Vitamin D receptor activator-associated calcium-alkali syndrome-like phenotype without calcium supplementation: a case series of seven patients.
Takuya Kumagai, Tsuyoshi Ono
✦ AI-curated · Sources linked
Case in brief
A retrospective series identified seven elderly women receiving vitamin D receptor activators who developed hypercalcemia, bicarbonate of at least 26 mmol/L, and acute kidney injury, meeting the study’s operational criteria for a calcium-alkali syndrome-like phenotype. Six had underlying chronic kidney disease, and three had no identified exogenous alkali source. The serum sodium–chloride difference was elevated in all seven. Renal function recovered completely in three, partially in two, and did not recover in one; one patient died from worsening heart failure. The retrospective data could not establish the temporal relationship between hypercalcemia and alkalosis.
What made this case unusual
The calcium-alkali syndrome-like pattern occurred during vitamin D receptor activator use without calcium supplementation; three patients also had no identified exogenous alkali source.
Diagnostic / clinical pearl
In older patients taking vitamin D receptor activators, consider a calcium-alkali syndrome-like phenotype when hypercalcemia, elevated bicarbonate, and acute kidney injury coexist; an elevated sodium–chloride difference may be a useful clue.
Why it matters
Renal outcomes were not uniformly reversible, supporting the authors’ emphasis on periodic calcium monitoring and prompt evaluation of nonspecific symptoms or acute kidney injury in patients receiving these agents.