CKD complications management

Anemia of CKD - The Pale Kidney

• Pathophysiology: Normocytic, normochromic anemia from ↓ erythropoietin (EPO) production by failing peritubular cells. Uremic toxins also shorten RBC lifespan.
• Diagnosis: Workup initiated when Hemoglobin <10 g/dL. Always rule out iron deficiency first (ferritin, TSAT).
• Management:
  • 1. Iron Repletion: If needed. Goal: Ferritin >100 ng/mL, TSAT >20%.
  • 2. ESAs: Erythropoiesis-stimulating agents (e.g., epoetin alfa, darbepoetin).
  • Hb Target: 10-11.5 g/dL. ⚠️ Avoid normalizing Hb (>13 g/dL) due to ↑ thromboembolic risk.

⭐ The most common side effect of ESA therapy is new-onset or worsening hypertension.

CKD-MBD - Bone & Mineral Mayhem

• Pathophysiology: ↓ GFR → ↑ PO₄ & ↓ active Vitamin D → ↓ Ca²⁺ → secondary hyperparathyroidism (↑ PTH).
• Renal Osteodystrophy Spectrum:
  • Osteitis Fibrosa Cystica: High-turnover from severe ↑ PTH; bone pain, fractures.
  • Adynamic Bone Disease: Low-turnover, often from PTH over-suppression.
  • Osteomalacia: Defective mineralization.
• Management:
  • Phosphate Binders: Sevelamer, calcium acetate (goal PO₄ < 5.5 mg/dL).
  • Vitamin D Analogs: Calcitriol (suppresses PTH).
  • Calcimimetics: Cinacalcet (↑ CaSR sensitivity).

⭐ Adynamic bone disease is now the most common renal osteodystrophy, often resulting from iatrogenic oversuppression of PTH during treatment.

Metabolic Acidosis - The pH Plunge

• Pathophysiology: ↓ GFR leads to impaired renal excretion of H+ and ↓ regeneration of bicarbonate ($HCO_3^-$).
• Complications: Worsens bone demineralization (renal osteodystrophy) and muscle catabolism. Can accelerate CKD progression.
• Diagnosis: ↓ Serum $HCO_3^-$ (< 22 mEq/L) and ↓ arterial pH.
• Treatment:
  • Goal: Maintain serum $HCO_3^-$ ≥ 22 mEq/L.
  • Initiate oral alkali replacement (sodium bicarbonate or citrate) when $HCO_3^-$ < 22 mEq/L.

⭐ Correcting acidosis may slow CKD progression, reduce muscle wasting, and improve bone health.

Hyperkalemia - Potassium's Peril

• EKG Changes: Peaked T waves → flattened P waves → widened QRS → sine wave pattern.
• Management Steps: 📌 C BIG K Drop
  • Cardiac Membrane Stabilization: IV Calcium Gluconate (if EKG changes).
  • Beta-agonists / Bicarb / Insulin + Glucose: Shift K+ intracellularly.
  • Kayexalate (SPS) / Diuretics / Dialysis: Remove K+ from body.

⭐ With EKG changes, the first and most crucial step is IV Calcium Gluconate to stabilize the cardiac membrane, preventing fatal arrhythmias.

HTN & Volume Overload - The Pressure Cooker

CKD impairs sodium and water excretion, leading to volume overload and hypertension. Management is crucial to slow progression.

• Volume Control:
  • Dietary sodium restriction: < 2 g/day.
  • Loop diuretics (e.g., furosemide) are preferred, especially with GFR < 30 mL/min.
• Blood Pressure Control:
  • Target: < 130/80 mmHg.
  • ACE inhibitors (ACEi) or ARBs are first-line agents, particularly in patients with albuminuria.

⭐ An initial, self-limiting increase in serum creatinine (up to 30%) after starting an ACEi/ARB is acceptable and not a reason to discontinue.

High‑Yield Points - ⚡ Biggest Takeaways

• Anemia of CKD is managed with iron and ESAs; target Hb 10-11.5 g/dL.
• CKD-MBD (↑PO₄, ↓Ca, ↑PTH) requires phosphate binders and vitamin D analogs.
• Treat metabolic acidosis with sodium bicarbonate if serum bicarb is <22 mEq/L.
• Acute hyperkalemia requires calcium gluconate for cardioprotection, then agents to shift K⁺ intracellularly.
• Uremic pericarditis is an absolute indication for immediate hemodialysis.
• Manage fluid overload with loop diuretics and sodium restriction.