Endocrine Abstracts

Introduction: Myxedema coma is the ultimate stage of severe long-standing hypothyroidism, representing a true endocrinological emergency. Many precipitating factors have been identified, including the initiation of certain drugs.

Case report: An 89-year-old woman was admitted to our emergency department due to an inaugural seizure. There was a history of progressive functional deterioration in the last 7 weeks, short after being diagnosed with lymph node tuberculosis (8 weeks before). There was no known history of previous thyroid disease. She suffered from atrial fibrillation, under chronic treatment with amiodarone, and she had undergone scalp radiotherapy for tinea capitis during her childhood. The patient presented with marked psychomotor lentification, hypothermia (33.4^o C), hypotension (75/25 mmHg) and hypoglycemia (41 mg/dl). Her blood sample revealed normocytic normochromic anemia (9.5 g/dl), mild hyponatremia (133 mmol/l), marked rhabdomyolysis (creatine kinase 610.6 U/l; myoglobin 789.0 μg/L) and primary hypothyroidism (TSH 288.0 μUI/ml; fT4 0.23 ng/dl) with negative antithyroid antibodies titer. There was no evidence of respiratory failure, ongoing acute infection or ischemic event. The brain CT revealed signs of chronic ischemic leukoencephalopathy. Confirming the diagnosis and its severity, the patient scored a total of 95 points in the Diagnostic Scoring System for Myxedema Coma. It is likely that the patient’s hypothyroidism was due to a Wolf-Chaikoff effect to amiodarone but the precipitating factor myxedema coma seemed to be the initiation of the antitubercular medication, namely rifampicin, which is a known inducer of CYP450 with a potential effect by increasing thyroid hormones’ metabolism. During hospitalization, the patient responded well to levothyroxine supplementation, gradually resolving every organic disfunction and was discharged under oral levothyroxine, 36 days after admission.

Discussion: Myxedema coma is a serious clinical condition with high morbidity and mortality.

When introducing medications that may alter the metabolism of thyroid hormones, namely CYP450 inducers or inhibitors, it is important to monitor thyroid function. This case highlights that this should be a routine procedure not only for patients with known hypothyroidism but also for those with risk factors for thyroid dysfunction.