Identifying and Managing Chronic Kidney Disease: A Practical Approach S. Neil Finkle, MD, FRCPC Associate Professor Division of Nephrology, Department of Medicine, Dalhousie University Program Director, Adult Nephrology, Dalhousie University
Disclosure Nil conflicts to disclose
Learning Objectives Recognize progressive renal disease Understand how the egfr and ACR are used to stratify patients at risk for progressive kidney disease Know investigation strategies for CKD Identify the complications of renal disease Identify when to refer to a Nephrologist
Overview Chronic Kidney Disease Markers of Renal Function Differential diagnosis CKD Stages CKD Risk factors for progression Clinical features Referral guidelines CKD Work-up and Management
Clinical Case 1 Edward DeYoung 70 year-old male from Yarmouth Hypertension X 25 years Diabetes 12 years, HgA1C often > 10 IHD with stable angina Smoker ½ ppd X 50 years Meds : ECASA 81 mg OD, Metoprolol 50 mg bid, Gliclazide O/E BP 160/90 Cr 250 Urinalysis 2 g/l protein, nil else albumin:creatinine ratio (ACR) 50 mg/mmol
Clinical Case 2 Roberta Kline 83 year-old female from Inverness Hypertension X 30 years OA knees Meds : Ibuprophen 300mg qid prn, Amlodipine 5 mg od O/E BP 150/90 Cr 130 Urinalysis trace protein, hyaline casts Urine albumin:creatinine ratio (ACR) 2.4 mg/mmol
Clinical Case Questions Is this CKD? What stage CKD? What is the likely cause of CKD? Should the patient be referred to Nephrology?
Renal Function
Renal Function GFR (ml/min) Glomerular filtration rate Sum of the flitration of all functioning nephrons Gives an estimate of nephron mass Various measures Creatinine clearance egfr (CKD EPI) Inulin clearance gold standard, rarely used
egfr GFR = 141 min (S cr /κ, 1) α max(s cr /κ, 1) - 1.209 0.993 Age 1.018 [if female] 1.159 [if black] There s a App for that! Qx MD Calculate App Store or Google Play MDCalc.com GFR 100 1 > 90 normal < 60 CKD < 15 kidney failure, often approaching dialysis https://www.kidney.org/content/ckd-epi-creatinine-equation-2009
Chronic Kidney Disease
Chronic Kidney Disease Definition Sustained (> 3 months) abnormalities of renal function Anatomic Radiographic Biomarkers Urinary Abnormalities
CKD by egfr Criteria Decreased glomerular filtration rate (GFR) <60 ml/min/1.73m normal GFR in young adults is approximately 125 ml/min/1.73m 2 Common in the elderly population Measure egfr over time to determine if kidney function is improving, stable or is declining egfr is calculated using the CKD-EPI 2009 equation Serum creatinine, age, gender and race
Causes of CKD
CKD Causes Diabetes Hypertension Ischemic Nephropathy Chronic Glomerulonephritis Chronic Interstitial Nephritis Cystic Renal Disease Chronic Obstruction Chronic Pylonephritis
CKD Staging and Classification KDIGO Guidelines 2012
CGA Staging: Cause Assign cause of CKD based on presence or absence of systemic disease and the location within the kidney of observed or presumed pathologic-anatomic findings Glomerular disease Tubulointersitial disease Vascular disease Cystic & congenital disease
CGA Staging Glomerular disease Vascular disease i.e. Diabetes i.e. Hypertension Cause Tubulointerstitial disease i.e. Systemic infections Cystic and congenital disease i.e. Polycystic kidney disease
Tip: CKD Stage 3 has been subdivided into 3a & 3b to improve risk stratification
Blood Pressure Targets People with CKD should be treated with BP lowering drugs to maintain a BP below 140/90 mmhg If albuminuria is present (ACR > 3.0 mg/mmol) a consistent BP below 130/80 should be achieved All pts with diabetes should maintain a consistent BP below 130/80
CKD Stages Clinical Features
CKD Stages Stage 1 (egfr> 90) nil Stage 2 (egfr 60-89) Hypertension, mild elevation PTH
CKD Stages Stage 3 (egfr 30-59) Reduced Ca absorption Reduced phosphate excretion Marked elevation PTH Renal anemia
CKD Stages Stage 4 (egfr 15-29) Metabolic Acidosis Hyperkalemia Renal replacement therapy planning
CKD Stages Stage 5 (egfr <15) Salt & water retention (looks like CHF) Anorexia, Vomiting Pruritis
CKD Progression Male gender Younger Age Low GFR (?< 45 ml/min) Hypertension Diabetes Proteinuria > 1 g/d ACR > 30 mg/mmol
CKD Evaluation and Management
CKD Screening
Evaluation in CKD Diagnosis (type of kidney disease) Severity, assessed by level of kidney function Complications, related to level of kidney function Risk for loss of kidney function Risk for cardiovascular disease
Treatment CKD Specific therapy, based on diagnosis Evaluation and management of comorbid conditions Slowing the loss of kidney function
Treatment CKD Prevention and treatment of complications of decreased kidney function Preparation for kidney failure and kidney replacement therapy
Medication in CKD Review of medications: Dosage adjustment based on level of kidney function Detection of potentially adverse effects on kidney function or complications of chronic kidney disease Detection of drug interactions Therapeutic drug monitoring (Digoxin, Lithium)
Medications to Use Cautiously in CKD Metformin, (Insulin may need reduction in dose) Lithium Digoxin Allopurinol Opiates Benzodiazepines Gabapentin
S - Sulfa A ACE Inhibitors D - Diuretics Sick Day Medication Adjustment with risk AKI M - Metformin A Angiotenisin Receptor Antagonists N - NSAID S SGLT2 inhibitors KDIGO 2013
Reversible Causes Renal Disease Obstruction Prerenal Causes Medications NSAIDs, Sulfa ACEI/ARB in setting severe RAS or prerenal state
Reversible Causes Renal Disease Medications Aminglycosides PPIs (colchicine not really) Bisphosphates NSAIDs TMP/SMX, teteracyclines Other Radiocontrast
CKD Management Complications CKD Anemia Metabolic Acidosis Mineral Metabolism Hyperkalemia Malnutrition Hypertension
RAS Inhibitor first line treatment (2D)
Nephrology Referral
Kidney Failure Risk Equation
http://kidneyfailurerisk.com/
http://kidneyfailurerisk.com/
http://kidneyfailurerisk.com/
When to Refer Acute Kidney Injury CKD patients with egfr <30 ml/min Rapidly progressive CKD Cause CKD unclear ACR > 30 mg/mol (> 60 mg/mmol) Especially if progressive decline egfr
CKD Work-Up
CKD Work-Up Serial Creatinines differentiate ARF vs. CKD Gauge rate of progression Electrolytes Calcium, Phosphate, Albumin Urinalysis Urine albumin:creatinine ratio (ACR) instead of 24 hr urine for protein Renal Ultrasound
Management While Waiting on Referral Stop NSAID, PPI D/C Metformin if egfr < 30 Urinalysis Renal Ultrasound Serial Cr s to gauge rapidity of decline
Back to Case 1 Edward DeYoung 70 year-old male from Yarmouth Hypertension X 25 years Diabetes 12 years, HgA1C often > 10 IHD with stable angina Smoker ½ ppd X 50 years Meds : ECASA 81 mg OD, Metoprolol 50 mg bid, Gliclazide O/E BP 160/90 Cr 250 currently, 225 1 year ago Urinalysis 2 g/l protein, nil else ACR 50 mg/mmol
Back to case 1 Is this CKD? What stage CKD? What is the likely cause of CKD? Should the patient be referred to Nephrology?
Back to case 1 Is this CKD? Yes No Answer Yes - Cr 225 one year prior dx CKD egfr 24 ml/min a year ago What stage CKD? Stage 1 Stage 2 Stage 3 Stage 5 Answers: Stage 3, egfr 22 ml/min, specifically G3bA3 the red zone, KRFE 19% at 2 years, 48% at 5 years
Back to case 1 What is the likely cause of CKD? A) Diabetes B) Ischemic kidney disease C) Hypertension D) Polycystic Kidney Disease Answer A, B and C are correct
Back to case 1 Should the patient be referred to Nephrology? Yes No Answer Yes egfr < 30 ml/min, ACR > 30 mg/mmol High risk for progressive kidney disease
Back to Case 2 Roberta Kline 83 year-old female from Inverness Hypertension X 30 years OA knees Meds : Ibuprophen 300mg qid prn, Amlodipine 5 mg od O/E BP 150/90, Weight 65 kg Cr 130 currently, Cr 120 2 years ago Urinalysis trace protein, hyaline casts ACR 2.4 mg/mmol
Back to case 2 Is this CKD? Yes No Answer Yes, Cr 120 2 years ago (egfr 37 ml/min) What stage CKD? A) Stage 1 B) Stage 2 C) Stage 3 D) Stage 5 Answer C, egfr 34 ml/min, stage G3bA1
Back to case 2 What is the likely cause of CKD? A) Hypertension B) Renal senscence C) NSAIDs analgesic nephropathy D) Diabetes E) Polycystic Kidney Disease Answer A, B, and C are correct
Back to case 2 Should the patient be referred to Nephrology? -Yes -No Answer No Not required at present. Stable egfr > 30 ml/min KFRE 1% at 2 years, 3% at 5 years
Back to case 2 Should the patient be referred to Nephrology? Yes No Answer No Not required at present. Stable egfr > 30 ml/min How should this patient be managed? Remove and nephrotoxins Serial bloodwork BP goal 140/90
Summary Chronic Kidney Disease Markers of Renal Function Differential diagnosis CKD Stages CKD Risk factors for progression Clinical features Referral guidelines CKD Work-up and Management