Subacute thyroiditis and thyroid inflammatory nodule secondary to COVID-19: a primary care case report.

Objective: To describe a case of subacute thyroiditis (SAT) secondary to COVID-19 in the primary health care (PHC).

Case Description: A 51-year-old woman was treated in a PHC facility for flu-like symptoms for 5 days and pain in the lower neck. Symptomatic drugs were prescribed, and the patient was tested for COVID-19. On reassessment, the patient presented a painful oedema on the thyroid gland, dysphagia, and improvement in flu-like symptoms. Nonsteroidal anti-inflammatories were prescribed, and thyroid function analysis and inflammatory markers were collected. Reassessment after 1 week showed positive polymerase chain reaction-rapid test for COVID-19, partial improvement of neck pain, alterations in thyroid hormone tests (suppressed thyroid stimulating hormone and slightly elevated T4), and elevated C-reactive protein. Thyroid gland ultrasonography (USG), anti-thyroglobulin, and anti-thyroid peroxidise (anti-TPO) antibodies were requested and prednisone was prescribed. Anti-thyroglobulin and anti-TPO antibodies were negative; thyroid USG showed a solid nodule in the left lobe (approximately 4 cm), classified as TIRADS-4. The patient was sent to the Endocrinology Service, and a thyroid fine needle aspiration was requested. USG prior to the examination evidenced a complete regression of the nodule, which was diagnosed as an inflammatory pseudo nodule.

Conclusion: We presented the case of a patient who was treated in a PHC facility for rare findings of SAT secondary to mild COVID-19, concomitant with a thyroid nodule that had complete remission after approximately 3 months and was interpreted as an inflammatory pseudo nodule secondary to SAT. PHC professionals should be aware of this condition and conduct adequate follow-up of these patients.