Endocrine Abstracts

TSH supression therapy with thyroid hormone is a mainstay of thyroid cancer treatment. Effectiveness of thyroid hormone therapy may be disrupted by nonadherence of the patient, interfering drugs, foods and intestinal disorders. We here present a case of papillary thyroid cancer with unsuccessful supression therapy.

Case: A 38 year old woman, underwent total thyroidectomy for euthyroid multinodular goitre, with a pathological diagnosis of papillary thyroid carcinoma was referred to our clinic for further evaluation. She recieved radioiodine ablative treatment and was started TSH supression therapy. Her past medical and family history were unremarkable. On physical examination, a blood pressure of 100/60 mmHg, heart rate of 72 beats/min, thyroidectomy scar, normal reflexes were recorded. Laboratory evaluation revealed; hemoglobin:11.6 g/dl (12–16), MCV:79.9 FL (80–95), calcium:8.8 mg/dl (8.4–10.2), albumin: 4.6 g/l (3.5–5), TSH: >75 IU/ml (0.4–5), free T4: 0.6 ng/dl (0.8–1.9), anti-thyroid peroxidase antibody: <10 IU/ml (0–50), anti-thyroglobuline antibody:<20 IU/ml (0–50). During follow up, the optimum TSH supression could not be achieved despite the progressive increaments in thyroid hormone dose (Levothyroxine sodium, 350 μ/day; levotriiodothyronine sodium, 150 μ/day). She had no compliance problems and told about mild diarrheal episodes when asked for malabsorbtive symptoms. Antiendomysium and antigliadin antibodies were negative. Endoscopic biopsy of the small intestine revealed intraepithelial lymphocytes and focal villous atrophy characteristic for celiac disease. Gluten free diet was started, her diarrheal episodes were relieved and her TSH level fell to target supression levels.

Conclusion: Oral thyroid hormone treatment is a relatively vulnerable therapy which is easily affected by ingested substances or medications. In a patient with unsuccessful thyroid hormone replacement or supression therapy, with no adherence problems and interfering substances or drugs, malabsorption should come into mind and be evaluated.