Treatment of unresponsive hypoparathyroidism when the oral route administration is not possible: considering subcutaneous teriparatide.

Treatment of unresponsive hypoparathyroidism when the oral route administration is not possible: Considering subcutaneous teriparatide Tratamiento con PTH subcutánea en el hipoparatiroidismo posquirúrgico de difícil control cuando la vía oral no está disponible PTH is a polypeptide of 84 amino acids with an active fragment of 34 amino acids in the N-terminal extreme. It is secreted by the parathyroid glands, and it is involved in the regulation of calcium metabolism; its deficiency produces hypocalcemia. Hypoparathyroidism is most commonly caused by radical surgery of the neck or total thyroidectomy; according to different series it affects to 8-12% of the patients temporarily, and 1-2% of the cases permanently. 1 The usual chronic management of hypopa-rathyroidism is supplementation with calcium and 1,25-OH vitamin D (calcitriol) in variable doses. However, this treatment is sometimes insufficient. We report the case of a 52-year-old man, with stage IV larynx carcinoma (lung metastases) diagnosed in 2011. Despite radiotherapy and several lines of chemothe-rapy, he presented slow progression of the neoplasic disease. In 2014, because of progressive dyspnea, he underwent total palliative laringuectomy, which included total thyroi-dectomy with extensive resection of surrounding tissues. Histopathological study showed a moderately differentiated squamous cell carcinoma, with lymphatic and vascular invasion, as well as infiltration of adjacent tissues. Pos-toperatively, he developed a pharyngo-cutaneous fistula, and a nasogastric tube (NGT) was then placed for enteral nutrition, awaiting the closure of the fistula. Levothyroxine replacement, calcium and calcitriol were started through the NGT. However, the patient developed unresponsive pos-toperative hypocalcaemia, and was thus referred to the Endocrinology Department. Pre-operative thyroid function and calcemia had always been normal. At the time of our assessment, the patient presented paresthesias. Calcemia reached a nadir of 5.8 mg/dL (normal 8.5-10 mg/dL), with normal albumin serum levels, while serum magnesium was as low as 1.3 mg/dL (normal 1.8-2.6 mg/dL). Serum phosphate was normal. The circulating post-operative PTH was undetectable (<2 pg/mL), and 1,25(OH)2 D3 was of 20 pg/mL (18-70 pg/mL). Conventional treatment of hypoparathyroidism with calcium, magnesium, and calcitriol supplementation was started. We reached high medication doses (calcitriol 4 ␮g/24 hs, diluted to prevent precipitation in the NGT; calcium 6000 mg/day; and magnesium 1152 mg/day). Nevertheless , magnesium and 1-25-OH vitD levels were persistently low (1.3 mg/dL and 24 pg/mL, respectively). Moreover, the patient had poor digestive tolerance of these large calcium load, and required frequent intravenous infusions of calcium due to hypocalcaemia, which prevented hospital discharge. On the …