Hyperthyroidism

Hyperthyroidism is a condition characterized by overproduction of the thyroid hormones and speeding up body metabolism which may affect some of the body’s main functions such as heart rate, blood pressure, body temperature and weight.

Mechanism of the thyroid gland:

The thyroid gland is a small, butter-fly organ located in the front of the neck under the larynx and plays a major role in metabolism, growth and development of our body by secreting the thyroid hormones triiodothyronine (T3) and tetraiodothyronine (T4) into the bloodstream. One of the main building blocks of the thyroid hormones is iodine which is absorbed from food to the bowel and then carried to the thyroid gland to be used for production of thyroid hormones.

The Thyroid gland is controlled by another gland called, the pituitary gland, a small gland located at the bottom of the brain. The pituitary gland produces the thyroid-stimulating hormone (TSH) which signals the thyroid gland to secrete thyroid hormones. TSH levels are rising or falling according to our body’s needs for the thyroid hormones. Also, the thyroid hormones are attached in the bloodstream to transport proteins and to function properly, the thyroid hormones must be released from these proteins in the free forms, freeT3 and free T4. 

Normally, the thyroid gland secretes the exact amount of thyroid hormones needed to balance the metabolism of our body. However, certain disorders may cause the thyroid gland to produce  more thyroid hormones (Hyperthyroidism) or insufficient thyroid hormones (Hypothyroidism), resulting in faster or slower metabolic rate.

Symptoms of Hyperthyroidism:

There are many symptoms of hyperthyroidism which vary between individuals and may be mild or severe symptoms:

1. Nervousness
2. Muscle weakness
3. Fatigue
4. Heat intolerance
5. Increased heart rate
6. Hyperactivity
7. Sleeping problems
8. Irregular menstrual period
9. Goiter

Causes of Hyperthyroidism:

Hyperthyroidism attributes to many causes which include:  

1. Grave’s disease: It is the most common cause of hyperthyroidism which is an autoimmune disease caused by autoantibodies attacking the thyroid gland causing overproduction of thyroid hormones.
2. Excess iodine: some foods and medications are rich in iodine which stimulates the thyroid gland to overproduce thyroid hormones.
3. Thyroiditis: It is an inflammation of the thyroid gland due to viral infection, bacterial infection, postpartum thyroiditis, or certain medicines. This condition causes the thyroid gland to leak thyroid hormones into the bloodstream and may develop into hypothyroidism, as the thyroid gland will not be able to produce enough thyroid hormones.   
4. Thyroid nodules: Thyroid nodules appear as abnormal lumps on the thyroid gland and enhance the production of more thyroid hormones causing hyperthyroidism.
5. Tumors of the testes or ovaries: which may overstimulate the thyroid gland to produce thyroid hormones. 
6. Thyroid hormone medications: People who are under hypothyroidism treatment may take high doses of thyroid hormones medications and develop hyperthyroidism.

Risk factors:

Some factors increase the risk of developing hyperthyroidism which include:

1. Gender: being female
2. Age: older age more than 60 years old
3. Pregnancy: pregnant women or postpartum 5 month after birth may be at higher risk
4. Excess iodine: medicines and foods rich in iodine increase the risk.
5. Genetics and Family history: a family history of hyperthyroidism or autoimmune diseases as diabetes type 1 and rheumatoid arthritis increases the risk.

Complications:

If hyperthyroidism left untreated, it may result in serious complications which include:

1. Grave’s Ophthalmology: About one third of people with hyperthyroidism develop grave’s ophthalmology,which is thyroid eye disease that occurs when the immune system attacks the tissues and muscles around the eyes.
2. Skin Problems: Like grave’s eye disease, Skin dermopathy may result from autoimmune attack of the skin causing inflammation,redness,and swelling of the skin
3. Heart problems:Since thyroid hormones play a major role in regulating heart beats, hyperthyroidism may cause increased heart rate,which in turn may increase the risk of heart failure,stroke and blood clots.
4. Osteoporosis: Hyperthyroidism is interrelated with bone loss as it interferes with the incorporation of minerals inside the bone leading to bone fracture and osteoporosis.  
5. Pregnancy problems: Hyperthyroidism may affect both the pregnant women and fetus and increases the risk of preeclampsia, stillbirth and preterm birth.
6. Thyroid Storm: Long term untreated hyperthyroidism may lead to a life threatening condition called thyroid storm or thyroid crisis. It is characterized by exaggerated hyperthyroidism symptoms as fast heart rate, fever, and loss of consciousness.  

Diagnosis:

Blood tests are even used to diagnose hyperthyroidism and include:

1. TSH : It is the primary test to diagnose thyroid problems. TSH is secreted from the pituitary gland to regulate the secretion of thyroid hormones T3 and T4 from the thyroid gland. Imbalance of thyroid hormones in our blood stream mostly affects TSH level.
2. T3: Triiodothyronine: it helps to diagnose hypothyroidism or hyperthyroidism. High level of T3 can be observed in hypothyroidism
3. T4: Thyroxine: Its level can be high in patients with hyperthyroidism and can be used to diagnose hypothyroidism or hyperthyroidism and to monitor treatment of thyroid disorders.
4. FT3: Free T3 or free triiodothyronine: It measures the free form of T3 to eliminate the effect of proteins binding to T3.
5. FT4: Free T4 or free thyroxine: It measures the free form of T4 to eliminate the effect of proteins binding to T4.
6. Thyroid antibodies: They help to identify autoimmune thyroid disorders and include: 
   Anti thyroid peroxidase antibody (Anti-TPO)
   Anti thyroglobulin Ab
   Anti TSH receptor antibody.
7. Thyroglobulin: It is used for the diagnosis of thyroiditis and to monitor thyroid cancer.