Thyroxine – Causes, Picture, Symptoms, Diagnosis and Treatment

You may have heard about thyroxine. It is the hormone in the body that is essential to maintain the regular function. But, in recent times, more people suffer from the imbalance of the thyroid hormone. The issue is more common than you think. The fact that it is also prevalent in developed countries like the USA makes you wonder about the severity of the issue. Therefore, thyroxine imbalance is not a problem that you can ignore. It is estimated that at least one in eight women can suffer from the issue at some point in their life. So, you need to pay attention to the changes in your body. The correct steps to rectify the issue can avoid the complications associated with it. Therefore, read ahead to gain more information about thyroxine.

What Is Thyroxine?

Thyroxine is one of the two major hormones secreted by the thyroid gland. It is responsible for the stimulation of oxygen in your body. So, the primary body function depends on the hormone. It can enhance the metabolic rates and have a major part in the growth. The thyroid gland secretes the thyroxine in the bloodstream. It has the following functions in your body:

  • Brain development
  • Proper Digestion
  • Heart Function
  • Bones Maintenance
  • Muscle Function

Chemical Structure Of Thyroxine

The thyroxine is formed in your body by the molecular addition of the iodine to the tyrosine (amino acid). The amino acid is bound to the thyroglobulin (protein). So, it is also known as 3, 5, 3′, 5′-tetraiodothyronine. Thyroxine is commonly referred to in the blood reports as T4. It is a very important hormone that creates a balance in your body for maintaining the functions. The excess or less secretion of the thyroxine can create imbalance leading to severe issues in your body. Therefore, you need to understand the significance of thyroxine. It will help you identify problems in the body associated with the irregular secretion.

What Is Thyroid?


Before knowing about the thyroxine, it is important to learn more about the gland that produces it. The thyroid is gland in your body that is located in the base of the neck. It has a butterfly shape and is a part of your endocrine system. So, it is made of glands that are significant for providing energy to all the organs in your body. The glands are helpful in producing, storing, and releasing the hormones that can control your body functions. The iodine in your food can aid in producing two main thyroid hormones:

  • T3: Triiodothyronine
  • T4: Thyroxine

The hormones are responsible for how your digestive system works and how your hearts beats. With the irregularity in the hormones, the body slows down. The glands that communicate with your brain to maintain the thyroxine and triiodothyronine are:

  • Hypothalamus
  • Pituitary Gland

The hypothalamus gland is responsible for the production of the TSH releasing hormone. The TSH releasing hormone triggers the pituitary gland that tells the thyroid glands to produce the T3 and T4 hormones. So, the thyroid gland produces TSH, which controls the excess or less release of T3 and T4 hormones.

Causes Of Irregular Thyroxine Levels

You have thyroid problems with the irregular secretion of the thyroid hormone. It is caused either due to the inappropriate TSH levels or complications in the thyroid gland. In both cases, the abnormal hormone levels cause an imbalance in the body. The deficiency and excess production of the thyroxine can lead to the following issues:


The underactive thyroid due to the deprivation of the thyroxine hormone is known as hypothyroidism. It affects women more compared to men. It can affect you after the age of sixty. But, many young people also suffer from hypothyroidism. It is easily discovered with the routine blood tests. Some symptoms also indicate the presence of the problems. The body needs the right level of T3 and thyroxine hormones to maintain its balance. Therefore, the low hormone production can cause imbalance. So, you need to take adequate steps to replace what your body lacks.

Reasons For Low Thyroxine Levels

The low T3 and T4 levels in the body suggests an underlying issue. The most common causes of hypothyroidism are:

Hashimoto’s thyroiditis


Hashimoto’s disease is the common cause of the hypothyroidism. The autoimmune disease attacks the thyroid gland. So, it leads to chronic inflammation of the thyroid gland. Your body has an immune system that protects the normal cells from getting attacked by a virus or bacteria. It sends fighter cells to destroy the harmful cells entered in the body. The autoimmune condition causes the body to confuse the normal cells as foreign ones. Therefore, your immune system attacks the healthy tissues.

Hashimoto’s disease causes chronic thyroid inflammation that reduces the secretion of thyroxine. It is a condition that is prevalent in more than one member of your family. So, if one person shows the signs of the disease, then it is better for others to check it. The condition is serious as it creates antibodies that can destroy significant parts of your thyroid hormone. Hence, getting the right medical treatment is necessary.

Pituitary Problems

The problem in the pituitary gland itself can cause less secretion of thyroxine hormone. The presence of a tumor can lead to the malfunctioning of the gland resulting in hypothyroidism.

Iodine Deficiency

Iodine is essential for making the thyroxine hormone. Therefore, the deficiency of it in the body can lead to hypothyroidism.

Hypothalamus Problems

The failure of the hypothalamus to secrete the thyroid stimulating hormone can result in low thyroxine levels.

Congenital Hypothyroidism

Some babies are born with the hypothyroidism issue. It happens due to the iodine deficiency, or in-born complications in the thyroid metabolism or the anatomical defect of the thyroid gland.

Certain medications and surgical removal of the gland can also result in the low thyroid levels. So, it can result in hypothyroidism.


It is the condition caused by the excess secretion of the thyroid hormones. The high levels of thyroxine are secreted into the bloodstream by the thyroid glands.

Causes Of Excess Secretion Of Thyroxine

Health problems can cause an imbalance in the thyroid hormones secretion. The different causes that lead to the hyperthyroidism in your body are:

Grave’s Disease

It is the most common cause that leads to excess thyroxine production in the body. So, the disease can trigger the immune system to produce an antibody. The antibody can make the thyroid gland overactive by stimulation. So, it produces high levels of thyroid hormone into the bloodstream.

Toxic Thyroid Adenoma

The issue arises with the growth of abnormal nodules of tissue in your thyroid hormone. It can cause abnormal secretion of thyroid hormones even when it is not necessary for the body.

Secondary Hyperthyroidism

It is a condition caused due to the abnormal functioning of the pituitary gland. So, it produces excess levels of TSH hormones that can increase the thyroxine levels. The main problem associated with the issue is the presence of a pituitary tumor. In rare cases, the pituitary gland can become unresponsive to the thyroid hormones. So, it no longer responds to the high hormone levels.


The inflammation of the thyroid gland is known as thyroiditis. It can lead to hyperthyroidism. You may suffer from temporary hyperthyroidism first, which is followed by hypothyroidism. But, it depends entirely on the type of thyroiditis.

Symptoms Of Thyroxine Problems

Depending on the type of problem you have, the symptoms vary. So, let us look into each one closely to understand its effects on your body.

Warning Signs Of Low Thyroxine Levels

The low thyroxine (T4) and T3 levels in the blood cause hypothyroidism. It results in the slowing down of your metabolism. So, you can experience symptoms like:

  • Forgetfulness or Confusion
  • Dry and Coarse hair
  • Constipation
  • Hair loss
  • Depression
  • Sluggishness/Fatigue
  • Weakness
  • Weight gain
  • Dry, scaly skin
  • Intolerance to cold climates
  • Enhanced menstrual flow in women
  • Muscle Cramps
  • Irritability
  • Slower heart rate

Complication Of Ignoring Hypothyroidism

You need to seek medical help to manage the symptoms of low thyroxine levels. The failure to do so can result in severe complications. So, you can experience your symptoms progressing into a rare form of hypothyroidism. It is known as myxedema and has the following symptoms:

  • Dulled mental processes
  • Low body temperature
  • The condition your heart cannot pump enough blood to meet your body’s needs (congestive heart failure)

The issue can further escalate into myxedema coma due to severe hypothyroidism with excess stress. It can also become worse with trauma, infection, col temperatures, and the use of medications (sedatives). You can experience seizures, loss of consciousness, and slow breathing.

Warning Signs Of High Thyroxine Levels

The excess thyroxine and T3 levels circulating in your blood can cause hyperthyroidism. The condition can trigger symptoms like:

  • High blood pressure
  • Elevated body temperature
  • Heart palpitations
  • Profuse Sweating
  • Nervousness
  • Agitation
  • Osteoporosis
  • Hand tremors
  • Sleep interruption
  • Restlessness
  • Tired/Fatigue
  • Weight loss
  • Frequent bowel movements
  • No menstrual cycle
  • Puffiness around the eyes
  • Sensitivity to light

Complications Of Hyperthyroidism

Ignoring the hyperthyroidism can lead to severe complications. You can experience more severe problems like:


Not taking treatment for the Grave’s disease (the common cause of hyperthyroidism) can lead to goiter. It is the bulging of the neck due to the enlargement of the thyroid gland. So, you can feel severe discomfort. It can also lead to your eyes bulging out, which doubles your vision.

Thyroid Storm

Another complication that arises due to avoiding high levels of thyroxine is the thyroid storm. It is the life-threatening complication due to the hyperactivity of the thyroid gland. Therefore, you can experience symptoms like:

  • Fever
  • Coma
  • Confusion
  • High blood pressure
  • Shock
  • Weakness
  • Irregular heartbeat
  • Mood swings
  • Muscle wasting
  • Jaundice
  • Restlessness

Thyroid storm is a medical emergency that requires immediate treatment. It is also triggered by infection, trauma, surgery, pregnancy, uncontrolled diabetes, labor, and taking high doses of thyroid medication.

Diagnosis Of Thyroxine Fluctuations

The thyroid is quite common today. But, it does not mean that you can ignore it completely. Getting the treatment after seeing the symptoms is ideal to prevent any complications. Once you seek an appointment with your doctor, you may have to undergo the following for a proper diagnosis.

Medical History

Your doctor may ask out your medical history to know the symptoms or issues you suffer. It is valuable to eliminate the possibility other underlying diseases with similar signs.

Physical Examination

It is to confirm if you have the thyroid problems. Your doctor may order additional tests to confirm the thyroxine abnormality.

Blood Test

Your blood work can shed light on the T3 and T4 levels in our body. The TSH is also measured to identify the problem. Based on T3 and Thyroxine levels, the type of thyroid disease is detected. The serology tests are conducted by your doctor to identify the antibody levels associated with the hyperthyroidism and hypothyroidism.

Functional Stimulation Test

Your doctor can suggest the test to differentiate if your thyroid glands or the pituitary glands cause the medical issue in your body.

Ultrasounds/Nuclear Thyroid Scan

The visual, as well as function examination of the thyroid glands or nodules, can offer an idea about the tumor. If your doctor suspects malignancy, it is sent for biopsy to test the presence of cancerous cells.

Depending on the diagnosis, your doctor can devise a treatment plan. Following the treatment plan is necessary to alleviate the symptoms and avoid complications.

Treatment Of Thyroxine Imbalance

Depending on the type of thyroxine issue you face, the doctor can adopt a proper treatment plan. With the proper diagnosis, it is easy to determine if you have excess or insufficient thyroxine secretion. The treatment varies with the type.

Hypothyroidism Treatment

The doctor can opt for the thyroid hormone replacement therapy to balance the thyroxine levels in the body. Hence, you need to take synthetic thyroid hormone to create balance in the hormone levels. The synthetic thyroxine medication is available in the pills to form for the convenience. You can take tablets like levothyroxine according to the doctor’s orders. The hormone replacement therapy is a life-long treatment. So, you need to continue taking the tablets religiously for your whole life.

The thyroid replacement therapy has no side-effects. But, taking the higher doses than prescribed by your doctor can cause serious issues in your body. So, you may experience problems like:

In such cases, you need to contact our doctor immediately. It is important that you follow the dose prescribed by your doctor correctly. Normally, the initial dose or the change in the dose takes effect after 4-6 weeks. You need to get your blood tested for the thyroxine levels every three months to know it if it within limits. Pregnant women with low thyroxine need to get tested to adjust their dose as they need 50% more than their normal dosage. Hence, getting a general physician’s opinion is highly necessary.

Hyperthyroidism Treatment

The hyperthyroidism treatment focusses on limiting the excess thyroxine production to the bloodstream. Therefore, your doctor may adopt the following treatment methods to control the thyroid hormone levels.

Radioactive Iodine

The method is highly effective in more than 80% of the cases to bring the hyperthyroidism under control. The radioactive iodine can destroy some parts of your thyroid gland. Your doctor may give you one dose of the radioactive iodine to bring the excess thyroxine levels under control. It is provided to you in low doses to avoid any damage to the other parts of the body. Pregnant women cannot undergo the treatment method as it destroys the thyroid gland of the fetus.

The treatment is then followed by providing you with larger doses of regular iodine. The regular iodine causes no damage to the thyroid glands. But, it can block the release of thyroxine hormones. In most cases, the iodine is given an emergency treatment during a thyroid storm. So, it is ideal to reduce excess thyroid hormone production before the thyroid surgery.

Anti-Thyroid Medications

The anti-thyroid medications block the production of excess thyroxine. So, it helps your body bring the hyperthyroidism under control. Medications like methimazole or Propylthiouracil (PTU) can control the issue within 6 to 12 weeks. It is effective in reducing the production of thyroid hormones. You must take the medications in small doses. The larger dose can cause issues like:

  • Liver Cell Injury
  • Loss Of Taste Sensation
  • Skin Rashes
  • The decrease in Blood Cell Production (Bone Marrow)
  • Nausea


If the other treatment does not improve the symptoms, then our doctor may suggest surgery. The surgery removes the thyroid glands. So, the thyroidectomy procedure is the last resort to control the excess thyroxine production. It is also suggested with the presence of cancerous nodules or with the non-cancerous nodules causing problems. The nodules with fluid can also pose issues. So, it may restrict your swallowing or breathing. In such cases, surgery is the option to alleviate the problems. Once the thyroid gland is removed, you need to start treatment for hypothyroidism.

Other Medications

Your doctor may also prescribe you medications to control other symptoms of the thyroid problem. It can help you manage the symptoms like:

  • Anxiety
  • Nervousness
  • Increased Heart Rate
  • Shakiness

Understand that it will only control the associated symptoms and not thyroid dysfunction.


Thyroxine problems are easy to determine with simple blood tests. Your doctor can suggest a good treatment to balance the hormone levels. Do not oversee the symptoms. So, you need to take adequate steps to overcome the problem without making it more complicated. Timely interference can save your health and avoid dangers.

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