An update on chronic renal failure: follow-up and when to refer ?

1. An update on chronic renal failure: follow-up and when to refer ? Assoc Prof Johan Rosman Renal Department Waitemata DHB johan.rosman@waitematadhb.govt.nz Apollo Health Centre, Albany www.bloodpressure.org.nz

2. Chronic renal failure • Diagnosis • Presentations and stages of CRF in general • Causes of CRF • Monitoring CRF • Consequences of CRF • Progression of CRF • Principles of treatment

3. Short History (ds-wks) Normal Hb Normal renal size No osteodystrophy Periph neuropathy - Normal Ca and P Normal PTH Long history (mo-yrs) Low Hb Reduced renal size Often osteodystrophy Periph neuropathy + Low Ca / elevated P Increased PTH Differentiation acute-chronic renal failure

4. Acute on chronic renal failure • Recrudescence of primary disease • Complication of primary disease • Accelerated hypertension • Volume depletion • Cardiac failure • Sepsis • Nephrotoxins (radiocontrast, drugs) • Renal artery occlusion • Urinary tract obstruction • Dietary protein load

5. Presentation of CRF • Asymptomatic serum biochemical abnormality • Asymptomatic proteinuria/haematuria • Hypertension • Symptomatic primary disease • Symptomatic uraemia • Complications of renal failure

6. Commonest causes of ESRF (ANZData) • Glomerulonephritis 30% • Diabetes 25% • Hypertension 10% • Polycystic kidney disease 5% • Vesicoureteral reflux 5% • Analgesic nephropathy 5% • Unknown 10% • Others 10%

10. GFR (glomerular filtration rate) equals creatinine clearance ?? • The accurate assessment of GFR is desirable • Planning for the treatment of end stage renal disease • Referral to nephrology • Trace the course of progression of chronic renal disease or response to therapy • What is the best, most practical way to assess GFR?

11. Creatinine: an imperfect marker Efferent arteriole Afferent arteriole Glomerulus Filtered Reabsorbed Secreted

12. 200 400 600 800 1000 [Creatinine]s micromole/L 20 40 60 80 100 120 GFR ml/min/1.73m2 BSA

13. “Normal” GFR by Age

14. Measuring glom. filtration rate • Many formulas have attempted to predict GFR from a serum creatinine measurement only, most factoring in age, weight/height, and gender, which are all independent of serum creatinine in influencing GFR. • This would be the easiest approach clinically • a serum creatinine of 130 umol/l is normal in an athlete, but can mean dialysis dependency in a 80 year old !

15. Aids in monitoring GFR (creat clearance) • Use the Cockroft Gault equation • Use the MDRD equation • But: in the follow up of a patient stick to the same way of estimating GFR • Formula’s for free available on the web (spreadsheet) or free for Palmtop (Medcalc) • Use 1/creatinine in individual patients to see whether a rise in creatinine represent an acute on chronic event

20. Renal Screen • BP • MSU • RBC morphology; ACR; 24-hour proteinuria • Serum urea, creatinine, Na+, K+ • Ultrasound scan renal tract • Albumin, calcium, phosphate • PTH • eGFR

21. Why do 24-hour urine collection? • Extremes of age / body size • Malnutrition or obesity • Catabolic states • Amputees / paraplegia / mm. wasting • Vegetarians / vegans • Pregnancy • Medication-dosing • Rapidly changing renal function

22. Problems of ESRD • Cardiovascular disease • Anaemia • Renal Bone Disease • Metabolic acidosis • Malnutrition • Sodium and water • Potassium • Bleeding Diathesis • Dermatologic manifestations • Neurologic manifestations • Endocrine abnormalities • Immunity • Psychological manifestations

23. Factors causing progression of CRF • Cont activity of primary disease • Systemic hypertension • Intraglomerular hypertension • Proteinuria • Nephrocalcinosis (dystr and metast) • Dyslipidaemia • Imbalance renal energy demands and supply

24. No Proteinuria Cardiovascular Morbidity and Proteinuria Proteinuria 40 30 p < 0.001 Cumulative incidence (%) of CV morbidity 20 10 0 0 1 2 3 4 5 6 7 8 9 10 Years Adapted from Samuelsson et al. J Hypertens 1985;3:72 RPLM Hoogma

25. Clinical trials of >3–years duration Relationship between BP and progression of CRF MAP (mm Hg) 98 100 102 104 106 108 110 0 r = 0.66; P<0.05 –2 –4 GFR (mL/min per year) –6 –8 –10 Adapted with permission from Bakris. Diabetes Res Clin Pract 1998;39:S35 RPLM Hoogma

26. Principles of treatment of pat with CRF • Differentiate from ARF on CRF • Establish aetiology • Establish severity • Seek and treat reversible factors • Seek and treat complications • Lifestyle improvements • Seek and treat factors that promote progression • Planned and timely refer to nephrologist

34. When to refer to renal physician? • eGFR < 30 ml/min/1.73m2 BSA • <45 in diabetics; anaemia (Hb < 100g/L) • Proteinuria > 1G per 24 hours • Glomerular haematuria • Difficult to control hypertension • Rapidly declining GFR • >15% in 3 months (Australia) • Electrolytes, vascular disease, etc.

35. Early detection is paramount • CKD • Preventable • Growing @ 6%pa • Delayed progression • Renal abnormality is prevalent! • 16% of Australians (AusDIAB) • 15% NZers (Simmonds) • 20 x more likely to die than get RRT • Keith et al. Arch Int Med 164:659; 2004 • Asymptomatic

41. The key to good care Communication Communication Communication 021- KIDNEY (021-543639)