New Onset Recurrent Acute Infectious Thyroiditis in an Adult Patient

Introduction: Acute infectious thyroiditis can be seen in patients with congenital abnormalities of the piriform sinus, underlying autoimmune disease, or the immunocompromised. In most patients, an upper respiratory tract infection precedes the development of the neck abscess. Case description: The patient is a 39-year-old Caucasian woman with history of Hidradenitis suppurativa (HS) and thrombocytopenia who presented to the hospital with sore throat, dysphagia and left-sided neck swelling. She was recently started on Humira for HS. Review of systems was significant for heat intolerance, weight loss, palpitations and panic attacks. Family history was positive for Hashimoto’s thyroiditis. Initial lab evaluation was significant for elevated erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), mildly elevated free T4 (FT4) with suppressed thyroid stimulating hormone (TSH). She was found to have a nearly 6 cm left-sided thyroid abscess, which was eventually drained. Contrasted CT imaging showed multiple left laryngeal space abscesses with extension to the left thyroid gland. TSH gradually increased over two months to nearly 4 times upper limit of normal accompanied by low normal FT4. TSI and TPO antibodies were negative. Clinical course was complicated by recurrent abscesses which required percutaneous drainage and intravenous antibiotics. Discussion: Acute infectious thyroiditis is extremely rare disorder of the thyroid gland in adults. Most patients present with recurrent abscesses early during childhood. Imaging studies such as CT scan, preferred over MRI, and barium swallow can show a fistula connecting the piriform sinus and left lobe of the thyroid gland. Treatment includes needle aspiration, followed by drainage and IV antibiotic therapy. Surgical excision of the entire sinus tract and the involved area of the thyroid gland is the best method to achieve definitive cure. Conclusion: Lower left-sided thyroid abscess extending from the pyriform fossa to the thyroid bed should raise the suspicion for underlying third or fourth branchial fistula. Most cases present during childhood, but one third of cases occur in adults. Surgical excision after confirming the presence of a fistulous tract with imaging is the treatment of choice.