Protect those nephrons! From AMR this week, a handy primer on CKD for your continuity clinic. 
When do your patients have CKD? Decline in GFR for >3 months PLUS Evidence of Kidney Disease (evidenced by one of the following)
- Albuminuria
- Urine sediment abnormalities
- Electrolyte and other abnormalities due to tubular disorders
- Abnormalities detected by histology
- Structural abnormalities detected by imaging
- History of kidney transplantation
Figure out what caused it: 75% are HTN and/or Diabetes
- Glomerular disease
- Obstructive uropathy
- Vascular diseases
- Hepatorenal/cardiorenal syndromes
- Congenital disease: PKD
Do the workup:
- GET THE UA Active sediment/proteinuria vs a bland UA will be a major branch point in your evaluation, so you have to get a UA. Spot urine protein and creatinine are also useful.
- US Looking for cystic kidneys, hydronephrosis, asymmetry, or even symmetric evidence of “medical renal disease” is useful.
- Based on historical clues, you can also check: HIV, hepatitis serologies, SPEP/UPEP, ANA, ANCAs
Stage it: based on GFR. VGFR- MDRD and CKD-EPI are most commonly used formulas. Here’s a handy calculator that gives you both, plus the stage.
| Stage | Description | GFR |
| 1 | Kidney damage with nl GFR | >90 |
| 2 | Kidney damage with increased GFR | 89-60 |
| 3a | Moderately decreased GFR | 59-45 |
| 3b | 44-30 | |
| 4 | Severely decreased GFR | 29-15 |
| 5 | Kidney failure | <14 or on dialysis |
Call for Backup: Nephrology Referral
- You don’t know why the patient has kidney disease
- It is progressing quickly (loss of 50% of their GFR within one year)
- Nephrosis: Lots of proteinuria (>3g/day)
- Nephritis: active urine sediment with blood, protein, casts
- Dialysis planning: sometime during stage3b is probably ideal, certainly by the time patient has GFR <30
- Mortality benefit for patients that see nephrology earlier.
OK, now what? Manage it:
- Fix reversible causes: remove nephrotoxins, relieve obstruction, treat CHF/Cirrhosis/HIV/Hepatitis
- Slow progression
- HTN: JNC8 guidelines recommend goal 140/90
- DM: ACCORD trial showed benefit with treatment to HbA1c <7.5
- Add an ACE-inhibitor or ARB if there is proteinuria
- Aggressive cardiovascular risk reduction (Cardiovascular disease is going to kill these patients before the renal disease does- see graph below)
- Deal with the complications
Sarnak M J et al. Circulation. 2003;108:2154-2169
What Complications?
- Hyperkalemia: Lasix helps
- Anemia: Replace Iron, consider EPO if Hgb <10
- Acidosis: consider when serum bicarb <22
- Volume Overload: Lasix helps
- Mineral Bone Disease: replace Vitamin D, bind PO4
Great posts by our own Dr.Centor on CKD here (don’t miss the comments) and here.
2012 KDIGO Guidelines for the evaluation and management of CKD.
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