Hyperthyroidism may have vague symptoms especially at the onset and this is one of the commonest reasons for the diagnosis being missed. However, if these symptoms persist over a period of time, a physician must be consulted and the condition evaluated with laboratory tests.

Subclinical hyperthyroidism, on the other hand, is a state in which the person does not present with any symptoms of hyperthyroidism but laboratory tests indicate abnormal thyroid hormone levels.

Here is a list of some of the common presenting symptoms of hyperthyroidism:

Excess appetite

Weight loss in spite of eating well

Goiter (enlarged thyroid gland)

Tremors

Muscle weakness

Fatigue

Palpitations

Nervousness

Intolerance to heat

Sleeplessness

Breathlessness

Increased frequency of stools

Hair loss

Excessive perspiration and warm moist skin

Rapid heart rate

Abnormalities of menses – irregular cycles, scanty flow

Staring gaze

Reduced concentration

Brittle nails

Decreased libido

Exophthalmos (swelling of the tissue behind the eyeballs leading to protrusion of the eyeball)

Double vision

All these symptoms may not be present at the same time in the same person and the combination of symptoms varies from person to person.

Thyroid storm or Thyrotoxicosis is a life-threatening complication of hyperthyroidism and it may present as a state of high fever, vomiting, extreme irritability, delirium and coma. It is usually triggered by a stressful event and typically has a sudden onset. Patient is generally found to have a high blood pressure and rapid heart rate. If left untreated, Thyrotoxicosis can be fatal.