Thyroiditis Types Pathophysiology Symptoms and Treatment

What is thyroiditis?

Thyroiditis is a medical term referring to a group of thyroid disorders characterized by inflammation of the thyroid gland and overactive or underactive thyroid (hyperthyroidism or hypothyroidism). The thyroid gland is located at the center of the neck wrapping around the trachea.[1]

Hyperthyroidism

What is hyperthyroidism?

Hyperthyroidism is a common disorder characterized by overactive thyroid that produces an excessive amount of thyroid hormones (T4 and T3). This, in turn, increases circulating levels of thyroid hormones, speeds up the rate of cellular metabolism, and increases the speed of metabolic reactions leading to the formation of a thyroid goiter.[1]

Hyperthyroidism is characterized by an increase in the overall production of thyroid hormones (T4 and T3)

What are the main symptoms of hyperthyroidism?

People with hyperthyroidism may experience some or all of the following symptoms:

1. Palpitations (increased heart beats)
2. Hypersensitivity
3. Wrinkled Fingertips (Shriveling skin on the fingers and toes)
4. Loss of weight
5. Enormous appetite (Polyphagia or hyperphagia)

Treatment

How to treat hyperthyroidism at home?

Levothyroxine is the drug of choice for the treatment of hypothyroidism and to suppress thyroid goiters, the average dose of levothyroxine needed is about 1.66 mcg per kg of body weight (about 0.75 mcg per pound of body weight). So optimally the patient should take one tablet 50 mcg levothyroxine at 4 o’clock in the morning each day. The symptoms start to decrease in a period of 1-2 weeks.[18][19][20]

Causes

What are the main causes of hyperthyroidism?

1-Graves’ disease (GD) is the second most common thyroid disorder after Hashimoto thyroiditis and the most common cause of hyperthyroidism worldwide, it is an autoimmune disease triggered by bacterial infection. However, in most cases (up to 90%), the disease is triggered by E coli infection, the outer surface of E coli bacteria have outer-membrane porin F protein (YE protein and its epitope) that shares cross-immunogenicity with LRR (leucine-rich repeat domain) of TSHR (Thyroid Stimulating Hormone Receptor). The epitope recognized by Antithyrotopin Receptor Antibodies is located in porin F protein within the amino acid sequences of 190-197, and the polyantibody against porin F protein showed autoantibodies activity. YE porin F is involved in the production of autoantibodies and plays a key role in the pathogenesis of GD through sequence similarities between foreign (pathogen-derived peptides) and self-peptides (TSHR) that results in the cross-activation of autoreactive T or B cells (molecular mimicry).[2][3][4] T-lymphocytes respond to bacteria and other pathogens in a similar manner; However, autoreactive T- and B-cells receptors recognize and detect Peptide analogs to pathogenic epitopes of the TSH hormone receptors, so the T-cells attack the body’s own healthy cells and tissues and treat them as a foreign body. The immune cells attack the Tsh receptors and make antibodies against them, these anti-thyroid autoantibodies (anti-thyroid peroxidase antibodies, thyrotropin receptor antibodies and thyroglobulin antibodies) are targeted against one or more components on the thyroid. After entering the thyroid follicles (thyroid follicular cells) the anti-Tsh receptor antibodies stimulate the thyroid to produce more thyroid hormones. If left untreated, Graves’ disease can lead to Graves’ eye disease, one of the main causes of exophthalmos of the eyes.

2- The presence of minor aplastic glands inside the major thyroid glands that are responsible for the production and secretion of thyroid hormones T4 (thyroxine) and T3 (triiodothyronine) within the existing follicular cells in the aplastic glands. This pathology occurs mostly in women older than 50.

3- Rarely, the condition can be caused by Thyroid-stimulating hormone tumors. The overproduction of TSH (thyroid-stimulating hormone) can lead to an overactive thyroid.

Symptoms of Hyperthyroidism

What are the symptoms of hyperthyroidism in humans?

People with hyperthyroidism often have some or all of these symptoms:

1- Heat intolerance, a feeling of being overheated
2- High blood pressure (hypertension)
3- Palpitations and increased heart rate (increased pulse)
4- Lost weight and increased appetite
5- Diarrhea with an increased digestion rate
6- Muscle atrophy (muscle wasting or loss in the muscular block)
7- Hypersensitivity (intolerance)
8- Emotional lability and a change in the personality
9- Hypersomnia
10- Poor ovarian reserve in women
11- Impotence in men
12- Exophtalmos (proptosis, a bulging of the eye anteriorly out of its orbit)

13- Pretibial myxedema, a thyroid dermopathy characterized by localized skin lesions

14- Thyroid goiter
15- Excessive sweating
16- High-heart rate during sleep (rapid heart rate while sleeping)
17- Diabetes mellitus
18- Malabsorption
19- Intestinal parasitism

Hyperthyroidism Diagnosis

How to diagnose hyperthyroidism in humans?

Diagnosis is made based on clinical symptoms and diagnostic test results

Common diagnostic tests include:

1- Blood test, a Thyroid Stimulating Hormone (TSH) blood test may show high thyroxine levels (T4) and low levels of TSH

2- Radionuclide thyroid scan is a type of nuclear medicine imaging that assess the activity and structure of the thyroid, it is commonly used in the diagnosis of hyperthyroidism. Thyroid scans and uptake tests use radionuclides (special chemicals), which provide information about the function and structure of the thyroid gland.

What causes the thyroid gland to enlarge?

Several factors can cause thyroid goiter (Thyroid Swelling) including hyperthyroidism (an overactive thyroid gland), hypothyroidism (an underactive thyroid gland), pregnancy or the menopause and, less commonly, thyroid goiter can be caused by hormone changes during puberty. Iodine is a chemical component of the hormones produced by the thyroid gland, intrathyroidal iodine is 25 times more concentrated than that found in the tissues in the rest of the body. Iodine deficiency (the lack of iodine) leads to insufficient production of thyroid hormones, which stimulates the pituitary to secrete more TSH hormone, which, in turn, stimulates the thyroid gland to produce T4 (thyroxine) and T3 (triiodothyronine) and promotes angiogenesis, capillary sprouting and blood vessel maturation, this in turn results in the formation of a thyroid goiter associated with hyperthyroidism.[1][5][6]

Treatment of thyroid goiter in this case can be achieved routinely by eating fish high in omega-3s and containing large amounts of iodine and salt.

Hypothyroidism

What is hypothyroidism?

Hypothyroidism (underactive thyroid), is a common endocrine disorder in which the thyroid is unable to produce enough thyroid hormones (it produces less thyroid hormone than it should), which, in turn, causes the metabolism to run too slow. Symptoms can vary from mild to severe; however, most patients complain of malaise (a feeling of sickness) and mental rigidity. Hypothyroidism is characterized by low T3 and T4 levels and elevated TSH levels.

Both T3 and T4 levels are low in hypothyroidism

Hypothyroidism is the most common thyroid disorder, it affects women up to five times more than men and its incidence increases with age.

Causes

What is hypothyroidism caused by?

1- Atrophic hypothyroidism (Autoimmune thyroiditis, Atrophic thyroid dysfunction) is a common autoimmune disease characterized by the development of Thyrotropin-Blocking Autoantibodies, Thyroid-Stimulating Autoantibodies and TSH-stimulation blocking antibodies (TSBAbs) that target the thyroid’s cells and destroys it leading to fibrosis and idiopathic atrophy of the thyroid gland, which, in turn, leads to functional hypothyroidism in the absence of goiter. Women are more likely to suffer from this disorder than men.

2- Hashimoto thyroiditis (chronic lymphocytic thyroiditis) is a chronic inflammatory autoimmune disease in which the thyroid gland is gradually destroyed. It is characterized by the development of anti-thyroid peroxidase (TPO antibodies or anti-TPO), antithyroglobulin (anti-Tg), and TSH receptor-blocking antibodies (TSBAbs, TSHR antibodies), and to a lesser extent, TSH-binding inhibitor immunoglobulin (TBII) that target the thyroid’s cells and destroys it leading to fibrosis with severe atrophy of thyroid follicles, which, in turn, leads to idiopathic myxedema and functional hypothyroidism in the presence of goiter. However, Hashimoto thyroiditis is a progressive disease that leads to idiopathic hypothyroidism over time, and idiopathic myxedema is the most advanced form of this disease.

Hashimoto thyroiditis may occur during the postpartum period (few days after delivery), or after an immunotherapy drug (a drug used to increase and strengthen the immune system) such as alpha interferons or interleukins.

It is the most common form of thyroiditis that has spread widely in recent decades; However, rapid rise in Hashimoto thyroiditis is linked to spread of urbanization. Moreover, it is the most common thyroid disorder in America, and for this reason the disease received a significant amount of media and healthcare attention in recent years. Epidemiologically, Hashimoto thyroiditis is spread worldwide, just like Type 1 diabetes, Addison’s disease and Malignant anemia, etc.[7][8][9]

3- Thyroid Goiters (Goiter or Goitre) is a progressive enlargement of the thyroid gland that creates a visible mass at the base of the neck (just below the Adam’s apple), In some cases, palpation may cause pain if the thyroid is inflamed (thyroiditis); however, most small to moderate sized goiters can be treated easily. Thyroid Goiters can occur in both hyperthyroidism and hypothyroidism, and are common in countries where iodine is rarely added to table salt (in countries that use non iodized salt).

Symptoms may be related to the size of the thyroid goiter. Common symptoms include discomfort, feeling of pressure in the neck. Less commonly, progressive pressure on the esophagus, can cause dysphagia and may lead to death due to lack of oxygen (hypoxia).

4- Iodine deficiency (the lack of iodine), it is common in mountainous countries where iodine in drinking water is relatively low (low Tap water iodine concentrations), which can cause a goiter.

5- Hypopituitarism (underactive pituitary) is a pathological condition in which the hypophysis (pituitary gland) does not produce normal amounts of some or all of its hormones. When the pituitary fails to produce enough TSH to stimulate the thyroid gland to produce T3 and T4.

6- After total or partial thyroidectomy, after surgery, when a portion of the thyroid gland is surgically removed (partial thyroidectomy), or when the entire thyroid is removed (total surgical removal of the thyroid gland).

7- Thyroid cancer is a very rare condition, when cancer spreads inside the thyroid gland.

• Papillary carcinoma (papillary thyroid cancer) is the most common thyroid malignancy, it accounts for about 80% of all thyroid cancers; however, papillary or follicular tumors are usually curable.[12][11][10]

8- Congenital Hypothyroidism (CH) is a pathological condition characterized by thyroid hormone deficiency present at birth, it occurs when thyroid follicles are unable to produce adequate amounts of thyroid hormones. It affects approximately 1 in every 4000 newborn infants. [1][13][14]

9- Mixed connective tissue disease (MTCD) is a rare connective tissue disorder characterized by features of SLE (systemic lupus erythematosus), systemic sclerosis (SSc), and polymyositis. The typical symptoms are malaise, Raynaud phenomenon (fingers become cold, pale to blue and numb suddenly), pale cold extremities (cold hands and feet), muscle weakness, insomnia and shortness of breath. In some affected individuals, lung involvement may lead to breathing difficulties and shortness of breath, which, in turn, may lead to coma. This clinical picture is common in patients with some connective tissue diseases.[1][15]

Symptoms

What are the symptoms of hypothyroidism in humans?

In most cases of hypothyroidism, mild to moderate T4 deficiency is asymptomatic

People with hypothyroidism often have some or all of these symptoms:

1- Weakness, malaise or generalized fatigue
2- Mental slowness and inattention
3- Cold Intolerance (the inability to tolerate cold)
4- Depression
5- Constipation
6- Muscle aches
7- Carpel tunnel syndrome
8- Dyslipidemia (elevation of plasma cholesterol and/or triglycerides)
9- Skin dryness
10- Low voltage on ECG
11- Tingling in the hands or feet
12- Unable to work hard
13- Articular pains (arthralgia)
14- Voice hoarseness
15- Irregular menstruation
16- Decreased appetite and weight gain
17- Hair dryness, baldness and hair loss
18- Low pulse
19- Emotional lability
20- Forgetfulness
21- A swelling in the neck (goiter)
22- Difficulty swallowing (dysphagia)

Pretreatment Diagnostic Guidelines before Treatment

Diagnostic assessments are designed to help doctors determine the severity of your condition. The severity of your symptoms will determine which treatment is recommended

The following diagnostic tests or procedures are recommended at any time prior to initiating therapy:

1- Heart rate and arterial pressure
2- Hair and skin conditions
3- Palpating the thyroid to check its nature
4- Heart and lung checkups
5- Nervous reflexes

How to diagnose hypothyroidism in humans?

Diagnosis of hypothyroidism is made based on clinical symptoms and diagnostic test results

Common diagnostic tests include:

1- Typical routine blood tests, a blood sample will be drawn once a month, we may need to check more than once every month to calibrate drug dosages and to know if the woman is pregnant
2- Ultrasound of the neck and thyroid
3-Thyroid Function Tests, evaluation of TSH, T4, T3 and Free T4 levels in the blood. The TSH Blood test is often the first test for evaluating thyroid function.
4- Antithyroid antibody lab tests are used to evaluate and rule out autoimmune thyroid disorders.
5- Thyroid Hormone Replacement Therapy, taking synthetic T4 (thyroxine) hormone supplementation is considered the standard treatment for hypothyroidism.

Elderly patients and patients with cardiovascular disease should receive a low initial dose of L-thyroxine that is increased every month until normalization of TSH levels.[1][16][17]

Free thyroxine (FT4, free T4) can be measured directly or by calculating the amount of TSH in blood in a period of 6 weeks to adjust dose of levothyroxine.

De Quervain thyroiditis

What is de quervain’s thyroiditis?

De Quervain thyroiditis (subacute granulomatous thyroiditis) is a painful giant cell thyroiditis caused by viral infection of the upper respiratory tract like influenza, coxackie virus, mumps, adenoviruses, etc. Less commonly, De Quervain thyroiditis may occur in the postpartum period; however, it affects males and females of all ages.

De Quervain thyroiditis have a couple of periods, a late period or hypothyroid and an initial period a hyperthyroid.

Common symptoms of the initial period (the hyperthyroid period) include neck pain, fever and dysphagia.

Symptoms of De Quervain thyroiditis

What are the symptoms of de quervain’s thyroiditis in humans?

People with de quervain’s thyroiditis often have some or all of these symptoms:

1- thyroid goiter (an abnormal enlargement of the thyroid gland)
2- Mild to severe pain in the thyroid gland at the front of the neck (Adam’s apple). The pain is often exacerbated by palpation (diffuse tenderness to palpation) and can be accompanied by odynophagia (painful swallowing). Sometimes the pain radiates from the neck to the jaw or ears
3- Fatigue
4- Difficulty swallowing (dysphagia)
5- Fever
6- Hoariness
7- Weakness

Symptoms during the initial period (hyperthyroidism) include:

1- Diarrhea
2- Heat intolerance
3- Constipation
4- Fatigue

Diagnosis

How to diagnose de quervain’s thyroiditis?

Diagnosis of de quervain’s thyroiditis is made based on clinical symptoms and diagnostic test results

Common lab test results during the initial period (hyperthyroidism) include:

1- Low TSH levels
2- High free T4 levels
3- Low radioactive iodine uptake
4- High serum Thyroglobulin levels (increased levels of thyroglobulin in the blood).
5- High ESR levels (raised erythrocyte sedimentation rate)

Common lab test results during the late period (hypothyroidism) include:

1- High Tsh levels
2- Low serum free T4 level

There may be low levels of anti thyroid antibodies.

Differential Diagnosis

The differential diagnosis is carried between Graves’s disease and subacute granulomatous thyroiditis.

For the differential diagnosis of De Quervain thyroiditis patients are given a radionuclide (a radioisotope) for Thyroid uptake determination (radionuclide uptake measurement), in Graves disease the radioactive iodine uptake test shows increased isotope uptake whereas in subacute thyroiditis the uptake is decreased.[1][21][22]

Treatment

How long does it take to recover from subacute thyroiditis?

De quervain’s thyroiditis is a self-limited thyroid disorder that goes away on its own. The acute phase of de quervain’s thyroiditis lasts from 3-6 weeks. In most cases of subacute thyroiditis, the symptoms usually go away within 12 to 18 months. However, some patients develop permanent hypothyroidism.

The euthyroid phase usually lasts from 1-3 weeks. This is often called the asymptomatic stage.

How to cure de quervain’s thyroiditis?

Combining different classes of drugs such as beta blockers and NSAIDs can help to relieve symptoms. Pain is treated with nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or aspirin whereas symptoms of hyperthyroidism are treated with beta blockers such as propranolol; however, corticosteroids are used if NSAIDs are ineffective.

Prednisone is a corticosteroid used to control inflammation.

Postpartum Thyroiditis

What is postpartum thyroiditis?

Postpartum thyroiditis is a medical term referring to painless inflammation of the thyroid gland following pregnancy, which results in mild to no thyroid enlargement.

Postpartum thyroiditis have two periods:

1- Hyperthyroidism
2- Hypothyroidism

What are the symptoms of postpartum thyroiditis and how long does postpartum thyroiditis last for?

The symptoms of postpartum thyroiditis are temporary. In most cases of postpartum thyroiditis, the symptoms usually resolve spontaneously within a period of 1 to 4 months.

New mothers may experience normal postpartum symptoms only such as sleep loss (lack of sleep), increased nervousness and depression. Symptoms of hyperthyroidism and/or hypothyroidism may not occur at all.

In postpartum thyroiditis, hyperthyroidism (thyrotoxicosis) occurs first followed by hypothyroidism.

Treatment of postpartum thyroiditis

How to cure postpartum thyroiditis?

Combining different classes of drugs such as beta blockers and Levothyroxine can help to relieve symptoms of postpartum thyroiditis

You can take Beta blockers such as propranolol (inderal) to relieve symptoms of postpartum thyroiditis. You can also take Levothyroxine for up to six months to correct T4 or T3 deficiency

Treatment of Thyroiditis

How to cure thyroiditis?

1- Radioactive iodine (l131) is a radioactive isotope that deposits inside the thyroid follicles, it is administered orally to suppress the production of T3 and T4; however, it used as a suppression therapy for follicular and papillary thyroid carcinoma.

Radioactive Iodine-131(RAI) possesses two types of ionizing radiation, Beta radiation can penetrate 0.5mm of the irradiation area without effecting the surrounding tissues, whereas gamma rays are more penetrating than beta rays. Radioactive Iodine-131 (l131) has a radioactive half life of about 8 days and its the most widely used treatment of patients with toxic goiter. Moreover, 131I is used in the pretreatment period of selected patients with thyroid cancers before undergoing a subtotal thyroidectomy.[23][24][25]

Radioiodine Iodine-131 is a vital component in the treatment of thyroid cancer; however, sodium and potassium salts should be administered along iodine l131 in thyroid cancer treatment.

Intravenous (IV) administration of Potassium preparations (chloride and bicarbonate) is recommended as a protective measure against the side effects of iodine-131 radiation.

It is noted that from 6 to 10% of patients develop hypothyroidism after radioactive iodine treatment.

Suppression of T3 and T4 production in patients with Postpartum thyroiditis

Acute-phase treatment

The following treatment is used for the management of hyperthyroidism within a period of few weeks:

1-Propylthiouracil (PTU) is the drug of choice used for the treatment of pregnant women with hyperthyroidism and for patients who are intolerant (suffering of hypersensitivity and allergy) to other drugs. The initial dose of Propylthiouracil ranges from 300 to 600mg daily. So optimally the patient should take PO 300 mg in 3 equal doses each day.[1][26][27]

2- Methimazole (Tapazole, Northyx) is a drug used to treat hyperthyroidism by suppressing thyroid hormone synthesis and secretion in the thyroid gland. The initial dose of methimazole ranges from 5 to 30 mg per day.[1][30]

3- Carbimazole is a drug is used to treat hyperthyroidism; however, this medicine may cause itching, spots and heat intolerance (a feeling of being overheated). The initial dose of Carbimazole ranges from 15 to 40 mg daily.[31][28][29]

Long-term therapy

The following treatment is used for long-term control of hyperthyroidism:

This group of medicine has the ability to deposit inside the thyroid gland, thus can be used to suppress T3 and T4 production; however, these effects will not be achieved quickly!

Beta blockers (Propranolol) are used to treat the symptoms of hyperthyroidism

Blockade of hormone release (i.e. iodine) or Blockade of hormone synthesis (i.e. antithyroid drugs) are only used to treat thyroid cancer with lung or bone metastasis

 

 

 

 

References

 

Thyroiditis

Verified by: Dr.Diab (July 12, 2018)

Citation: Dr.Diab. (July 12, 2018). Thyroiditis Types Pathophysiology Symptoms and Treatment. Medcoi Journal of Medicine, 59(2). urn:medcoi:article3150.