Thyroid hormones in diabetic ketoacidosis before and after therapy

Fifteen IDDM patients were evaluated for thyroid hormone abnormalities before and after control of diabetes mellitus/ketoacidosis. Blood sugar mean +/- SEM mg/dl on admission was 430 +/- 20.3 and after therapy fasting and post prandial blood sugar values were 120 +/- 14.5 and 150 +/- 20.2 respectively. GHb mean +/- SEM % on admission was 15.2 +/- 0.36. Serum T3 mean +/- SEM ng/dl of 0.36 +/- 0.04 was in hypothyroid range and rT3 mean +/- SEM ng/ml 0.40 +/- 0.6 was significantly raised (P < 0.001) before therapy. After metabolic control both T3 and rT3 became normal. T4 concentration mean +/- SEM meg/dl of 5.5 +/- 0.7 was well within normal range before therapy and rose to mean +/- SEM mcg/dl 8.8 +/- 0.5 after therapy (P < 0.01). TSH response to TRH was blunted in uncontrolled state. It is concluded that peripheral changes in T3, T4 and rT3 (low T3, high rT3 and low or normal T4) occurred in uncontrolled diabetic state during ketoacidosis. TSH response to TRH was blunted due to suppression of hypothalamic pituitary thyroid axis which takes more than a week for complete recovery.