Chapter 9

1. Chapter 9 Renal Disease

2. Learning Objectives • Describe the basic functions of the kidneys. • Identify the clinical symptoms and serum parameters of renal disease. • Identify risk factors for the development of renal disease. • Discuss the principles of nutritional management, including the control of disease and promotion of good nutritional status.

3. Functions of Kidneys Help maintain proper metabolism and hormonal balance Converts the inactive form of vitamin D2 into the active form D3 Produces the enzyme renin, which affects blood pressure Produces erythropoietin, which stimulates red blood cell production in the bone marrow Reabsorbing important body constituents, such as electrolytes Excreting toxins and waste material through the 1 million nephrons

4. Anatomy of a Kidney

5. Main Types of Renal Diseases Nephropathy: any disease of the kidneys Chronic Kidney Disease Glomerulonephritis, nephritis: an inflammatory state of the glomeruli; can be caused by autoimmune disorders, creatine supplements as used by athletes Glomerulosclerosis, nephrosclerosis: related to scarring of the glomeruli; can be caused by diabetes, toxins, HTN, or hyperhomocysteinemia Nephrotic syndrome: involves the loss of the glomerular barrier to protein with resulting loss of protein into the urine May lead to End Stage Renal Disease(ESRD)

6. Factors Related to Increased Risk of Nephropathy Genetics HTN—goal to maintain BP <120/80 Hyperglycemia—goal to maintain A1c <7% Smoking Older age Male gender High-protein diet (Ayodele et al., 2004) UTIs—found with high BG; include cranberry juice in moderation Orlistat with associated fat malabsorption(Singh et al., 2007) Contrast dyes (Iyisoy et al., 2008) Iga nephropathy—may be due to untreated celiac (La Villa et al., 2003)

7. Acute Renal Failure Occurs with a sudden decrease in glomerularfiltration rate (GFR) May be short-lived with symptoms treated—low potassium diet, low protein May occur due to rhabdomyolysis from medications or undue muscular stress (trauma), infection, severe dehydration, hypotension

8. Uremia Noted with elevated serum creatinine>1.5 mg/dL Signs and symptoms: Metallic taste Nausea and vomiting Intense itching of the skin Headache Altered consciousness

9. Lab Values & Diagnosis of Renal Disease Proteinuria Elevated blood urea nitrogen (BUN) Elevated serum creatinine—a nitrogen containing compound found in muscle that the kidneys regulate Low glomerular filtration rate (GFR) Hyperkalemia, Hypernatremia, Hyperphosphatemia Imbalances of serum calcium (low) & serum phosphate (high) Anemia—verify form; may be reduced erythropoietin or actual iron deficiency or other cause such as anemia of chronic disease (related to inflammation), treat accordingly

10. Effects of Loss of Protein Albumin <3.0 mg/dL found with: Peripheral edema Ascites (abnormal fluid accumulation in the abdominal cavity) Anasarca (generalized massive edema) Reduced vitamin D-binding proteins, leading to depletion of active vitamin D and osteomalacia (soft bones) Hyperlipidemia resulting from loss of lipid-carrying proteins Increased risk of thrombosis because of decreased anticlotting factors

11. Treatment of CKD Control glucose in people with DM HgbA1c <7.2% associated with 50% reduced risk of kidney disease progression Control blood pressure (lifestyle and/or medication) Slow weight loss as needed Increased fiber intake helps promote nitrogen excretion through the feces Stop smoking Inclusion of omega-3 fats may reduce inflammation Decrease homocysteine levels with increased B vitamins: B2, B6, B12, and folate Avoidance of toxins: Certain medications & painkillers

12. Treatment (continued) Potential Restrictions: Provide adequate protein as tolerated (.8g/kg, reduced protein intake may be needed per serum lab values) Potassium Phosphorous Phosphate binders Sodium 2000mg Edema associated with low serum albumin levels should NOT be treated with excess restriction of sodium intake Fluid (500-1000mg + urine output)

13. Stages of Chronic Kidney Disease (CKD) Stages 1 and 2: GFR normal >60 Goal to prevent further damage by controlling BG, BP, aiming for a healthy diet Stage 3: GFR 30-59 or creatinine >2 mg/dL Goals include above along w/ maintaining stable weight, restricting potassium as warranted per labs, controlling anemia, maintaining or achieving good vitamin D status Stage 4: GFR 15-29 Goal to delay dialysis via above, protein restriction to 0.6 to 0.8 g (maximum 1 g) PRO/kg BW, limit phosphorus intake, monitor serum Ca++ and treat prn Stage 5: GFR <15 In addition to above, if no dialysis, monitor for need of fluid restriction (500-1000 mL plus urine output)

14. Role of Exercise Helps lower insulin resistance and control BG and BP Helps reduce cardiovascular disease associated with CKD Helps maintain quality of life Improves variety of health outcomes associated with CKD (Chan et al., 2007)

15. End-Stage Renal Disease (ESRD)or Chronic Renal Failure Associated with severe loss in the glomerular filtration rate and may be associated with oliguria (severe reduction in urine production) or anuria (no urine output) Fluid restriction required with reduced urine output Dialysis or renal transplant is warranted at this stage of renal disease

16. Dialysis Issues PRO goal ≥1.2 g/kg BW Aim for dry weight stabilization (weight after dialysis when BP normal), between dialysis sessions (interdialytic weight gain) with fluid restriction as needed Supplement with water-soluble vitamins Supplement with Ca++ (when phosphate normal) and active form of vitamin D (D3) Consider zinc and magnesium supplements Undertake iron studies to rule out need for FeSo4 Consult a dietitian: multiple restrictions result in a complicated diet that is difficulty to follow and malnutrition is common

17. Nephrolithiasis (Kidney Stones) Increasing in frequency, believed due to rise in obesity rates Increase in fluid intake (water) is most useful to keep urine dilute Dietary restrictions must be based on the type of kidney stone

18. Calcium Oxalate Stones (Most Common Form) Increased frequency found among persons with Roux-en-Y bariatric weight loss procedure Increased frequency found with use of Orlistat and fat malabsorption Increase fluid intake Decrease oxalate intake Avoid excess vitamin C because it results in oxalate formation; increase magnesium (milk; fatty fish also beneficial and rich in magnesium) Legumes, nuts, dark-green leafy vegetables, berries, citrus fruits 800 to 1200 mg calcium (2.5 to 4 cups milk or equivalent milk products) Mild sodium restriction

19. Uric Acid Stones (Second Most Common Form) Often found with type 2 diabetes Goal to reduce urine acidity With potassium citrate or calcium carbonate Moderate PRO intake (50g/day) Decrease intake of meat, eggs, legumes, whole grains Increase intake of milk and milk products Increase fruit & vegetable intake Except cranberries and plums/prunes

20. Study Guide • Vocabulary • Nephropathy • Nephritis • Nephrotic Syndrome • Nephrosclerosis • Nephrolithiasis • Blood Urea Nitrogen • Creatinine • Hyperkalemia • Hypernatremia • Uremia • Oliguria • Anuria

21. Study Guide (continued) • Function of the kidneys • Risk factors for nephropathy • Signs & symptoms of CKD • Nutritional treatment of CKD and ESRD • Nutrition management of Calcium oxalate stones and uric acid stones • Role of exercise