Increased production of thyroid hormones causes the body functions to speed up. The symptoms depend upon the severity of the disease, age of the person and the cause of hyperthyroidism. Some of the signs and symptoms of hyperthyroidism are:

  • Weakness and fatigue
  • Sweating and intolerance to heat
  • Skin is warm and moist because of dilatation of blood vessels in the skin and increased sweating
  • Hair is finesilky and friable; hair loss may be excessive
  • Nails are soft and friable. A characteristic finding is Plummer’s nails in which there is separation of the nail from the nail bed (onycholysis). At times there may be clubbing and swelling of fingers (acropachy)
  • Frequent bowel movements occasionally diarrhea
  • Weight loss in spite of increased appetite and food intake
  • Protrusion of eye ball (exophthalmos)
  • Decreased sleep
  • Menstrual irregularities. Periods either become less frequent or stop altogether
  • Cardiovascular (heart) effects include increased heart rate, myocardial excitability and arrhythmias (abnormal heart rhythm as in atrial fibrillation, premature ventricular contractions etc.)
  • Central nervous system effects include:
    • emotional lability which causes the person to lose temper easily and have episodes of crying by slightest provocation.
    • nervousness characterized by restlessness, shortness of attention span and a compulsion to move about.
    • hyperkinesia (an abnormal increase in muscular activity) as a result person cannot stand still, taps the foot or shifts positions frequently.
    • fine finger tremors at rest.

On the basis of the description of symptoms by the patient hyperthyroidism may be suspected if the following characteristics such as weight loss, nervousness, palpitations, muscle weakness, excessive sweating, bulging eyeballs are seen; particularly in females (20-50 years).

  • Thyroid storm: It is a sudden, extreme over activity of the thyroid gland. It is a life threatening emergency necessitating prompt treatment. It may be precipitated by infection, injury, surgery, poorly controlled diabetes, fear, pregnancy/labor, discontinuance of thyroid medication, or other stresses. Mortality (death) rate is 50-75%. Notable features include:
    • high fever
    • tachycardia (rapid heart rate)
    • mood swings
    • altered consciousness (even coma)
    • other symptoms may include vomiting, diarrhea, enlarged liver with mild jaundice

In old people symptoms may not be so marked (masked or apathetic hyperthyroidism). They may simply complain of weakness and sleepiness. They appear to be confused and depressed. However heart problems like abnormal heart rhythm are common in older people and they may suffer from heart failure or angina (pain in the chest).