CC | PRIMER CKD & AKI

1. Pathophysiology AKI: Sudden, potentially reversible decline in GFR. Prerenal: Decreased perfusion (hypovolemia, shock, HF). Oliguria occurs without tissue damage; reversible with fluids. Intrarenal: Direct tissue damage, 90% from Acute Tubular Necrosis (ATN) (ischemia, sepsis, nephrotoxins). Postrenal: Mechanical obstruction (BPH, calculi) causing urine reflux. CKD: Gradual, irreversible nephron loss (GFR <60 for >3 months). Primary causes: Diabetes (50%), Hypertension (25%). Stage 5 (ESRD) GFR <15. 2. Clinical Phases & Manifestations AKI Phases: Oliguric (<400 mL/d): Fluid overload (edema, hypertension, pulmonary edema), acidosis, hyperkalemia (ECG: peaked T, wide QRS), and uremia. Diuretic (1–5+ L/d): Osmotic diuresis (high urea). Risk of hypovolemia, hypotension, hyponatremia, and hypokalemia. Recovery: GFR increases, BUN/Creatinine stabilize (takes up to 12 months). CKD Manifestations (Uremia): Cardiovascular: Leading cause of death; due to vascular calcification, volume overload, and hypertension. Hematologic: Anemia from decreased erythropoietin. CKD-MBD: Low active Vitamin D reduces calcium absorption. Hypocalcemia triggers PTH release, causing bone demineralization (osteomalacia, osteitis fibrosa) and calcifications. 3. Diagnostics & Priority Interventions Metrics: GFR is the best indicator of kidney function. Creatinine is the best AKI marker. Proteinuria is first sign of CKD. Hyperkalemia Emergency Care: Cardioprotection: IV Calcium Gluconate (stabilizes myocardium). Shift K+ Intracellularly: IV Regular Insulin + Glucose, or IV Sodium Bicarbonate. Definitive Removal: Hemodialysis or Kayexalate (avoid in paralytic ileus due to bowel necrosis). Fluid Limits: Oliguric AKI: previous 24-hr loss + 600 mL. Anemia: Exogenous EPO. Monitor for hypertension, clots; supplement iron. 4. RRT & Post-Op Care HD: Rapid fluid/solute shifts. Assess AV Fistula for thrill and bruit. Safety: No BP/blood draws/IVs in access arm. Complication: Hypotension, cramps. PD: Uses peritoneal membrane. Core complication: Peritonitis (abdominal pain, rebound tenderness, cloudy effluent). CRRT: Slow, continuous solute/fluid removal for hemodynamically unstable AKI. Transplantation: Post-op priority is fluid/electrolyte balance. Watch for massive diuresis (replace mL-for-mL) or ATN. CVD is the leading cause of death post-transplant.