Clinical meaning
CKD staging by eGFR (CKD-EPI): G1 (>=90 with albuminuria), G2 (60-89), G3a (45-59), G3b (30-44), G4 (15-29), G5 (<15). Albuminuria staging: A1 (<30), A2 (30-300), A3 (>300 mg/g). Progressive nephron loss activates RAAS increasing intraglomerular pressure. SGLT2 inhibitors reduce hyperfiltration via tubuloglomerular feedback. Complications: anemia (decreased EPO), CKD-MBD (secondary hyperparathyroidism), metabolic acidosis, hyperkalemia.
Diagnosis & workup
Diagnostics & workup: - Renal ultrasound for size, echogenicity, obstruction, masses - Urine albumin-to-creatinine ratio (UACR >30 mg/g = albuminuria) - Fractional excretion of sodium (FENa): <1% prerenal, >2% intrinsic renal - Urinalysis with microscopy (casts, crystals, cells) - Comprehensive metabolic panel (electrolytes, calcium, phosphorus, bicarbonate) - PTH and vitamin D levels for renal osteodystrophy assessment - Serum creatinine with eGFR calculation (CKD-EPI equation)
Risk factors: - Family history of polycystic kidney disease or Alport syndrome - NSAID use >7 days (prostaglandin-mediated afferent arteriolar constriction) - Autoimmune disease (SLE lupus nephritis, ANCA vasculitis) - Age >60 with age-related GFR decline - IV contrast administration (contrast-induced nephropathy) - Multiple myeloma with cast nephropathy - Diabetes mellitus (leading cause of CKD, 44% of new ESRD)