Endocrine Abstracts

Case history: A 65 year old unresponsive female, admitted as a stroke call, was found to have myxoedema crisis with admission TSH level of >100 mIU/l and T4 of 0.7 pmol/l. She was known hypothyroid with poor medication compliance. ITU admission for intubation and ventilation, CVVH (renal filtration) and vasopressors was required. Total length of ITU stay was 62 days, prolonged by cardiac complications during correction. There was no known cardiac history. On Day 7 of admission, X had increasing noradrenaline requirements alongside new ST depression and troponin rise. Cardiology diagnosed type two MI. Aspirin, clopidogrel and a beta-blocker were commenced. On Day 34 of admission there was further deterioration. X required return to DuoPAP having been on BiPAP for 5 days. Serial troponins showed a substantial rise reaching 1066. X received 4 stents in angiography on Day 44 of admission. The first ECHO carried out was Day 5 of admission, which showed moderate mitral regurgitation. This deteriorated during admission to severe MR with new RWMAs and a pericardial effusion. Pulmonary oedema, not present on admission, required intensive offloading and bilateral drainage.

Investigations: Weekly Thyroid Function Tests. Serial troponin and ECHOs.

MDT team: ITU, Endocrinology and Cardiology

Results and treatment: Liothyronine 10 μg IV BD was initiated. Levothyroxine was started at Day 3 at 25 μg NG and increased by increments of 25 μg every 7 days until 150 μg. Hydrocortisone, initiated at 100 mg QDS was weaned. Cortisol levels showed no adrenal insufficiency.

Thyroid function tests:

Week 0: TSH >100 mIU/l T4 0.7 pmol/l

Week 1: TSH 28.15 mIU/l; T4 0.6 pmol/l

Week 2: TSH 10.78 mIU/l; T4 2.8 pmol/l

Week 3: TSH16.48 mIU/l; T4 3.4 pmol/l

Week 4: TSH 39.55 mIU/l; T4 8.1 pmol/l

Week 5: TSH 55.84 mIU/l; T4 12.4 pmol/l

Week 6: TSH 11.43 mIU/l; T4 16.5 pmol/l

Conclusion and points for discussion: True myxoedema crisis is rare. Therefore, there are limited studies to guide on the optimum rate of thyroid function correction. Rapid thyroid replacement risks precipitating myocardial infarction, particularly in those with poor cardiac baseline. This case highlights the importance of establishing a cardiac baseline (i.e., an admission ECHO) to plan for a slower correction and early involvement of the cardiology team. Myxoedema coma continues to have poor prognosis, which is worsened further in those that experience cardiac complications. Avoiding these events through a better understanding of optimum correction rates will improve outcomes in this subsection of patients.