What is the management plan for a patient with impaired renal function, indicated by elevated creatinine, blood urea nitrogen (BUN), and decreased estimated glomerular filtration rate (eGFR)?

Management of Stage 4 Chronic Kidney Disease (eGFR 15 mL/min/1.73 m²)

This patient has Stage 4 CKD (eGFR 15 mL/min/1.73 m²) and requires immediate nephrology referral for preparation of renal replacement therapy, as they are approaching Stage 5 kidney failure. 1

Immediate Actions

Nephrology Referral - URGENT

• Refer immediately to nephrology for any patient with eGFR <30 mL/min/1.73 m² 1, 2, 3, 4
• Stage 4 CKD (eGFR 15-29 mL/min/1.73 m²) requires preparation for renal replacement therapy, which should begin well before Stage 5 (eGFR <15 mL/min/1.73 m²) 1
• Late referral is associated with increased mortality after dialysis initiation 1

Assess for Dialysis Readiness

• Renal replacement therapy (dialysis or transplantation) should be considered when eGFR <30 mL/min/1.73 m² 1
• Preparation includes vascular access planning, patient education, and evaluation for transplant candidacy 1

Essential Diagnostic Workup

Determine CKD Etiology and Reversibility

• Obtain urinary albumin-to-creatinine ratio (UACR) to assess albuminuria 1, 2
• Perform urinalysis for hematuria, pyuria, casts, and proteinuria 1
• Review medication list for nephrotoxins (NSAIDs, contrast agents) 2, 3
• Assess for prerenal causes: volume depletion, hypotension, decreased cardiac output 1
• Assess for postrenal obstruction: bladder scan, renal ultrasound if indicated 1
• Evaluate for acute-on-chronic kidney injury if creatinine recently increased 1

Baseline Laboratory Assessment

• Complete metabolic panel including electrolytes, calcium, phosphorus 1
• Complete blood count to assess for anemia 1, 2
• Parathyroid hormone (PTH) and vitamin D levels 2
• Lipid panel 2
• Hemoglobin A1c if diabetic 1

Medical Management

Blood Pressure Control

• Target blood pressure <140/90 mmHg 3
• For patients with albuminuria (UACR ≥30 mg/g), use ACE inhibitor or ARB 1, 3
  • ACE-I/ARB strongly recommended if UACR >300 mg/g or eGFR <60 mL/min/1.73 m² 1
  • Monitor serum creatinine and potassium closely; do not discontinue for creatinine increases <30% without volume depletion 1, 5
  • Be vigilant for hyperkalemia given Stage 4 CKD 5

Cardiovascular Risk Reduction

• Initiate statin therapy for cardiovascular risk reduction 2, 6
• Consider SGLT2 inhibitor if diabetic with eGFR >30 mL/min/1.73 m² and UACR >300 mg/g 1
• Consider GLP-1 receptor agonist if diabetic for cardiovascular and renal protection 1, 6

Glycemic Control (if diabetic)

• Target hemoglobin A1c ≤7% 3
• Adjust doses of oral hypoglycemic agents based on eGFR 2, 3
• Avoid metformin at eGFR <30 mL/min/1.73 m² 2

Dietary Modifications

• Restrict dietary protein to approximately 0.8 g/kg/day 1
• Sodium restriction to support blood pressure control 3
• Potassium restriction if hyperkalemia present 5
• Phosphorus restriction as needed 2

Medication Safety

• Review and adjust all medication doses based on eGFR 15 mL/min/1.73 m² 2, 3
• Avoid nephrotoxins: NSAIDs, aminoglycosides, contrast agents when possible 2, 3
• Discontinue or adjust antibiotics, antivirals, and other renally cleared medications 3

Monitor for CKD Complications

Electrolyte Abnormalities

• Monitor serum potassium regularly; treat hyperkalemia with dietary restriction, diuretics, or potassium binders 1, 5
• Assess for metabolic acidosis (serum bicarbonate); treat if present to slow CKD progression 2, 3

Mineral and Bone Disorder

• Monitor calcium, phosphorus, PTH, and vitamin D levels 2
• Initiate phosphate binders if hyperphosphatemia develops 2
• Treat vitamin D deficiency and secondary hyperparathyroidism per nephrology guidance 2

Anemia Management

• Evaluate for anemia of CKD (typically develops when eGFR <30 mL/min/1.73 m²) 1, 2
• Nephrology will guide erythropoiesis-stimulating agent therapy if indicated 2

Common Pitfalls to Avoid

• Do not discontinue ACE-I/ARB for minor creatinine increases (<30%) without assessing volume status 1, 5
• Do not use potassium supplements, potassium-sparing diuretics, or salt substitutes without close monitoring 5
• Do not delay nephrology referral; Stage 4 CKD requires specialist co-management 1, 3, 4
• Do not assume normal serum creatinine excludes significant CKD; always calculate eGFR 1, 7
• Do not prescribe NSAIDs or other nephrotoxins 2, 3