副甲狀腺切除後機動調整鈣劑量可以預防低血鈣

作者：Kathleen Louden  
出處：WebMD醫學新聞

　　October 20, 2009（伊利諾州芝加哥訊）－一項新研究結果顯示，罹患原發性副甲狀腺功能低下的病患，成功接受副甲狀腺切除後，提供他們術後口服鈣補充，且根據他們發生低血鈣的風險進行劑量調整，病患可以立即出院回家。
　　
　　主要作者Tampa南加大第一年外科住院醫師Marie Vasher表示，有症狀的低血鈣，是副甲狀腺切除後一個常見的問題，在4年的研究期間，6,000位病患有超過92%（5,540位）成功預防這個問題發生。
　　
　　她指出，發生術後低血鈣症狀，例如手部感覺麻痺、嘴巴周圍刺痛、意識模糊，460位（7.7%）病患確實發生術後低血鈣，幾乎所有病例可以在家自我投予鈣及維生素D補充品。根據文獻摘要，460位病患中僅有7位需要至急診接受靜脈注射鈣。
　　
　　Vasher醫師於美國外科醫學會第95屆年會臨床學會的卓越功績會議上發表這些結果。
　　
　　【其他中心也可以使用這個方案】
　　Vasher醫師表示，雖然她的中心進行副甲狀腺切除的數量很多，對於原發性副甲狀腺功能亢進相關外科手術進行比較少的中心，我認為這個鈣補充方案將可以適用。在病患離院前，他們可以實行類似的方案。
　　
　　Vasher醫師在一次與Medscape外科學的訪談中表示，這項研究中的所有病患都在2.5個小時內出院，且被教導如何使用口服檸檬酸鈣-維生素D錠劑（Citracal Regular 250 mg + D[拜耳藥廠健康照護LLC]），每個錠劑含有250 mg的鈣與200 IU的維生素D），在手術後3個小時內開始投予。這些病患在兩個星期後報告他們發生的低血鈣相關症狀。
　　
　　Vasher醫師表示，這個鈣補充方案是「機動性的」，臨床醫師在手術後頭兩個星期，一開始處方最高劑量，接著在第三個星期開始降低他們的起始劑量，以維持濃度。
　　
　　她指出，起始劑量是根據病患是罹患腺瘤或是增生。如果病患有比較多的術後症狀性低血鈣危險因子，則副甲狀腺切除術後的鈣與維生素D劑量會比較高。
　　
　　Vasher醫師解釋，這些危險因子包括罹患腺瘤患者術前血清鈣的上升的幅度（超過12、13甚至14 mg/dl的濃度）、嚴重骨質疏鬆症（T指數低於-3）、病態性肥胖（身體質量指數大於等於40 kg/m2）、切除超過一個以上副甲狀腺、以及對於使用剩下的腺體或進行切片。舉例來說，一位罹患副甲狀腺腺瘤患者術前的血鈣濃度越高，在術後發生症狀性低血鈣的風險越高，因此術後處方的鈣就應該更多。
　　
　　她表示，每增加一個危險因子，病患的每日基準點鈣補充量需要增加315 mg。
　　
　　她向Medscape外科學表示，我們的方案代表成功接受副甲狀腺切除治療原發性副甲狀腺功能亢進的患者，所需要的鈣補充基準量。每位病患最終將會根據他或是她對基準量來個人化每天服用的鈣錠劑數量。
　　
　　這些新的數據確認了一項由Vasher醫師與其他作者於兩年前報告的收納病患數較少小型研究結果（Endocr Pract. 2007;13:105-113）。早期的研究包括有關這項研究使用的鈣補充方案相關細節。
　　
　　【為積極的策略辯護】
　　臨床會議計劃委員會主席Barbara Bass醫師主持一項壁報座談會的討論時段，他向Medscape一般外科表示，這項研究為一項移除副甲狀腺後處方鈣與維生素D補充物以預防低血鈣症狀的積極策略辯護。
　　
　　Bass醫師是德州休士頓Methodist醫院外科部的主任，他並沒有參與這項研究，他宣稱適當的鈣補充可以預防低血鈣。這些研究結果可能協助不確定如何對接受副甲狀腺切除病患進行鈣補充的外科醫師。
　　
　　然而，她附帶表示，我想這個國家大部分的外科醫師在副甲狀腺切除後會對每個病患補充鈣與維生素D。要預防這些病患發生低血鈣並不難，鈣是個非常便宜且安全的補充品。
　　
　　Vasher醫師與Bass醫師表示已無相關資金上的往來。

Sliding Scale Calcium Dosing After Parathyroidectomy Prevents Hypocalcemia

By Kathleen Louden
Medscape Medical News

October 20, 2009 (Chicago, Illinois) — Patients with primary hyperparathyroidism can go home immediately after successful parathyroidectomy, provided that they receive postoperative supplemental oral calcium, with doses adjusted according to their assessed risk for hypocalcemia, a new study finds.

Symptomatic hypocalcemia, a common problem after this procedure, was prevented in more than 92% of 6000 patients (n = 5540) over the 4 years of the study, said lead author Marie Vasher, MD, a first-year surgical resident at the University of South Florida in Tampa.

The 460 patients (~7.7%) who did experience postoperative hypocalcemia symptoms, such as hand paresthesia, perioral tingling, and mental fog, were able to successfully self-medicate with calcium and vitamin D supplements at home in almost all cases, she said. Only 7 of the 460 patients required a visit to the emergency department for intravenous calcium, according to the abstract.

Dr. Vasher presented the results here at the American College of Surgeons 95th Annual Clinical Congress during the Posters of Exceptional Merit session.

Other Centers Can Use This Protocol

Although her center performs a high volume of parathyroidectomies, Dr. Vasher said that "for centers with a smaller volume of [primary hyperthyroidism-related] surgery, I think this calcium protocol would be applicable. They can institute a similar protocol before the patient leaves the hospital."

All patients in the study were discharged within 2.5 hours and were instructed to take oral calcium citrate–vitamin D tablets (Citracal Regular 250 mg + D [Bayer HealthCare LLC], with each tablet containing 250 mg of calcium and 200 IU of vitamin D) beginning 3 hours postoperatively, Dr. Vasher said in an interview with Medscape General Surgery. Patients reported their hypocalcemia symptoms for 2 weeks.

The calcium dosing protocol is a "sliding scale," with the physicians initially prescribing the highest doses during the first 2 postoperative weeks and decreasing these baseline doses to maintenance levels by the third week, Dr. Vasher said.

The baseline dose depends on whether the patient has an adenoma or hyperplasia. Higher calcium–vitamin D doses are prescribed after parathyroidectomy to patients who have a greater number of risk factors for symptomatic postoperative hypocalcemia, she said.

These risk factors include degree of preoperative serum calcium elevation (levels greater than 12, 13, or 14 mg/dL) in patients with adenomas, severe osteoporosis (bone density T-score less than ?3), morbid obesity (body mass index greater than or equal to 40 kg/m2), the removal of more than 1 parathyroid gland, and the manipulation or biopsy of the remaining glands. For instance, the higher the calcium level preoperatively in a patient with a parathyroid adenoma, the greater the risk for symptomatic hypocalcemia after surgery and, thus, the more calcium that is prescribed postoperatively, Dr. Vasher explained.

Each independent risk factor increases the patient's daily baseline calcium requirement by 315 mg, she said.

"Our protocol represents a baseline for the amount of calcium that a given patient will require following successful parathyroidectomy for the treatment of primary hyperparathyroidism," she told Medscape General Surgery. "Each patient . . . will ultimately require an individualized number of calcium tablets per day based upon his or her response to the baseline dosage."

The new data confirm results of a study of a smaller number of patients that Dr. Vasher's coauthors reported 2 years ago (Endocr Pract. 2007;13:105-113). That earlier study includes specific details about the calcium protocol used in this study.

Proactive Approach Justified

Clinical Congress Program Committee Chair Barbara Bass, MD, who led a discussion of the poster session, told Medscape General Surgery that this study justifies a proactive approach of prescribing calcium–vitamin D supplements after parathyroid gland removal to prevent the development of hypocalcemia symptoms.

Dr. Bass, chair of the Department of Surgery at Methodist Hospital in Houston, Texas, who was not affiliated with the study, called calcium supplementation appropriate treatment to prevent hypocalcemia. The results, she said, might help surgeons who are unsure whether to supplement with calcium their patients undergoing parathyroidectomy.

However, she added, "I would say that most surgeons around the country give every patient a calcium–vitamin D supplement after parathyroidectomy. It's easy to prevent hypocalcemia in these patients. Calcium is such an inexpensive, safe supplement."

Dr. Vasher and Dr. Bass have disclosed no relevant financial relationships.

American College of Surgeons 95th Annual Clinical Congress: Surgical Exhibit SE109. Presented October 14, 2009.