Severe hypothyroidism in patients dependent on prolonged thyroxine infusion through a jejunostomy

Enteral absorption of thyroxine (T4) is variable; the duodenum and jejunum appear to be the most important sites of absorption. Our objective is to demonstrate that T4 infused via a standard jejunostomy may occasionally be poorly absorbed.

Two patients underwent esophagolaryngeal resection for carcinoma of the cervical esophagus. The procedure was accompanied by complete removal of the thyroid and parathyroid glands. A neck fistula at the gastropharyngeal anastomosis led to a restriction of oral intake; daily requirements of T4 and nutrients were given via the jejunostomy. T4 plasma levels deteriorated and thyroid-stimulating hormone (TSH) levels increased and in the third postoperative week, T4 (300 microg) was administered via a nasogastric tube.

Although given a high dose (300 microg) of T4, both patients developed severe hypothyroidism. Infusion of T4 through the nasogastric tube precipitated the normalization of T4 and TSH plasma levels. Both patients (cases 1 and 2) resumed oral intake during the fifth and sixth postoperative weeks respectively.

T4 malabsorption may occur in patients dependent on prolonged T4 infusion via a standard jejunostomy.