Pneumocystis Pneumonia and Hypercalcemia: An Underrecognized and Atypical Feature of a Common Opportunistic Infection

Pneumocystis pneumonia (PCP) is a common opportunistic infection that presents as acute hypoxemic respiratory failure with fever and respiratory distress in immunocompromised patients. However, the diagnosis of PCP can be difficult to confirm, emphasizing the importance of recognizing atypical features of infection. This article describes three cases of PCP presenting with parathyroid hormone–independent hypercalcemia in patients receiving immunosuppressive medications for autoimmune conditions. These patients did not meet established criteria for prophylaxis before presentation. In each case, patients’ hypercalcemia resolved with empirical treatment of PCP. These cases affirm the relationship between PCP and hypercalcemia in patients without obvious risk factors.