Presentation on theme: "Chapter 26 Acute Renal Failure and Chronic Kidney Disease"— Presentation transcript:
1 Chapter 26 Acute Renal Failure and Chronic Kidney Disease Essentials of PathophysiologyChapter 26 Acute Renal Failure and Chronic Kidney Disease
2 Pre lecture quiz true/false Acute renal failure is not a reversible process.Chronic renal failure leads to hyperkalemia and the risk for cardiac arrhythmias.Exposures to nephrotoxic drugs, heavy metals, and organic solvents are possible causes of intrinsic or intrarenal acute renal failure.During chronic renal failure, the activation of vitamin D is increased.Dietary management is a minor component in the treatment of chronic renal failure.
3 Pre lecture Quiz__________ failure, the most common form of acute renal failure, is characterized by a marked decrease in renal blood flow.An accumulation of nitrogenous waste products in the blood is called __________.__________, which literally means “urine in the blood,” is the term used to describe the clinical manifestations of renal failure.Sodium and water imbalance that results from chronic renal failure contributes to an increased vascular volume, which leads to edema and __________, eventually contributing to heart failure.Chronic __________, the most profound hematologic alteration that accompanies renal failure, is due to the decreased production of the hormone______________anemiaazotemiaPrerenalhypertensionUremiaErythropoietin
4 When Kidneys Fail Less waste is removed More waste remains in the bloodNitrogenous compounds build up in the bloodBUN: Blood urea nitrogenCreatinineRenal function approximated by: initial creatinine level ÷ current creatinine levelBUN/Creatinine should/be approx 10If >15 suggest non renal cause of Urea ElevationIf < 10 Possible liver diseaseIf both go up in ratio it suggests Kidney failure
6 Acute Renal Failure Prerenal Postrenal Intrinsic Decreased blood supplyShock, dehydration, vasoconstrictionPostrenalUrine flow is blockedStones, tumors, enlarged prostateIntrinsicKidney tubule function is decreasedIschemia, toxins, intratubular obstruction
7 QuestionWhich type of acute renal failure (ARF) would be most likely to accompany benign prostatic hypertrophy?PrerenalPostrenalIntrinsicExtrinsic
8 Answerb. Postrenal Postrenal ARF occurs when the flow of urine is blocked by kidney stones, tumors, or an enlarged prostate gland. Because the male urethra passes through the prostate, if it is enlarged, the urethra may become blocked.
9 Radiocontrast Agents Can Cause ARF Giving N-acetylcysteine reduces the risk of ARF by 50% in a meta-analysisRecommended for clients at risk of renal failure who are receiving radiographic contrast mediaDiabetics, clients with sepsisUnderlying vascular, renal, or hepatic diseaseReceiving other nephrotoxic drugs(Kellum, J.A. . A drug to prevent renal failure? Lancet 362, )
10 His BUN is 86 mg/dL (7-20 mg/dl = Normal) Question: ScenarioA man developed acute renal failure after emergency surgery for a severed left legHe came in with a serum creatinine of 1.2 mg/dL, but now it is 5.6 mg/dLHis BUN is 86 mg/dL (7-20 mg/dl = Normal)Produced by the liver when protein is digested & cleared by the KidneysQuestion:Why would leg damage cause renal failure?What is his remaining kidney function? (next Slide)
12 Urine Containing Tubular Cell Casts Casts are formed when cells are packed together in the tubule lumenThey block the tubuleWhen the mass of cells washes loose, it appears in the urine
13 Mr. J is an alcoholic with kidney problems ScenarioMr. J is an alcoholic with kidney problemsHe is severely dehydrated with an infected leg ulcer, benign prostatic hypertrophy, and anemiaHis urine is dark and contains myoglobin and tubular cell castsHis creatinine and BUN are both elevatedQuestion:What may have caused his acute tubular necrosis?
14 Fewer nephrons are functioning Remaining nephrons must filter more Chronic Renal FailureFewer nephrons are functioningRemaining nephrons must filter moreHyperperfusionHypertrophy
15 Development of CRF Diminished renal reserve Nephrons are working as hard as they canRenal insufficiencyNephrons can no longer regulate urine densityRenal failureNephrons can no longer keep blood composition normalEnd-stage renal disease
16 Uremia Uremia = “Urine in the Blood” Renal filtering function decreasesAltered fluid and electrolyte balanceAcidosis, hyperkalemia, salt wasting, hypertensionWastes build up in bloodIncreased creatinine and BUNToxic to CNS, RBCs, plateletsKidney metabolic functions decreaseDecreased erythropoietinDecreased Vitamin D activation
17 Vitamin D ActivationVitamin D obtained from sun exposure, food, and supplements is biologically inert andmust undergo addition of 2 –OH groups in the body for activation.The first occurs in the liver and converts vitamin D to calcidiol.The second occurs primarily in the kidney and forms calcitriolCalcitrol is necessary for absorption of Ca2+ by the small intestine.
19 QuestionWhich of the following renal disorders is characterized by increased BUN and creatinine levels?ARFCRFUremiaAll of the aboveb and cO||C/ \NH2 NH2UREA
20 AnswerAll of the aboveIn each disorder listed, the ability to remove nitrogenous waste is diminished. This causes nitrogenous compounds (BUN and creatinine) to accumulate in the blood.
21 Scenario A man has chronic renal failure. He has high creatinine and BUN, hyperkalemia, acidosis with normal pCO2, and severe anemiaHis blood glucose has reached 340 mg/dL one hour after a hospital mealHe complains of having broken two toes in the last few weeks, even though he eats a lot of dairy products for calcium
22 Scenario (cont.)Question:What is the most likely cause of his chronic renal failure?What caused his anemia?Why are his bones brittle even though he eats dairy products?
23 Cardiovascular Consequences of CRF Decreased blood viscosity+Increased blood pressureDecreased oxygen supplylesserythropoietinanemialower bloodviscosityblood flows throughvessels more swiftlyheart rate increases
24 Cardiovascular Consequences of CRF increased workload on left heartleft ventricle dilation andhypertrophynot enough oxygen to support LVcontractionanginaischemiaLHF
25 QuestionTell whether the following statement is true or false. CRF leads to decreased cardiac output (CO).
26 AnswerTrue The increased blood pressure (HTN) and hypoxemia that accompany CRF lead to increased myocardial work (the heart has to work harder to meet the metabolic demands of body tissues). Eventually the heart becomes unable to meet these metabolic demands, and CO will decrease.
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