What investigations should be done for a patient with chronic kidney disease stage 5, hypertension, anasarca, and hypoalbuminemia?

Investigations for CKD Stage 5 with Hypertension, Anasarca, and Hypoalbuminemia

This patient requires comprehensive laboratory evaluation including complete blood count, comprehensive metabolic panel with electrolytes, calcium, phosphate, parathyroid hormone, lipid panel, urinalysis with albumin-to-creatinine ratio, and echocardiography to assess for hypertension-mediated organ damage and guide preparation for renal replacement therapy. 1

Essential Laboratory Investigations

Renal Function and Electrolyte Assessment

• Serum creatinine and eGFR calculation using race-free CKD-EPI equation to confirm CKD stage 5 (GFR <15 mL/min/1.73 m²) 1
• Urine albumin-to-creatinine ratio (UACR) via spot urine collection, which is preferred over 24-hour collections for convenience and accuracy 2, 3
• Serum electrolytes including sodium, potassium, chloride, and bicarbonate to assess for hyperkalemia and metabolic acidosis 2, 4
• Blood urea nitrogen (BUN) to evaluate uremic status 1

Mineral and Bone Disease Evaluation

• Serum calcium and phosphate to screen for CKD-mineral and bone disorder, as hyperphosphatemia is highly prevalent in stage 5 CKD 1, 5
• Parathyroid hormone (PTH) levels, which should be monitored when eGFR falls below 60 mL/min/1.73 m² 1, 2
• Vitamin 25(OH)D levels to assess for deficiency 2

Hematologic Assessment

• Complete blood count (CBC) with differential to evaluate for anemia, which affects 96% of predialysis CKD patients 1, 6, 5
• Anemia evaluation becomes critical in stage 5 CKD as prevalence increases dramatically with declining GFR 4, 6

Cardiovascular Risk Assessment

• Lipid panel including total cholesterol, LDL, HDL, and triglycerides, as dyslipidemia is present in 67% of predialysis CKD patients 1, 5
• Serum albumin to assess nutritional status and cardiovascular risk, as hypoalbuminemia is an independent predictor of cardiovascular disease and mortality in CKD 5, 7, 8

Additional Blood Work

• Hemoglobin A1c (HbA1c) if diabetes is suspected or known 1
• Thyroid-stimulating hormone (TSH) as part of routine evaluation 1

Urinalysis and Microscopy

• Urinalysis with microscopy to evaluate for casts, epithelial cells, and red/white blood cells to help determine etiology of CKD 1
• Urine chemistry to assess for proteinuria and other abnormalities 1

Cardiac Imaging

Echocardiography

• 12-lead ECG is mandatory as initial routine work-up to assess for left ventricular hypertrophy and atrial fibrillation 1
• Transthoracic echocardiography is recommended given the presence of hypertension and anasarca (suggesting volume overload and possible heart failure) 1
  • Should be performed as a full, standardized, two-dimensional study with tissue Doppler and strain assessment 1
  • Assesses for hypertensive heart disease, left ventricular hypertrophy, diastolic dysfunction, and established cardiovascular disease 1
  • Left ventricular hypertrophy is present in 77.6% of predialysis CKD patients 5

Optional Cardiac Biomarkers

• High-sensitivity cardiac troponin and/or NT-proBNP may be considered to assess for hypertension-mediated organ damage 1

Renal Imaging

Ultrasound

• Renal ultrasound with Doppler examination should be considered to assess kidney structure, determine causes of CKD, and exclude renoparenchymal and renovascular hypertension 1
• Ultrasound can identify small echogenic kidneys, dysplastic or polycystic kidneys, renal scarring, or hydronephrosis 1
• Ultrasound contrast media are not nephrotoxic, making them ideal for microvascular imaging in CKD stage 5 1

Advanced Imaging Considerations

• CT or magnetic resonance renal angiography are alternative options if renovascular disease is suspected 1
• Unenhanced MR angiography (MRA) techniques may be diagnostic without contrast 1
• Given stage 5 CKD, if patient is already on hemodialysis or peritoneal dialysis with no residual renal function, contrast-enhanced CT may be performed if clinically indicated 1

Monitoring Frequency for Stage 5 CKD

• eGFR and UACR should be monitored every 1-3 months in stage 5 CKD 2
• More frequent monitoring is required given the severity of disease and preparation for renal replacement therapy 2

Additional Investigations Based on Clinical Context

For Anasarca Evaluation

• Serum albumin is critical given hypoalbuminemia and anasarca, as it helps differentiate nephrotic syndrome from other causes of edema 1, 7
• Consider 24-hour urine protein collection if nephrotic-range proteinuria is suspected (though spot UACR is generally preferred) 1

For Hypertension Assessment

• Fundoscopy may be considered to assess for hypertensive retinopathy and exclude hypertensive emergency (hemorrhages, exudates, papilloedema) 1
• Ankle-brachial index to assess for lower-extremity arterial disease 1

For Preparation for Renal Replacement Therapy

• Hepatitis B and C serology, HIV testing as part of pre-dialysis evaluation 1
• Vascular mapping ultrasound for arteriovenous fistula planning if hemodialysis is anticipated 1

Critical Pitfalls to Avoid

• Do not rely on serum creatinine alone—always calculate eGFR using a prediction equation 2, 3
• Avoid iodinated contrast unless there is an overriding clinical question that cannot be answered with alternative imaging, as this patient has severe CKD 1
• Do not delay nephrology referral—patients with GFR <30 mL/min/1.73 m² require nephrologist involvement for preparation for kidney replacement therapy 1
• Monitor for clinically significant changes: >20% decline in eGFR or doubling of UACR warrants immediate investigation 2
• Assess for reversible causes including obstruction (via renal ultrasound), volume depletion, nephrotoxic medications, and renovascular disease 1