Reevaluation of the thyroidal radioactive iodine uptake test, with special reference to reversible primary hypothyroidism with elevated thyroid radioiodine uptake

Journal Article · Sat Oct 01 04:00:00 EDT 1988 · J. Clin. Endocrinol. Metab.; (United States)

DOI:https://doi.org/10.1210/jcem-67-4-720· OSTI ID:7055387

Okamura, K; Sato, K; Ikenoue, H; Yoshinari, M; Nakagawa, M; Kuroda, T; Fujishima, M

The clinical significance of the thyroidal radioactive iodine uptake (RAIU) test was reevaluated in patients with various thyroid disorders. Compared with 262 normal subjects or 194 patients with euthyroid diffuse goiter with normal serum TSH levels, RAIU values were significantly higher in 100 patients with latent primary hypothyroidism (serum TSH, 5-40 mU/L). In 126 patients with overt primary hypothyroidism (serum TSH, greater than 40 mU/L), RAIU values were either extremely high (49 patients with reversible hypothyroidism and 10 patients with postpartum hypothyroidism) or low (67 patients with irreversible hypothyroidism). The increase in RAIU values in latent, or reversible overt hypothyroidism was TSH dependent, and there was a good correlation between RAIU values and serum TSH levels (r = 0.6203; P less than 0.001). In overt primary hypothyroidism, spontaneous recovery of thyroid function during iodide restriction alone occurred in 52 of 53 patients with RAIU values above 35%, in only 7 of 23 patients with RAIU values between 10-35%, and in none of 50 patients with RAIU below 10%. Thus, recovery was predicted by high RAIU values (P less than 0.001; prediction rate, 91.4%). Goiter was found in about 80% of the patients with reversible hypothyroidism, compared with only 34% of the patients with irreversible hypothyroidism. Recovery of thyroid function during iodide restriction also occurred in 71% of the patients with latent hypothyroidism. However, RAIU measurements did not predict the prognosis of patients with latent hypothyroidism. We conclude that iodine-induced reversible hypothyroidism is common in our patient population, and RAIU measurements may be helpful in determining the prognosis of patients with overt primary hypothyroidism.

• Research Organization: Kyushu Univ., Fukuoka (Japan)
• OSTI ID: 7055387
• Journal Information: J. Clin. Endocrinol. Metab.; (United States), Journal Name: J. Clin. Endocrinol. Metab.; (United States) Vol. 67:4; ISSN JCEMA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ALKALI METALS
BODY
DIAGNOSIS
DISEASES
DYNAMIC FUNCTION STUDIES
ELEMENTS
ENDOCRINE DISEASES
ENDOCRINE GLANDS
GLANDS
GOITER
HORMONES
HYPOTHYROIDISM
IODINE ISOTOPES
ISOTOPES
METALS
ORGANS
PATIENTS
PEPTIDE HORMONES
POTASSIUM
THYROID
THYROID HORMONES
UPTAKE