10. Chronic Kidney Disease

Definition

One of the following:

  • ≥3 months with GFR <60cc/min/1.73m2.
  • Kidney damage: abnormal pathology (from biopsy), imaging, or blood/urine markers (spot urine albumin:creatinine >30mg/g, or urine protein:creatinine ratio >0.2).
  • Staging:
    • Stage 1: GFR >90, with kidney damage.
    • Stage 2: GFR 60-90, with kidney damage.
    • Stage 3: GFR 30-60 (subgroup 3a = 45-60, 3b = 30-45).
    • Stage 4: GFR 15-30.
    • Stage 5: GFR <15 or on dialysis.

** Now modified by degree of proteinuria to predict progression to ESRD and mortality: 

  • A1 (<30mg albumin/g creatinine) – normal.
  • A2 (30-299mg albumin/g creatinine) – formerly microalbuminuria.
  • A3 (>300mg albumin/g creatinine) – macroalbuminuria.

Etiology

  • DM and HTN are responsible for up to 2/3 of all cases.
  • Other causes include glomerulonephritis, APKD, rheumatologic disease, repeated infections/stones.

Evaluation

  • Need to rule out acute kidney injury and rapidly progressive glomerulonephritis. 
  • Workup should include: UA with microscopy, urine sediment exam, spot UProt/Cr, chem 10, CBC (for CKD-related anemia), and renal US. 
  • Ultrasound usually shows echogenic, small kidneys bilaterally (some exceptions are DM, myeloma, HIV, amyloid, PCKD).

Management

  • History: ask about risk factors for CKD (e.g., DM and HTN). Check meds for nephrotoxic agents and drugs needing dose adjustment. 
  • Physical: blood pressure, complications of CKD/uremia (uremic encephalopathy, volume overload, pericarditis), signs of underlying cause of CKD.
  • Screening for complications: chem 10, Fe studies, PTH, 25-OH Vit D, albumin. Patients with CKD stage 3b-5 are at much higher risk of calcium/phosphate metabolism derangements, chronic acidosis, and CKD related anemia which should be addressed in the hospital even if patient is not admitted on appropriate medications.
    • Supplement vitamin D if insufficient and Ca <9.5, phosphate <5.
    • Start phosphate binders: calcium acetate if Ca <9.5, phosphate >7 OR sevelamer if Ca >9.5, phosphate >7.
    • Start bicitra PO if HCO3 <20.
  • BP control.
  • If age >50 with proteinuria or anemia, consider SPEP/UPEP/IFE (or serum free light chains instead of SPEP/UPEP/IFE).

Key Points

  • When to consult nephrology:
    • Any patient on HD or PD is admitted.
    • Help for evaluation of AKI, CKD, proteinuria, glomerulonephritis, or renal stones.
    • Management of electrolyte imbalances or difficult-to-control HTN.
    • Management of patients with kidney transplant (KTU fellow) or neurogenic bladder.
  • Choosing Wisely: please consult nephrology prior to placement of a PICC line in patients with advanced CKD (stages III-V) to prevent subclavian stenosis and to preserve sites for future AVG/AVF for hemodialysis.
  • Reducing proteinuria reduces the progression of CKD. ACEI and ARBs are the medications of choice. 

 

Drawz P, Rahman M. Chronic Kidney Disease. Ann Intern Med. 2015;162(11):ITC1.

Ifudu O. Current concepts: Care of patients undergoing hemodialysis. N Engl J Med 1998;339:1054-1062.

KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. http://kdigo.org/home/guidelines/ckd-evaluation-management/

Lederer E, Ouseph R. Chronic kidney disease. Am J Kidney Dis 2006;49:162-171.

Parmar MS. Chronic renal disease. BMJ 2002;325:85-90.