Clinical meaning
Fluid & Electrolytes (3) involves disruption of renal filtration, tubular function, electrolyte homeostasis, or acid-base balance specific to fluid & electrolytes (3).
Diagnosis & workup
Diagnostics & workup: - Fractional excretion of sodium (FENa): <1% prerenal, >2% intrinsic renal - Comprehensive metabolic panel (electrolytes, calcium, phosphorus, bicarbonate) - 24-hour urine collection for proteinuria quantification and CrCl - Urine albumin-to-creatinine ratio (UACR >30 mg/g = albuminuria) - CBC for anemia of CKD evaluation - Serum creatinine with eGFR calculation (CKD-EPI equation) - BUN/Creatinine ratio (>20:1 suggests prerenal etiology)
Risk factors: - Autoimmune disease (SLE lupus nephritis, ANCA vasculitis) - IV contrast administration (contrast-induced nephropathy) - Recurrent UTIs or urinary tract obstruction - NSAID use >7 days (prostaglandin-mediated afferent arteriolar constriction) - Nephrotoxic medications (aminoglycosides, vancomycin, amphotericin B) - Diabetes mellitus (leading cause of CKD, 44% of new ESRD) - Hypertension (second leading cause of CKD)