Chapter 26 Acute Renal Failure and Chronic Kidney Disease. Less waste is removed More waste remains in the blood Nitrogenous compounds build up in the blood BUN: Blood urea nitrogen Creatinine - PowerPoint PPT Presentation
Text of Chapter 26 Acute Renal Failure and Chronic Kidney Disease
ACUTE RENAL FAILURE AND CHRONIC KIDNEY DISEASE
WHEN KIDNEYS FAILLess 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 level
ACUTE RENAL FAILUREPrerenalDecreased blood supplyShock, dehydration, vasoconstrictionPostrenalUrine flow is blockedStones, tumors, enlarged prostateIntrinsicKidney tubule function is decreasedIschemia, toxins, intratubular obstruction
QUESTION Which type of acute renal failure (ARF) would be most likely to accompany benign prostatic hypertrophy?PrerenalPostrenalIntrinsicExtrinsic
ANSWER b. Postrenal Postrenal ARF occurs when the flow of urine is blocked by kidney stones, tumors, or an enlarged prostate gland. Because the male utethra passes through the prostate, if it is enlarged the urethra may become blocked.
RADIOCONTRAST AGENTS CAN CAUSE ARFGiving 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 362,589-590.)
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/dL His BUN is 86 mg/dLQuestion:Why would leg damage cause renal failure?What is his remaining kidney function?
URINE CONTAINING TUBULAR CELL CASTSCasts 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
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 elevated Question:What may have caused his acute tubular necrosis?
CHRONIC RENAL FAILUREFewer nephrons are functioningRemaining nephrons must filter more HyperperfusionHypertrophy
DEVELOPMENT OF CRFDiminished renal reserveNephrons 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
UREMIAUremia = Urine in the BloodRenal 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 erythropoietin Decreased Vitamin D activation
QUESTION Which of the following renal disorders is characterized by increased BUN and creatinine levels?ARFCRFUremiaAll of the aboveb and c
ANSWER All 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.
SCENARIOA man has chronic renal failureHe has high creatinine and BUN, hyperkalemia, acidosis with normal pCO2, and severe anemia His 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
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?
CARDIOVASCULAR CONSEQUENCES OF CRFDecreased blood viscosity +Increased blood pressure +Decreased oxygen supplyless erythropoietinanemialower blood viscosityblood flows through vessels more swiftlyheart rate increases
left ventricle dilation and hypertrophynot enough oxygen to support LV contractionanginaischemiaLHFincreased workload on left heart
QUESTION Tell whether the following statement is true or false:CRF leads to decreased cardiac output (CO).
ANSWER TrueThe increased blood pressure (HTN) and hypoxemia that accompany CRF leads 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.