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Published on: March 17, 2023
Pyrexia of unknown origin due to subacute thyroiditis
Rohini S1, Merin Thomas1, Vishnu Rajan Nair1
1Respiratory Medicine, Amrita Institute of Medical Sciences and Research Centre, Kochi, Kerala, India.
BMJ Case Reports
|June 18, 2026
Summary
Subacute thyroiditis can present as pyrexia of unknown origin (PUO) without typical symptoms. This case highlights considering thyroiditis in unexplained fever, even without neck pain.
Area of Science:
- Endocrinology
- Internal Medicine
Background:
- Subacute thyroiditis typically causes neck pain and thyrotoxicosis.
- Presentation as pyrexia of unknown origin (PUO) is rare and can delay diagnosis.
Purpose of the Study:
- To report a case of subacute thyroiditis presenting solely as PUO.
- To emphasize considering subacute thyroiditis in unexplained fever with elevated inflammatory markers.
Main Methods:
- A case report of a patient in their late 50s presenting with PUO.
- Diagnostic workup included physical examination, thyroid function tests, and technetium-99m thyroid scintigraphy.
- Treatment involved corticosteroids.
Main Results:
- Initial extensive evaluation for common causes of PUO was negative.
- Thyroid function tests revealed suppressed TSH and elevated thyroid hormones.
- Thyroid scintigraphy showed reduced uptake, confirming subacute thyroiditis.
- Corticosteroid treatment led to rapid fever resolution.
Conclusions:
- Subacute thyroiditis should be considered in the differential diagnosis of PUO, even without classic thyroid symptoms.
- Early consideration and appropriate testing can prevent diagnostic delays in such cases.
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