This results in palpitations, a rapid heart rate, agitation, difficulty tolerating heat, hand tremours and other problems. Too little thyroxin precipitates hypothyroidism, a slowing down of the accelerator. In this case, a lack of thyroxin triggers a decreased rate of oxygen consumption and lessened energy production. Patients complain of fatigue, poor concentration, weak muscles, dry skin, unexplained weight gain, difficulty tolerating cold and infrequent bowel movements. Diagnosis may be apparent only after several symptoms of the disease appear.
Hypothyroidism is the more common disorder and can occur at any time.
But it is more common after 50 years of age. And for reasons that are poorly understood, it strikes women five to 10 times more often than men. And in severe cases this deficiency can mimic senility. Some cases of hypothyroidism occur after thyroid surgery to treat an overactive thyroid or following treatment with radioactive iodine for the same purpose. But the majority of cases of hypothyroidism are due to what's known as Hashimoto's thyroiditis.