What is hyperthyroidism?
Hyperthyroidism, also known as overactive thyroid, is a condition in which the thyroid gland makes excess thyroid hormone. Hyperthyroidism causes the body’s metabolism to increase significantly leading to rapid weight loss, irregular or fast heartbeat, sweating, irritability or nervousness.
The thyroid gland is a butterfly-shaped gland present in the front of the neck. It controls metabolism, or the way a body turns food into energy and also has effects on the heart, cholesterol, bones and muscles. Although, the gland in itself is quite small, it has a huge impact on a person’s health as every aspect of metabolism is controlled by thyroid hormones.
What are the causes of the disorder?
The thyroid produces two main hormones, thyroxine (T4) and triiodothyronine (T3), which regulate the rate at which the body consumes carbohydrates and fats, maintain body temperature, influence heart rate, and also regulate protein production. Further, the rate at which thyroid releases T3 and T4 is governed by the pituitary gland and the hypothalamus, both in the brain.
The hypothalamus directs the pituitary gland to release thyroid-stimulating hormone (TSH), and the existing levels of T3 and T4 in the bloodstream again determine the amount of TSH released. Also, the thyroid gland releases T3 and T4 hormones depending on the amount of TSH it receives. Thus, if the thyroid gland is diseased and releases excess T3 and T4 on its own, the levels of TSH will drop below normal, and vice versa.
In hyperthyroidism, the thyroid gland releases excess T3 and T4 hormones. A number of conditions can cause hyperthyroidism, which include Grave’s disease, toxic adenoma, Plummer’s disease (toxic multi-nodal goitre) and thyroiditis.
What one needs to know about symptoms or signs?
Common symptoms of hyperthyroidism include:
- Poor concentration
- Goitre (or visibly enlarged thyroid gland or), thyroid nodules
- Frequent bowel movements
- Increased appetite
- Heat intolerance
- Increased sweating
- Irregular menstrual cycles in women
- Restlessness, nervousness
- Sleep disorders
- Weight loss
Sometimes, patients may also experience an uncommon problem known as Grave’s opthalmopathy that affects the eyes. The eyeballs protrude beyond their normal protective orbits and may even bulge out of them, causing the front surface of eyeballs to become dry. This results from swelling of tissues and muscles behind the eyes. Signs of Grave’s opthalmopathy include
- Red or swollen eyes
- Protruding eyeballs
- Discomfort or tearing in one or both eyes
- Blurred vision, inflammation, reduced eye movement, sensitivity to light
Which specialist should be consulted in case of signs and symptoms?
Patients suspected of having hyperthyroidism must consult an endocrinologist (doctor who specializes in hormone glands of the body and its disorders). Those with eye involvement may also be referred to an ophthalmologist (eye doctor).
What are the screening tests and investigations done to confirm or rule out the disorder?
- Physical examination: A physical exam by the doctor will check for high blood pressure, increased heart rate, enlarged thyroid gland, swelling around eyes, and tremors in hands.
- Blood tests: Blood tests are carried out to measure the levels of thyroid hormones (TSH, T3 and T4), cholesterol and glucose levels.
- Radioactive iodine uptake: The patient is given a small dose of radioactive iodine, which accumulates in the thyroid gland over time since the gland uses iodine to synthesise hormones. Patient is checked after two, six and 24 hours to determine the level of iodine absorbed by the thyroid gland. A high uptake of the radioactive iodine indicates excess production of thyroxine and hyperthyroidism.
- Thyroid scan: During this test, the patient is injected with a radioactive isotope into the vein present on the inside of elbow or vein in the hand. The patient is then asked to lie on a table with head stretched back as a camera produces images of the thyroid gland on a computer screen.
What treatment modalities are available for management of the disorder?
Treatment for hyperthyroidism depends on the exact cause and severity of symptoms. It may be treated in the following ways:
- Anti-thyroid medication – These medications prevent the thyroid gland from producing excess hormones, reducing the symptoms of the disorder.
- Radioactive iodine – Radioactive iodine is taken orally, where the thyroid gland absorbs it. This causes the gland to shrink. Symptoms subside within three to six months. However, this treatment can cause the thyroid gland to become underactive, and patient may require medication to replace thyroxine.
- Beta-blockers – Though these drugs are generally used to treat high blood pressure, they can reduce a rapid heart rate and prevent palpitations.
- Surgery – The surgery that removes most of the thyroid gland is called thyroidectomy. The risks involved in undergoing this treatment are damage to vocal cords and parathyroid glands. This is used mostly in cases when a patient cannot tolerate anti-thyroid drugs or is unable to undergo radioactive iodine surgery.
What are the known complications in management of the disorder?
Complications of hyperthyroidism include:
- Heart issues like rapid heart rate, abnormal heart rhythm, heart failure
- Surgery complications like scarring of neck, hoarseness of voice due to damage to voice box, low calcium levels due to damage to parathyroid levels and hypothyroidism.
What precautions or steps are necessary to stay healthy and happy during the treatment?
The most important element after diagnosis of hyperthyroidism involves receiving required medical attention. During the course of treatment too, a patient can cope with the condition and aid healing by practising certain habits:
- Regular exercise – Helps improve cardiovascular system and muscle tone, reduce appetite and increase energy levels.
- Relaxation techniques – Helps in maintaining a positive attitude, especially as stress is a risk factor in Grave’s disease.
What are the dietary and physical activity requirements during the course of the treatment?
Extra calories and including protein in diet is beneficial for patients as they cope with weight loss and muscle wastage. Hyperthyroidism can lead to thinning of bones and it is important to get enough calcium and vitamin D to prevent osteoporosis.
“Hyperthyroidism,” MedlinePlus, NLM, NIH, https://www.nlm.nih.gov/medlineplus/ency/article/000356.htm
“Hyperthyroidism,” WebMD.com, https://www.webmd.com/a-to-z-guides/hyperthyroidism-topic-overview
“Hyperthyroidism (overactive thyroid),” MayoClinic.com, Mayo Clinic Staff, https://www.mayoclinic.org/diseases-conditions/hyperthyroidism/basics/definition/con-20020986
“Overactive thyroid,” NHS.uk, https://www.nhs.uk/Conditions/Thyroid-over-active/Pages/Introduction.aspx
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