Case Presentation

An 81 y/o woman was admitted to our hospital due to bloody stool noted for 2 weeks.

The patient was a case of end-stage renal disease. She had been treated with hemodialysis trice a week regularly at a local clinic for one and a half year. Generalized bone pain had been complained of since about 3 months ago. Constipation, nausea, poor appetite, and body weight loss developed gradually, and she became totally bedridden afterwards. Bloody stool was noted 2 weeks before admission, and hemorrhoid bleeding was initially impressed. As bloody stool persisted and bone pain became more severe, she was sent to our hospital for further management. Tracing back her past history, she was a hepatitis B carrier without regular follow-up, and she had not taken any drug.

She looked weak and stupor at admission. The body temperature was 35.5 ℃, the pulse was 90 beats per minute, and the respiration rate was 18 per minutes. Her blood pressure was 129/58 mmHg. Her conjunctivae were pale and her neck was supple. A grade III/VI systolic ejection murmur was noted at left lower sternal border. Diffuse abdominal tenderness and generalized edema were found. Bloody stool was noted by digital examination. Other physical check-up was not significant.

Table 2. Blood Chemical Values.

Alb	Glo	Sugar	Bil (T)	GOT	GPT	BUN	Cr
g/dL	g/dL	mg/dL	mg/dL	U/L	U/L	mg/dL	mg/dL
2.2	3.7	103	0.6	49	21	87	3.5

Stool routine: parasite ova (-), O.B. (+++)
CEA 16.5 ng/mL
αFP 4.76 ng/mL
intact parathyroid hormone 12 pg/mL

As the patient had hypercalcemia and inadequate intravascular volume, 2.5% glucose-saline 250 mL was infused after hospitalization. Hemodialysis with low-calcium dialysate was prescribed. Empirical antibiotics with cefazolin and gentamycin were given for possible infection. Supine chest film showed mild infiltration at right lower lung area and small amount of right side pleural effusion. Abdominal sonography showed liver cirrhosis with multiple liver tumors, left renal stones, and moderate amount of ascites. Colonofibroscopic examination revealed a cauliflower-like tumor mass 10 cm above anal verge which was later confirmed to be adenocarcinoma pathologically.

The family preferred supportive treatment only as the patient was old and suffered from colon cancer with multiple metastases. Therefore the patient was discharged when her condition became stable.

病案分析
本病人患有高血鈣症，並出現部份高血鈣症的典型症狀，包括便秘、食慾不振、全身無力及意識遲鈍。至於病人發生高血鈣症的原因，分析可能有四: (一) 病人食慾不振及血清白蛋白過低，使血管內有效容積不足; (二) 病人長期臥床，使骨骼中的鈣質流失; (三) 病人患有大腸癌合併骨骼轉移; (四) 高鈣透析液的使用。治療方面，需針對高血鈣症的原因對症下藥。至於降血鈣的方法，除了給予病人低鈣飲食外，一般為補充水份和使用furosemide類的利尿劑來減少尿鈣的吸收，但本病人為末期腎病的患者，幾乎無尿，而且已有全身水腫，不適合大量補充水份，加上使用利尿劑的效果也不佳，故在病人住院後只給與適量的輸液補充而已。Pamidronate等biphosphonates類藥物可有效抑制骨骼再吸收，但其作用時間較慢; pamidronate及clodronate在腎衰竭病人不適合使用。Calcitonin的作用時間較快但很短，它能有效抑制骨骼再吸收，也可以增加尿鈣的排泄。類固醇藥物一般使用在患有如淋巴癌及多發性骨髓瘤的病人身上，但需注意類固醇的各項副作用。在接受透析治療的病人，則可使用無鈣或低鈣透析液。

1. 身體中的鈣約百份之九十九儲存在骨骼中，剩下的百份之一大部份是在細胞外液中。
2. 鈣的代謝主要由副甲狀腺素及活性維生素D來調節。副甲狀腺素可透過刺激骨骼的再吸收、增加腎鈣的重吸收及促進活性維生素D的產生等三種途徑來增加血清中的鈣濃度。
3. 引起高血鈣症的原因主要分為三大類:
   (一) 因維生素D的增加而使腸道的鈣吸收增加，如結核病和維生素D中毒等;
   (二) 骨骼中的鈣流失增加，如副甲狀腺功能亢進、癌症合併骨骼轉移和長期臥床等;
   (三) 腎臟對鈣的重吸收增加，如服用過量的鈣片和使用thiazides類的利尿劑等。
4. 正常的血清鈣濃度為8.6-10.3 mg/dL，但一般超過12 mg/dL才會有症狀的出現。
5. 高血鈣症的症狀包括噁心、嘔吐、食慾不振、便秘、疲倦、意識不清、昏迷、多尿、腎結石及急性腎衰竭等。
6. 高血鈣症的心電圖變化為QT節段的縮短。
7. 高血鈣症的診斷，以下皆可作為輔助檢查:
   A. 腎臟功能 – 可知道病人是否已出現急性腎衰竭的併發症，有助於治療方法的選擇。
   B. 副甲狀腺素 – 可確定是否有副甲狀腺亢進的情形。
   C. 尿鈣排出速率 – 可排除家族性低尿鈣高血鈣症的情形。
   D. 血清ionized鈣濃度 – 在血清白蛋白濃度不正常的時侯，應測量血清ionized鈣濃度。
   E. 血清鈉濃度為非必要檢查。
8. 在輕度的高血鈣症，一般只要補充生理食鹽水輸液即可。
9. 在重度高血鈣症合併腎衰竭的病人，應給予低鈣和低磷飲食，利用furosemide類利尿劑可促進尿鈣的排出，若需透析可使用無鈣或低鈣透析液。至於bisphosphonates，因靠腎臟代謝，在腎衰竭病人應避免使用。
10. Calcitonin降血鈣的作用最快，只需數小時即可有效地降低血鈣。