Management of Chronic Kidney Disease. Kate Culley ST3 College road Surgery. What is CKD?. The gradual, substantial, and irreversible reduction in the excretory and homeostatic functions of the kidney characterised by progressive destruction of renal tissue over time. Why does it matter?.
ST3 College road Surgery
The gradual, substantial, and irreversible reduction in the excretory and homeostatic functions of the kidney
characterised by progressive destruction of renal tissue over time
Estimated ~ 1 in 5 men and 1 in 4 women between 65-74y has some degree CKD.
More common in South Asian/black
Cardiovascular disease is the most common cause of death in patients with CKD.
Cardiovascular mortality doubled in patients with a GFR below 70 ml/minute.
Used to measure severity kidney damage.
Calculation based on serum creatinine level, age, sex, race.
Most widely based on MDRD equation
Normal GFR is approximately 100mls/min/1.73m2
Stages of CKD based on eGFR
eGFR is estimated GFR calculated by the abbreviated MDRD equation: 186 x (Creat / 88.4)-1.154 x (Age)-0.203 x (0.742 if female) x (1.210 if black)
* Structural (eg APCKD), functional (eg proteinuria) or biopsy proven GN
Review all previous measurements of creatinine
Review all medication including OTC
Urinalysis: haematuria + proteinuria suggest GN
Repeat creat < 2w to exclude rapid progression.
Enter into a chronic disease management register
Check criteria for referral
Immediate referral for:
Urgent referral for:
Routine referral for:
Urine ACR/ PCR
Bloods (Hb, U+Es, creat, alb, Ca, PO4, chol, HbA1c)
All previous serum creat values with dates
Results of renal USS if appropriate
Should all have been referred
3-monthly tests: eGFR, Hb, Ca, PO4, HCO3, PTH.
Immunisation against hepatitis B.
Ix/ Tx PO4 retention and hyperparathyroidism.
Timely provision of dialysis depending on choice.
Correction of acidosis.
Risk factor management
Includes haemodialysis, peritoneal dialysis, CAPD or renal transplantation
* Applies to all stages of CKD *
If creatinine rises >30% or GFR fall >25%, repeat tests, consider other causes including volume depletion, NSAID use. If no explanation stop drug, consider investigation for renal artery stenosis.
Do not discontinue for lesser changes in eGFR/creatinine – repeat in 1-2w
Any comments or questions?
It is only an estimate. A significant error is possible. eGFR is most likely to be inaccurate in people at extremes of body type, for example malnourished, amputees. It is not valid in pregnant women or in children. Underestimates funtion in kidney donors.
Confidence intervals: confidence intervals are quite wide, e.g. 90% of patients will have a measured GFR within 30% of their estimated GFR. 98% have measured values within 50% of the estimated value. For an individual patient values will be much more consistent than this, just as creatinine values are - e.g. a 20% fall in eGFR is certain to reflect an important change.
Race: Some racial groups may not fit the MDRD equation well. It was originally validated for US white and black patients. For Afro Caribbean black patients, eGFR was 21% higher for any given creatinine in the MDRD study. So if race was not included in the estimate you have, it should be increased by approx. 20% for a black patient. In the UK white population the equation seems to work quite well -may not perform so well in all racial groups.
Not so good near normal: The MDRD equation tends to underestimate normal or near-normal function, so slightly low values should not be over-interpreted. Furthermore, laboratory differences in creatinine estimations may make significant differences. Routine reporting of eGFR values >90 is not recommended and many labs are now reporting all values over 60 as >60. Note however that a significant (e.g. 20%) rise in creatinine while eGFR is >60 may still be important as it will usually reflect a real change in GFR.
Creatinine level must be stable: eGFR calculations assume that the level of creatinine in the blood is stable over days or longer. They are not valid if it is changing.
Age: The MDRD equation is not valid for under-18s. Use the Counahan-Barrat method for children
Review all previous measurements of serum creatinine to estimate GFR and assess rate of deterioration.
Review all medication including over-the-counter drugs; particularly consider recent additions (e.g. diuretics, non-steroidal anti-inflammatory drugs (NSAIDs), or any drug capable of causing interstitial nephritis, such as penicillins, cephalosporins, mesalazine, diuretics).
Urinalysis: haematuria and proteinuria suggest glomerulonephritis, which may progress rapidly.
Clinical assessment: e.g. look for sepsis, heart failure, hypovolaemia, palpable bladder.
Repeat serum creatinine measurement within 5 days to exclude rapid progression.
Check criteria for referral (above). If referral not indicated, ensure entry into a chronic disease management register and programme.