Hi Erin. I have Hypothyroidism, diagnosed in 2000 when I was 24 years old. I have been taking Synthroid for 8 years.
First of all, why do you think you have a thyroid problem? If you have symptoms-- which are varied, depending on whether you have hypo or hyper--you need to make an appointment with your doctor to have labs done--TSH and Thyroid panels (T3 & T4) to determine if you do indeed have a problem.
If you have hypothyroidism, your TSH level, or thyroid stimulating hormone, will be too high. The stimulating hormone does just that--it tries to "stimulate" your thyroid to secrete the proper amount of hormones. Some symptoms include:
Fatigue
Weakness
Weight gain or increased difficulty losing weight
Coarse, dry hair
Dry, rough pale skin
Hair loss
Cold intolerance (can't tolerate the cold like those around you)
Muscle cramps and frequent muscle aches
Constipation
Depression
Irritability
Memory loss
Abnormal menstrual cycles
Decreased libido
Treatment for hypothyroidism is medication, such as Synthroid, or levothyroxine is the generic name. You would then go back to have bloodwork done periodically to make sure the dosage of medicine is working.
If you have hyperthyroidism, your thyroid is in overdrive, secreting way too much--and therefore your TSH level will be low. In severe cases, the thryoid has to be actually "killed" with radiation. Some symptoms include:
Palpitations
Heat intolerance
Nervousness
Insomnia
Breathlessness
Increased bowel movements
Light or absent menstrual periods
Fatigue
Fast heart rate
Trembling hands
Weight loss
Muscle weakness
Warm moist skin
Hair loss
Staring gaze
This would also result in having to have medication because the thyroid is no longer producing ANY hormones. I have a close friend who's had this done, and she actually takes a higher dose of medicine than me.
Now as for your original question--can it kill you if left untreated?
If your thyroid function is severely out of whack, you can end up with a "Thyroid Storm" or a "Myxodemic Coma". Since I've been long winded, I won't go into great detail, but you can find information easily on the web. You need to get educated on the disease, and then make an appointment with your MD. I wouldn't play around with it, and if you do have a problem, you will feel much better once it is under control. I had gotten to the point where I could hardly get out of bed and my doctor thought I had chronic fatigue syndrome until I suddenly gained 23 pounds in 2 weeks and he decided to check my thyroid panel. After starting medicine, my symptoms diminished greatly.
So get yourself checked out. If you find that you do have a problem, it is not the end of the world and it can be treated. True, if you have to take medicine, you will have to take it every day for the rest of your life. But it becomes routine, just like brushing your teeth--
Hope this is helpful~~