What should you know about hyperthyroidism underactive?

Hyperthyroidism means the thyroid is releasing too much hormone. An underactive thyroid, or hypothyroidism, means the body is receiving too little. Radioactive iodine and thyroid surgery can reduce thyroid activity, and antithyroid treatment may occasionally need adjustment. Thyroiditis can also move through an overactive phase into a low-thyroid phase as stored hormone is used up.

The symptoms point in different directions but can overlap. Palpitations, sweating, heat intolerance and difficulty sleeping fit raised thyroid activity; tiredness, feeling unusually cold, constipation or dry skin are more suggestive of low activity. Blood tests, not symptoms alone, establish which state is present.

Tell your clinician if symptoms change after starting or changing thyroid treatment. Keep appointments for repeat thyroid tests and take replacement hormone or antithyroid medicine at the instructed time. Do not add iodine or change the dose to correct symptoms yourself. Record new fatigue, cold sensitivity, bowel changes, racing heartbeat or sweating so the pattern can be reviewed.

Seek urgent help for chest pain, fainting, severe breathlessness, confusion, a very fast heartbeat or a high temperature with severe agitation. Arrange prompt review if you develop marked weakness, increasing sleepiness, worsening palpitations, or cannot take prescribed medicine. Pregnancy or plans for pregnancy should be discussed early because thyroid levels need careful management.

Ask whether your current results show high or low thyroid activity, whether treatment could explain the change, when testing will be repeated, and what symptoms should prompt an earlier review.