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Presentation adapted from previous CAAGs Concepts at a Glance – AKI and CKD V I A N C A S H A H – Y 5 M E D I C A L S T U D E N T 0 6 / 1 2 / 2 3How do we define an AKI?How do we define an AKI? • Acute renal failureHow do we stage an AKI?How do we stage an AKI? • KDIGO classificationMCQ • An 84-year-old woman admitted for the treatment of a lower respiratory tract infection becomes anuric on the ward for the last 6 hours. Bloods tests taken show: • Urea 11 mmol/l (baseline 5 mmol/l) • Creatinine 156 umol/l (baseline 78 umol/l) • Which stage of AKI is this patient at?MCQ • An 84-year-old woman admitted for the treatment of a lower respiratory tract infection becomes anuric on the ward for the last 6 hours. Bloods tests taken show: • Urea 11 mmol/l (baseline 5 mmol/l) • Creatinine 156 umol/l (baseline 78 umol/l) • Which stage of AKI is this patient at? • STAGE 2Causes of an AKIPre-renal causes • Systemic hypoperfusion Hypotension - sepsis Hypovolaemia Low CO (acute HF) • Local hypoperfusion Renovascular disease – renal artery stenosis/thrombosis, hepatorenal syndrome Intra-renal vasomotor changes (NSAIDs/ACEi)Renal causes ATN AIN + other causes: Rhabdomyolysis,Tumour Lysis SyndromePost-renal causesMCQ Which of the following are risk factors for developing AKI? (Can choose multiple) • A: Chronic kidney disease (CKD) • B: No previous history of AKI • C: Heart failure • D: On ACE inhibitor for hypertension • E: Recently had a non-contrast CTMCQ Which of the following are risk factors for developing AKI? (Can choose multiple) • A: Chronic kidney disease (CKD) • B: No previous history of AKI • C: Heart failure • D: On ACE inhibitor for hypertension • E: Recently had a non-contrast CTRisk factors • Chronic kidney disease (CKD) • Other organ failure and chronic disease (e.g. heart failure, liver disease, diabetes mellitus) • Previous history of AKI • Recent use of nephrotoxic drugs (e.g. diuretics,ACE inhibitors, angiotensin II receptor antagonists, metformin, NSAIDs) • Recent use of iodine-containing contrasts • Age >= 65 years • Oliguria (urine output < 0.5 ml/kg/hour)InvestigationsInvestigations • Blood tests: U&Es to check Na+, K+, urea, creatinine; eGFR to see if reduced • Urinalysis: look for proteinuria or haematuria (looking for ?renal cause of AKI) • Imaging: do a renal ultrasound within 24 hours of assessing the patient IF • The patient has no identifiable cause of their AKI • The patient may be at risk of urinary tract obstruction • NB: renal ultrasound = US KUB (kidneys, ureters, bladder)Management • Address cause • Manage associated hyperkalaemia • Fluid balance managementManagement : fluids • Pre-renal – fluids important • Renal – don’t fluid overload them • Post-renal – fluids not helpfulManagement: fluids • Give maintenance IV fluids where appropriate – tend to give crystalloids IV fluid Examples • Adults: 25 – 30 ml/kg/day water, 50 – 100 g/day glucose, Na+: 1 Crystalloids •Isotonic fluids which contain electrolytes: mmol/kg/day, K+: 0.5 - 1 mmol/kg/day e.g. 0.9% NaCl, Hartmann’s • Children: Holliday-Segar formula (100 ml/kg/day for the first 10 kg of Colloids •Gelatinous solutions containing particles which can’t pass through cell membranes: weight, 50 ml/kg/day for the second 10 kg of weight, 20 ml/kg/day for e.g. albumin, Gelofusine a weight over 20 kg) Blood •Separated components of blood: e.g. FFP, products platelets, albuminManagement: stop nephrotoxic drugs Need to stop in AKI as may worsen renal Usually safe to continue in AKI function •Paracetamol Stop the DA(M)N drugs •Warfarin •Diuretics •Statins •ACE inhibitors •Aspirin, at cardioprotective dose of 75 •Angiotensin II receptor antagonists mg OD (ARBs) •Clopidogrel •Aminoglycosides •Beta-blockers •NSAIDs (except if aspirin at cardio- protective dose of 75 mg OD) May need to stop in AKI as increased risk of renal toxicity •Metformin •Lithium •DigoxinReferral criteria • Renal transplant • ITU patient with unknown cause of AKI • AKI with no known cause • Vasculitis, glomerulonephritis, tubulointerstitial nephritis, myeloma • Inadequate response to treatment • Complications of AKI • Patient has CKD stage 4 or 5 • Patient qualifies for renal replacement, hyperkalaemia, metabolic acidosis, complications of uraemia, signs of fluid overloadAKI vs CKD • Generally CKD shows bilateral small kidneys • Key exceptions: ADPKD Diabetic nephropathy (early stages) Amyloidosis HIV-associated nephropathy • CKD may associated hypocalcaemiaCKD Classification •Classify CKD by CGA staging, which is based on the degree of kidney function • C = Identify cause of CKD • G = Assign GFR category (stage 1 – 5) • A = Assign albuminuria category (1 – 3) KDIGO 2009 •Relative risks by GFR and albuminuria (ACR)Classification of CKD Stage GFR Information CKD stage 1 > 90 •Only CKD if there is other evidence of kidney damage (e.g. proteinuria, haematuria, tubular disorder, transplant) CKD stage 2 60 – 90 CKD stage 3a 45 – 59 •Mild-moderate reduction in GFR CKD stage 3b 30 – 44 •Moderate-severe reduction in GFR CKD stage 4 15 – 29 •Severe decrease in GFR CKD stage 5 < 15 •Established kidney failure (dialysis or a kidney transplant may be needed) Given often GFR is estimated (eGFR) – what other factors do you think can affect the result?Classification of CKD Stage GFR Information CKD stage 1 > 90 •Only CKD if there is other evidence of kidney damage (e.g. proteinuria, haematuria, tubular disorder, transplant) CKD stage 2 60 – 90 CKD stage 3a 45 – 59 •Mild-moderate reduction in GFR CKD stage 3b 30 – 44 •Moderate-severe reduction in GFR CKD stage 4 15 – 29 •Severe decrease in GFR CKD stage 5 < 15 •Established kidney failure (dialysis or a kidney transplant may be needed) Given often GFR is estimated (eGFR) – what other factors do you think can affect the result? Pregnancy, muscle mass, eating red meat 12hrs before sample takenAlbuminuria category Albumin:creatinine ratio (ACR) (mg/g) Category A1 < 30 Normal to mildly increased A2 30 – 300 Moderately increased A3 > 300 Severely increasedMCQ What is the most common cause of CKD in the UK? • A: Chronic pyelonephritis • B: Autosomal dominant polycystic kidney disease (ADPKD) • C: Excessive consumption of red meat • D: Acute kidney injury (AKI) • E: Diabetes mellitusMCQ What is the most common cause of CKD in the UK? • A: Chronic pyelonephritis • B: Autosomal dominant polycystic kidney disease (ADPKD) • C: Excessive consumption of red meat • D: Acute kidney injury (AKI) • E: Diabetes mellitus Diabetic nephropathy à CKD • Chronic hyperglycaemia = microvascular damage in the kidneys •Thickening of basement membrane •Increased mesangial matrix which can be diffuse, but becomes more nodular (Kimmelstiel-Wilson nodules)Causes of CKD • The most common causes of CKD in the UK are: • Diabetes (24%) • Glomerulonephritis (13%) • Hypertension/renovascular disease (11%) • Pyelonephritis • Polycystic kidney diseaseSigns and symptoms • Usually asymptomatic and generally diagnosed following abnormal U&Es • Some patients with undetected late-stage CKD may become symptomatic • Possible features: • Peripheral oedema • Lethargy • Pruritis (secondary to high urea) • Nausea and vomiting • HypertensionInvestigationsInvestigations • Blood tests: U&Es to check Na+, K+, urea, creatinine; eGFR to see if reduced • Urinalysis: look for proteinuria or haematuria, also measure ACR • Imaging: ultrasound, MRI, CT scan used to assess for any obstruction • Kidney biopsy: to assess for any microscopic evidence of kidney damageMCQ What combination of vitamin D, calcium and phosphate levels do we see in patients with CKD? • A: Low vitamin D, low calcium, high phosphate • B: Low vitamin D, low calcium, low phosphate • C: High vitamin D, high calcium, low phosphate • D: High vitamin D, high calcium, high phosphate • E: Low vitamin D, high calcium, low phosphate MCQ What combination of vitamin D, calcium and phosphate levels do we see in patients with CKD? • A: Low vitamin D, low calcium, high phosphate •1-alpha hydroxylation to form vit D occurs in kidneys •Kidneys normally excrete phosphateComplications of CKD • Na+ retention, hypertension and fluid overload (due to loss of Na+ balance) • Hyperkalaemia (due to loss of K+ excretion) • Metabolic acidosis (due to loss of H+ excretion) • Hyperphosphataemia and hypocalcaemia (due to low calcitriol levels and loss of phosphate excretion) • Anaemia (due to loss of EPO)Management of hypertension • ACEi • Generally need 2+ drugs to treat hypertension – follow hypertension algorithms • As cause reduction in filtration pressure – small rise in Cr expected (up to 30% or eGFR decrease up to 25% is acceptable)Management of mineral bone diseaseManagement of proteinuria • ACEi • SGLT-2 with or without diabetesManagement of anaemia • Optimise iron status • Consider erythropoietin stimulating agents – if on an ESA / if target iron levels not reached in 3 months may require IV ironApproaching a renal patientHPC Urine abnormalities •Amount (oliguria < 0.5 ml/kg/hour or anuria or polyuria) •Nocturia and urinary frequency •Poor urinary stream •Colour Loin pain •Think renal calculi, infection, polycystic kidney disease Oedema •Think volume overload, nephrotic syndrome Hypertension •Think CKD Anaemia •Think EPO deficiency Uraemia •Think AKI or CKD Hyperphosphataemia •Think AKI or CKDPMH • Any renal problems? Any assessment of renal function? • Any PMH of conditions which can precipitate AKI? • Any PMH of conditions which can precipitate CKD? • Any PMH of conditions which can cause proteinuria?Systems review • Any illnesses before presenting to A&E/GP? • Any vomiting or diarrhoea or blood loss? • Sepsis? • Non-specific symptoms which may suggest an autoimmune disease that can affect the kidneys? (joints, eyes, GI, GU, skin, anything suggesting systemic vasculitis)Drug history • Check nephrotoxic drugs (diuretics, ACE inhibitors/ARBs, metformin, NSAIDs)! – any nephrotoxic medications? • Started taking any new medications recently? • Taking any medications which are mostly excreted by the kidneys? (e.g. digoxin, allopurinol)Family history • Important for hereditary kidney diseases • Most common genetic disorder affecting the adult kidney is autosomal dominant polycystic kidney disease (APKD) • Alport’s syndrome (nephritic syndrome + sensorineural deafness) • Some forms of focal segmental glomerulosclerosis (FSGS) • Autoimmune conditions, e.g. SLESocial history • Does the patient smoke? • What is their line of work? • IVDU?