Endocrine Abstracts

Introduction: Refractory hypothyroidism is known as the persistence of clinical and biological signs of hypothyroidism after 6 weeks of treatment or therapeutic adjustment, despite a dose exceeding 1.9μg/Kg/d of Levothyroxine. Several etiologies may be incriminated.

Observation: A 36-year-old patient, followed for Gougerot-sjogren syndrome, having benefited from a thyroidectomy in 2015 in a context of biological hyperthyroidism, on Levothyroxine (LT4) 200μg/d and Liothyronine sodium (LT3) 25μg/d with persistence of refractory hypothyroidism. The clinical examination revealed a slightly slowed down patient, presenting a mucocutaneous infiltration, a hoarse voice, a bilateral galactorrhea evolving since 1 year, and a chronic constipation. All this in a context of generalized asthenia. At the workup, TSHus was 500μUI/l, free T4 <0.4 ng/dl (0.7-1.5), hypertriglyceridemia at 12.9g/l put on fenofibrate 160 mg/d. Brain MRI showed a pituitary bulge with no other detectable abnormality. After elimination of poor compliance and possible drug interactions, the diagnosis of refractory hypothyroidism was retained. Parasitological examinations of the stools showed Giardiasis and the patient was put on metronidazole. The Helicobacter Pylori serology came back positive with a pangastritis aspect at the oeso-gastro-duodenal fibroscopy, put under eradication treatment. As hypothyroidism persisted, the patient was put on Dexamethasone 1 mg/d for one week, then tapered to 0.5 mg/d, reduction of levothyroxine dose to 175μg/d and maintenance of Liothyronine sodium at 25μg/d, with clinical improvement of hypothyroidism signs. The thyroid check-up showed a TSHus of 4.63μUI/ml, and a free T4 of 19.86 pmol/l (10.6-19.4)

Conclusion: High-dose glucocorticoids may be considered in some cases of hypothyroidism, especially in patients requiring high doses of thyroid hormones when even the LT4 + LT3 combination is insufficient to achieve euthyroidism.