Diagnosis of Hyperthyroidism

Hyperthyroidism or thyrotoxicosis is a clinical condition characterized by an abnormal increase of thyroid hormones. Thyroid gland is located below and behind the ligament protrusion of the neck, commonly known as the ‘Adam’s apple’. The main function of thyroid glands is to regulate fast energy utilization by the body, sustain a balance between other hormones and also metabolism of proteins. Thyroid gland secretes two important hormones, thyroxine (T4) and triiodothyronine (T3). Another major role that thyroid hormones play is in the regulation of metabolism that affects, directly or indirectly, other functions of the body. When the body produces abnormally high levels of thyroid hormones, the condition is called as hyperthyroidism. Diagnosis of hyperthyroidism is generally done be a physician after noting the signs and symptoms of the patient and necessary physical examination.

There is a difference between signs and symptoms. Symptoms are those that are reported by a patient to the doctor, whereas, signs are those that are observed the doctor. Thus, in the diagnosis of hyperthyroidism, both, signs and symptoms are equally important. Symptoms such as unexplained and sudden weight loss, intolerance to heat, excessive sweating, fatigue, reduced energy and sleeping disorders are commonly reported to the physician. The physician would then note distinctive signs like body temperature, heart rate, swelling over the neck etc. which are important in the diagnosis of hyperthyroidism. Apart from the signs and symptoms, the physician also takes a detailed case history taking in to consideration the past history of the presenting complaints, family history for thyroid disease, and other such relevant aspects. All these are important in establishing a provincial diagnosis of hyperthyroidism. Only when the general practitioner is convinced that the cause is related to thyroid disorder, he may suggest for some blood investigations. Levels of thyroid hormones, T3 and T4, are measured in the laboratory. If the levels are above normal (T3 greater than 2 micro grams per liter and T4 greater than 20 nanograms per liter), it can signify hyperthyroidism.

Another blood test that may be useful in the diagnosis of hyperthyroidism is the measurement of thyroid stimulating hormone (TSH) which is secreted by the pituitary gland. TSH basically stimulates the thyroid gland to produce thyroid hormones. Thus, lower the thyroid stimulating hormone level, higher is the chance of hyperthyroidism. Frequently used test in the diagnosis of hyperthyroidism is the radioimmunoassay (RIA) which measures the T3 and T4 serum levels. An additional radiometric assay of the thyroid stimulating hormone may be essential in the diagnosis of hyperthyroidism. Another test that is prescribed in case of normal thyroid gland function but high level of T3 and T4 is the thyroid binding globulin (TBG) test. Apart from blood tests, iodine uptake is measured to verify the amount of iodine being absorbed by the body. This test is done on an empty stomach. Thyroid scanning, if required, is simultaneously done during the iodine uptake test.

Scanning of the thyroid glands helps in the diagnosis of hyperthyroidism and determines the presence or absence of tumors or nodules that may be modifying the thyroid function. In summary, the physician takes a detailed case history, does physical examination, recommends blood tests, scanning and other biochemical tests that may be required depending on the cause and condition of the thyroid gland. All these measures help in ascertaining or ruling out the diagnosis of hyperthyroidism. One must understand that right diagnosis is usually just the beginning in framing a treatment plan. Once the diagnosis of hyperthyroidism is confirmed, appropriate medication and continuous monitoring may become necessary. Apart from medication, a healthy lifestyle, physical activity and proper diet, all contribute in keeping this condition under control. Understanding the symptoms and reporting them to a physician is vital.

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