Acute Thyroiditis

Overview

Acute thyroiditis is a sudden inflammation of the thyroid gland, the butterfly-shaped gland in the front of the neck that produces hormones controlling metabolism. Unlike the more common autoimmune forms of thyroiditis, acute thyroiditis is usually caused by an infection, most often bacterial, and is sometimes called acute suppurative thyroiditis when pus forms.

It is uncommon because the thyroid is generally resistant to infection, but when it occurs it causes a painful, tender, swollen neck and often fever. Acute thyroiditis is a potentially serious condition that needs prompt medical evaluation and treatment, as an untreated infection can spread or form an abscess.

The condition stands apart from the more common forms of thyroid inflammation, which are usually autoimmune, develop slowly, and affect hormone levels. Acute thyroiditis comes on quickly, is driven by infection, and behaves more like other deep neck infections, which is why early antibiotics and, when needed, drainage are central to recovery.

Symptoms

Acute thyroiditis typically comes on quickly with signs of infection in and around the thyroid:

• Pain and tenderness in the front of the neck, often on one side, which may spread to the jaw or ear
• Swelling of the thyroid or a tender lump in the neck
• Fever and chills
• Redness or warmth of the overlying skin
• Difficulty or pain when swallowing or turning the head
• A hoarse voice in some cases

Thyroid hormone levels usually stay normal, so symptoms of an overactive or underactive thyroid are not typical. High fever, rapidly increasing swelling, difficulty breathing, or trouble swallowing are warning signs needing urgent care.

Causes

Acute thyroiditis is most often caused by a bacterial infection that reaches the thyroid gland. This can happen when bacteria spread from a nearby infection in the throat or neck, through the bloodstream, or through an abnormal connection between the throat and the thyroid that is present from birth (more common in children).

Less commonly, fungal or other organisms are responsible, particularly in people with weakened immune systems. Anything that lowers the body's ability to fight infection can make acute thyroiditis more likely.

Risk Factors

• A pre-existing abnormality of the thyroid, such as a goiter or nodules
• A congenital connection (fistula) between the throat and thyroid, especially in children
• A weakened immune system
• A recent throat or neck infection
• Recent neck surgery or procedures

Diagnosis

Doctors diagnose acute thyroiditis by combining the clinical picture with tests:

• Examination and history: A painful, tender, swollen thyroid with fever.
• Blood tests: Markers of infection and inflammation are raised; thyroid hormone levels are usually normal.
• Neck ultrasound: To look for inflammation or an abscess (a collection of pus).
• Fine-needle aspiration: Sampling fluid or pus to identify the causative organism and guide antibiotic choice.

Treatment

Treatment targets the infection and relieves symptoms, and it should be started promptly.

• Antibiotics: The mainstay of treatment for bacterial infection, sometimes given intravenously at first for severe cases.
• Drainage: If an abscess has formed, it may need to be drained surgically or with a needle.
• Pain and fever relief: Anti-inflammatory medicines and pain relievers ease discomfort.
• Treating the source: Identifying and addressing any underlying cause, such as a congenital fistula, to prevent it from returning.

With timely treatment, most people recover fully and thyroid function usually remains normal. Severe cases may need a short hospital stay for intravenous antibiotics and close monitoring of the airway.

Recovery and Follow-Up

• Complete the full course of prescribed antibiotics even if you feel better
• Attend follow-up so the infection can be confirmed to have cleared
• If a congenital connection between the throat and thyroid is found, discuss treatment to prevent recurrence
• Seek prompt care for any return of neck pain, swelling, or fever

When to See a Doctor

See a doctor promptly if you develop a painful, tender, swollen area in the front of your neck along with fever, as acute thyroiditis needs early treatment.

Seek emergency care if you have difficulty breathing, trouble swallowing, rapidly increasing neck swelling, a high fever with severe illness, or your voice suddenly changes, as these can indicate a spreading infection or airway problem that requires immediate attention.

Related Topics

Frequently Asked Questions

References

1. American Thyroid Association. Thyroiditis.
2. Mayo Clinic. Thyroiditis.
3. MedlinePlus, U.S. National Library of Medicine. Acute thyroiditis.
4. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Thyroid disease.