Chapter 26 Acute Renal Failure and Chronic Kidney Disease

1. Chapter 26 Acute Renal Failure and Chronic Kidney Disease

2. Less waste is removed • More waste remains in the blood • Nitrogenous compounds build up in the blood • BUN: Blood urea nitrogen • Creatinine • Renal function approximated by: initial creatinine level/current creatinine level When Kidneys Fail

4. Prerenal • Decreased blood supply • Shock, dehydration, vasoconstriction • Postrenal • Urine flow is blocked • Stones, tumors, enlarged prostate • Intrinsic • Kidney tubule function is decreased • Ischemia, toxins, intratubular obstruction Acute Renal Failure

5. Which type of acute renal failure (ARF) would be most likely to accompany benign prostatic hypertrophy? • Prerenal • Postrenal • Intrinsic • Extrinsic Question

6. 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. Answer

7. Giving N-acetylcysteine reduces the risk of ARF by 50% in a meta-analysis • Recommended for clients at risk of renal failure who are receiving radiographic contrast media • Diabetics, clients with sepsis • Underlying vascular, renal, or hepatic disease • Receiving other nephrotoxic drugs (Kellum, J.A. [2003]. A drug to prevent renal failure? Lancet 362,589-590.) Radiocontrast Agents Can Cause ARF

8. A man developed acute renal failure after emergency surgery for a severed left leg… • He came in with a serum creatinine of 1.2 mg/dL, but now it is 5.6 mg/dL • His BUN is 86 mg/dL Question: • Why would leg damage cause renal failure? • What is his remaining kidney function? Scenario

9. Urine Containing Tubular Cell Casts • Casts are formed when cells are packed together in the tubule lumen • They block the tubule • When the mass of cells washes loose, it appears in the urine

10. Mr. J is an alcoholic with kidney problems… • He is severely dehydrated with an infected leg ulcer, benign prostatic hypertrophy, and anemia • His urine is dark and contains myoglobin and tubular cell casts • His creatinine and BUN are both elevated Question: • What may have caused his acute tubular necrosis? Scenario

11. Fewer nephrons are functioning • Remaining nephrons must filter more • Hyperperfusion • Hypertrophy Chronic Renal Failure

12. Diminished renal reserve • Nephrons are working as hard as they can • Renal insufficiency • Nephrons can no longer regulate urine density • Renal failure • Nephrons can no longer keep blood composition normal • End-stage renal disease Development of CRF

13. Uremia = “Urine in the Blood” • Renal filtering function decreases • Altered fluid and electrolyte balance • Acidosis, hyperkalemia, salt wasting, hypertension • Wastes build up in blood • Increased creatinine and BUN • Toxic to CNS, RBCs, platelets • Kidney metabolic functions decrease • Decreased erythropoietin • Decreased Vitamin D activation Uremia

14. Which of the following renal disorders is characterized by increased BUN and creatinine levels? • ARF • CRF • Uremia • All of the above • b and c Question

15. All of the above In each disorder listed, the ability to remove nitrogenous waste is diminished. This causes nitrogenous compounds (BUN and creatinine) to accumulate in the blood. Answer

16. A man has chronic renal failure… • He 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 meal • He complains of having broken two toes in the last few weeks, even though he eats a lot of dairy products for calcium Scenario

17. 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? Scenario (cont.)

18. Decreased blood viscosity + • Increased blood pressure + • Decreased oxygen supply Cardiovascular Consequences of CRF less erythropoietin anemia lower blood viscosity blood flows through vessels more swiftly heart rate increases

19. increased workload on left heart left ventricle dilation and hypertrophy not enough oxygen to support LV contraction angina ischemia LHF

20. Tell whether the following statement is true or false: CRF leads to decreased cardiac output (CO). Question

21. True The 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. Answer

22. Manifestations of Kidney Failure

23. Types of Dialysis