Hypercalcemia

Hypercalcemia means too much physiologically active calcium in the extracellular fluid. Calcium helps regulate neuromuscular transmission, smooth-muscle activity, renal water handling, and cardiac conduction. When the concentration rises, excitable tissues become less responsive. The patient becomes weak, sluggish, constipated, confused, and vulnerable to conduction disturbances. The symptom pattern is often gradual, especially in primary hyperparathyroidism. A patient may report fatigue, depressed mood, constipation, thirst, or “just not feeling right” long before the calcium is recognized as the cause. Severe elevations can produce delirium, stupor, coma, bradyarrhythmias, and acute kidney injury. The kidneys amplify the problem. Excess calcium impairs renal concentrating ability, causing polyuria and polydipsia. Fluid is lost in the urine, intravascular volume falls, glomerular filtration declines, and the kidneys excrete less calcium. This creates a self-reinforcing cycle: high calcium causes dehydration, and dehydration makes calcium rise further. Common manifestations cluster by system: - Renal: polyuria, polydipsia, dehydration, nephrolithiasis, declining urine output as kidney injury develops. - Gastrointestinal: anorexia, nausea, vomiting, constipation, and occasionally ileus. - Musculoskeletal: proximal weakness, fatigue, bone pain when bone resorption is prominent. - Neuropsychiatric: lethargy,...