Rapid weight loss, breathlessness and diarrhoea in a bone marrow transplant recipient.
A Theodoraki, P Kottaridis, PM Bouloux and B Khoo.
Royal Free Hospital NHS Trust, Hampstead.
A 56 year old man presented with a two week history of weight loss, breathlessness, palpitations and diarrhoea. Six months prior to his admission, he had received an allogeneic bone marrow transplant from a matched unrelated donor for Chronic Myeloid Leukaemia. In the post-transplant period he developed grade I skin Graft versus Host Disease and followed by acute EBV infection.
On examination he was noted to be tachycardic with bilateral hand tremor and marked lid lag. His thyroid was not tender on palpation and was not felt to be enlarged. Thyroid function tests showed biochemical thyrotoxicosis with a suppressed TSH <0.02mU/L and FT4 >100pmol/L, ESR was 112mm/h, CRP 37 mg/L and WBC 1.98 x10^9/L with 1.53 x10^9/L neutrophils.
A thyroid Tc99 uptake scan showed reduced uptake function at 0.13% suggestive of thyroiditis. He was started on propranolol for symptom relief. Ten days later his FT4 was 28.9pmol/L. Five weeks from the initial presentation he became hypothyroid and was commenced on levothyroxine which he continues one year after the initial presentation. Interestingly Thyroid peroxidase and TSH receptor antibodies were not detectable. Of note, his thyroid function before and three months after the bone marrow transplant was normal.
Thyroiditis in bone marrow transplant recipients is though to result from a combination of toxic factors and immune processes. Graft versus host disease in unrelated donor transplants and the use of alemtuzumab for T cell depletion are thought to be contributory.