What are the other Names for this Condition? (Also known as/Synonyms)

• Acute Suppurative Thyroiditis
• Infectious Thyroiditis
• Microbial Inflammatory Thyroiditis

What is Acute Infectious Thyroiditis? (Definition/Background Information)

• Thyroiditis is an inflammation of the thyroid gland from various causes, which results in a set of associated signs and symptoms. Acute Infectious Thyroiditis (AIT) is a highly uncommon form of thyroiditis that develops from an infection (usually bacterial) of the thyroid gland
• The condition is mostly observed in elderly adults, children, and individuals with a weak immune system; many individuals are known to have a preexisting thyroid gland disorder. The causative pathogens of Infectious Thyroiditis include bacteria (mostly Streptococcus sp.), fungus, and certain parasites
• Acute Infectious Thyroiditis may result in hyperthyroidism (increased thyroid hormone secretion) or hypothyroidism (decreased thyroid hormone secretion), with a return to euthyroid state (a state of normal thyroid function) following resolution of the condition; but, this may vary from one individual to another
• The signs and symptoms of Acute Infectious Thyroiditis may include fever, pain, and swelling of the thyroid gland. Hyperthyroidism may present with rapid weight loss, irritability, heat sensitivity, diarrhea, and irregular heartbeat. Hypothyroidism may result in weight gain, irritability, cold intolerance, constipation, slow heartbeat, sweating, and fatigue
• The treatment of Acute Infectious Thyroiditis may involve the use of antibiotics, antifungal, or antiparasitic agents. Symptomatic treatment and rarely, a surgical incision and drainage of the infected abscess, may be necessitated. The prognosis is mostly good with adequate treatment, but may vary from on a case-by-case basis

Who gets Acute Infectious Thyroiditis? (Age and Sex Distribution)

• Acute Infectious Thyroiditis is an extremely rare form of thyroid gland disorder
• Individuals of all ages may be affected, although most cases are noted in older adults, immunocompromised individuals, and children
• Both males and females are affected and no preference for any gender is noted
• Worldwide, individuals of all racial and ethnic groups are affected

What are the Risk Factors for Acute Infectious Thyroiditis? (Predisposing Factors)

The risk factors associated with Acute Infectious Thyroiditis include:

• Advancing age
• Individuals with weakened immunity or on immunosuppressive drugs
• Presence of embryonic abnormalities with congenital manifestation, such as persistent thyroglossal duct or pyriform sinus fistula
• Thyroid gland dysfunction due to developmental issues
• Cancer involving the thyroid gland
• Most infections are noted during autumn and winter (cold weather seasons)
• Intravenous (IV) drug use, in rare cases

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Acute Infectious Thyroiditis? (Etiology)

Acute Infectious Thyroiditis is caused by pathogenic microorganisms that invade and infect the thyroid gland. It is also known as Suppurative Thyroiditis.

• The infections are mostly bacterial; other infectious agents may be mycobacteria, fungi, or parasites. Bacteria that cause the condition commonly include Streptococcus pyrogenes, S. aureus, and S. pneumoniae
• The factors that increase the risk for infection include a poor immune system, preexistent thyroid abnormalities, and older age of the individual

What are the Signs and Symptoms of Acute Infectious Thyroiditis?

The signs and symptoms of Acute Infectious Thyroiditis may vary from one individual to another. It may also be mild or severe and may be related to the pathogen type, underlying thyroid gland conditions (if any), and immune status of the individual. The progression of the infection is usually rapid.

It is reported that individuals may present hyperthyroidism or hypothyroidism or both over a period of time. If there are no pre-existent thyroid gland abnormalities noted, then the function of the gland may not be severely affected.

The signs and symptoms of Acute Infectious Thyroiditis may include:

• Neck pain and swelling in the thyroid gland
• Tenderness of skin over the thyroid; redness of skin may be noted
• Swallowing difficulties
• Hoarseness of voice
• Fever and malaise
• Enlarged lymph nodes in the region

The associated signs and symptoms of hyperthyroidism (if present) may include:

• Sleeping difficulties including insomnia
• Excess sweating and intolerance to heat
• Increased to excessive hunger
• Irritation, restlessness, and nervousness
• Protrusion of the eyes
• Menstrual abnormalities in women; menstruation may be irregular or short
• Abnormal heartbeat rate including rapid heart rate
• Sudden weight loss

The signs and symptoms associated with hypothyroidism (if present) may include:

• Difficulty concentrating or thinking
• Fatigue and tiredness
• Dry skin
• Hair loss, which may be in excess while showering
• Constipation or difficult bowel movements
• Weight gain that may be slow and gradual
• Heavy and irregular periods (in women)
• Abnormal sensitivity to cold; the affected individuals may not tolerate cold very well

How is Acute Infectious Thyroiditis Diagnosed?

The diagnosis of Acute Infectious Thyroiditis may involve the following tests and procedures:

• Complete evaluation of medical history and a thorough physical examination
• Assessment of the signs and symptoms
• Complete blood count (CBC), antibody test, and culture studies
• Blood tests to evaluate the levels of:
  • T3 and T4; thyroid hormones produced in the thyroid gland
  • Serum TSH
  • Antithyroid peroxidase antibody (anti-TPO); antibodies against thyroid peroxidase, an enzyme in the thyroid gland
  • Antithyroglobulin antibody; antibodies interacting with thyroglobulin, a protein found on the thyroid cells
• Ultrasound scans of the thyroid gland
• Fine needle aspiration (FNA) biopsy or core biopsy of the thyroid gland, if needed

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Acute Infectious Thyroiditis?

Complications may be noted with severe infections and delayed treatments. Some potential complications of Acute Infectious Thyroiditis include:

• Emotional stress
• Abscess formation in the gland
• Spread of infection to the entire body (systemic infection)
• Poor response to antibiotic therapy
• Permanent injury to the thyroid due to hemorrhaging (bleeding)
• Respiratory problems such as breathing difficulties

Complications may arise from an underlying condition, if any present.

How is Acute Infectious Thyroiditis Treated?

The following treatment measures may be considered for Acute Infectious Thyroiditis:

• Administration of pain relievers and steroids
• Antibiotics for bacterial infections; oral or parenteral antibiotics may be prescribed
• Use of antifungal or antiparasitic agents, as appropriate, for fungal and parasitic infections respectively
• Surgical drainage of pus and fluid from the infected gland, if necessary
• In some children, if the condition is severe, a small part of the thyroid gland may be surgically removed (termed hemithyroidectomy)
• Beta-blockers are known to relieve an elevated heart rate and excessive sweating; these may be required in some cases
• Anti-thyroid drugs may be prescribed for hyperthyroidism, if necessary
• Sometimes, thyroid hormone replacement is needed if severe symptoms of hypothyroidism are noted 

Follow-up care with screening and check-ups are important at regular intervals.

How can Acute Infectious Thyroiditis be Prevented?

The preventative measures for Acute Infectious Thyroiditis may include: 

• Early detection and prompt treatment of thyroid disorders may lower one’s risk for Infectious Thyroiditis
• Undertake prompt treatment for any condition causing weak immune system
• Follow good hygiene practices such as washing hands regularly
• Avoid use of illegal drugs and other substances of abuse

What is the Prognosis of Acute Infectious Thyroiditis? (Outcomes/Resolutions)

• In a majority of cases, the prognosis of Acute Infectious Thyroiditis is good with appropriate early treatment of the infection
• However, this also depends on several factors including the associated thyroid disorder, immunocompetent or immunocompromised state of the individual, age of the individual, and one’s response to therapy

Additional and Relevant Useful Information for Acute Infectious Thyroiditis:

The following article links will help you understand thyroid-stimulating hormone (TSH), total T3, and total T4 laboratory tests:

http://www.dovemed.com/common-procedures/procedures-laboratory/thyroid-stimulating-hormone-tsh-test/

http://www.dovemed.com/common-procedures/procedures-laboratory/total-t3-blood-test/

http://www.dovemed.com/common-procedures/procedures-laboratory/total-t4-blood-test/