Chronic kidney disease involves progressive destruction of nephrons from sustained glomerular and tubulointerstitial injury. As GFR declines, the kidneys lose the ability to excrete nitrogenous waste (uremia), regulate electrolytes (hyperkalemia, hyperphosphatemia, hypocalcemia), maintain fluid balance (volume overload), produce erythropoietin (normocytic normochromic anemia), and activate vitamin D to calcitriol (secondary hyperparathyroidism and renal osteodystrophy). CKD is staged by GFR: Stage 1 (≥90, with kidney damage), Stage 2 (60-89), Stage 3a (45-59), Stage 3b (30-44), Stage 4 (15-29), Stage 5 (<15, kidney failure). The nurse must manage complex medication regimens, monitor for electrolyte derangements, implement dietary and fluid restrictions, assess dialysis access patency, and provide comprehensive patient education.