Chronic kidney disease - Nephrology Symposium - Aug 2014


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By Wael FM Hussein
Nephrology Fellow
Palo Alto, CA

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Chronic kidney disease - Nephrology Symposium - Aug 2014

  1. 1. Chronic Kidney Disease for the non-nephrologist SAMA – AUG 2014 WAEL FM HUSSEIN STANFORD UNIVERSITY HOSPITAL, PALO ALTO, CALIFORNIA
  2. 2. CKD - Overview What is CKD? How common is it? What is the significance of recognizing CKD? How to identify CKD Management aspects of CKD
  3. 3. Definition of CKD Low GFR (<60 ml/min/1.73m2) for more than 3 months OR Kidney damage with or without low GFR Kidney damage: ◦ Pathologic abnormalities ◦ Markers of damage ◦ Blood or urine tests ◦ Imaging studies
  4. 4. How common is CKD In the US: ◦1 in 10 adults have CKD ◦Kidney disease is the 9th cause of death ◦Age distribution: ◦ 0.5% in young individuals ◦ About 25% in over 60 years old individuals
  5. 5. Significance of CKD Cardiovascular risk Mortality and morbidity ◦ CKD patients have 56% increased mortality after adjustment for other risk factors ◦ Even higher risk (75%) for patients with stage 4 and 5 CKD ◦ Dialysis patients: ◦ 5 year survival is 35% ◦ 25% in patients with DM ◦ Most common cause of death in dialysis patients is cardiovascular disease ◦ 10 to 20 times as common as in the general population Effect on QOL
  6. 6. Go AS et al. N Engl J Med 2004;351:1296-1305.
  7. 7. How to identify CKD GFR ◦ S Cr Urinary testing Imaging
  8. 8. Serum Creatinine is Not a Good Measure of Renal Function 120 mol/L ( 1.35 mg/dL) 120 mol/LsCr 130 mL/min30 mL/minGFR • Age • Gender • Body weight • Muscle mass • Race
  9. 9. Who to screen for CKD  High risk of obstructive nephropathy  High risk of silent development of CKD  Htn, DM, CHF, Atherosclerotic disease  Patients on potentially nephrotoxic drugs  ACEI/ARB, NSAID, lithium  Multisystem diseases that may involve the kidney; eg SLE, RA, MM
  10. 10. DM and HTN are the most common causes of CKD Abboud et al. NEJM. Jan 2010
  11. 11. Identification of the cause History ◦ PMH ◦ Medications ◦ Don’t forget about the herbs ◦ Family history Clinical examination Investigations ◦ Blood tests ◦ Urinary tests ◦ Radiology
  12. 12. Proteinuria Dipstick 24 hour collections Urine Protein: Cr ratio Urine Albumin: Cr ratio The urine protein/creatinine ratio (in g prot/g creat (or mg/mg!)) is roughly equal to grams of protein/day.
  13. 13. Protein:Creatinine ratio Check the ratio in order to correct for dilution ◦ A dilute urine will have less creatinine On a random urine sample (ie, spot urine, no need for 24 hour urine collection) If lab is not familiar with test, ask them to check ◦ concentration of creatinine (mg/dL) ◦ concentration of protein (mg/dL) ◦ Then divide the values (make sure you have the same units for both): urine protein/ urine creatinine Units: The value is unitless, but is reported as mg prot/ mg creat (or mg/mg), or g/g. Get familiar with what your lab offers
  14. 14. Urine protein:creatinine ratio How to interpret the result: ◦ The value you obtain is an approximation of the number of grams of protein in a 24 hour urine sample ◦ Normally: undetectable protein, or less than 0.15 (mg/mg) ◦ Eg: Urine prot:cr ratio = 0.2 (mg prot/mg cr)  approximately 0.2 g protein in 24 hours ◦ Eg: U prot:cr ratio = 1  approximately 1 g protein in 24 hours urine (significant subnephrotic proteinuria) ◦ Eg: U prot:cr ratio = 5  approximately 5 g protein in 24 hours urine (nephrotic range proteinuria)
  15. 15. Urine albumin:creatinine ratio Usually requested when following up a diabetic patient who is not known to have proteinuria There is no consensus as to when to prefer alb:cr ratio vs prot:cr ratio. Proteinuria is specific to albuminuria in some diseases but not all. In the States, albumin:cr ratio is reported as mg alb/ g creatinine. And the interpretation is slightly different from the interpretation of prot:cr ratio because of the units: Eg Alb:Cr ratio of 100 mg/g  approximately 100 mg albumin in a 24 hours urine sample Preferably get the random urine alb:cr ratio test on an early morning urine sample, but mind the logistics for the patient and clinic.
  16. 16. Proteinuria Causes for false positive tests: ◦ Fever ◦ Exercise ◦ Prolonged standing ◦ Infection
  17. 17. When to screen for proteinuria newly-discovered GFR <60 ml/min/1.73 m2 newly-discovered hematuria newly-diagnosed hypertension unexplained edema suspected multisystem disease, eg systemic lupus erythematosus (SLE), diabetes mellitus
  18. 18. Evaluate Hematuria Two causes: ◦Glomerular/renal (rare) ◦Urological (common) Hematuria + >1 gram proteinuria/day suggests glomerular disease Refer to urology for persistent isolated hematuria
  19. 19. Haematuria Nephrology OR Urology?? Micro/Macro Proteinuria Age GFR
  20. 20. Hematuria – simplified referral plan Macroscopic => urology Microscopic ◦ +proteinuria => nephrology ◦ - proteinuria ◦ Age >50 => urology ◦ Age <50 => refer to nephrology if renal fn deteriorating or if eGFR<60 If urology Ix unyielding -> nephrology
  21. 21. Factors that may cause disease progression Underlying renal disease Systemic hypertension Nephrotoxins (eg, nonsteroidal anti-inflammatory drugs [NSAIDs], intravenous contrast media) Decreased perfusion (eg, from severe dehydration or episodes of shock) Proteinuria (in addition to being a marker of CKD) Hyperlipidemia Hyperphosphatemia with calcium phosphate deposition Smoking Uncontrolled diabetes
  22. 22. Management aspects of CKD Identify the cause Cardiovascular risk reduction Slowing down progression of kidney disease Management of complications Preparation for RRT
  23. 23. How to slow disease progression Stop NSAIDS, herbal teas, Tenofovir Aggressive BP control: ◦ More aggressive in patients with proteinuria ◦ Preferred agents in CKD: ◦ start with ACE or ARB ◦ A diuretic is second line (Loop if eGFR is low) Aggressive proteinuria control: ◦ Goal < 500mg/day ◦ Dual RAAS blockade? No!
  24. 24. Additional Interventions in Diabetic patients Glycemic control (A1C <7.5) Yearly Urine protein/creatinine ratio Lifestyle modifications: stop tobacco, daily exercise, salt restriction ASA 81mg daily in patients >40yrs with CKD Lipid lowering
  25. 25. Management of CKD 4 / 5 EDUCATE Conservative management Renal replacement therapy Preemptive transplant Access planning / Tx WU PD HD
  26. 26. Hyperkalemia RAAS DM Diet Management ◦ Diet ◦ Diuretics ◦ Avoidance of ACEI/ARB therapy and NSAIDs ◦ Correction of acidosis
  27. 27. Metabolic acidosis Protein intake Associated with GFR decline, muscle weakness and bone disease Management: ◦ Diet ◦ Alkali
  28. 28. Anemia EPO deficiency Reduced RBC survival Bleeding tendency from platelet dysfunction Anaemia NOT always due to CKD Recommended initial investigations ◦ FBC (Hb / MCV / WCC / PLT) ◦ Reticulocyte count ◦ Ferritin (marker iron storage) ◦ TSAT (marker of adequacy of iron for erythropoeisis)
  29. 29. Management of CKD – Mineral & Bone Disease Different types of bone disease occur with CKD: ◦ High-turnover bone disease from high parathyroid hormone (PTH) levels ◦ Low-turnover bone disease (adynamic bone disease) ◦ Defective mineralization (osteomalacia) ◦ Mixed disease ◦ Beta-2-microglobulin–associated bone disease Extra-skeletal manifestations: ◦ Increased vascular calcifications ◦ Soft tissue calcification
  30. 30. MBD Parameters: ◦ Phosphate ◦ Parathyroid hormone ◦ PTH ◦ ALP Causes of secondary hyperparathyroidism: ◦ Hyperphosphatemia ◦ Hypocalcemia ◦ Decreased synthesis of 1,25-dihydroxycholecalciferol (1,25-dihydroxyvitamin D, or calcitriol) ◦ Intrinsic alteration in the parathyroid glands ◦ Skeletal resistance to PTH
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  33. 33. Management of CKD 4/5 – Immunisation Check Hepatitis B / C status Immunise against Hep B ◦ according to local protocol Regular influenza and pneumococcal vaccine
  34. 34. Patient education Importance of avoiding factors leading to increased progression Natural disease progression Prescribed medications (highlighting their potential benefits and adverse effects) Avoidance of nephrotoxins Diet Renal replacement modalities, including peritoneal dialysis, hemodialysis, and transplantation Timely placement of vascular access for hemodialysis Pregnancy counseling for women in the child-bearing age
  35. 35. Management of CKD 4/5 – Diet Multidisciplinary team must include Dietitian Reasons for referral ◦ Protein intake ◦ Potassium control ◦ Phosphate control ◦ Salt / water intake ◦ Glycaemic control ◦ Alcohol intake ◦ Weight reduction / supplements
  36. 36. The renal clinic All patients ◦ Monitoring renal function – renal profile, urinalysis ◦ Management of risk factors – hypertension, diabetes etc ◦ Volume, electrolytes, acid-base balance ◦ Anemia ◦ Bone and mineral metabolism ◦ Preparation for RRT or palliative therapy
  37. 37. Take home messages Estimate GFR and identify the stage of CKD Check for proteinuria and measure its amount Check for hematuria Refer to nephrologist when indicated Beware of high risk patients ◦ Screen population at risk: CKD can be silent until late stages Management of hypertension and avoidance of more renal insult are the main interventions that can slow progression besides treatment of the underlying cause Complications of CKD include fluids and electrolytes disturbances (and BP), acid-base disturbances, anaemia and bone and mineral disease Planning for ESKD is an important part of the management of late CKD