Thyroiditis

Question 1

Define thyroiditis

Answer 1

De Quervain’s thyroiditis or subacute granulomatous thyroiditis is a self-limiting inflammation of the thyroid gland. It is associated with a triphasic clinical course that lasts for a few weeks to many months, characterised by transient thyrotoxicosis, hypothyroidism, and then a return to normal thyroid function.

Question 2

What are the causes/risk factors of thyroiditis?

Answer 2

The aetiology is presumed to be viral, especially an URTI. A seasonal variation has been noted in several studies in many countries, with the highest incidence in the summer and autumn. Candidate viruses include:
• Coxsackie virus
• Mumps virus
• Adenoviruses

Question 3

What are the symptoms of thyroiditis?

Answer 3

• History of an abrupt onset of virus-like illness.
• Fever ( > 38 0C)
• Myalgia
• Weakness
• Pharyngitis, and neck pain radiating to the ear.
• Symptoms of hyperthyroidism at first.

Question 4

What are the signs of thyroiditis?

Answer 4

• pyrexia
• enlarged, firm, tender thyroid gland
• signs of hyperthyroidism

Question 5

What investigations are carried out for thyroiditis?

Answer 5

• TFTS - initially, Primary Hyperthyroidism –Raised T4/T3 and Low TSH.
- Then: Primary Hypothyroidism: Low T4/T3 and High TSH.
- Then, Euthyroid.
• T3:T4 Ratio - when moderately or highly thyrotoxic from subacute granulomatous thyroiditis, the T3:T4 ratio is generally <15:1.
• Radioisotope Uptake Scan I-123 radioactive iodine scan or Technetium-99 Pertechnetate:
- Very low or no uptake,
• CRP/ ESR - elevated
• FNA - multi-nucleated giant cells, with a background of degenerated follicular epithelium cells, rare epithelioid granulomas, and mixed inflammatory cells.
• Thyroid USS - focal heterogeneous dark areas with irregular margins in the area that is painful; decreased internal vascular flow with decreased or normal peripheral vascular flow by Doppler.

Question 6

What is the management for thyroiditis?

Answer 6

• Treatment is focused on providing pain relief and treating any manifestations of hyper- or hypothyroidism that may be present.
• Not all patients require treatment, as symptoms may be mild and/or subsiding by the time the diagnosis is made.
• It is a self-resolving viral infection and thus bed rest is the most appropriate treatment.

Hyperthyroid Phase:
• Analgesia: NSAIDs
• Beta-Blockers e.g. propranolol for severe symptoms of hyperthyroidism.
• ATDs do not work since it is due to the release of pre-formed iodothyronines.

Hypothyroid Phase:
• If the hypothyroidism is very severe, treat with exogenous levothyroxine. This is not needed in most cases.

Question 7

What are the complications of thyroiditis?

Answer 7

• thyroid strorm
• long-term Hypothyroidism: Approximately 10% of patients will have permanent hypothyroidism and will require lifelong levothyroxine to normalise the TSH. This occurs when the patients do not progress to the 3rd phase