Endocrine Abstracts

A 51-year-old lady known to suffer from Graves’ disease with associated orbitopathy since the age of 29 years, presented to endocrine outpatient clinic in view of recurrent symptoms of hyperthyroidism. She complained of heat intolerance, lethargy, tremor and diarrhoea. Appetite was normal and her weight remained stable. She had no worsening of visual symptoms. She was on carbimazole 5 mg daily since a year before. She had multiple courses of carbimazole in the past with subsequent recurrence. On examination she was clinically euthyroid. She had exophthalmos, lid retraction and lid lag bilaterally. There was no diplopia and full range of eye movements. Neck examination showed a diffuse smooth goitre with no retrosternal extension or bruits. There was no cervical lymphadenopathy.

Thyroid function tests on presentation were as follows:

TSH 0.033 mIU/l (0.3–3) ↓

Free T4 (fT4) 36 pmol/l (11–18) ↑

Free T3 (fT3) 9.03 pmol/l (3.5–6.5) ↑

Carbimazole was increased to 20 mg. Thyroid function tests improved and she was referred for thyroidectomy once rendered euthyroid on treatment. Post-thyroidectomy, she became hyperthyroid again on even small doses of levothyroxine and thus the latter was stopped (Table 1). She remained hyperthyroid even off levothyroxine and she was investigated for residual thyroid tissue. An NM Thyroid Scan initially showed no evidence of thyroid tissue in the neck. Stroma ovarii was also ruled out as there was no significant tracer uptake in the abdomen and pelvis. The patient was restarted on carbimazole as she remained hyperthyroid. A whole body Iodine scan performed at the time the patient was subclinically hypothyroid on treatment (TSH 11.954 mIU/l; fT4 15.25 pmol/l), showed a relevant focus of increased tracer uptake in the neck, practically at the midline, suggestive for the presence of residual thyroid tissue. The patient was referred for surgical re-evaluation.