ReVersible Changes of Clinical Chemical Tests in Severe Hypothyroid Patients with Differentiated Thyroid Cancer Who Were Admitted for Radioiodine Therapy

ABSTRACT

PURPOSE: Severe hypothyroidism can cause abnormalities in numerous clinical chemical test results. We observed various reVersible changes of clinical chemical test results in patients with severe hypothyroidism who were admitted for radioiodine ablation therapy after total thyroidectomy. The purpose of this study was to describe and discuss the findings. METHODS: The study comprised 168 patients (24 males, 144 females, mean age 49+/-14 years) who underwent total thyroidectomy due to differentiated thyroid cancer and who were admitted for I-131 ablation therapy. Patients who had hepatic or renal dysfunction were excluded. RESULTS: Serum mean levels of aspartate transaminase, alanine transaminase, cholesterol, high density lipoprotein, lactic dehydrogenase, total bilirubin, indirect bilirubin, and creatinine were significantly increased to the upper normal range during severe hypothyroid state (serum thyroid stimulating hormone >30 uIU/ml). While serum levels of alkaline phosphatase (ALP), triglyceride (TG) and blood urea nitrogen (BUN) remained unchanged. Six patients who showed abnormal serum creatinine level during hypothyroid condition returned to normal after recovery of thyroid function. CONCLUSION: Results of clinical chemical tests for hepatic, lipid and renal function are often increased reversibly in severely hypothyroid patients. Reversible, abnormal serum creatinine levels may develop in some cases. Follow-up study is necessary in induced severely hypothyroid patients for radioiodine therapy to differentiate the reversibility of chemical tests.