Chronic Kidney Disease


Stages of CKD

 Stage 1
  • Normal GFR > 90 mL/min and persistent albuminuria

Management

  • Dx and Tx of comorbid conditions, slowing progression, CV risk reduction
Stage 2
  • GFR between 60 to 89 mL/min and persistent albuminuria

Management

  • Estimating progression

 

Stage 3
  • 3a—GFR between 45 and 59 mL/min
  • 3b—GFR between 30 and 44 mL/min

Management

  • Evaluating and Tx of complications

 

Stage 4
  • GFR between 15 and 29 mL/min  ( < 30 )

Management

  • Prep for kidney replacement, Nephrology referral

 

Stage 5 = end-stage renal disease (ESRD)
  • GFR < 15 mL/min

Management

  • Replacement/dialysis
  • PO4 should be maintained between 3.5 and 5.5
  • Lipid Management:
    – Triglycerides < 500
    – LDL to < 100 mg/dL
    – Non-HDL cholesterol to < 130 mg/dL.

Laboratory Evaluation

  • UA with microscopic exam
  • CBC, CMP
  • 25-OH Vit D, iPTH, Ca, phosphorous level
  • Uric acid level
  • 24-hour urine CrCl or estimated GFR
  • 24-hour urine or random protein excretion
  • Serum protein electrophoresis (SPEP) -- to R/O Multiple Myeloma
  • HepBsAg, Hepatitis C antibody; HIV
  • ANA
  • C3, C4, & CH50
  • ANCA
  • Anti-GBM antibody
 

Radiology Evaluation

  • Renal ultrasound
  • CT scan of the kidneys and liver
  • MRI of the kidneys
  • Renal angiogram
  • Voiding cystourethrogram
 

Management

Anemia of Chronic Disease—Rx
  • Treat underlying cause of the ACD
  • Erythropoiesis-stimulating agent
    • Continuing symptomatic anemia despite Rx of underlying cause
    • Darbepoetin (Aranesp)
    • Epoetin alfa (Epogen, Procrit)
    • Supplemental iron
      • Maintain transferrin saturation ≥ 20%
      • Maintain serum ferritin ≥ 100 ng/mL
         
    • Black box warnings
      • Increased mortality and serious CV events in CKD
        • MI, CVA, CHF
      • Increased mortality and tumor progression in cancer patients
      • Increased thromboembolic events in surgery patients
    • Contraindicated in uncontrolled hypertension

       
  • Red cell transfusion
    • If continue to have symptomatic anemia despite
      • Treatment of the underlying cause
      • Use of an erythropoiesis-stimulating agent
Treatment of Acidosis
  • Na bicarbonate
    • 0.5- 1 mg/kg/day
    • Target HCO3 = 23-29
       
  • Na citrate (eg, Shohl’s solution)
    • Metabolized to bicarbonate
    • Less bloating
    • Do not use with aluminum antacids
      • Enhances intestinal aluminum absorption
         
  • Ca citrate
  • Ca acetate (PhosLo, Eliphos, Phoslyra)
  • Ca carbonate (Tums)
Mineral Bone Density Guidelines
  • Dietary phosphorus should be restricted to 800 to 1,000 mg/day when serum PO4 levels are elevated
  • Serum PO4 should be monitored every month following the initiation of dietary phosphorus restriction. (OPINION)
  • In CKD 3 & 4
    • Use PO4 binders if PO4 or intact PTH levels cannot be controlled despite dietary phosphorus restriction. (OPINION)
    • Calcium-based phosphate binders are effective
  • In CKD-5
    • Both calcium-based phosphate binders and other noncalcium-, nonaluminum-, nonmagnesium-containing phosphate-binding agents are effective. (OPINION)
       
  • Parathyroidectomy is recommended
    • Severe hyperparathyroidism (PTH > 800 pg/mL)
    • Hypercalcemia and/or hyperphosphatemia that are refractory to medical therapy. (OPINION)
Treatment of Hyperphosphatemia
  • Dietary phosphate restriction = 900 mg/day
     
  • Oral phosphate binders:
    • Calcium-containing:
      • Calcium carbonate
      • Calcium acetate (PhosLo, Eliphos, Phoslyra)
        • 1300-2600 mg with each meal
      • NOTE:
        • Usually cheaper
        • Better if pt has low Ca+
           
    • Non-calcium
      • Sevelamer (Renegel, Renleva) 800-1600 mg TID
      • Lanthanum (Fosrenol) 1500-3000 mg/day
      • NOTE:
        • Better with normal or high Ca++
        • On Vit D supplementation
           
Lipid Guidelines
  • Lipid Management:
    – Triglycerides < 500
    – LDL to < 100 mg/dL
    – Non-HDL cholesterol to < 130 mg/dL.
 

Indications for Nephrology Referral

  • Acute, complex, or severe cardiovascular disease
  • Anemia of CKD (Hb < 10)
  • Bone and mineral disorder of CKD
  • Difficult to manage adverse effects of medications
  • Hyperkalemia
    •  K+ > 5.5 mEq/L (despite treatment)
       
  • Refractory proteinuria
    – Urinary protein/creatinine ratio > 500 to 1,000 mg/g
    – Urinary albumin/creatinine ratio > 300 mg/g
     
  • Resistant hypertension
    – Target blood pressure not achieved with use of at least three BP drugs
     
  • Stage 4 CKD
    GFR < 30 mL/minute
     
  • Unexplained decrease in GFR > 30 percent over 4 months
 

Evidence-Based Guidelines

  • ACE inhibitor or an angiotensin II receptor blocker
    – Nondiabetic kidney disease and a random urine total protein-to-creatinine ratio > 200 mg/g
    – Diabetic kidney disease
     
  • Concurrent use of ACE inhibitors and ARBs
    – Should be avoided because of symptomatic hypotension and worsening kidney function
     
  • Erythropoiesis-stimulating agents
    – Hb goal should not exceed 11 g/dL
    • Due to the risk of major cardiovascular events
       
  • Avoid gadolinium if
    – GFR < 30 mL/min per minute
    – AKI due to hepatorenal syndrome