DEFINITION: WHAT IS HYPOTHYROIDYSM?Hypothyroidism, commonly known as an underactive thyroid, is defined as the insufficient production of hormones by the thyroid gland. This dysfunction is the reverse of hyperthyroidism (overactive thyroid).The thyroid is a butterfly-shaped gland located in the neck, just below the Adam's apple. It secrets hormones (T3 and T4) that play a vital role in the body. They regulat the basic metabolism of body cells, and control the heart rate, muscle energy, mood, and body temperature.There are two forms of hypothyroidism. Congenital (or neonatal) hypothyroidism is present at birth. All newborns are screened for this as it can cause serious bodily developmental issues. Acquired hypothyroidism occurs later on in life as a result of various causes or factors.Hypothyroidism mainly affects women over the age of 50 years old. 3% of women and 1.5% of men are affected.SYMPTOMSSymptoms of hypothyroidism are relative and can be very similar to those of other conditions. Signs of hypothyroidism can sometimes take several years to develop and tend to manifest gradually, which makes it difficult to diagnose the condition. Common symptoms of hypothyroidism can include:- fatigue and weakness - weight gain- constipation- sensitivity to cold temperatures - depression- cramps and aching muscles- dry skin and brittle hair and nails- loss of sex drive - irregular or heavy menstruation amongst women Whilst the condition is usually diagnosed before later symptoms appear, further symptoms can occur if left untreated. Later symptoms can cause physical changes as well as complications such as:- raspy or low-pitched voice- sparse eyebrows - puffy appearance of the face- slow heart rate- anaemia - loss of hearing CAUSES OF HYPOTHYROIDISMThe main cause of hypothyroidism is Hashimoto's thyroiditis. It is an autoimmune disease resulting from an immune system dysfunction. This sends antibodies that destroy the cells of the thyroid, preventing the synthesis of T3 and T4 hormones.Hypothyroidism can occur as a result of thyroid-altering therapy done for issues such as thyroid cancer, thyroid nodule, or hyperthyroidism. In most cases, removal of the thyroid gland results in permanent hypothyroidism.In case of dietary insufficiency, iodine deficiency can cause swelling of the thyroid gland and the appearance of a goiter at the base of the neck. This cause is rare in developed countries because table salt now contains iodine that provides daily requirements.DIAGNOSIS AND TREATMENTIn order to avoid later complications, it is important to diagnose hypothyroidism as early as possible. Lowered levels of the thyroid hormones can change the way the body can process fats. This can lead to high cholestrol or heart problems such as angina. Hypothyroidism is diagnosed most accurately by means of a blood test. It can also determine whether a patient is likely to develop the condition in the future. The main form of treatment for hypothyroidism is a man-made form of the thyroid hormone called levothyroxine. This medication comes in the form of tablets to be taken daily as hormone replacement. It usually takes time to determine correct dosage whilst the body responds to the medication. After initial dosage, the patient will usually have follow-up blood tests to ensure optimum dosage. Once the patient begins the correct dosage, they will then have a blood test once a year in order to monitor hormone levels with the medication.