Table 1 Metabolic bone labs and treatment regimens in Twin A and B (Conventional unit values are represented in parentheses)
Time | Twin | Vitamin D, 25-Hydroxy: 75–250 nmol/L (30–100 ng/mL) | Total Calcium, serum: 2.13–2.65 mmol/L (8.5–10.6 mg/dL) | Phosphorus: 1.45–2.16 Mmol/L (4.5–6.7 mg/dL) | PTH, intact 1.6–6.9 pmol/L (15–65 pg/mL) | Alkaline Phosphatase 104–345 U/L | Treatment comments |
|---|---|---|---|---|---|---|---|
Day 0 | A | 17.5 (7) | 2.18 (8.7) | 0.77 (2.4) | 47.3 (446) | 964 | Started Ergocalciferol 50,000 IU weekly and Calcium carbonate (Ca carb) elemental Ca at 50 mg/kg/day |
B | 15 (6) | 2.08 (8.3) | 0.74 (2.3) | 36.6 (345) | 1367 | ||
Day 5 | A | 1.95 (7.8) | 0.90 (2.8) | 40.4 (381) | 599 | Started Calcitriol 0.2 mcg bid due to drop in serum total calcium levels and elevated PTH levels. Increased Ca carb to 100 mg/kg/day. Started sodium phosphate 2 mmol.kg/day. | |
B | 1.65 (6.6) | 0.94 (2.9) | 51.8 (488) | 923 | |||
Day 7 | A | 2.10 (8.4) | 0.94 (2.9) | 46.3 (436) | 610 | Increased Calcitriol dose to 0.4 mcg bid due to persistent hypocalcemia (Twin A ionized Ca 0.99 and Twin B iCa 0.92. (normal 1.14–1.40 mmol/L), further increase in PTH levels. Urine Ca/Creatinine ratio: Twin A- 0.08; Twin B- 0.1 (normal 0.6) | |
B | 1.78 (7.1) | 1.10 (3.4) | 65.6 (618) | 1014 | |||
Day 10 | A | 2.2 (8.8) | 0.77 (2.4) | 39.5 (372) | 692 | Decreased Calcitriol to 0.4 mcg qd and discontinued Sodium phosphate. (serum phos trending down due to additional phos possibly stimulating FGF23 and further exacerbating phosphaturia. Underlying issue for low phos is secondary hyperparathyroidism from Vitamin D deficiency) | |
B | 1.93 (7.7) | 0.87 (2.7) | 48.8 (460) | 1113 | |||
Week 3 | A | 2.38 (9.5) | 0.68 (2.1) | 33.1 (312) | 878 | Discontinued Calcitriol as serum total calcium levels and PTH were improving. Increased Ergocalciferol to 50,000 IU two times/week as PTH still elevated after 3 doses of Vitamin D2. Decreased Calcium carb to 50 mg/kg/day. Discharged to home. | |
B | 2.33 (9.3) | 0.84 (2.6) | 36.2 (341) | 1759 | |||
Week 5 | A | 15 (6) | 2.50 (10) | 0.61 (1.9) | 12.3 (116) | 755 | Twins were readmitted for G tube placement and liver biopsy. They missed Ergocalciferol doses at home. Increased Ergocalciferol to 50,000 IU three times/week Restarted Calcitriol at 0.1 mcg bid. Discharged after 1 week. |
B | < 12.5 (< 5) | 2.35 (9.4) | 0.58 (1.8) | 26.8 (253) | 1367 | ||
Week 10 | A | 22.5 (9) | 2.68 (10.7) | 1.74 (5.4) | 6.6 (62) | 743 | Twins were seen outpatient and decreased Calcitriol to 0.1 mcg qd. Family adherent to Vitamin D therapy. Week 12: Internal biliary diversion surgery was performed. |
B | 25 (10) | 2.53 (10.1) | 1.39 (4.3) | 10.5 (99) | 849 | ||
Week 14 | A | 32.5 (13) | 2.70 (10.8) | 1.91 (5.9) | 1.4 (13) | 341 | Discontinued Calcitriol and decreased Ca to 30 mg/kg/day. Continued Ergocalciferol 50,000 IU three times/week. Urine Ca/Creat: Twin A- 0.21; Twin B 0.26 |
B | 40 (16) | 2.85 (11.4) | 1.81 (5.6) | 2.0 (19) | 333 | ||
Week 15 | A | 2.55 (10.2) | 1.74 (5.4) | 2.9 (27) | 287 | Switched to Ergocalciferol 16,000 IU daily and continued Ca carb at 30 mg/kg/day for 2 weeks following which they were switched to maintenance dose of Vitamin D3 2000 IU daily and 25-OH Vitamin D levels were monitored. | |
B | 2.53 (10.1) | 1.94 (6) | 3.6 (34) | 302 |