Various causes Rapidly and severely decline of gFr Kidneys fail to excretion and regulation in hours to days Oliguria or anuria Retention of nitrogenous wastes(azotemia) water/electrolyte acid-base disturbance Oliguria is usually emphasized in the past, but in some cases does not change. It is called non-oliguriaaRp urine volume patients have high level bun(azotemia) while 16
16 Oliguria or anuria Retention of nitrogenous wastes (azotemia) water/electrolyte acid-base disturbance Rapidly and severely decline of GFR Kidneys fail to excretion and regulation in hours to days Various causes Oliguria is usually emphasized in the past, but in some cases, patients have high level BUN (azotemia) while urine volume does not change. It is called non-oliguria ARF
I Causes and classification Acute renal failure(ARF) may result from a wide variety of diseases(shock, heart failure, severe infection, hepatic diseases) trauma, surgical procedures, drugs, renal toxins and urinary tract obstruction According to causes arf may be divided into three main categories: Prerenal Intrarenal (acute renal failure Postrenal 17
17 l. Causes and classification Acute renal failure (ARF) may result from a wide variety of diseases (shock, heart failure, severe infection, hepatic diseases), trauma, surgical procedures, drugs, renal toxins and urinary tract obstruction. According to causes, ARF may be divided into three main categories: Prerenal Intrarenal acute renal failure Postrenal
(1)Prerenal failure(functional RF or prerenal azotemia) caused by any disorder external to the kidneys that rapidly and severely decreases the blood supply to the nephron (2)Intrarenal failure(parenchymal RF) caused by disease of the renal tissue itself, affecting the blood vessels, glomeruli or tubules (3)Postrenal failure(Obstructive RF, Postrenal azotemia) caused by obstructive disorders(uretal or urethral) that can block or partially block urine flow, while the kidney's blood supply and other functions are initially normal 18
18 caused by any disorder external to the kidneys that rapidly and severely decreases the blood supply to the nephron. caused by disease of the renal tissue itself, affecting the blood vessels, glomeruli or tubules. caused by obstructive disorders (uretal or urethral) that can block or partially block urine flow, while the kidney's blood supply and other functions are initially normal. ( l ) Prerenal failure (functional RF or prerenal azotemia) (2) Intrarenal failure (parenchymal RF) (3) Postrenal failure (Obstructive RF, Postrenal azotemia)
serena fallure Hypovolemia, Acute heart failure Expanded vascular bed volume Sudden decrease of (Hepatorenal syndrome renal perfusion Anaphylactic shock, etc.) Renal vascular blockage or GORI auto-regulation disturbances Nat, H2O reabsorption Azotemia(urinary Cr/plasma Cr> 40) Oliguna(<400ml/day) Urinary Nat<20 mmol/L Urine gravity >1.020 No rbC. WbC or cast in urine 19
19 Sudden decrease of renal perfusion Hypovolemia, Acute heart failure Expanded vascular bed volume (Hepatorenal syndrome Anaphylactic shock, etc. ) Renal vascular blockage or auto-regulation disturbances ( l ) Prerenal failure Azotemia(urinary Cr/plasma Cr > 40 ) Oliguna (<400ml/day) Urinary Na+<20 mmol/L Urine gravity > 1.020 No RBC, WBC or cast in urine GFR↓ Na+ , H2O reabsorption↑
(2)Intrarenal failure Causes: intrinsic(parenchymal) renal diseases 1. Renal tubular diseases Acute renal ischemia Acute Tubular necrosis Acute renal poisoning (most common) Renal tubule blocked by Hb or mb 2. Glomerular diseases Glomerulonephritis, pyelonephritis, etc 3. Renal interstitial diseases Severe infection, drug allergy, etc 4. Renal blood vessel diseases Thrombosis. DIC. etc 20
20 (2) Intrarenal failure Causes: intrinsic (parenchymal) renal diseases 1. Renal tubular diseases 2. Glomerular diseases 3. Renal interstitial diseases 4. Renal blood vessel diseases Acute Tubular Necrosis (most common) Acute renal ischemia Acute renal poisoning Renal tubule blocked by Hb or Mb Glomerulonephritis, pye1onephritis, etc Severe infection, drug allergy, etc Thrombosis, DIC, etc