Acute respiratory distress syndrome associated with hypercalcemia without parathyroid disorders

Acute lung injury (ALI) can be induced by various causes. The occurrence of ALI associated with hypercalcemia has rarely been reported and the mechanisms are unknown. In the present study, we reported the clinical manifestation and pathological findings in patients with hypercalcemia and metastatic calcification. In addition, we addressed the possible mechanism and the preventive strategy for the acute episode of ALI due to hypercalcemic crisis. We encountered five patients with long-term malignancy of various origins. They displayed hypercalcemia and metastatic calcification in the kidney and stomach. One case with transitional cell carcinoma of the urinary bladder developed acute episode of acute respiratory distress syndrome (ARDS). The plasma calcium was elevated to above 5 mM. Simultaneously, He manifested ARDS followed by ALI. The pathological examination revealed severe alveolar edema with multiple calcification. In the other three cases, the plasma calcium level ranged from 3.1 to 4.4 mM and ARDS or ALI did not occur. One patient with esophageal squamous cell carcinoma experienced an acute hypercalcemia (plasma calcium 4.8-5.1 mM) accompanied by ARDS. Corticosteroid and calcitonin were prescribed to reduce the plasma calcium. The symptoms of ARDS also subsided and ALI did not occur. Chronic hypercalcemia results in severe metastatic calcification. The kidney and stomach are the most vulnerable organs. An increase in plasma calcium above 5 mM is a risk factor for developing ARDS and ALI. Our recent experiment in conscious rats and isolated rat's lungs supported this contention. In addition, corticosteroid and calcitonin were able to reduce the plasma calcium and to prevent the occurrence of ARDS and ALI.