59- year-old), who did not have contact with excess iodine or
bromide, but in other two women, capture index is decreased.
This decreased capture index indicates that function of iodine
trapping has been blocked, due to amiodarone in patient (58-year-
old) and carvolol (contains ethylbromoacetate) in patient
Differential diagnosis between iodine-induced
hyperthyroidism and non iodine-induced hyperthyroidism
with computed tomography
Ramchandra Sargar
1
, Kurnikova I A
1
and
Tomashevskiy I O
2
1
RUDN University, Russia
2
Central clinical hospital №2 named after N.A. Semashko, Moscow, Russia
Ramchandra Sargar et al., J Clin Mol Endocrinol 2018, Volume 3
DOI: 10.21767/2572-5432-C2-005