The use of bisphosphonates seems to be associated with the development of ONJ. Length of exposure seems to be the most important risk factor for this complication. The type of bisphosphonate may play a role and previous dental procedures may be a precipitating factor.

We read with great interest the case report by Bartko and colleagues (1) concerning a patient with osteomalacia due to longstanding hypophosphatemia after long-term intravenous (iv) iron administration. We would like to add our experience regarding a similar case of a male patient with Hirschsprung disease suffering from severe hypophosphatemia due to continuous iv iron administration. A 31-year-old man with extensive Hirschsprung disease (involving the colon and the distal one-third of ileum) was referred to our department suffering from insufficiency fractures and severe hypophosphatemia. Disease onset was on the second day after birth with meconium ileus. By the age of 2 years, he underwent near total colectomy and excision of the distal one-third of the ileum by the Duhamel retrorectal transanal technique. Since then, he suffered from mild iron-deficiency anemia (IDA) and B12 and vitamin D deficiency, managed with oral iron treatment (OIT) and B12 and D2 im injections. Serum phosphate levels were within normal range (1.065 to 1.227 mmol/L). At the age of 26 years, IDA became refractory to OIT because of multiple bleeding ulcers at the site of rectal anastomosis. At that time, monthly ferric carboxymaltose (FCM) iv injections were administered for the management of IDA along with occasional need for blood transfusions. At the age of 29 years, he suffered multiple insufficiency fractures (4th left metatarsal and bilateral rib fractures). Laboratory evaluations performed on several occasions revealed severe hypophosphatemia (as low as 0.355 mmol/L) and secondary hyperparathyroidism. At presentation, the patient had diffuse skeletal pain, gait disturbance, and progressive loss of mobility. Laboratory evaluation revealed severe hypophosphatemia (0.419 mmol/L), mild hypocalcemia (2.09 mmol/L), and secondary hyperparathyroidism (parathyroid hormone [PTH] 104.8 pg/mL). 25 (OH) D levels were normal (77.25 nmol/L), whereas 1,25 (OH) 2 D levels were at the low normal level (24 pg/mL). Urinary calcium excretion was low (1.28 mmol/24 hr), whereas phosphate excretion was elevated (32.16 mmol/24 hr, tubular maximum reabsorption of phosphate to glomerular filtration rate [TmP/GFR] 0.2827 mmol/L [reference range 1.00-1.35]; Table 1). Intact FGF-23 level (Kainos Laboratories, Inc., Tokyo, Japan) was elevated (96 pg/mL [reference range 10-50] (2) ). Dual-energy X-ray absorptiometry (DXA) revealed a low BMD at the lumbar spine (LS) (0.92 mg/cm 2 , Z-score -2.7) and the femoral neck (FN) (0.725, Z-score -2.1). These results pointed to a combined defect: FGF-23 mediated hypophosphatemia due to FCM iv injections, leading to renal phosphate wasting and low calcitriol levels, and calcium and phosphate malabsorption due to low calcitriol and short bowel syndrome. Secondary hyperparathyroidism amplified phosphate wasting.The patient was treated with calcium citrate (500 mg tid) and alphacalcidol (1 mcg bid), was instructed to increase milk intake, and switched to oral iron therapy (ferric hydroxide polymaltose). He was referred to a te...

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Sjögren's syndrome (SS) is a chronic autoimmune disease of unknown etiology characterized by lymphocytic infiltration of the exocrine glands and a polyclonal B-cell activation; it is demonstrated by the presence of multiple autoantibodies against organ- and non-organ-specific autoantigens. SS is associated with malignant lymphomas, Waldenstrom's macroglobulinemia and benign monoclonal gammopathy, while its relationship with multiple myeloma is extremely rare. The association between multiple myeloma and rheumatoid arthritis and other autoimmune diseases has been established, but it is not clear why a B-cell proliferation like myeloma occurs more rarely than other B-cell disorders in patients with SS. We describe a patient who presented with multiple myeloma and SS that might have existed for at least 2 years prior to the appearance of myeloma.