Chronic Kidney Disease (CKD)
Persistent decline in GFR or kidney damage for ≥3 months, staged by eGFR and albuminuria.
Also known as: CKD, chronic renal insufficiency, chronic renal failure
Overview
Abnormalities of kidney structure or function present for >3 months with implications for health. Defined by eGFR <60 mL/min/1.73 m² OR markers of kidney damage (albuminuria ≥30 mg/g, urine sediment abnormalities, electrolyte/structural abnormalities, biopsy findings, or kidney transplant) lasting ≥3 months.
Epidemiology
Affects ~14% of US adults. Diabetes and hypertension cause >70% of cases. Black, Hispanic, and Native American populations have higher incidence and progression rates.
Keep reading — start your free trial
You've read your 2 free diagnosis previews. Create your free account to unlock the full Chronic Kidney Disease (CKD) outline — plus all 514 diagnoses, 5,500+ board-style questions, flashcards, and an AI tutor. Your 7-day free trial includes everything, and there's no credit card required.
Risk factors
- Diabetes mellitus (leading cause)
- Hypertension (second leading cause)
- Glomerulonephritis, polycystic kidney disease, recurrent AKI
- Age >60, family history, obesity, smoking, nephrotoxin exposure
- APOL1 high-risk genotype (African ancestry)
Pathophysiology
Progressive nephron loss triggers compensatory hyperfiltration in surviving glomeruli → glomerular hypertension, sclerosis, and tubulointerstitial fibrosis. Activation of the renin-angiotensin-aldosterone system, oxidative stress, and inflammatory cytokines accelerate decline. Loss of functional mass impairs erythropoietin production, vitamin D activation, acid-base homeostasis, and phosphate excretion.
Clinical presentation
Symptoms
- Often asymptomatic until advanced (stage 4-5)
- Fatigue, weakness, anorexia, weight loss
- Pruritus, restless legs, muscle cramps
- Foamy urine (albuminuria), nocturia, peripheral edema
- Late: dyspnea, nausea, confusion, bleeding
Signs / physical exam
- Hypertension (cause and consequence)
- Pallor (anemia of CKD), volume overload (edema, elevated JVP, crackles)
- Uremic features: sallow skin, asterixis, pericardial rub
- Diabetic retinopathy, peripheral neuropathy supportive of diabetic etiology
Classic findings
Small echogenic kidneys on ultrasound (except in diabetes, amyloid, HIV-associated nephropathy, and PKD where kidneys may be normal or enlarged).
Differential diagnosis
- Acute kidney injury — Abrupt onset (<3 months), often reversible; baseline labs critical to distinguish — small echogenic kidneys favor CKD
- Diabetic nephropathy — Long-standing diabetes, retinopathy, gradual albuminuria progression; biopsy shows Kimmelstiel-Wilson nodules
- Hypertensive nephrosclerosis — Long-standing HTN, minimal proteinuria, small bilateral kidneys, no active sediment
- Glomerulonephritis (chronic) — Persistent proteinuria, hematuria, active sediment; biopsy diagnostic
- Polycystic kidney disease — Family history, enlarged kidneys with cysts on imaging, extrarenal cysts
- Obstructive uropathy — Hydronephrosis on US, history of stones, BPH, or pelvic malignancy
- Multiple myeloma / monoclonal gammopathy — Anemia disproportionate to CKD stage, hypercalcemia, bone pain; SPEP/UPEP with free light chains
Diagnostic workup
Diagnostic criteria
CKD requires kidney damage OR eGFR <60 for ≥3 months. Staged G1-G5 by eGFR (G1 ≥90, G2 60-89, G3a 45-59, G3b 30-44, G4 15-29, G5 <15) and A1-A3 by UACR (A1 <30, A2 30-300, A3 >300 mg/g).
Labs
- Serum creatinine with eGFR (CKD-EPI 2021 race-free equation)
- Urine albumin-to-creatinine ratio (UACR) on spot sample — preferred over dipstick
- Urinalysis with microscopy
- BMP (K, HCO3, Ca, phosphate), CBC (anemia), albumin
- Stage 3-5: PTH, 25-OH vitamin D, iron studies, lipid panel
Imaging
- Renal ultrasound — assess size, echogenicity, cysts, obstruction
Diagnostic algorithm
| Stage | eGFR (mL/min/1.73 m²) | Description | Action |
|---|---|---|---|
| G1 | ≥90 | Normal GFR with kidney damage | Treat comorbidities, slow progression |
| G2 | 60-89 | Mild GFR decrease with damage | Estimate progression |
| G3a | 45-59 | Mild-moderate decrease | Evaluate and treat complications |
| G3b | 30-44 | Moderate-severe decrease | Evaluate and treat complications |
| G4 | 15-29 | Severe GFR decrease | Prepare for RRT, transplant referral |
| G5 | <15 | Kidney failure | RRT if uremia present |
Treatment
First-line
- BP target <120/80 (KDIGO 2021); use validated office BP measurement
- ACEi (lisinopril, ramipril, enalapril) or ARB (losartan, valsartan, irbesartan) — first-line for albuminuria or diabetes; reduces progression
- SGLT2 inhibitor — dapagliflozin, empagliflozin, canagliflozin — for diabetic or non-diabetic CKD with eGFR ≥20 and UACR ≥200 (proven mortality and renal benefit)
- Nonsteroidal MRA — finerenone — for type 2 diabetes with albuminuric CKD on maximal ACEi/ARB
- Glycemic control: A1c 6.5-8% individualized; metformin safe down to eGFR 30
- Statin therapy — atorvastatin, rosuvastatin — for all adults ≥50 with CKD or any age with diabetes/CVD
Second-line / adjunct
- Anemia: iron repletion first; ESA (epoetin alfa, darbepoetin) when Hb <10 with caution to avoid >11.5
- Mineral-bone disease: phosphate binders (sevelamer, lanthanum, calcium acetate), active vitamin D (calcitriol, paricalcitol), calcimimetics (cinacalcet, etelcalcetide)
- Metabolic acidosis: sodium bicarbonate when HCO3 <22 (slows progression)
- Hyperkalemia: dietary restriction, loop diuretic, potassium binder — patiromer, sodium zirconium cyclosilicate
- Prepare for RRT at eGFR ~20: education, vascular access (AV fistula 6+ months in advance), transplant referral
Complications
- Cardiovascular disease (leading cause of death in CKD)
- Anemia (decreased EPO production)
- CKD-mineral bone disease: hyperphosphatemia, low calcitriol, secondary hyperparathyroidism, renal osteodystrophy
- Metabolic acidosis, hyperkalemia, hypocalcemia
- Uremic complications: pericarditis, encephalopathy, platelet dysfunction
- Progression to ESRD requiring dialysis or transplant
PANCE pearls
- The 2021 CKD-EPI equation removed the race coefficient and is now the standard eGFR calculation in the US.
- ACEi/ARB may cause an initial 30% Cr rise — this is acceptable and does not require discontinuation if K stable.
- SGLT2 inhibitors are now first-line for CKD with proteinuria regardless of diabetes status (DAPA-CKD, EMPA-KIDNEY).
- Avoid NSAIDs, gadolinium (eGFR <30), and excessive iodinated contrast in CKD.
- Refer to nephrology at eGFR <30, rapid decline >5 mL/min/year, persistent UACR >300, or refractory complications.
References
- KDIGO 2024 — KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease (Kidney Int 2024)
- KDIGO 2021 BP — KDIGO 2021 Clinical Practice Guideline for the Management of Blood Pressure in CKD
- DAPA-CKD — Dapagliflozin in Patients with Chronic Kidney Disease (Heerspink et al., NEJM 2020)
- EMPA-KIDNEY — Empagliflozin in Patients with Chronic Kidney Disease (NEJM 2023)
Practice Renal/Urology questions on FirstPassPA
Turn this outline into retention. 5,500+ board-style questions with an AI tutor that explains every answer — free to start, no card required.
Start studying free → Browse all 514 diagnosesEducational use only. This outline is a study aid for PA students and is not medical advice or a substitute for clinical judgment. FirstPassPA is an independent study tool and is not affiliated with, endorsed by, or sponsored by NCCPA or PAEA. PANCE® and PANRE® are registered trademarks of the National Commission on Certification of Physician Assistants; End of Rotation™ is a program of the Physician Assistant Education Association.