Bisphosphonate therapy for Paget's disease in a patient with hypoparathyroidism: profound hypocalcemia, rapid response, and prolonged remission

The use of bone-modifying agents in multiple myeloma

Multiple myeloma is a hematological neoplasm characterized by abnormal proliferation of plasma cells in the bone marrow and is usually associated with increased bone pain and skeletal-related events such as pathological fracture and/or spinal cord compression. Myeloma bone disease results in changes in the bone-marrow microenvironment evidenced by increased osteoclastic activity and/or decreased osteoblastic activity, which negatively affect quality of life. Treatment of myeloma bone disease includes bisphosphonates or denosumab (bone-modifying agents). These agents do not induce the formation of new bone or repair existing bone damage, but they can decrease bone pain and the risk of pathological fracture. While these agents improve quality of life, it is not known whether they improve overall survival. This review focuses on different classes of bone-modifying agents, their mechanisms of action, time of initiation, duration of therapy, and potential survival benefits.

Short-Term Safety of Zoledronic Acid in Young Patients With Bone Disorders: An Extensive Institutional Experience

CONTEXT

Zoledronic acid (ZA) is increasingly used in young patients with bone disorders. However, data related to the safety of ZA administration in this population are limited.

OBJECTIVE

The study aimed to characterize the short-term safety profile of ZA and identify risk factors for ZA-related adverse events (AEs) in young patients.

DESIGN, SETTING, AND PARTICIPANTS

This was a retrospective chart review of inpatients and outpatients less than 21 years old who received at least one ZA infusion between July 2010 and January 2014 at The Children's Hospital of Philadelphia.

RESULTS

Eighty-one patients (56% male; median age, 12 y; age at first infusion, 0.5 to 20 y) with diverse skeletal disorders received a total of 204 infusions. The most common indications were osteoporosis (33% of cohort) and osteogenesis imperfecta (27.2%). The median ZA dose was 0.025 mg/kg (interquartile range, 0.025-0.05); the median dosing interval was 6 months (range, 1 to 25.6 mo). AEs were mild and more common after the first ZA infusion in patients with no previous bisphosphonate exposure: hypophosphatemia (25.2% of infusions), acute phase reactions (19.1%), and hypocalcemia (16.4%). Symptomatic hypocalcemia requiring iv calcium occurred after two infusions. ZA dose was significantly associated with hypophosphatemia, but not other AEs. Hypocalcemia was more common in patients with high bone turnover as assessed by preinfusion alkaline phosphatase levels. AEs were not associated with diagnosis, baseline serum calcium, or calcium/calcitriol supplementation.

CONCLUSION

Acute AEs related to ZA infusion in youths are common, occur principally after the first ZA infusion in bisphosphonate-naive patients, and are typically mild and easily managed. Future prospective studies are needed to determine the potential long-term risks, as well as benefits, of ZA therapy in the pediatric population.

Symptomatic intracranial hypertension and prolonged hypocalcemia following treatment of Paget's disease of the skull with zoledronic acid

Skull involvement in Paget's disease of bone can lead to neurological symptoms, prompting treatment. Intravenous zoledronic acid (ZA) has emerged as an effective and safe treatment option for patients with Paget's, leading to sustained remission and improved quality of life. A previously untreated 61-year-old female presented with 2-year history of facial asymmetry with progressive hearing impairment. Serum calcium levels were normal with upper normal levels of PTH and low 25OHD levels. Serum alkaline phosphatase was markedly increased and bone scan showed extensive pagetic involvement of the skull. Head CT and MRI revealed hydrocephalus with cerebellar tonsillar herniation, platybasia and basilar invagination. In the absence of clinical signs or symptoms of intracranial hypertension, she was treated with intravenous ZA after 15-day supplementation with calcium and vitamin D. Twelve hours after the infusion, the patient became confused, agitated and disoriented and developed urinary incontinence; cortical sulci became effaced on CT indicating increased intracranial pressure. Over the following days, she developed frank hypocalcemia requiring intravenous calcium infusion and calcitriol. Neurological status returned to normal within 24 h of onset, except for urinary incontinence. Nine months later she remained incontinent and still required calcitriol to maintain normocalcemia. Zoledronic acid is a first-line option for the treatment of Paget's disease, yet there can be complications in particular clinical scenarios such as pagetic hydrocephalus, as seen in this case. Plentiful supplementation of calcium and vitamin D before bisphosphonate therapy is paramount in order to minimize the risk of prolonged post-treatment hypocalcemia.

Profound hypocalcemia following effective response to zoledronic acid treatment in a patient with juvenile Paget's disease

Juvenile Paget's disease (JPD) is a rare, autosomal recessive osteopathy. Although it has phenotypic overlap with Paget's disease of bone (PDB), it is probably a distinct entity. Because of its rarity, optimal disease management has not yet been established by randomized controlled trials. However, clinical, biochemical, and radiographic improvement has been reported after treatment with antiresorptive agents, including calcitonin and bisphosphonates (BPs). Compared with other BPs, zoledronic acid (ZOL) has a higher affinity to bone mineral and is a stronger inhibitor of the enzyme farnesyl pyrophosphate synthase (the main target of nitrogen-containing BPs), properties that explain the prolonged effect of ZOL on bone turnover and render it a therapeutic option for JPD, similar to PDB. We describe hereby, for the first time in the literature, the case of a patient with JPD who developed severe hypocalcemia and secondary hyperparathyroidism following effective treatment with ZOL.

Hypocalcemia after Alendronate Therapy in a Patient with Celiac Disease

OBJECTIVE

To describe a patient with osteoporosis who was treated with alendronate and developed hypocalcemia, which ultimately led to the diagnosis of celiac sprue.

METHODS

We present the clinical and laboratory findings in a patient with osteoporosis, in whom hypocalcemia developed after treatment with alendronate. This patient was subsequently diagnosed with celiac sprue. The pertinent literature regarding orally administered bisphosphonate-induced hypocalcemia is reviewed.

RESULTS

A 79-year-old man who was diagnosed with osteoporosis was treated with alendronate. He was subsequently found to have asymptomatic hypocalcemia (serum calcium concentration, 8.3 mg/dL), which resolved after alendronate therapy was discontinued. He was then treated with calcium, vitamin D, and calcitonin nasal spray, which did not cause hypocalcemia. Because of his reduced bone density, however, he was subsequently referred for endocrine consultation. Evaluation at that time showed normal levels of serum calcium, phosphorus, creatinine, alkaline phosphatase, 25-hydroxyvitamin D, thyrotropin, and parathyroid hormone as well as 24-hour urine calcium excretion. An endomysial antibody titer was dramatically elevated. Upper endoscopy showed villous atrophy, and small bowel biopsy confirmed the presence of villous blunting and chronic inflammation, consistent with celiac sprue. He was treated with a gluten-free diet and then subsequently treated with orally administered risedronate, which he tolerated well without evidence of hypocalcemia.

CONCLUSION

To the best of our knowledge, this is the first report of orally administered bisphosphonate-induced hypocalcemia, which subsequently led to the diagnosis of previously unrecognized, otherwise asymptomatic celiac sprue. Patients with unexplained hypocalcemia should be screened for celiac sprue, even in the absence of gastrointestinal symptoms.

Reversible Congestive Heart Failure Related to Profound Hypocalcemia Secondary to Hypoparathyroidism

A 71-year-old man presented with acute pulmonary edema related to new onset of severe left ventricular dysfunction (ejection fraction, 30%). His symptoms did not improve with emergency therapy with diuretics and dobutamine. He was noted to be severely hypocalcemic (5.5 mg/dL) and subsequently showed dramatic improvement in symptoms and ejection fraction (58%) with correction of hypocalcemia with intravenous calcium and calcitriol replacement. Hypocalcemia was related to surgically induced hypoparathyroidism. The patient had been instructed to decrease calcium supplements and to discontinue calcitriol 3 months previously due to hypercalcemia. Additional factors that may have contributed to hypocalcemia included vitamin D deficiency, alendronate therapy for osteoporosis, and chronic kidney disease. We concluded that the patient's congestive heart failure was precipitated by severe hypocalcemia and resolved with correction of hypocalcemia. Hypocalcemia is a rare cause of reversible congestive heart failure that should be in the differential diagnosis in any patient presenting with heart failure and not responding to traditional therapy.

Management of the adverse effects associated with intravenous bisphosphonates

Intravenous bisphosphonates are widely used to treat hypercalcemia and to reduce skeletal-related morbidity among cancer patients. However, serious complications, generally occurring in less than 2% of patients participated in phase III clinical trials, including acute systemic inflammatory reaction, ocular inflammation, renal failure, nephrotic syndrome, electrolyte imbalance, and osteonecrosis of the maxilla and mandible have all been increasingly reported. Yet, strategies to deal with these complications are becoming clear. Acute systemic inflammatory reaction is often self-limited and becomes less intense during subsequent treatments. For patients who develop ocular symptoms, prompt ophthalmologic evaluation is crucial to determine the safety of a subsequent bisphosphonate therapy. Patients who receive long-term pamidronate should be evaluated at intervals for early sign of nephritic syndrome as timely cessation of the agent may result in a full recovery. To reduce the risk of severe electrolyte abnormalities, particularly hypocalcemia, correcting any pre-treatment electrolyte abnormality and supplementing vitamin D and calcium may be helpful. Finally, to reduce the risk of osteonecrosis of the maxilla and mandible, obtaining a full dental evaluation before treatment and avoidance of invasive dental procedures is suggested. The three commonly used intravenous bisphosphonates (pamidronate, zoledronic acid, and ibandronate), are generally safe; ibandronate has to date been the least reported to be associated with renal side effects. As clinical indications of intravenous bisphosphonates continue to expand, prescribing clinicians should be familiar with these possible adverse effects and discuss them with patients before commencing or continuing on therapy.

Bisphosphonate-induced hypocalcemia: report of 3 cases and review of literature

OBJECTIVE

To report 3 cases of bisphosphonate-induced hypocalcemia and review the relevant literature.

METHODS

We present the clinical and laboratory findings in 3 cases of bisphosphonate-induced hypocalcemia, and discuss the pathophysiologic mechanisms and the pertinent literature.

RESULTS

In our first patient (case 1), symptomatic hypocalcemia developed after intravenous administration of pamidronate for management of multiple myeloma. He had vitamin D insufficiency and impaired renal function at the time of pamidronate therapy. Our second patient (case 2) presented with symptomatic hypocalcemia 12 weeks after initiation of alendronate therapy for osteoporosis. Her serum 25-hydroxyvitamin D level was low (3 ng/mL), attributable to a combination of poor vitamin D intake, limited exposure to sunlight, use of phenytoin, and previous intestinal resections. In our third patient (case 3), hypocalcemia developed on 2 different occasions, each episode occurring after intravenous administration of pamidronate for hypercalcemia of malignancy. All 3 patients had underlying conditions that impaired the homeostatic response to bisphosphonates and contributed to the severe hypocalcemia. Review of published reports on symptomatic bisphosphonate-induced hypocalcemia disclosed that hypocalcemia develops in patients with unrecognized hypoparathyroidism, impaired renal function, or vitamin D deficiency. Overall, the rate of the development of hypocalcemia was related to the potency of the bisphosphonate administered.

CONCLUSION

The increasing use of bisphosphonates and the introduction of more potent agents impose a considerable risk for bisphosphonate-induced hypocalcemia in a substantial number of patients. Greater awareness of this complication, a better understanding of the underlying mechanisms, and proper assessment of patients in whom bisphosphonate therapy is contemplated should reduce the frequency of occurrence of this potentially life-threatening complication.

Hypocalcemia following pamidronate administration for bone metastases of solid tumor: three clinical case reports

Bisphosphonates, such as pamidronate, are a new class of drugs, initially described for treatment of neoplasic hypercalcemia. Currently, they also may be used in the treatment of bone metastases from solid tumor, even without hypercalcemia. Hypocalcemia is a potential adverse effect of these drugs, which is considered infrequent and rarely symptomatic. We describe three cases of severe hypocalcemia following one injection of pamidronate. The three patients had bone metastases from solid tumors (breast in two cases, prostate in one), at least partially osteoblastic, and none had hypercalcemia. The induced hypocalcemia was rapid in onset, severe, and durable. The mechanism seems to be multiple and may include both the expected reduction of osteolysis and also a rapid and direct action on parathyroid glands followed by resistance to parathormone. Some elements could amplify the phenomenon, such as latent hypoparathyroidism after surgery, cervical radiotherapy, hypomagnesemia, or low 25 hydroxy vitamin D (25OH D). For patients who have such risk factors, it may be useful to check calcium several days after the first injection.