From the FDA Drug Label
The recommended dose of pamidronate disodium in moderate hypercalcemia (corrected serum calcium* of approximately 12 to 13.5 mg/dL) is 60 to 90 mg given as a SINGLE-DOSE, intravenous infusion over 2 to 24 hours. *Albumin-corrected serum calcium (CCa, mg/dL) = serum calcium, mg/dL + 0.8 (4. 0-serum albumin, g/dL).
To manage a 34-week pregnant patient with hypercalcemia (calcium level of 10.6 mg/dL) and low albumin (2.6 g/dL), first, we need to calculate the albumin-corrected serum calcium level. Using the formula: CCa (mg/dL) = serum calcium (mg/dL) + 0.8 (4.0 - serum albumin (g/dL)), we can calculate the corrected calcium level as follows: CCa = 10.6 + 0.8(4.0 - 2.6) = 10.6 + 0.8(1.4) = 10.6 + 1.12 = 11.72 mg/dL.
Given that the corrected serum calcium level is approximately 11.72 mg/dL, which falls into the moderate hypercalcemia category, the recommended dose of pamidronate disodium is 60 to 90 mg given as a single-dose, intravenous infusion over 2 to 24 hours 1.
Key considerations:
- Vigorous saline hydration should be initiated promptly to restore urine output to about 2 L/day throughout treatment.
- Overhydration, especially in patients with cardiac failure, must be avoided.
- Diuretic therapy should not be employed prior to correction of hypovolemia.
- The patient's serum creatinine should be assessed prior to each treatment, and treatment should be withheld for renal deterioration 1.
It is essential to monitor the patient's condition closely and adjust the treatment plan as needed to ensure the best possible outcome.
From the Research
Management of a 34-week pregnant patient with hypercalcemia and low albumin requires careful consideration of both maternal and fetal well-being, with initial steps including calculation of the corrected calcium level and aggressive intravenous hydration. To determine the true severity of hypercalcemia, the corrected calcium level should be calculated by adding 0.8 mg/dL for every 1 g/dL that albumin is below 4 g/dL. Given the patient's calcium level of 10.6 mg/dL and albumin of 2.6, the corrected calcium level would be 10.6 + (0.8 * (4 - 2.6)) = 10.6 + 1.2 = 11.8 mg/dL. Initial management includes aggressive intravenous hydration with normal saline at 200-300 mL/hour to promote calcium excretion, with close monitoring of fluid status to avoid pulmonary edema, as suggested by 2. Loop diuretics like furosemide (20-40 mg IV every 12 hours) can be administered after adequate hydration to enhance calcium excretion. For moderate to severe hypercalcemia (corrected calcium >12 mg/dL), calcitonin 4 IU/kg subcutaneously every 12 hours can be used for short-term management, as it has a good safety profile in pregnancy, according to 3. Bisphosphonates should be avoided due to potential fetal risks. Continuous fetal monitoring is essential, particularly after 34 weeks when delivery may be considered if hypercalcemia remains uncontrolled. The underlying cause of hypercalcemia should be investigated, with primary hyperparathyroidism and malignancy being common etiologies, as noted in 4. Low albumin may be due to pregnancy-related hemodilution, malnutrition, or liver dysfunction, and should be addressed accordingly. Multidisciplinary management involving maternal-fetal medicine, endocrinology, and neonatology is crucial for optimal outcomes, as emphasized by 5. It is also important to consider rare causes of hypercalcemia, such as necrotizing leiomyoma, as reported in 5, and to be aware of the potential for hypercalcemic crisis, as described in 6. Overall, the management of hypercalcemia in pregnancy requires a comprehensive approach that prioritizes both maternal and fetal well-being.