I am a hypothyroid patient. I have had hypothyroidism for 20 years. It is hereditary. Recently, I got my blood tested. My TSH level (RIA) was 20 and my sugar level was 166 mg/dl [9.2 mmol/L]. This is the first time that my sugar level was this high. In the past, I did not have symptoms of diabetes. Is my diabetes problem related to my hypothyroid or not? If it is, how? What treatment should I have?

First, it sounds like your TSH is too high and suggests you are not replaced at the proper level with your dose of thyroid hormone, that is, providing you have taken your medications as scheduled. With regard to your glucose level of 166 mg/dl [9.2 mmol/L], this needs to be qualified in terms of when the sample was drawn. If the test was drawn fasting (having eaten nothing over the night and the blood sample drawn in the morning), this level is too high. Two fasting samples greater than 126 mg/dl [7.0 mmol/L] makes the diagnosis of diabetes. If this were a random sample, having been taken within an hour or two of eating, you need to have the sample redrawn after fasting. The undertreatment of the thyroid is not likely to have brought on the elevated blood sugar. It does happen that type 1 diabetes and primary hypothyroidism occur more frequently in the same person because both are diseases associated with overactive immune systems. Hypothyroidism is not necessarily related to type 2 diabetes, the most common form of diabetes.

JTL