Chapter 28 Acute Renal Failure and Chronic Kidney Disease I Renal Failure a Decreased GFR b Results in retention of i Salt and water high BP ii Urea uremia and uremic poisoning iii Metabolic Acids Acidosis c Dialysis Treatment II wastes ii Azotemia Acute Renal Failure a No treatment 3 6 weeks abrupt more severe b Pathophysiology 1 Increased pressure in the body increased fluids leaking from cells pitting edema begins in feet 2 Juxtoglomeri cells decrease filtrate Urine stimulate RAAS secrete renin 3 Aldosterone retain NA and H2O to increase i Passes blood through membrane channels bathed in a plasma like solution to remove i Abrupt reduction in renal function causing accumulation of waste materials in blood ii Occurs over hours weeks iii Potentially reversible c Etiology i Aging ii Comorbidities hemorrhage decrease in blood volume and nephrotoxins iii iv Tubular Obstruction casts which causes urine to flow back in tubules and Bowman s Insults to kidneys capsule Tubular backleak d Monitor renal function i Serum creatinine high and creatinine clearance GFR e Types i Extrinsic 1 Prerenal conditions that impair renal blood flow manifested with low GFR oliguria high urine specific gravity and osmolality low urine sodium signs of fluid overload stimulated by RAAS increased Na and H2O prolonged disease can lead to intrarenal failure a Hemorrhage b Dehydration c Burns d Decreased Cardiac Output e MI 2 Postrenal obstruction within the urinary collecting system distal to the kidney that results in elevated pressure in Bowman s capsule and impeded glomerular filtration manifestation depend on duration and prolonged disease can cause intrarenal failure Intra Abdominal Tumors a Benign Porstatic Hyperplasia excess number of cells b c Strictures d Calculi ii Intrinsic 1 Prolonged Postrenal Failure 2 Radiographic contrast media 3 Acute Glomerulonephritis 4 Acute Allergic Interstitial Nephritis 5 Acute Pyelonephritis 6 Emboli iii Intrarenal 1 Primary dysfunction of nephrons 2 Etiology a Problem in renal tubules that results in acute tubular necrosis most common b Glomerular vascular interstitial 3 Laboratory Value Differences in Perenal and Intrarenal Acute Renal Failure a Proteinuria i Prerenal Absent Nephron not affected yet ii Intrarenal Possible b Urine Specific Gravity i Prerenal 1 020 ii c Urine Sodium Intrarenal 1 010 1 020 i Prerenal 10 ii Intrarenal 20 d Urinary Sediment i Prerenal Few hyaline casts ii Intrarenal Tubular RBC and WBC casts iv Intrerenal ATN 1 Low GFR Low Urine High BP 2 Acute Tubular Necrosis 3 Etiologies a Nephrotoxic or ischemic insults 4 Clinical Manifestations depend on ATN stage 5 Oliguric Stage a Lasts 1 2 Weeks b Oliguria progressive uremia decreased GFR hypervolemia c May need dialysis 6 Diuretic Stage a Lasts 2 10 Days b 7 Recovery Increased urine volume tubular dysfunction persists azotemia a Lasts up to 12 months b Gradual normalization of serum creatinine and BUN i Shows we are filtering nitrogenous waste products c Often results in some degree of renal insufficiency III Chronic Renal Failure a Definition decreased kidney function or kidney damage of 3 months duration based on blood tests urinalysis and imaging studies i GFR 60 mL min 1 73m 2 for 3 months without signs of kidney damage b Pathophysiology progressive and irreversible nephron loss c Final Outcome of chronic kidney disease leads to ESRD i Dialysis or renal transplant d Global health problem often linked to other comorbidities including hypertension and diabetes mellitus e Risk Factors i Diabetes Mellitus increased blood sugar deposition in kidney and damaged glomerulus ii Hypertension iii Recurrent pyelonephritis and glomerulonephritis iv Polycystic Kidney Disease Multiple cysts in the kidney 1 Autosomal Dominant a Adult onset b Survival rate is better 2 Autosomal Recessive a Congenital b Infants c Low survival rate f Stages i Two Staging Techniques 1 Percentage of nephron loss 2 Reduction in GFR ii Diagnosis Based on 1 Presence of Kidney Damage 2 Level of function according to GFR iii Stages According to Nephron Loss 1 Decreased renal reserve a 75 of nephron loss b No signs or symptoms c BUN and creatinine normal d May go undiagnosed 2 Renal insufficiency a 75 90 nephron loss b Polyuria nocturia c Slight elevation in BUN and creatinine d May be controlled by diet and medication 3 End Stage Renal Disease ESRD a 90 nephron loss b Azotemia uremia c Fluid and electrolyte abnormalities d Osteodystrophy e Anemia f Dialysis or transplantation essential iv Stages According to GFR 1 Stage 1 3 Stage 3 3 months with a GFR under 60 is considered Chronic Renal Failure a Kidney damage with normal or increased GFR b GFR 90 mL min 1 73m 2 2 Stage 2 a Mildly decreased GFR b GFR 60 89 m min 1 73m 2 a Moderately decreased GFR b GFR 30 59 mL min 1 73m 3 a Severely decreased GFR b GFR 15 29 mL min 1 73m 2 4 Stage 4 5 Stage 5 a ESRD b GFR 15 mL min 1 73m 2 or dialysis g Complications i Hypertension and Cardiovascular Disease 1 Hypervolemia accelerated atherosclerosis increase of lipids produced by the liver increased RAAS activity increased SNS activity 2 GFR is low distal convoluted tube simulate excretion of which stimulates the RAAS system retain sodium Pitting and water Hypervolemia edema ii Uremic Syndrome 1 Metabolic waste retention iii Metabolic Acidosis 1 Acidic waste product retention kidneys lose ability to secrete H ion and bicarb 2 Potassium can t get into DCTs either 3 Decrease in production of bicarbonate 4 Can t excrete H 5 Uric Acid iv Electrolyte Imbalance 1 O K P and Mg retention in blood v Renal Osteodystrophy 1 Elevated PTH caused altered bone and mineral metabolism kidneys cannot reabsorb Ca 2 Activates vitamin D without we cannot absorb calcium in blood system stimulates parathyroid gland to secrete parathyroid hormone which takes calcium from the bones and causes osteodystrophy demineralizes the bone 1 Decreased intake due to uremic syndrome depression dietary limitations and vi Malnutrition changes in taste vii Anemia 1 Lack of erythropoietin h Management i Prevention 1 Early risk identification lifestyle modifications and comorbidity treatment a Diet low sodium low protein 2 Maintain fluid volume status and cardiac output a Restrict Fluids Hypervolemia Hypertension but don t dehydrate 3 Avoid and monitor nephrotoxic chemicals a Go off Aspirin NO KUB 4 Avoid and treat infections ii Therapeutic Interventions 1 Slow progression of CKD focus of management until stage 4 or 5 a Stage 4 managing