Chart — Renal
AKI vs CKD Comparison Chart
Side-by-side comparison of acute kidney injury (AKI) and chronic kidney disease (CKD) — onset, reversibility, kidney size, laboratory findings, and treatment priorities.
Source: KDIGO 2012/2022 CKD Guidelines; KDIGO 2012 AKI Guidelines; National Kidney Foundation. Ranges reflect standard clinical references — verify with institutional norms.
Educational use only. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
Key NCLEX distinction: AKI is potentially reversible; CKD is irreversible. This single distinction is the most commonly tested renal concept. Know the defining features of each cold.
Acute Kidney Injury (AKI)
Sudden decline · Potentially reversible · Hours to days
Chronic Kidney Disease (CKD)
Progressive decline · Irreversible · Months to years
| Feature | AKI | CKD |
|---|---|---|
| Definition | Sudden, acute decline in kidney function — occurs over hours to days | Progressive, chronic loss of kidney function — occurs over months to years (≥3 months) |
| Onset | Rapid (hours to days) | Insidious, gradual (months to years) |
| Reversibility | Potentially REVERSIBLE — early treatment can restore function | IRREVERSIBLE — nephrons permanently lost; cannot be restored |
| Kidney size (imaging) | Normal or enlarged kidneys (edematous from acute process) | Small, shrunken kidneys (bilaterally contracted from chronic scarring) |
| Primary causes | Prerenal: dehydration, HF, shock Intrarenal: ATN, GN, AIN Postrenal: obstruction (BPH, stones) | Diabetic nephropathy (#1), Hypertensive nephrosclerosis (#2), Glomerulonephritis, PKD, Chronic obstruction |
| Serum creatinine | Rises acutely — diagnostic if rise ≥0.3 mg/dL in 48 hrs | Elevated chronically — rises slowly as GFR declines progressively |
| BUN:Creatinine ratio | >20:1 in prerenal AKI; ~10:1 in intrarenal AKI | Usually normal (~10–15:1) in stable CKD — both BUN and Cr elevated proportionally |
| Urine output | Often oliguric (<400 mL/day) — may be anuric in severe cases | Variable — polyuria common in early-mid CKD; oliguria in ESRD |
| Anemia | Absent or mild (too acute for EPO deficit to manifest) | Characteristic — normocytic, normochromic; significant decreased EPO production |
| Calcium/Phosphorus | May be acutely abnormal in severe AKI | Progressive hyperphosphatemia, hypocalcemia, secondary hyperparathyroidism (renal osteodystrophy) |
| Urinary casts | ATN: muddy-brown granular casts GN: RBC casts AIN: WBC casts | Waxy or broad casts (indicate chronically dilated tubules from long-standing disease) |
| Urinalysis clues | Active sediment with casts (AKI type-specific) FENa <1% (prerenal); >2% (intrinsic) | Persistent proteinuria (albuminuria) Broad waxy casts in advanced stages |
| Systemic symptoms | Rapid-onset uremia: nausea, altered mental status, fluid overload | Uremic syndrome develops slowly: fatigue, pruritus, nausea, bone pain, anemia symptoms |
| Treatment goal | Identify and reverse underlying cause — restore kidney function | Slow progression, manage complications, prepare for RRT (dialysis/transplant) |
| Dialysis indication | Temporary — bridges until recovery (CRRT preferred in unstable patients) | Permanent — ESRD requires ongoing dialysis unless transplanted |
| Key NCLEX distinction | Potentially reversible — the treatable acute kidney problem | Irreversible — the progressive chronic kidney disease |
AKI Staging (KDIGO)
| Stage | Creatinine Criteria | Urine Output Criteria |
|---|---|---|
| Stage 1 | 1.5–1.9× baseline in 7 days, OR rise ≥0.3 mg/dL in 48 hrs | <0.5 mL/kg/hr for 6–12 hours |
| Stage 2 | 2.0–2.9× baseline | <0.5 mL/kg/hr for ≥12 hours |
| Stage 3 | ≥3.0× baseline, OR ≥4.0 mg/dL, OR initiation of RRT | <0.3 mL/kg/hr for ≥24 hrs, OR anuria ≥12 hrs |
Related Resources
Standards & sources
Fact-checked Jun 21, 2026This page is written to align with KDIGO 2012/2022 AKI and CKD Guidelines; National Kidney Foundation. It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →