Endocrine Abstracts

A 76 year old female presented in 2000 with thyrotoxicosis secondary to Grave’s disease. She was treated successfully with propylthiouracil (PTU) for 2 years then opted for and received a standard therapeutic dose of radioactive iodine (¹³¹I) in September 2003. Her thyroid function tests (TFTs) normalised in the first 6 months after treatment (FT4 <14 pmol/l) and she was started on replacement thyroxine 50 mcg od for 8 weeks. She presented in March 2004 with symptoms and signs of thyrotoxicosis (FT4>50,FT3>20) and was admitted and treated with B-blockers and PTU but deteriorated rapidly with development of type 2 respiratory failure secondary to hospital acquired pneumonia, hypotension and fast atrial fibrillation (AF) and cardiac arrest necessitating admission to intensive care unit on 2 occasions. During her admission she had severe thyrotoxicosis (FT4 >77, FT3 13.5) and was hospitalised for over 3 months as she made a slow recovery and was discharged on PTU 250 mg/day. She received a second standard therapeutic dose of ¹³¹I August 2004 but relapsed 3 months later (FT4 26,FT3 6.6) and was recommenced on PTU (up to 750 mg /day). The dose of PTU was gradually reduced as the patient became profoundly hypothyroid after 6 months of treatment (TSH 61.8,FT4 6, FT3 3.8) and PTU was eventually stopped in April 2005. She remained euthyroid until July 2005 when repeat TFTs showed biochemical recurrence (FT4 20.8, FT3 6.8, TSH <0.05) and PTU was recommenced at 50 mg od.

This case illustrates the fact that some patients have atypical very potent hyperthyroidism and that thyroid storm can occur even in well-prepared patients following radioiodine. These patients may have a more potent variety of hyperthyroidism.