TPO stands for thyroid peroxidase, an enzyme found in the thyroid, which plays a key role in hormone production. A blood test can detect the presence of antibodies to TPO, which suggests that the thyroid dysfunction is autoimmune in nature. That's certainly the case with Hashimoto's thyroiditis, where the immune system's attack on the gland interferes with its ability to produce the vital hormones that regulate our metabolism.
Deficiency of thyroid hormones, known as hypothyroidism, causes a general slowing down of the whole body. You may feel weak and tired all the time. You may gain weight (because your body isn't burning calories at its normal rate). Skin may become dry, rough and pale, and you may notice hair loss. Other frequent symptoms are cold sensitivity, muscle or joint aches, constipation, depression, irritability, memory loss, abnormal menstrual cycles with heavy flow, and decreased sex drive.
As far as iodine supplements are concerned, you heard correctly: you should not take them. An iodine deficiency plays no role in Hashimoto's thyroiditis, so there is no reason to supplement. In fact, it's best to avoid kelp pills and any dietary supplements that list iodine as an ingredient.
Since autoimmune diseases tend to flare up and subside in response to emotional ups and downs, I recommend experimenting with some type of mind/body treatment - hypnosis, psychotherapy, and guided imagery therapy. You might also consult a practitioner of Chinese medicine in addition to working with a conventional endocrinologist. In most cases, Hashimoto's thyroiditis eventually "burns out," leaving you with an underactive thyroid and the need to stay on thyroid hormone replacement.
Andrew Weil, M.D.