Albright's osteodystrophy in a patient with renal hypercalciuria

Area of Science:

• Endocrinology
• Nephrology
• Metabolic Bone Disease

Background:

• Renal hypercalciuria and pseudohypoparathyroidism are distinct conditions affecting calcium and phosphate metabolism.
• Both conditions can present with elevated parathyroid hormone levels, complicating diagnosis.
• Albright's osteodystrophy is a characteristic feature of pseudohypoparathyroidism.

Observation:

• An 18-year-old female presented with symptoms overlapping both renal hypercalciuria and pseudohypoparathyroidism.
• She exhibited hypercalciuria, elevated parathyroid hormone, hypocalcemia, and Albright's osteodystrophy.
• Despite these findings, her serum 1,25-dihydroxycholecalciferol was elevated, and renal responses to parathyroid hormone were normal.

Findings:

• The patient's presentation included features atypical for isolated renal hypercalciuria, such as Albright's osteodystrophy.
• Her normal renal response to parathyroid hormone infusion contrasted with typical pseudohypoparathyroidism.
• Elevated 1,25-dihydroxycholecalciferol levels were observed, differing from pseudohypoparathyroidism expectations.

Implications:

• This case challenges the strict differentiation between renal hypercalciuria and pseudohypoparathyroidism.
• It suggests a potential 'forme fruste' (mild or incomplete form) of pseudohypoparathyroidism in some patients with renal hypercalciuria.
• Further research is warranted to explore this overlap and refine diagnostic criteria for these conditions.