CKD Stages & Management

A patient's GFR drops from 45 to 28 mL/min — their labs look different, their diet changes, and new medications appear. Knowing which stage drives which intervention separates safe nursing care from reactive care.

Chronic kidney disease is classified into five stages based on glomerular filtration rate (GFR). Stage 1 (GFR ≥90) and Stage 2 (GFR 60–89) often show no symptoms; management centers on controlling the underlying cause — usually diabetes or hypertension — with ACE inhibitors or ARBs to slow progression and reduce proteinuria. Stage 3 (GFR 30–59) is where lab derangements appear: rising creatinine and BUN, early hyperkalemia, hyperphosphatemia, and declining calcium. Dietary restrictions begin here — limit protein to 0.8 g/kg/day, restrict sodium to <2 g/day, and monitor potassium intake. Phosphate binders (sevelamer, calcium acetate) are taken WITH meals to bind dietary phosphorus. Erythropoietin-stimulating agents (epoetin alfa) address renal anemia once hemoglobin drops below 10 g/dL because failing kidneys lose erythropoietin production. Stage 4 (GFR 15–29) triggers preparation for renal replacement therapy — vascular access planning (AV fistula ideally created 6 months before anticipated dialysis) or transplant evaluation — while managing fluid overload, metabolic acidosis (oral sodium bicarbonate when serum bicarb <22 mEq/L), and secondary hyperparathyroidism with active vitamin D. Stage 5 (GFR <15) is end-stage renal disease; dialysis or transplant becomes necessary when uremic symptoms (nausea, pericarditis, encephalopathy, intractable fluid overload) emerge.

Key Distinctions

Don't confuse acute kidney injury (sudden GFR drop, often reversible) with CKD (progressive, irreversible). Students mix up phosphate binders (taken WITH meals) with other renal meds taken on empty stomachs. Restricting protein slows CKD progression but too-severe restriction causes malnutrition — the target is 0.8 g/kg/day in pre-dialysis stages, not zero protein.

Clinical Pearl

Phosphate up, calcium down, PTH up — that's the CKD bone disease triad. If you remember that sequence, you'll never miss secondary hyperparathyroidism on the exam.