Q: When IV calcium is contraindicated in symptomatic hypocalcaemia?
Answer: Hypocalcaemia induced by severe life threatening hypophosphatemia
Essential to the treatment of phosphate toxicity is increasing urinary excretion. In patients with normal renal function, expansion of the extracellular space with saline have shown to increase renal phosphate excretion. Therefore, aggressive hydration is the mainstay of treatment, guided by urine output. Dialysis is usually not required, but should be considered given clinical situation as Hemodialysis can clear phosphate at a significantly higher rate than that achieved by normal kidneys.
IV calcium infusion in hypocalcaemia from severe hypophosphatemia can be dangerous because of the possibility of metastatic calcifications when the calcium-phosphate concentration product is >70 mg2/dL2.
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