not-yet-known not-yet-known not-yet-known unknown Case History, Examination, and Investigation A 27-year-old female with a history of papillary thyroid carcinoma has presented with general fatigue and cold intolerance. The patient was diagnosed with papillary thyroid carcinoma at the age of nine and underwent total thyroidectomy. Since then, the patient has been committed to oral levothyroxine (LT4) daily. However, at the age of 22, a recurrence was discovered in the lymph nodes and she had a neck dissection, the pathology was positive for metastasis in 6 out of 20 lymph nodes on the left side and 8 out of 18 lymph nodes on the right side, followed by radio-iodine ablation (RIA). The patient had another neck dissection at the age of 24, due to disease recurrence. By that time, positron emission tomography (PET) scans showed uptake in the thyroid bed and posterior neck, in addition to increased levels of thyroglobulin, and later in the same year, a biopsy demonstrated papillary thyroid carcinoma in the right lobe. However, the multidisciplinary team decided there was no need for the surgery, and the patient will continue to have regular follow-up visits, PET scans, and daily oral LT4 400 mg. At the age of 27, and despite being committed to LT4, the patient starts feeling fatigued and shows cold intolerance. Other physical exam findings were normal. Laboratory values showed TSH levels of 66 mIU/L, hemoglobin of 8 g/dL, and deficiency in vitamin D and B12. The patient was admitted for further follow-up, given IV levothyroxine 300 mcg daily for four days, and put on IV thyroxine once a month in addition to the oral dose. The patient’s status improved after the IV administration, and TSH doped to 3 mIU/L.