Subacute Thyroiditis in Early Pregnancy: A Rare Case Report
Journal of the Endocrine Society
Background Subacute thyroiditis (SAT) is a self-limiting inflammatory disorder that can be caused by a viral infection and presents with neck pain, fever, and fatigue. To date, only 8 cases of SAT have been reported in pregnant women. Hyperthyroidism during pregnancy is associated with both maternal and neonatal complications. The early diagnosis and treatment of SAT during pregnancy may play a vital role in prevention of adverse fetal outcomes. Case Presentation A 37-year-old female in her 6th week was referred to the endocrinology clinic for neck pain that started two months ago following a viral sore throat. She also reported exhaustion, palpitations, and occasional dysphagia. This is her 10th pregnancy, and she reports a history of thyroid isthmic cysts with hemorrhagic degeneration drained in 2014.The patient is a former occasional smoker and denies alcohol or drug use. Family history is significant for autoimmune disease in her sibling, and type 2 diabetes mellitus in her father. On physical exam, her neck is soft, supple, with no lymphadenopathy. The thyroid gland is enlarged to approximately 40 grams and is mildly tender to palpation. Labs were significant for thyroid-stimulating hormone (TSH) of 0.01 uIU/ml (reference range 0.4-4.5 uIU/ml), serum-free triiodothyronine (FT3) of 4.7 pg/ml (reference rage 1.7-3.7 ng/dl), serum-free thyroxine (FT4) 1.6 pg/ml (reference range 0.7-1.5 pg/ml), ESR 67 mm/hr (reference range 0-18 mm/hr), CRP 52.6 mg/L(reference range <8 mg/L). Thyroid ultrasound revealed enlarged heterogeneous thyroid gland , with poorly defined hypoechoic areas. Based on patients’ symptoms, physical examination, and laboratory findings she was diagnosed with SAT. After review of prior literature and coordination with the patient’s obstetrician, she was started on prednisone 20 mg with a plan to taper by 5 mg weekly with close observation of thyroid function tests. Antibody assessment of thyroid was diffusely negative. Repeat assessment of the patient’s thyroid function tests showed improvement in tsh, FT3, and FT4 to 0.04, 2.4, and 0.9 respectively. The patient reported feeling significantly improved at the 2 week mark. Discussion and conclusion SAT during pregnancy is rare but requires careful management. To date, various treatment modalities are reported in case studies but there is a lack of consensus on medication dosing given the rarity of the presentation. The pathogenesis of SAT is still unknown but is thought to be secondary to destruction of thyroid follicular cells, resulting in the release of thyroid hormone and symptoms of thyrotoxicosis. SAT diagnosis is based on the patient's medical history, symptoms, physical and laboratory findings, and exclusion of other reasons for thyroid dysfunction. Pregnant women with hyperthyroidism need to be differentiated from Graves' disease, and monitoring of thyroid hormone levels is important for fetal outcomes.
El Sayed F, Shelden D. Subacute thyroiditis in early pregnancy: a rare case report. J Endocr Soc. 2023 Oct;7(Suppl 1):A949-A950. doi:10.1210/jendso/bvad114.1779