CHRONIC KIDNEY DISEASE DIAGNOSIS

Transcription

1 CHRONIC KIDNEY DISEASE DIAGSIS GFR categories, description and range CLASSIFICATION OF CKD CKD is classified according to estimated GFR (egfr) and albumin:creatinine ratio (ACR) (see table ), using 'G' to denote the GFR category (G1 G5) and 'A' for the ACR category (A1 A3), for example: egfr of 25 and an ACR of 15 = CKD G4A2. egfr of 50 and an ACR of 35 = CKD G3aA3. egfr of < 15 (GFR category G5) is referred to as kidney failure. WHO SHOULD BE TESTED FOR CKD Monitor GFR at least annually in people prescribed drugs known to be nephrotoxic, such as calcineurin inhibitors (for example, cyclosporin or tacrolimus), lithium and non-steroidal antiinflammatory drugs (NSAIDs)) Offer testing for CKD using egfr, creatinine and ACR to people with any of the following risk factors: diabetes hypertension acute kidney injury cardiovascular disease (ischaemic heart disease, chronic heart failure, peripheral vascular disease or cerebral vascular disease) structural renal tract disease, recurrent renal calculi or prostatic hypertrophy multisystem diseases with potential kidney involvement for example, systemic lupus erythematosus family history of end-stage kidney disease (GFR category G5) or hereditary kidney disease opportunistic detection of haematuria. *MARKERS OF KIDNEY DAMAGE These include: albuminuria (ACR more than 3 mg/mmol) urine sediment abnormalities electrolyte and other abnormalities due to tubular disorders abnormalities detected by histology structural abnormalities detected by imaging history of kidney transplantation CLASSIFICATION OF CKD USING egfr AND ACR CATEGORIES GFR and ACR categories and risk of adverse outcomes 90 Normal and high Mild reduction related to normal range for a young adult Mild-moderate reduction G1 G2 ACR categories (mg/mmol) description and range <3 Normal to mildly increased TesTing f o r pro Teinuria G3a Measure albumin:creatinine ration on a spot G3b urine sample (preferably early morning) Moderate-severe reduction If the initial ACR is >30 and <70 mg/mmol, confirm by G4 a subsequent early morning sample. If the initial ACR Severe reduction is 15 >70mg/mmol a repeat G5 sample need not be tested Kidney failure In people without Diabetes, clinically significant proteinuria is present when ACR REPORTING AND >30mg/mmol. INTERPRETING GFR VALUES PROTEINURIA In people with Diabetes microalbuminuria (ACR If GFR > 90 ml/min/1.73 m2, use an increase in serum creatinine concentration of more >2.5mg/ than 20% mmol to infer in significant men and reduction ACR >3.5mg/mmol in in kidney function women) is clinically significant Interpret egfr values testing of 60 for ml/min/1.73 haematuria m2 or more with caution, bearing in Use mind raegent that estimates strips of rather GFR become than less urine microscopy accurate as the true GFR increases Evaluate further if there is a result of 1+ or more Confirm an egfr result of less than 60 ml/min/1.73 m Do not use urine microscopy Starting to 2 in a ACE confirm inhibitor a positive therapy person not previously tested by repeating the test within 2 result 3-30 Moderately increased >30 Severely increased A1 A2 A3 No CKD in the absence of markers of kidney damage* Do not use reagent strips to identify proteinuria unless they are capable of specifically measuring albumin at low concentrations and expressing the result as an ACR. Use urine ACR in preference to protein:creatinine ratio (PCR), because it has greater sensitivity than PCR for low levels of proteinuria. ACR is the recommended method for people with Diabetes. If initial ACR = 3-70 confirm with a subsequent early morning sample. If initial ACR > 70 mg/mmol, a repeat sample need not be tested. weeks. Allow for biological Check renal and function analytical and variability electrolytes of serum 1-2 weeks after Confirmed starting/dose ACR change 3 signifies clinically important proteinuria. creatinine (±5%) when A fall interpreting egfr of <25% changes is acceptable. in egfr Quantify urinary albumin or urinary protein loss : If >25% stop ACEi or ARB and consider seeking specialist advice people with Diabetes HAEMATURIA If potassium >6mmol/l and not on Spironolactone. Stop ACEi people or ARB. without Consider Diabetes arranging with low a GFR potassium < 60 diet When testing for the and presence re-instituting of haematuria, ACEi or ARB use once reagent potassium strips normalised rather than urine microscopy. If egfr falls by 5-25% recheck in 2-3 weeks to ensure decline is not progressive. Evaluate further if there is a result of 1+ or more. V1.2 Date of preparation: May For review: May

2 CHRONIC KIDNEY DISEASE REFERRAL ALGORITHM egfr<60 (Non-fasting blood sample) Frequently Asked Questions are useful learning tools. These are accessible on the Hounslow CCG website Is patient unwell? Manage acute illness Is this acute kidney injury (AKI)? Repeat egfr within 1 week, refer urgently if declining Urine dipstick Persistent haematuria ( 1+)? AND > 50 YRS Urology referral AND < 50 YRS Is malignancy excluded? Send Hb, Ca, Phosphate, K, Bicarbonate Consider ultrasound ACR >70? Nephrology advice/referral Ensure prescribing is consistent with CKD Ensure patient understands sick day rules for relevant drugs eg ACE/ARBs/ Metformin Smoking cessation advice Weight and exercise advice BP encourage home monitoring Target BP: < 140/90 if ACR 70 (PCR 100) <130/80 if ACR >70 (PCR >100) Use maximal doses of ACEi or ARB For elderly patients or those with diabetes consider targeting to standing BP Dyslipidaemia treat to guidelines Aspirin start if CV disease 10 year risk >20 or secondary prevention Review all drug doses with reduced GFR Vaccinate for influenza and pneumococcus Avoid NSAIDs Discuss vein preservation STAGE G3a and G3b egfr every 6-12 months Annual Hb/K/Ca/Phosphate/Bicarb Refer if: Sustained decrease in GFR of 25%, and a change in GFR category within 12 months Sustained decrease in GFR of 15ml/min within 12 months Repeat egfr stable? STAGE G4 Most patients with CKD 4 should be being followed in secondary care Discuss with nephrology egfr every 3 months Stop Metformin Refer if: Sustained decrease in GFR of 25%, and a change in GFR category within 12 months Sustained decrease in GFR of 15ml/min within 12 months egfr<20 Hb<10.5, K>6, Ca<2.1 Phosphate>1.5 Nephrology referral if declining What is cause for CKD? refer to nephrology for diagnosis if this is uncertain Queries about referral and management of CKD3 patients via e-advice service on following address: ICHC-tr.ckdadvice@nhs.net V1.2 Date of preparation: May For review: May

3 CHRONIC KIDNEY DISEASE REFERRAL CRITERIA Injectable treatment but not insulin URGENT N-URGENT INVESTIGATING THE CAUSE OF CKD Suspected multisystem disease with evidence of renal involvement Suspected acute kidney injury Newly diagnosed egfr < 15 Stage 3 CKD where diagnosis uncertain Asymptomatic CKD G4 or G5 with or without Diabetes ACR > 70 mg/mmol, unless known to be caused by Diabetes and already appropriately treated Determining the risk of adverse outcomes Agree a plan to establish the cause of CKD during an informed discussion with the person with CKD, particularly if the cause may be treatable (for example, urinary tract obstruction, nephrotoxic drugs or glomerular disease). Nephrotic syndrome Accelerated hypertension Severe hyperkalaemia ACR > 30 mg/mmol together with haematuria Sustained decrease in GFR of 25%, and a change in GFR category or sustained decrease in GFR of 15ml/min within 12 months Hypertension that remains poorly controlled despite the use of at least 4 antihypertensive drugs at therapeutic doses Known or suspected rare or genetic causes of CKD Suspected renal artery stenosis (serum creatinine rises by >30% or egfr falls by >25% after starting ACEI/ARB) Use the person's GFR and ACR categories to indicate their risk of adverse outcomes (for example, CKD progression, acute kidney injury, all cause mortality and cardiovascular events) and discuss this with them. INDICATIONS FOR RENAL ULTRASOUND Offer a renal ultrasound scan to all people with CKD who: have accelerated progression of CKD have visible or persistent invisible haematuria have symptoms of urinary tract obstruction have a family history of polycystic kidney disease and are aged over 20 years have a GFR of less than 30 ml/min/1.73 m2 (GFR category G4 or G5) are considered by a nephrologist to require a renal biopsy. Advise people with a family history of inherited kidney disease about the implications of an abnormal result before a renal ultrasound scan is arranged for them. MINIMAL INFORMATION REQUIRED FOR REFERRAL OR ADVICE Dates and results of all previous creatinine/egfr measurement Medical history Drug history Current BP Urine results: dipstick and a measure of urine proteinuria Renal Ultrasound result (unless exceptional reason delineated) V1.2 Date of preparation: May For review: May

4 CHRONIC KIDNEY DISEASE ONGOING MANAGEMENT GFR categories, description and range MANAGEMENT OF STABLE CKD Agree management plan with patient Lifestyle advice (Exercise/Weight/Meditation) BP: Encourage home BP monitoring Target standing BP: < 140/90 if ACR 70 < 130/80 if ACR > 70 Prioritise ACEI or ARBs Cardiovascular risk: Aspirin if CV risk at 10yrs >20% Statins treat according to national guidelines Smoking cessation advice Vaccinate for influenza and pneumococcus Investigations: egfr every 6 months Annual Hb/Ca/Phosphate/Bicarb/K Conside advice if calcium outside normal range Ensure patient understands sick day rules for relevant drugs eg ACE/ARBs/Metformin FREQUENCY OF MONITORING egfr (NUMBER OF TIMES PER YEAR) GFR and ACR categories and risk of adverse outcomes 90 Normal and high Mild reduction related to normal range for a young adult Mild-moderate reduction Moderate-severe reduction REFER BACK TO RENAL CLINIC: Severe reduction egfr sustained decline 15ml/min within 12 months egfr sustained decline 25% per 3 years Hb <10.5 (having ruled out non renal causes) 15 K >6 Kidney failure Ca <2.1, Phosphate >1.5 Diabetes: Consider stopping Metformin as egfr approaches 30 Ease target HbA1C in Stage G3b to ACE INHIBITORS AND CKD ACR categories (mg/mmol) description and range <3 Normal to mildly increased 3-30 Moderately increased >30 Severely increased A1 A2 A3 G G G3a G3b G G RENAL ANAEMIA ACEi and ARB prevent scarring in CKD and should be used preferentially in patients with proteinuria Patients with progressive CKD can develop renal anaemia which may require treatment with erythropoietin. Renal anaemia should only be diagnosed after other causes of anaemia - for instance iron deficiency, folate or B12 deficiency, haemolysis - have been excluded, with further investigation of the underlying cause (eg of iron deficiency) according to standard medical practice. Renal anaemia is unusual in CKD3 but if suspected nephrology advice should be sought. Assess kidney function and electrolytes. 1-2 weeks after initiating therapy, watch out for hyperkalemia Assess kidney function after any subsequent increase in dose A small rise in creatinine or a mild fall in egfr values is expected with therapy repeat the assessment of kidney function if the rise in creatinine is greater than 15% STOP therapy - If serum creatinine rises by >30% or egfr falls by >25% fall seek specialist advice (to exclude possible renovascular disease) If K>6.0 stop ACEi/ARB and start low potassium diet if the patient has proteinuria and would benefit from an ACEi/ARB seek Nephrological advice as introduction of frusemide or bicarbonate can facilitate reintroduction of these agents Cautious use of ACEi/ARB with spironolactone and other potassium sparing diuretics, very close monitoring of potassium required. V1.2 Date of preparation: May For review: May

5 TYPE 2 DIABETES PREVENTING RENAL COMPLICATIONS DIABETIC NEPHROPATHY Diabetic Nephropathy is characterised by the excretion of abnormal amounts of albumin in the urine, arterial hypertension and progressive decline in kidney function BACKGROUND POINTS The earliest sign of kidney involvement in Type 2 Diabetes is abnormal amounts of albumin excretion in the urine which is assessed by laboratory measurement of the albumin creatinine ratio (ACR). Depending on this measure, individuals are categorized into the stages of microalbuminuria or proteinuria (see below). MANAGEMENT OF INDIVIDUAL WITH DIABETIC NEPHROPATHY Patient education is an integral part of overall management Lifestyle changes, weight loss and smoking cessation should be advised Target HbA1c: mmol/mol (6.5% - 7%) in CKD G mmol/mol in CKD G3b/G4 (individualisation of patient target) Microalbuminuria is an independent CV risk factor. It is also associated with a higher risk of progression to proteinuria. Reduction in albuminuria is a viable target and aggressive targeted control of multiple risk factors is the corner stone of management. Proteinuria is associated with a high risk of worsening kidney function and progression to end stage kidney disease. egfr Estimated Glomerular Filtration Rate (egfr) is the best available parameter of kidney function and should be monitored in all individuals with diabetic nephropathy. Maintain blood pressure below 140/90 (130/80 if ACR > 70) - Maximal doses of ACE inhibitors or Angiotensin II receptor blockers (ARBs) are recommended first line drugs (unless contraindicated) - Calcium channel blocker (non-dihydropyridine class) drugs and low dose thiazide diuretics are useful second line agents - Loop diuretics are useful in the presence of volume overload (e.g. leg oedema not caused by the side effects of calcium channel blockers) - Additional antihypertensive therapy may be required. Treat dyslipidaemia (serum cholesterol, LDL cholesterol and serum triglycerides to targets) Aspirin therapy if indicated (2⁰ prevention) Ensure prescribing is consistent with CKD Ensure patient understands sick day rules for relevant drugs eg ACE/ARBs/ Metformin All patients with Diabetes should be on a register and minimum data should include annual measures for microvascular disease. Please see Cardiovascular Risk for additional requirements. PROTEINURIA MEASUREMENTS AND BLOOD PRESSURE TARGETS ACR PCR BP target /90 > 70 > /80 V1.2 Date of preparation: May For review: May