This document discusses hypercalcemia and hypocalcemia, including their causes, symptoms, and management. Hypercalcemia can be caused by hyperparathyroidism, certain malignancies, vitamin D toxicity, and other conditions. Symptoms range from none in mild cases to fatigue, nausea, and cognitive issues in severe cases. Treatment focuses on rehydration, bisphosphonates, calcitonin, surgery, and addressing the underlying cause. Hypocalcemia is usually asymptomatic but can cause tingling and seizures in severe cases. It is often caused by hypoparathyroidism, vitamin D deficiency, or tumor lysis syndrome. Treatment involves calcium and vitamin D supplementation to address the deficiency. Laboratory tests are important to