Subacute Thyroiditis

Clinic A/P, adults, Clinic A/P, Peds, ENDOCRINOLOGY

Background
Subacute thyroiditis = deQuervain thyroiditis=a common, transient condition that usually presents after a recent viral illness such as an upper respiratory infection. Typically affects young and middle-aged women. Symptoms include an acute, very painful enlargement of the thyroid gland with dysphagia, fever, and fatigue. The pain often radiates to the jaw or ears. About 50% of patients will develop symptoms of thyrotoxicosis, including palpitations, diaphoresis,  N/V, and a high fever.
Diagnosis
H&P
Labs: Low TSH, elevated T4, and very elevated ESR.

Treatment
Anti-inflammatory therapy: An NSAID or prednisone. Start with NSAIDs and if no symptom relief, stop the NSAIDs and start prednisone.
-Naproxen 250 to 500 mg q12h; OR Ibuprofen 300 to 800 mg three or four times daily (tid-qid). If there is no improvement in 2 or 3 days, D/c the abd start prednisone 40 mg daily. If the dx is right, prednisone should provide relief in 2 days. If not, reconsider diagnosis. Taper the prednisone by dropping about 5-10 mg every week in a way that still controls the patient’s pain. The total duration of treatment is usually 2 to 8 weeks of prednisone is required. Rarely, the course may be longer.
Propranolol for symptoms of hyperthyroidism.
Prognosis: The symptoms of hyperthyroidism can last for several weeks and may be followed by 4-6 months of hypothyroidism. Normal thyroid function usually comes back within 12 months. 5% of patients will need long-term thyroid replacement medication.

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“The initial “destructive” phase of subacute thyroiditis presents with signs, symptoms, and laboratory findings of overt hyperthyroidism; however, a radioactive iodine uptake scan is negative in this phase. Graves disease and toxic multinodular goiter also present with overt hyperthyroidism, but radioactive iodine uptake is high. Factitious thyrotoxicosis is associated with low TSH and elevated or normal free T4 and total T3, but a goiter is not present. A TSH-secreting pituitary adenoma results in elevated TSH, free T4, and total T3.” ABFM critique 2017

**Some authors recognize three different forms of subacute thyroiditis. Take a look at this intro from Medscape authors:
“Subacute thyroiditis is a self-limited thyroid condition associated with a triphasic clinical course of hyperthyroidism, hypothyroidism, and return to normal thyroid function. Subacute thyroiditis may be responsible for 15-20% of patients presenting with thyrotoxicosis and 10% of patients presenting with hypothyroidism. Recognizing this condition is important; because it is self-limiting, no specific treatment, such as antithyroid or thyroid hormone replacement therapy, is necessary in most patients.

In general, the following 3 forms of subacute thyroiditis are recognized:

  • Subacute granulomatous thyroiditis – Also known as subacute painful thyroiditis or de Quervain thyroiditis.
  • Subacute lymphocytic thyroiditis – Also known as subacute painless thyroiditis
  • Subacute postpartum thyroiditis”  Subacute thyroiditis, Medscape.

On the other hand, an article on the Thyroid Foundation of Canada lists:

  • Subacute thyroiditis
  • Silent thyroiditis
  • Post-partum thyroiditis

As different types of thyroiditis and not sub-forms of subacute thyroiditis.

 

Further Reading
Hyperthyroidism: Diagnosis and treatment. Am Fam Physician 2016;93(5):363-  370.

 

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