(ARF) Acute Renal Failure Exam Completely Solved

Acute Renal Failure - - Rapid decrease in renal function leading to the collection of metabolic wastes in the body - Sudden onset (hours to days) - Nephron involvement = 50% - Duration = 2-4 weeks and 3 months - Prognosis generally good for return of renal function ARF is delineated by causes - Prerenal failure: inadequate kidney perfusion Intrarenal/Intrinsic failure: damage to the glomeruli, interstitial tissue or tubules Postrenal failure: obstruction of urine flow Prerenal failure Won't look edematous - inadequate kidney perfusion leads to ischemia in the nephrons Causes: hemorrhage, shock, dehydration, extensive burns, heart failure, hemorrhage, obstruction in vasculature before kidneys, prolonged hypotension, severe dehydration, severe anemia Sign and symptoms: dizziness, dry mouth, hypotension, tachycardia, thirst, low urine output Treatment: increased BP, improve CO, replace intravascular volume Renal Blood Flow - Abdominal aortaRenal arteryAfferent arterioles (lots coming in)Glomeruluswater and small particles are filtered from blood to make urineefferent arterioles (only 2 since filtered and less to put out)peritubular capillaries or vasa rectarenal veininferior vena cava Attempts at compensation Body tries to hold onto fluid (renin system) and anti-diuretic hormone is released - Prerenal failure: hypoperfusion Autoregulatory response: change in blood flowrenal blood vessels constrict activation of renin-angiotensin-aldosterone pathwayrelease of antidiuretic hormone (ADH)decreased urine output Intrarenal failure Nsaids, IV dye, Gentamicin are nephrotoxic Will look edematous because vasculature is overloaded - need to unclog the kidneys (flush it out with water) - 90% of internal failure is caused by toxins or ischemia that leads to acute tubular necrosis (ATN) Damage to glomeruli, interstitial tissue or tubules Causes: infections, nephrotoxic agents, infiltrating tumors, glomerulonephritis, vasculitis, acute hemolytic transfusion reactions (watch for acute renal failure) - stop the transfusion