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

Management of Hydrocephalus in Paget's Disease of Bone: Systematic Review and Illustrative Case

OBJECTIVE

Paget's disease of the bone (PDB) is a focal bone disorder characterized by excessive resorption and deposition of pathologic bone. It can involve the skull and cause neurologic dysfunction. Hydrocephalus occurring as a complication has also been reported. However, owing to its rarity, the optimal treatment has not yet been determined.

METHODS

We report the case of a 60-year-old woman with a diagnosis of PDB who had presented with symptomatic hydrocephalus and was successfully treated with ventriculoperitoneal shunt insertion. We also performed a systematic review of the Scopus and PubMed databases for case reports and series documenting patients with PDB complicated by hydrocephalus and discussed the clinical features and therapeutic strategies used.

RESULTS

We found 28 cases of PDB complicated by hydrocephalus in reported studies, including the present case. The median age was 67 years (range, 48-85 years; interquartile range, 7 years), with a female sex predilection. The most common neurologic manifestations were cognitive impairment, gait unsteadiness, urinary incontinence, hearing loss, and headache. Surgery had been performed in 73% of the 28 cases. The most common operation was insertion of a ventriculoperitoneal shunt (63.2%). Cerebrospinal fluid diversion resulted in significant or complete neurologic recovery in 78.9% of the 28 patients. Posterior fossa decompression was performed in 15.8% of operative cases but did not significantly alter the clinical course.

CONCLUSION

Patients with hydrocephalus occurring as a complication of PDB will most commonly present with cognitive impairment, gait unsteadiness, and urinary incontinence. Surgery plays an important role in the treatment, with CSF diversion procedures resulting in significant neurologic recovery in most cases.

Effect of zoledronic acid on serum calcium in Paget's disease patients after educational strategies to improve calcium and vitamin D supplementation

OBJECTIVE

Bisphosphonates are the most effective therapeutic agents in patients with Paget's disease of bone. As a result of their inhibition of osteoclastic activity, hypocalcemia of variable frequency and severity following intravenous bisphosphonate therapy has been reported. The present study assessed the effect of physician and patient education on adequate supplementation of calcium and vitamin D to reduce the potential risk of developing hypocalcemia following infusion of 5 mg zoledronic acid.

METHODS

This was an open-label, multicenter, controlled registry trial in which patients with Paget's disease were treated with a single intravenous infusion of zoledronic acid. Physicians were provided with educational materials focusing on optimization of calcium and vitamin D supplementation following zoledronic infusion that they used to educate their patients. The primary safety variable was the percentage of patients with serum calcium level <2.07mmol/l 9-11 days after zoledronic acid infusion.

RESULTS

A total of 75 patients were evaluable in the post dose hypocalcemia safety analysis. Of these, only 1 patient had treatment-emergent hypocalcemia, with a serum calcium level of 1.92 mmol/l 4 days following therapy. Hypocalcemia-related symptoms were not reported in this patient and the serum calcium returned to normal range at 2.17 mmol/l within 1 week on oral calcium supplementation.

CONCLUSIONS

These results suggest that, with optimization of calcium and vitamin D supplementation by physician and patient education, hypocalcemia is an infrequent occurrence following zoledronic acid infusion.

Diagnosis and treatment of Paget's disease of bone: a mini-review

Paget's disease of bone (PDB) is a chronic progressive disorder of bone metabolism that may go undetected for many years, and endocrinologists should be alert to its clinical signs and promptly diagnose and treat PDB before it results in irreversible complications, such as deformity, fracture or neurological sequelae. Most commonly, PDB is suspected upon the incidental finding of elevated serum alkaline phosphatase levels or a radiographic abnormality in an otherwise healthy individual above 55 years of age. Some of these individuals may have symptoms such as bone pain or enlargement with increased warmth. In general, a basic laboratory evaluation of bone metabolism, plain radiographies of affected bones and bone scintigraphy are sufficient to corroborate the diagnosis. Antiresorptive therapy with bisphosphonates is the mainstay of treatment of symptomatic PDB, and intravenous zoledronic acid has emerged as an effective and safe treatment option, leading to sustained remission and improved quality of life. It is extremely important, though, to ensure calcium and vitamin D sufficiency before and during treatment in order to prevent hypocalcemia. The benefit of treating all asymptomatic patients is not clear, but treatment is warranted if the pagetic lesion is located in a site where progression to fracture, deformity, or compression would significantly impair the patient quality of life. This mini-review focuses on important aspects of the diagnosis and treatment of PDB.