Kerr D, Skinner D W, Hosking D J, Bradley P J, Salama F D
Metabolic Unit, University Hospital, Nottingham.
Eur J Surg Oncol. 1990 Oct;16(5):436-42.
We have studied calcium regulation in 11 consecutive patients undergoing radical surgery for upper aerodigestive tract malignancy. Eight patients received postoperative parenteral nutrition including calcium (19 mmol/day) and tri-iodothyronine (30 micrograms/day) supplementation. Three patients received enteral nutrition with calcium (70 mmol/day), 1.25 dihydroxycholecalciferol (1 microgram) and thyroxine (150 micrograms/day) via a nasogastric tube. Mean (SEM) corrected calcium fell from 2.42 (0.013) to 2.03 (0.036) mmol/l after 24 h (P less than 0.01). Replacement therapy generally maintained the serum calcium above 2.0 mmol/l. However, values were associated with only one episode of tetany. Phosphate increased from 1.10 (0.05) to 1.79 (0.11) mmol/l, 7-9 days postoperatively (P less than 0.001). Tubular calcium reabsorption fell and urinary calcium excretion rose, consistent with loss of parathyroid hormone (PTH) action on the distal nephron. However, the renal leak of calcium can be considerably reduced by concomitant salt depletion. This enhances proximal tubular sodium and calcium reabsorption thereby limiting calcium delivery to the distal nephron. This offsets the consequences of the loss of PTH which normally regulates distal calcium reabsorption.
我们研究了11例连续接受上消化道恶性肿瘤根治性手术患者的钙调节情况。8例患者术后接受肠外营养，包括补充钙（19 mmol/天）和三碘甲状腺原氨酸（30微克/天）。3例患者通过鼻胃管接受肠内营养，补充钙（70 mmol/天）、1,25-二羟胆钙化醇（1微克）和甲状腺素（150微克/天）。24小时后，校正钙均值（标准误）从2.42（0.013）降至2.03（0.036）mmol/L（P<0.01）。替代治疗一般可使血清钙维持在2.0 mmol/L以上。然而，这些数值仅与1次手足搐搦发作相关。术后7 - 9天，磷酸盐从1.10（0.05）升至1.79（0.11）mmol/L（P<0.001）。肾小管钙重吸收下降，尿钙排泄增加，这与甲状旁腺激素（PTH）对远端肾单位作用丧失一致。然而，同时限制盐分摄入可显著减少肾脏钙流失。这增强了近端肾小管对钠和钙的重吸收，从而限制了钙向远端肾单位的输送。这抵消了正常调节远端钙重吸收的PTH丧失的后果。
