Læknablaðið - 15.01.1993, Blaðsíða 25

LÆKNABLAÐIÐ
19
fyrsta árið og allt að 80% eftir sjö ár frá
meðferð. Kirtilstærð og joðupptaka reyndust
marktækt hærri í þeim 19% sjúklinga sem
þurftu á endurtekinni meðferð að halda.
Geislajoðmeðferð hefur aukist hérlendis, en
hér eins og annars staðar virðist skjótur bati
á ofstarfsemi með geislameðferðinni kosta
aukna tíðni á vanstarfsemi kirtilsins.
SUMMARY
Half a century ago the Icelanders were reported
to have the smallest thyroid gland of all nations
whose thyroid gland weight was known. This
has been thought to be caused by the rich iodine
content of the Icelandic food. For that reason and
others it is of interest to study some of the thyroid
pathology and treatment in Iceland. Treatment
of hyperthyroidism with radioiodine (1-131) has
become the method of choice amongst adults
in Iceland during the last decade. From the
beginning of 1985 to the end of October 1991 a
total number of 267 hyperthyroid patients were
treated with radioiodine at the radioisotope unit
of Landspítalinn, the only unit in Iceland involved
in that treatment. The radioactivity administered
to the patients, the dose of radioactive iodine,
was relatively small and aimed at 7000 rads
to the thyroid gland. Of 216 patients treated
during the years 1985-1990, 41 (19%) needed
a second treatment or more due to persisting
hyperthyroidism. These patients had significantly
larger thyroid glands and higher iodine uptake
than the rest of the patients. Two measurements of
serum TSH and T4 within 6 months after treatment
indicated that about one third of the patients were
going from hypothyroid state to euthyroid or
hyperthyroid state and vice versa up to that time.
These measurements further indicated that about
50% of the patients were hyperthyroid and about
27% hypothyroid at the end of 6 months. A further
study by mailed questionnaire to 241 patients
(response rate = 75.1%) revealed that about 30%
had developed hypothyroidism within 8 months
and about 50% within 2 years of treatment. Of the
whole group 60% had developed hypothyroidism
7 years after treatment. When groups of patients
for each year were studied it was found that there
was about 6% average increase of hypothyroidism
each year beyond the incidence of the first year.
In 7 years from treatment 77% of the patients had
developed hypothyroidism. This is a considerably
higher incidence than reported in Iceland earlier
and is in agreement with observations in other
countries showing that the rate of hypothyroidism
after radioiodine treatment has been increasing
during the last 2 or 3 decades. Irregular pulse rate
before treatment was more common (53%) than
reported elsewhere. Eye complaints, minor ones
mostly, were reported by 22% of the patients. It is
concluded that the incidence of hypothyroidism
in Iceland after relatively small doses of 1-131
treatment is comparatively high and has increased
during the last 20 years for unknown reasons.
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