Clémentine Gillet

Calcium and vitamin D metabolism in granulomatous diseases

SummaryOverproduction of the active metabolite of vitamin D, 1,25-dihydroxyvitamin D (1,25(OH)2D) has been described in sarcoidosis and other granulomatous diseases. High circulating concentrations of 1,25(OH)2D lead to increased intestinal absorption of calcium, possibly to enhanced bone resorption, and may result in hypercalcaemia and/or hypercalciuria. Data obtained in vivo and in vitro demonstrated that the unregulated production of 1,25(OH)2D lies within the granulomatous tissue and is controlled by glucocorticoids. This abnormal production of 1,25(OH)2D seems to be a general phenomenon of granulomatous processes, which is not exceptional in sarcoidosis, but appears seldom in tuberculosis. These abnormalities, however, are not pathognomonic of granulomatous processes, since they have been described in other diseases such as lymphomas.

Bone mineral content in idiopathic renal stone disease and in primary hyperparathyroidism

Bone mineral content (BMC) was measured with the Norland Cameron apparatus in 120 renal stone formers (RSF) with idiopathic stone disease and in 41 patients with primary hyperparathyroidism. RSF were classified, according to an oral calcium load test, into three groups: no hypercalciuria (HC; 41 cases); absorptive HC (53 cases), and resorptive or renal HC (25 cases). BMC values in RSF as a group were significantly lower than normal (p less than 0.001, Mann-Whitney test) though higher than in hyperparathyroid patients. There was a trend for BMC to decrease from male RSF without HC to patients with renal or resorptive HC. No statistical difference was found between the groups, however, BMC values in absorptive HC were different from normal (p less than 0.001). Why patients with HC are demineralized is unclear since no correlation was found between BMC and basal values of serum phosphate, TRP, calculated TmP/GFR, urinary calcium or hydroxyproline. Nevertheless our results indicate that urolithiasis, and possibly its treatment, is not a benign condition for the skeleton.

Paget's disease of bone: five regimens of pamidronate treatment.

SummaryThe efficacy of five therapeutic regimens using (3-amino-1-hydro-xypropylidene)-1,1-bisphosphonate (APD or pamidronate) was assessed in patients with Pagets disease of bone. These regimens were as follows: (a) pamidronate 600 mg/day given orally during six months; (b) iv infusion of 20 mg daily for 10 days; (c) iv infusion of 40 mg daily for 5 days; (d) iv infusion of 10 mg daily for 4 days and (e) a single iv infusion of 10 mg. Six months after the initiation of therapy, urinary excretion of hydroxyproline and serum alkaline phosphatase activity (expressed as percent of their initial value) were: Group a: 30±10 (mean±SE) and 30±6, Group b: 55±8 and 46±6, Group c: 54±7 and 57±6, Group d: 53±7 and 69±4, and Group e: 85±10 and 98±4 respectively. Oral route was accompanied by digestive intolerance. On the contrary, except for rare and transient “flu-like syndromes”, the iv treatment was not associated with any serious secondary effect. Intravenous infusion of pamidronate, 20 mg for 10 days or 40 mg for 5 days, appears as an interesting alternative to the oral route in the treatment of Pagets disease of bone.

Calcium metabolism disturbances in sarcoidosis.

SummarySarcoidosis was confirmed by biopsy in 13 out of 16 patients in which the disease was suspected. Hypercalcemia was present in 4 patients, associated with renal insufficiency; hypercalciuria without hypercalcemia was found in 3 patients with a normal glomerular filtration rate; 9 patients had normal serum and urinary calcium. Circulating 1, 25-dihydroxyvitamin D (l,25(OH), D) was increased in hypercalcemic patients, in spite of renal insufficiency. Corticosteroid treatment rapidly normalized l,25(OH)2D levels in a few days, and corrected hypercalcemia. In one patient, the progressive reduction of prednisolone to 2.5 mg/day was followed by the recurrence of hypercalcemia. One patient exhibited before corticotheraPy a recurrent seasonal hypercalcemia. The absence of calcium metabolism abnormalities in about 50% of our patients could correspond in some cases to inactive sarcoidosis and/or to a low level of 25-hydroxyvitamin D, the precursor of l,25(OH)2D, but remained without explanation in other patie...