PTHrP-associated hypercalcemia of pregnancy resolved after delivery: a case report

A 35-year-old oriental woman, who was 32 weeks pregnant, was hospitalized with suspected preeclampsia. Subsequently, she developed stupor and lethargia. Biochemical assessment showed severe hypercalcemia (21 mg/dl) with undetectable parathyroid hormone (PTH) and markedly elevated PTH-related peptide (PTHrP) levels (26 pmol/l, normal values <1.1 pmol/l). The patient was treated with i.v. fluid administration, which resulted in an unsatisfactory reduction in serum calcium. Therefore, a cesarean section was performed to deliver the baby. Serum calcium levels promptly normalized after delivery with undetectable PTHrP levels. She delivered a healthy infant only presenting with transient mild jaundice and slightly prolonged QT interval with serum calcium level of 7.8-8.4 mg/dl (corrected for albumin levels). In the subsequent days, the patient developed a transient 'hungry bone' syndrome (calcium 6.7 mg/dl, phosphorous 2.1 mg/dl, and PTH 100.4 pg/ml). In conclusion, this pregnant patient presented with PTHrP-associated hypercalcemia, presumably of placental origin. Delivery resulted in prompt reduction of serum calcium levels and a transient 'hungry bone' syndrome.