Hypercalcemia beyond hyperparathyroidism: broadening the etiological perspective with insights from case series

Background

Hypercalcemia is a common electrolyte abnormality with varied etiologies and clinical manifestations. Although primary hyperparathyroidism and malignancy account for the majority of cases, less common causes may present diagnostic challenges. Case Presentations: We report three unusual cases of hypercalcemia secondary to disseminated tuberculosis, sarcoidosis and acute lymphoblastic leukemia. The first case involved a 44-year-old woman presenting with fever and altered sensorium. Laboratory investigations revealed severe anemia, acute kidney injury, pancreatitis and PTH independent hypercalcemia. Cerebrospinal fluid analysis was normal but chest imaging and lymph node biopsy confirmed disseminated tuberculosis. After initiation of antitubercular therapy, she developed drug-induced hepatitis followed by progressive multiorgan dysfunction, culminating in death. The second case involved a 48-year-old woman presenting with generalized body aches and a past history of cervical cancer. Malignancy-related hypercalcemia was initially suspected. However, further evaluation established a diagnosis of sarcoidosis. Management with intravenous hydration and corticosteroids led to normalization of serum calcium levels. The third case involved a 17-year-old boy who presented with fever, abdominal pain, generalized lymphadenopathy and hepatomegaly. Investigations demonstrated anemia, acute kidney injury and PTH independent hypercalcemia while peripheral blood film was unremarkable. Subsequent bone marrow examination revealed B-cell acute lymphoblastic leukemia. Although hypercalcemia improved with intravenous fluids and denosumab, he developed severe infection and died before chemotherapy could be initiated.