Tuberculous Thyroiditis Post COVID-19 Infection

Thyroid tuberculosis (TT) is a rare disease and can be a diagnostic challenge. Here we highlight a case of TT following COVID-19 infection. A 38-year Myanmar immigrant female presented with nocturnal fever, fatigue, nausea, sore throat, appetite and weight loss for 1 week with dysphagia, neck swelling, dyspnea, and watery diarrhea. Medical history included renal transplant due to ESRD from IgA nephropathy, DM and treated latent TB with no prior or family history of thyroid disease. She had COVID 7 months ago, complicated by allograft rejection. She was tachycardic, febrile but not in acute distress. Neck exam revealed diffuse thyromegaly with tenderness on right lobe without bruit, palpable cervical lymphadenopathy nor tremors. Labs showed WBC 12.8x10(9)/L (4.8-10), and ESR 50 ml/hr (20-40). On admission, she developed AKI and immunosuppressant meds were discontinued. She was started on broad-spectrum antibiotic. CT chest reported moderate loculated right pleural effusion with mid and lower lobe consolidation. Blood and urine culture, pleural fluid, sputum culture for acid-fast bacilli (AFB) and QuantiFERON-TB were negative. Upon persistent fever, RIPE therapy (rifampin, isoniazid, pyrazinamide, ethambutol) was started and stopped after 10 days due to transaminitis and negative TB PCR. Further labs showed TSH 0.04 mIU/ml (0.27-4.2), FT4 2.81 ng/dl (0.93-1.7), TT3 127 ng/dl (80-200), negative TPO and TSI. Endocrinology was consulted for thyroiditis. Ibuprofen and Propranolol were initiated with continuation of prednisone. Repeat thyroid labs normalized in 4 days. US thyroid noted diffuse, heterogenous thyromegaly without hypervascularity or abscess. CT neck showed diffuse thyromegaly 4.2x7.2x7.5 cm in size; right thyroid lobe extended to posterior clavicle with enhanced capsule, without discrete lymph node or vascularity changes, suggestive of thyroiditis. Fine needle aspiration (FNA) of left thyroid lobe drained 3 ml purulent fluid and AFB were seen on direct smear. She was diagnosed as TT, but unable to restart RIPE therapy due to worsening liver function. She expired after cardiac arrest due to intracranial bleeding and brain abscess. Thyroid tuberculosis is a rarely reported clinical entity. This is the first reported case of secondary TB (TT) in post-COVID infected patient from reactivation of latent TB. In our case, follicular destruction caused initial hyperthyroidism with later recovery. It can be difficult to distinguish subacute from suppurative thyroiditis due to TB. Imaging may not always show clear abscess formation. FNA is crucial for diagnosis, and drainage of any abscess. Anti-TB meds can be given, surgery is rarely required. TT should be considered in any immunocompromised patient with fever and neck pain. Imaging should also include evaluation for any CNS spread of TB. Early detection and treatment will help reduce significant morbidity and mortality.