Endocrine Abstracts

Section 1: History: Myxoedema coma is a rare, emergency presentation of extreme hypothyroidism, but without robust evidence to base management recommendations on. We present the case of a woman in her seventies who was admitted following a fall. Collateral history revealed five days of worsening mobility, drowsiness, and confusion with poor oral intake. This progressed to slurred, incoherent speech, and brief vacant episodes. Her background included glaucoma, mastectomy, and iron deficiency anaemia. No recent illnesses prior to this admission was reported.

Section 2: Investigations: On examination, she was bradycardic and hypothermic, with a depressed sensorium. Initial blood tests demonstrated hyponatraemia (115 mmol/l) and raised Creatine Kinase (11236 U/l). Inflammatory markers were within normal range. CT head excluded intracranial haemorrhage. TSH was elevated at 88 mU/l, with depressed free thyroxine <5.5 pmol/l and free T3 2.2 pmol/l, supporting the diagnosis of myxoedema coma. Cortisol was 808 nmol/l. No obvious precipitating event was identified on work up.

Section 3: Results and Treatment: Endocrinology input was sought and they initially recommended intravenous (IV) loading doses of both T3 (liothyronine) and T4 (levothyroxine), followed by a maintenance prescription. However, IV formulation of T4 was not available immediately, therefore a nasogastric feeding tube was placed. T3 was delivered intravenously and T4 was administered enterally. Under this regimen and supportive measures, remarkable clinical improvement was observed. In 72 hours, serum T3 normalised, and the TSH reduced to 16.9 mU/l. T3 subsequently discontinued. Follow up for hypothyroidism was arranged as an outpatient.

Section 4: Conclusion and Points for Discussion : Myxoedema coma has a high mortality rate and controversy exists as to the optimum regimen for thyroid hormone replacement. Recommendations are largely based on case reports and expert opinion. There is debate as to whether to employ purely T4 or use it in combination with T3. Concerns also exist about safety in those with arrhythmias and coronary artery disease. There is also potentially impaired enteral absorption in this situation. However, there are multiple case reports of enteral routes being utilised to deliver thyroid hormone treatment in this setting. In our patient, the choice of replacement was influenced by both the clinical status and the immediate availability of drugs. Endocrinologists are encouraged to make themselves aware of the local availability patterns to prevent delays in an emergency situation. The decisions regarding replacement strategies are guided by a case-by-case approach.