Acute Renal Failure Year 4 Internal Medicine Notes OmpathStudy

Acute Renal Failure Year 4 · Internal Medicine Collection: 4TH YEAR ALL NOTES / IMED / IMED 4.2 / Mogere -- Slide 1 Acute Renal Failure/AKI Dr. Alex Mogere Consultant Physician Slide 2 Syndrome Rapid decline in GFR ( hrs – weeks) Retention of nitrogenous waste Perturbation of – Extracellular fluid volume – Electrolytes \n– Acid base homeostasis Most ARF\n- Reversible\n- Multi-causal\n- Major in hospital morbidity & mortality Slide 3 Acute Renal Failure/AKI Potential to Reverse Potential for Mortality [50%] in clinically apparent Preserved renal size [u/s] Looks too ill for level of Cr/BUN Usually multi causal (60%) Even a minor acute reduction in function has an adverse prognosis Slide 4 Ct. intro. Approximately 7% of all hospitalised patients and 20% of acutely ill patients develop signs of AKI. In uncomplicated AKI, such as that due to haemorrhage or drugs, mortality is low, even when renal replacement therapy is required In AKI associated with serious infection and multiple organ failure, mortality is 50–70%\nDrugs that may be associated with renal dysfxn-ACE I, NSAIDs Slide 5 Causes of acute kidney Injury Slide 6 RIFLE Provides graded defn of AKI that is implicit in the staging criteria Proposed, in 2004, by Acute Dialysis Quality Initiative workgroup. It’s a multilevel classification system for acute kidney injury Slide 7 Rifle Classification Slide 8 Staging of AKI Slide 9 AKIN/KDIGO(Kidney dse improving global outcomes) Provide both diagnostic and staging criteria\nKDIGO defines AKI as any of the following:\nan increase in serum creat by ≥ 0.3mg/dL(≥26.4umol/l) within 48 hrs or\nan increase in serum creat by ≥ x1.5 baseline, which is known or presumed to have occurred within the prior 7 days Slide 11 CT. classification for RIFLE. AKIN &KDIGO criteria Slide 12 ARF Conveniently divided in: Diseases that cause renal hypoperfusion (Prerenal azotemia, Pre-renal ARF)….ATN Diseases that involve renal parenchyma (Renal azotemia, intrinsic renal ARF) Diseases associated with urinary tract obstruction (Post renal azotemia, post renal ARF) Slide 13 Phases of ARF Initiation Oligo-anuria Polyuria restitution Slide 14 Prerenal failure Decreased renal perfusion accounts for 40–80% of cases of acute renal failure\nBlockade of prostaglandin production by NSAIDs can result in severe vasoconstriction and acute renal failure. Blocking angiotensin action with ACE inhibitors or ARBs decreases efferent arteriolar tone and in turn decreases glomerular capillary perfusion pressure. Slide 15 Ct. prerenal failure Patients taking NSAIDs and/or ACE inhibitors/ARBs are most susceptible to hemodynamically mediated ARF when blood vol. is reduced for any reason bilateral RAS(or stenosis in a solitary kidney) -dependent on efferent arteriolar vasoconstriction to maintain glomerular filtration Pa and are particularly susceptible to a precipitous decline in GFR when given ACE inhibitors or ARBs. Slide 17 Post renal azotemia Urinary tract obstruction accounts for <5 % of cases of ARF Obstruction is usually diagnosed by the presence of ureteral and renal pelvic dilation on renal ultrasound. Slide 18 Hypoperfusion Reduced Intravascuscular volume\n- GIT loss\n- Renal loss\n- Skin loss\n- Sequestration Reduced cardiac output Vasodilatation 3rd spacing Slide 19 Intrinsic Renal Disease (Parenchymal Renal Disease) Processes involve: Tubules (ATN) – (Ischaemic or nephrotoxin) Glomeruli (glomerulonephritis, vasculitides) Micro vasculature Interstitial (Interstitial nephritis) Large renal vessels (Renal artery thrombosis, renal vein thrombosis Intratubular deposition & obstruction Renal allograft rejection Slide 20 Post Renal (Bilateral) Intra-renal calcification Retro peritoneal fibrosis, DXT Bladder tumours, schistosomiasis Bladder outlet obstruction\nProstate\nNeurogenic Urethra - stricture\n- PUV Slide 21 Situational Differences in causes DEVELOPING Vs DEVELOPED COUNTRY COMMUNITY Vs HOSPITAL ACQUIRED PAEDIATRIC Vs ADULT AGE GROUP Slide 22 Symptoms of ARF Symptoms - Related to 1o condition\n- Excretory failure, and\n- Multisystem Retain H2O [Oedema] Na+ [Oedema, hypertension] K+ [Hyper-kalaemia] N – products [Uraemic symptoms] Acids [Hyperventilation etc] Slide 23 EVALUATION BLOOD\nSerum U/E/Cr, Ca, P, U.A\nCystatin C\nURINALYSIS\nIMAGING\nUltrasound KUB\nChest X-ray\nOTHERS as appropriate for primary diagnosis and complications Slide 24 Invx of pts with established AKI Slide 25 Ct.Invx of pts with established AKI Slide 26 eGFR Formulas used widely to estimate kidney function from PCr:\nCockcroft-Gault:\nCockcroft-Gault: CrCl (mL/min) = (140 − age (years) × weight (kg) ×[0.85 if female])/(72 × PCr (mg/dL) (2)four-variable MDRD (Modification of Diet in Renal Disease):\neGFR (mL/min per 1.73 m2 ) = 186.3 × PCr (e−1.154) × age (e−0.203) ×(0.742 if female)×(1.21 if black).\n (3)CKD-EPI:\neGFR = 141 × min (PCr/k, 1)a × max (PCr/k, 1)−1.209 × 0.993Age × 1.018 [if female] × 1.159 [if black], Slide 27 Ct. symptoms Oliguria- 24 hr urine output < 400ml A