title: Unexpected prolonged extreme hypocalcaemia and an inadequate PTH response in a patient with metastatic breast carcinoma.
abstract: Although hypercalcaemia is often encountered during the course of malignant disease, hypocalcaemia appears to be rather rare. We describe a 37-year-old patient with metastatic carcinoma of the breast, who developed extreme hypocalcaemia (as low as 0.75 mmol calcium per litre) after chemotherapy. This is caused by a combination of hungry-bone syndrome and an insufficient parathyroid response. The latter may be the result of a direct toxic effect of chemotherapy on parathyroid hormone (PTH) synthesis possibly in combination with microscopic tumour infiltration in the parathyroid glands. Correction of the extreme hypocalcaemia over a period of 100 days by oral and intravenous calcium supplementation, corresponding to a total of 352 gram elemental calcium (1/3 of the total body calcium), resulted in gradual symptomatic relief. The possible mechanisms for these findings are discussed and the literature is briefly reviewed.
authors.affiliation: MEDIAL Medical Diagnostic Laboratories, Kennemer Gasthuis, Boerhaavelaan 22, 2035 RC Haarlem, the Netherlands. fbergkam@kg.nl
authors.forename: F J M
authors.initials: FJ
authors.lastname: Bergkamp
authors.forename: A M
authors.initials: AM
authors.lastname: van Berkel
authors.forename: P W G
authors.initials: PW
authors.lastname: van der Linden
authors.forename: J P M C
authors.initials: JP
authors.lastname: Gorgels
mesh_terms: D000328:Adult; D001859:Bone Neoplasms / Q000150:complications / Q000556:secondary*; D001943:Breast Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000097:blood / Q000209:etiology* / Q000628:therapy; D010281:Parathyroid Hormone / Q000097:blood*
chemical_list: D010281:Parathyroid Hormone