Thyroiditis: Types, Causes, Symptoms and Diagnosis

The thyroid gland, situated at the base of the neck, is an integral component of metabolism, energy generation, and hormonal equilibrium. The thyroid regulates essential physiological processes ranging from heart rate to body temperature and weight management through the secretion of hormones like thyroxine (T4) and triiodothyronine (T3).

Thyroiditis develops due to the inflammation in the thyroid gland. This disorder can result in interruptions in hormone production, leading to various symptoms. This article explains thyroiditis, its causes, symptoms, and how it can be treated for effective management.

What is Thyroiditis?

Thyroiditis is the inflammation of the thyroid, which often affects the production of thyroid hormones. Overproduction or underproduction of these hormones may lead to various symptoms that depend on the type and progression of the disease. 

There are many potential causes of thyroiditis, such as:

• Autoimmune disease
• Bacterial or viral infection 
• Drugs
• Pregnancy

Types of Thyroiditis

There are several forms of thyroiditis with varying features. These are:

1. Hashimoto's Thyroiditis

The most common type of thyroiditis is Hashimoto's thyroiditis, an autoimmune disorder. In such cases, the immune system wrongly attacks and destroys the thyroid gland. This results in inflammation and destruction of thyroid tissue, which can cause a progressive decrease in the production of thyroid hormones.

Consequently, people with Hashimoto’s thyroiditis frequently become hypothyroid, a condition marked by fatigue, weight gain, dry skin, and cold intolerance. The disease progresses slowly, and untreated individuals can have long-term complications.

2. Subacute Thyroiditis

Subacute thyroiditis is most often the result of viral infections, including those involved with upper respiratory illnesses. This condition involves painful, sudden swelling of the thyroid gland and can include fever and temporary fluctuations in thyroid hormone levels.

Initially, this can result in an excessive release of thyroid hormones (hyperthyroidism) and associated symptoms including:

• Weight loss
• Increased heart rate 
• Irritability

3. Postpartum Thyroiditis

Postpartum thyroiditis develops within 12 months after giving birth. The diagnosis is more common in women and usually manifests as a phase of hyperthyroidism (excess production of hormones) followed by a phase of hypothyroidism (insufficient production of hormones).

Possible symptoms in the hyperthyroid phase include

• Fatigue
• Irritability 
• Concentration issues 

On the other hand, possible symptoms in the hypothyroid phase include

• Weight gain
• Depression
• Cold intolerance 

4. Silent Thyroiditis

Postpartum thyroiditis and silent thyroiditis are alike, but the latter occurs outside the timeframe of pregnancy. It is characterised by self-limiting thyroid dysfunction with no significant thyroid pain or swelling. As with postpartum thyroiditis, silent thyroiditis generally starts off as hyperthyroid and then progresses to hypothyroid.

5. Drug-induced Thyroiditis

Some medications can stimulate thyroiditis, including:

• Amiodarone (for heart arrhythmias) and 
• Interferon-alpha (for cancer and viral infections)

Such doses of these medications produce thyroid dysfunction either in the form of hyperthyroidism or hypothyroidism, depending on the response of the individual.

Causes and Risk Factors of Thyroiditis

There are various causes of thyroiditis, with the most common causes being autoimmune disease, infection, and medications.

Autoimmune Factors

Autoimmune thyroid disorders are the most common cause of thyroiditis. In autoimmune diseases like Hashimoto's thyroiditis and Graves’ disease, the immune system mistakenly attacks the thyroid gland. 

In Hashimoto’s thyroiditis, the immune system attacks and destroys thyroid cells, resulting in hypothyroidism.
In contrast, in Graves’ disease, the immune system prompts the thyroid to produce excess hormones, resulting in hyperthyroidism.

Viral or Bacterial Infections

Thyroiditis is also commonly caused by infections. For example, viral infections, particularly in the upper respiratory tract, are known to cause subacute thyroiditis. Inflammation of the thyroid gland can be caused by other bacterial infections as well.

Genetic Predisposition

Thyroiditis is more common in people who have a family history of thyroid disorders or autoimmune diseases. Genetic mutations that predispose some people to autoimmune thyroid diseases make them more likely to develop thyroid inflammation.

Symptoms and Signs of Thyroiditis

Depending on the type of thyroiditis, symptoms can vary and may occur gradually or suddenly. Both chronic and acute adrenal insufficiency have a wide range of possible symptoms.

Common Symptoms of Thyroiditis

• Fatigue: A common symptom, especially when thyroid hormone levels are low (hypothyroidism).
• Weight Gain/Loss: Unexplained weight gain (hypothyroidism) or weight loss (hyperthyroidism).
• Temperature Sensitivity: Cold intolerance in hypothyroidism; heat intolerance in hyperthyroidism.
• Increased Sensitivity/Neck Swelling: The thyroid gland may become swollen or tender, particularly in subacute thyroiditis or when there is a goitre.
• Difficulty Swallowing: An enlarged thyroid can compress other neck structures, making swallowing painful or difficult.

Symptoms Specific to Thyroiditis Types

Hashimoto’s Thyroiditis: Symptoms tend to come on slowly and include fatigue, dry skin, thinning hair, and weight gain.

• Subacute Thyroiditis: Abrupt neck pain, fever, and transient hyperthyroidism evolving to hypothyroidism.
• Postpartum and Silent Thyroiditis: Hyperthyroidism episodes towards the beginning, then hypothyroidism, with little or no pain in the thyroid area.
• Drug-induced Thyroiditis: Symptoms vary by whether the person develops hyperthyroid or hypothyroid states with the drug.

Diagnosis of Thyroiditis

Diagnosing thyroiditis involves a combination of blood tests, imaging studies, and physical examination.

Blood Tests and Imaging

Thyroid function tests are vital for diagnosing thyroiditis. These tests help doctors measure the levels of TSH, T3, and T4 and evaluate whether the thyroid is overactive or underactive.

Thyroid-specific antibodies may also be assessed to identify concerning autoimmune thyroiditis, especially in Hashimoto’s or Graves’ disease.

Ultrasound and other imaging tests can be utilised to measure the size of the enlarged gland and identify potential goitres or inflammatory changes.

Physical Examination

A healthcare provider may conduct a physical examination to look for signs of thyroid dysfunction. This might involve feeling the area to detect thyroid enlargement, tenderness, or irregularities. 

They might also look for other symptoms, including tremors, skin texture changes, or heart rate changes.

Treatment and Management of Thyroiditis

Thyroiditis treatment depends on the type and severity of symptoms. Most treatments focus on restoring normal thyroid hormone levels and managing symptoms.

Medications

Underactive Thyroid: The standard treatment for hormonal deficiency is synthetic thyroid hormone, like levothyroxine.

Overactive Thyroid: Beta-blockers can help control symptoms such as a fast heart rate, while anti-thyroid medications can reduce thyroid hormone production in cases of autoimmune hyperthyroidism or drug-induced thyroiditis.

Surgical Options

Surgical treatment is rare but may be needed in cases of chronic thyroiditis, large goitres that cause difficulty breathing or swallowing, and if cancer is suspected.

Lifestyle Modifications

Following a diet rich in nutrients, keeping stress low, and exercising regularly may help improve thyroid function and alleviate symptoms.

Complications of Thyroiditis

Some complications that may arise due to untreated or poorly managed thyroiditis are:

• Hypothyroidism: Chronic hypothyroidism can necessitate long-term hormone replacement therapy.
• Hyperthyroidism: It can cause health problems like heart palpitations, anxiety, and even cardiovascular complications.
• Goitre: Enlargement of the thyroid gland caused by iodine deficiency or autoimmune diseases like Graves’ or Hashimoto’s disease can lead to hyper or hypothyroidism.

Prognosis and Long-Term Management of Thyroiditis

With an early diagnosis and proper treatment, the prognosis of thyroiditis is generally positive. However, autoimmune thyroiditis, like Hashimoto’s thyroiditis, usually needs continuous management, which includes regular thyroid hormone level monitoring.

Diet and Lifestyle Considerations for Thyroiditis

A balanced diet helps support a healthy thyroid. Nutrients like iodine, selenium, and antioxidants also play a role in managing thyroiditis. Stress management, relaxation techniques, meditation, and good sleep can all help mitigate the effects of thyroiditis on overall well-being.

Conclusion

There are different types of thyroiditis, with various causes and manifestations. Early diagnosis, treatment, and lifestyle changes are essential for controlling symptoms and preventing complications. Most people with thyroiditis can live healthy and fulfilling lives with appropriate treatment, including regular medication, dietary and lifestyle modifications, and regular follow-up.