ConditionHormones & metabolism
Acute (Suppurative) Thyroiditis
Acute thyroiditis, also called acute suppurative thyroiditis, is a rare bacterial infection of the thyroid gland. It causes sudden, severe pain and swelling at the front of the neck, fever, pain on swallowing and redness of the skin over the gland, and it can form an abscess. In children it is usually linked to a small developmental tract (a pyriform sinus fistula) from the throat to the thyroid. It needs urgent antibiotics and often drainage.
Also called: Acute suppurative thyroiditis, infectious thyroiditis, bacterial thyroiditis, thyroid abscess
At a glance
- What it is
- A bacterial (rarely fungal) infection of the thyroid gland.
- How common
- Rare, because the thyroid is well protected; most cases occur in children.
- Symptoms
- Sudden painful, tender swelling in the front of the neck, fever, sore throat and pain on swallowing.
- Diagnosis
- Ultrasound or CT, needle aspiration for culture, and a barium swallow or scope to find a fistula.
- Treatment
- IV antibiotics, abscess drainage, and closing any fistula to prevent recurrence.
When to get help
Call 911 or go to the ER
- Neck swelling with difficulty breathing, noisy breathing, drooling or inability to swallow saliva
- High fever with a rapidly enlarging, painful neck swelling and feeling very unwell
See a doctor within a day or two
- A painful, tender lump or swelling in the front of the neck with fever
- Redness and warmth of the skin over the thyroid area
- Repeated episodes of left-sided neck swelling and pain in a child, especially after colds
Book a routine appointment
- A painful thyroid that has persisted for weeks after a viral illness, with no fever or redness (possible subacute thyroiditis)
What acute thyroiditis is
The thyroid is a butterfly-shaped gland at the front of the neck that makes thyroid hormone. It normally resists infection because it has a rich blood supply, a protective capsule and a high iodine content. When infection does occur, bacteria cause inflammation and often pus (suppuration), forming an abscess.
Acute thyroiditis is different from the more common types of thyroiditis:
| Type | Cause | Pain | Fever | Thyroid hormone |
|---|---|---|---|---|
| Acute (suppurative) | Bacterial infection | Severe, one-sided | High | Usually normal |
| Subacute (de Quervain's) | Probably viral, after a cold | Moderate to severe, may move sides | Low-grade | High, then low |
| Hashimoto's | Autoimmune | Painless | None | Gradually low |
| Painless and postpartum | Autoimmune | Painless | None | High, then low |
Causes and risk factors
- Pyriform sinus fistula: a remnant of fetal development that connects the throat (the pyriform sinus) to the thyroid region. It accounts for most cases in children and is almost always on the left side. Infection often follows an upper respiratory infection, and episodes can recur.
- Spread from nearby infections: deep neck infections, infected thyroid cysts or nodules.
- Bloodstream spread in people with weakened immune systems.
- Procedures: fine-needle biopsy of the thyroid, rarely.
- Pre-existing thyroid disease: goiter, nodules or thyroid cancer.
Common bacteria include Staphylococcus aureus, Streptococcus species and mouth anaerobes. In people with weakened immunity, fungi and tuberculosis are possible.
Symptoms
- sudden pain and tenderness at the front of the neck, often on one side
- swelling or a lump that may become soft as an abscess forms
- pain spreading to the jaw or ear
- fever and chills
- pain when swallowing, and sometimes hoarseness
- red, warm skin over the swelling
- the head held bent forward to relieve pain
Thyroid hormone levels are usually normal, but occasionally the damaged gland leaks hormone, causing temporary symptoms of hyperthyroidism.
Diagnosis
- Examination: a tender, swollen thyroid region, usually one-sided.
- Blood tests: raised white blood cell count and inflammation markers, thyroid function tests, and blood cultures.
- Ultrasound or CT of the neck: shows an abscess and its extent. CT can also show gas or a tract.
- Fine-needle aspiration: draws pus for culture and helps choose antibiotics.
- Finding a fistula: once the acute infection settles, a barium swallow, CT or direct laryngoscopy is used to look for a pyriform sinus fistula, especially in children or recurrent cases.
Treatment
- IV antibiotics covering staph, strep and mouth bacteria, adjusted to culture results, then oral antibiotics.
- Drainage of an abscess by needle aspiration or surgery.
- Airway monitoring in severe cases.
- Treating the fistula: surgical removal, or closing the opening in the throat by cautery or other endoscopic methods, greatly reduces the chance of recurrence.
- Removal of part of the thyroid is occasionally needed for extensive infection or recurrence.
Complications
Without prompt treatment, infection can spread into the deep neck spaces or chest (mediastinitis), compress the airway, or rupture into the trachea or esophagus. Recurrent infection is common if a fistula is not treated. Long-term thyroid function is usually normal, though temporary low thyroid levels can occur.
Outlook
With early antibiotics and drainage, most people recover fully. Treating an underlying fistula usually prevents further episodes.
Frequently asked questions
What is the difference between acute and subacute thyroiditis?
Acute thyroiditis is a bacterial infection, causing high fever, severe one-sided pain, redness and sometimes an abscess. Subacute thyroiditis is a post-viral inflammation with neck pain, low-grade fever and a temporary phase of overactive then underactive thyroid. It is treated with anti-inflammatory medicines, not antibiotics.
Is acute thyroiditis serious?
Yes. It is uncommon, but an untreated thyroid abscess can spread into the neck or chest or threaten the airway. With prompt antibiotics and drainage, most people recover fully.
Why does acute thyroiditis keep coming back in children?
Repeated episodes in children are usually caused by a pyriform sinus fistula, a small tract from the throat to the thyroid left over from development. Bacteria travel down it, often after a cold. Once the infection settles, the fistula can be found and closed.
Does acute thyroiditis affect thyroid hormone levels?
Usually not. Thyroid hormone levels are generally normal. Occasionally, destruction of thyroid tissue releases stored hormone and causes temporary hyperthyroidism, or later a temporary underactive phase. Doctors check thyroid function during and after the illness.
Sources
This guide was written from current patient and clinical guidance, including:
- American Thyroid Association: Thyroiditis
- MedlinePlus: Thyroiditis
- Endotext (NCBI Bookshelf): Acute and subacute and painless thyroiditis
- NHS: Thyroiditis overview
- American Academy of Otolaryngology: Neck masses