If a blood test confirms hypo-or hyperthyroidism and verifies that you have switched between them, there could be several possible explanations. If you don't have a history of thyroid problems, the most common reason for a change in thyroid function is inflammation of the thyroid gland (thyroiditis).
http://newsnetwork.mayoclinic.org/discussion/thyroiditis-may-be-to-blame-for-switching-between-hypo-and-hyperthyroidism/
Hyperthyroidism can mimic other health problems, which may make it difficult for your doctor to diagnose. It can also cause a wide variety of signs and symptoms, including:
http://www.mayoclinic.org/diseases-conditions/hyperthyroidism/basics/symptoms/CON-20020986
When to see a doctor. If you experience unexplained weight loss, a rapid heartbeat, unusual sweating, swelling at the base of your neck or other symptoms associated with hyperthyroidism, see your doctor.
http://www.mayoclinic.org/diseases-conditions/hyperthyroidism/basics/symptoms/CON-20020986
If you're already being treated for a thyroid problem, and your thyroid function begins to shift between underactive and overactive, thyroiditis probably isn't the source of the problem. More likely, your medication is to blame.
http://newsnetwork.mayoclinic.org/discussion/thyroiditis-may-be-to-blame-for-switching-between-hypo-and-hyperthyroidism/
Both hypothyroidism and hyperthyroidism can be caused by autoimmune diseases, which occur when your body’s immune system misfires against its own organs, including the thyroid.
http://www.everydayhealth.com/thyroid-conditions/living-with-both-hypothyroidism-and-hyperthyroidism.aspx
An underactive thyroid (hypothyroidism) doesn't produce enough hormone. An overactive thyroid (hyperthyroidism) produces too much hormone. Symptoms may include unintentional weight gain or loss, persistent fatigue, palpitations, and sensitivity to hot or cold temperatures. But because other health problems cause similar symptoms, diagnosing hypothyroidism or hyperthyroidism based on symptoms alone is not possible.
http://newsnetwork.mayoclinic.org/discussion/thyroiditis-may-be-to-blame-for-switching-between-hypo-and-hyperthyroidism/
Symptoms wax and wane based on the type of antibodies that your body develops, Dr. Sood says. Some antibodies may indicate Grave’s disease (a form of hyperthyroidism) , but over time the antibodies may trigger Hashimoto thyroiditis (a form of hypothyroidism). “It is definitely possible,” says Dr. Lam. “The most common forms of hyperthyroidism and hypothyroidism are autoimmune-mediated.. They can’t occur as co-morbidities, or at the same time, but they can occur in the same person over the course of his or her lifetime, he explains.
http://www.everydayhealth.com/thyroid-conditions/living-with-both-hypothyroidism-and-hyperthyroidism.aspx
Graves’ disease is caused by antibodies in the blood that turn on the thyroid and cause it to grow and secrete too much thyroid hormone. This type of hyperthyroidism tends to run in families and it occurs more often in young women.
http://www.thyroid.org/hyperthyroidism/
It is not surprising then that some of the symptoms of hyperthyroidism are nervousness, irritability, increased perspiration, heart racing, hand tremors, anxiety, difficulty sleeping, thinning of your skin, fine brittle hair and weakness in your muscles—especially in the upper arms and thighs.
http://www.thyroid.org/hyperthyroidism/
Eye problems often improve without treatment. Signs and symptoms of Graves' ophthalmopathy include: 1  Protruding eyeballs. 2  Red or swollen eyes. 3  Excessive tearing or discomfort in one or both eyes. 4  Light sensitivity, blurry or double vision, inflammation, or reduced eye movement.
http://www.mayoclinic.org/diseases-conditions/hyperthyroidism/basics/symptoms/CON-20020986
symptoms of hyper and hypothyroidism
Weight gain or loss, persistent fatigue, palpitations, and sensitivity to hot or cold temperatures are the symptoms of hyper and hypothyroidism. The symptoms of hyper and hypothyroidism are weight gain or loss, persistent fatigue, palpitations, and sensitivity to hot or cold temperatures.