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CamillaSchalin-Jäntti

Subacute Thyroiditis

Inflammation of the thyroid gland, typically associated with neck pain, fever and tenderness of the thyroid gland
Rapid response to glucocorticoid treatment confirms the diagnosis.

The ESR is elevated in most patients, as is CRP.
Initially there is often a transient thyrotoxic phase with a slightly decreased TSH concentration and a slightly increased free T4 concentration. This is followed in 20% of cases by transient hypothyroidism 1-2 months after treatment. Permanent hypothyroidism develops in 2-3% of the patients.
Diagnosis: fever, tender thyroid gland, clinical picture of hyperthyroidism, elevated ESR and CRP, rapid response to glucocorticoid therapy. Also TSH and free T4 should be determined at the initial stage; TSH is typically slightly below reference range and free T4 slightly increased.
Thyroid gland scintigraphy is nowadays rarely needed.
Differential diagnosis is sometimes difficult, and then in addition to thyroid gland test results and inflammation parameters, TPO antibodies and TSH-receptor antibodies should be determined, as necessary. Thyroid ultrasound scan combined with fine-needle biopsy may offer additional help.

Thyroiditis can be managed in primary care.
The disease responds to glucocorticoid treatment within days (the fever comes down, thyroid pain lessens). If there is no response consider alternative diagnoses, such as tonsillitis, and refer the patient to specialized care if necessary.
The symptoms tend to recur if glucocorticoids are discontinued too early or the dose is reduced too quickly.

Administer a glucocorticoid http://www.dynamed.com/condition/subacute-thyroiditis#MEDICATIONS, e.g. prednisone or prednisolone at 40 mg/day for 1 week, 30 mg/day for 1 week, 20 mg/day for 1 week, 10 mg/day for 2 weeks and 5 mg/day for 2 weeks.
- If symptoms recur when the dose is reduced, the patient returns back to the previous dosage level.
- The dose may also be tapered at a more rapid pace if the response is quick and permanent.
- The activity of the inflammation is monitored by CRP and ESR.
- Treatment duration is usually 6-12 weeks.
If symptoms last for more than one year the patient is referred to specialized care for the consideration of surgical treatment.
NSAIDs at normal doses may be sufficient in mild cases http://www.dynamed.com/condition/subacute-thyroiditis#MEDICATIONS.
Hyperthyroidism is treated with beta-blockers, not with antithyroid drugs http://www.dynamed.com/condition/subacute-thyroiditis#MEDICATIONS.
Serum TSH and free T4 concentrations are monitored if needed according to the patient's clinical condition, if symptoms of hypothyroidism should develop. The initial thyrotoxicosis phase is often followed by a transient hypothyroid phase that does not require treatment. However, if the patient is symptomatic, temporary thyroxine substitution therapy may be commenced. It can usually be discontinued after 6 to 12 months from the symptom onset.

Hennessey JV. Subacute Thyroiditis. In: Feingold KR, Anawalt B, et al. (eds.) Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000.2018 Jun 12.[PubMed]