Name: Dawn Ortiz

Renal Learning Activity

1. Describe 7 functions of the kidney.

1. Excretory functions via blood filtration (eliminating waste)

2. Blood pressure regulation

3. Maintenance of volume and composition of body fluids

4. Maintenance of calcium-phosphorus homeostasis

5. Acid-base balance

6. Endocrine Functions: Produces active form of Vitamin D which aids in calcium absorption and bone formation; produces erythropoietin which stimulates RBC synthesis

7. Metabolic clearance of hormones

2. Provide a brief explanation of the following conditions and describe nutrition management:

a. Acute Renal Failure: Deterioration of renal function, usually reversible and characterized by fluid and electrolyte imbalances and muscle wasting. Prerenal ARF is caused by decreased blood flow to the kidneys, may be caused by a tumor, hypotension, dehydration or CHF. There is no nutrition intervention, other than to rehydrate the patient, as the doctor works to fix prerenal ARF. Postrenal ARF is an obstruction in the urine caused by bladder/prostate cancer, stone formation or urethral occlusion. There is no nutrition intervention for postrenal. However, in intrarenal ARF nutrition intervention is crucial. Intrarenal is actual damage to the kidney organ itself, including vascular, glomerular and intestinal disorders. Phase 1 of ARF is called the Oliguric Phase, which lasts 8-14 days. During this phase fluid should be restricted because urine output is less than 500 cc/day and electrolytes are imbalanced. BUN, creatinine, potassium, phosphorus, magnesium are elevated, while sodium, carbon dioxide, calcium and H/H are low and should be replaced. Phase 2, the Diuretic Phase lasts about 10 days. Fluid intake should be increased, as patients are at risk for dehydration since urine output increases to 150-200% of normal levels. Potassium levels are low and should be replaced, while sodium may be either elevated or decreased. Phase 3, the Convalescent Phase occurs in reversible ARF and lasts 4-6 months. During this phase renal function normalizes and lab values stabilize. In general, nutrition therapy for ARF depends on the current labs. Energy needs are approximately 35 kcal/kg/d. Protein should be restricted if not being dialyzed (0.5-0.8 g/kg/d). If patient is being dialyzed protein needs are 1.0-1.5 g/kg/d.

b. Chronic Kidney Disease: Is the slow, progressive loss of kidney function and categorized by GFR < 20 mL/min. Adequate protein and caloric intake is important to prevent tissue catabolism. Maintaining good nutritional status and decreasing uremic toxicity is also important to slow the rate of renal failure. If GFR is less than 25 mL/min, protein should be 0.6 g/kg/d. Energy needs for CKD are 35 kcal/kg/d for under 60 year and 30-35 kcal/kg/d for 60+ years old.

c. Nephrotic Syndrome: A kidney disorder with many etiologies and is characterized by proteinuria. Patients exhibit muscle wasting and malnutrition primarily from protein deficiency, edema from decreased plasma oncotic pressure and dyslipidemia with elevated serum cholesterol and triglycerides. MNT for Nephrotic Syndrome is moderate protein (0.8-1.0 g/kg/day), 35 kcal/kg/day, less than 30% calories from fat, less than 2 g sodium and fluid restricted diet. Calcium and potassium supplements may be necessary based on lab values.

d. Renal Osteodystrophy: Complex lesions of bone present in the majority of patients with CKD, including osteitis and osteomalacia. MNT: low animal-based protein, phosphorus restricted (800-1000 mg/day) diet. Calcium acetate is usually prescribed to act as a phosphate binder as well.

e. Idopathic Kidney Stones: oxalate kidney stones result from bile salt malabsorption. MNT: high fluid intake (2.5-3 liters/day), sodium < 2300 mg/day because it increases calcium excretion in urine, limit protein intake (0.8 g/kg/day) because it increases calcium in urine excretion, normal intake of calcium spread out throughout the day (with meals) and avoid high oxalate foods (rhubarb, spinach, strawberries, chocolate, wheat bran, nuts, tea, beets and turmeric).


Hark L., Darwin D., and Morrison G. Medical Nutrition and Disease: A Case-Based Approach, 5th. Ed. Philadelphia, PA: Wiley-Blackwell; 2014: 409-11; 399.

3. Define hemodialysis and the nutrition management for patients on it.

Hemodialysis is the most common treatment option for end stage renal disease. A machine acts as the damaged kidneys to filter and cleanse blood, removing excess fluids and waste products. HD cannot replace the kidneys’ endocrine functions. Treatment is typically 3 times per week, 2-5 hours each time. There is a movement for patients to receive HD more often, even daily which would be closer to real kidney function. Nutrition management includes detailed education to improve quality of life. HD renal diets should be 2000-3000 mg/day maximum Na and K, 1.2 g/kg/d protein and 35 kcal/kg (under 60), 30-35 kcal/kg (over 60). Iron, active form of vitamin D, vitamin C (only RDA), calcium and water soluble vitamin supplements may be necessary. Vitamin A should not be supplemented because the body cannot process it. Fluid should be restricted to 500-1000 mL/d + urine output.

4. Explain the difference between a fistula and a graft used for hemodialysis.

A fistula is the preferred, permanent access type for HD and used in about 27% of dialysis patients. It is a non-synthetic, internal vein and artery connection. The downfall is that a fistula takes several months to mature. Another type of permanent access for an HD patient is a graft. This option is actually more popular and used in about 53% of patients. It only takes weeks to mature, but connects the vein and artery using an artificial tube. Grafts are associated with increased risk of stenosis and thrombosis.

5. What is the National Kidney Foundation’s “Kidney Disease Outcomes Quality Initiative” or K/DOQI?

This is a multidisciplinary group, established in 1995, that works to establish clinical practice guidelines for dialysis patients based on current medical literature. The goals of K/DOQI are to improve survival rates, decrease morbidity, improve quality of life and increase efficiency of care. Some K/DOQI areas of focus have been; hemodialysis adequacy, peritoneal dialysis adequacy, vascular access, anemia, nutrition, osteodystrophy and blood pressure.

6. Define peritoneal dialysis and the nutrition management of patients on it.

PD cleanses blood by using the lining of the abdomen. Dialysate is drained from a bag into the abdomen, fluid and waste flows through the lining and the dialysate is drained from the abdomen, removing excess waste and fluid. In nutrition management for PD fluid, Na and K are less restricted and protein needs are higher than for HD (1.2-1.5 g/kg/d). H/H-oral iron supplementation and EPO injections are necessary. Energy needs are the same for HD, however the calories from the glucose absorbed in the dialysate solution must be included in caloric intake.

7. Describe the various procedures used for peritoneal dialysis.

• Continuous Ambulatory Peritoneal Dialysis (CAPD): Uses gravity to have the dialysate pass from a hanging plastic bag through a catheter and into the abdomen. After several hours, the solution is drained back into a disposable bag and the abdomen is filled with fresh solution to begin the cleansing process again.

• Continuous Cyclic Peritoneal Dialysis (CCPD): Is good for students or people that need to be out of the house during the day. The machine automatically fills and drains the majority of dialysate from the abdomen during the night, while the patient is sleeping (3-5 times) and only 1 exchange that lasts the whole day.

• Continuous Renal Replacement Therapy (CRRT): Usually only takes place in the ICU, for patients who are too unstable to tolerate HD and need 24 hour dialysis support. Instead of using a pump CRRT relies the patient’s own pressure gradient to move the blood along.

8. What is kinetic modeling? Why is it used?

Urea kinetic modeling uses Kt/V values to prescribe and measure dialysis therapy. The "K" stands for "clearance" of urea in milliliters per minute, "t" for "time" in minutes, and "V" for body water "volume" in liters. The calculation uses the patient's individual body water volume, to "normalize" the value. Pre and post treatment BUN values are incorporated into the calculation. The protein catabolic rate is also calculated to ensure dialysis patients are receiving adequate protein in their diet.


RenalWeb Dialysis Outcomes: Adequate Hemodialysis Therapy. . Last updated November 22, 2014. Accessed on November 24, 2014.

9. If a patient is on peritoneal dialysis receiving 4 exchanges of 3 liters of 2.5% dextrose, how many kcals is he likely to absorb from this regimen?

Approximately 70% of calories are absorbed in PD:

4 exchanges of 3L of 2.5% dextrose = 1020 kcals total x .07 = 714 kcal

10. Describe the nutrition management of a renal transplant recipient in the immediate post-op period.

Immediately following renal transplant, MNT consists of a high protein diet (1.3-1.5 g/kg/day) due to possible protein catabolism in the post-op stage. Calories should be 30-35 kcal/kg (based on UBW or dry weight). Hyperglycemia may occur post-op so carbohydrates may need to be controlled. Dyslipidemia may also occur so a low fat diet is recommended. If edema occurs, fluid and sodium restriction may be necessary. Phosphorus depletion may occur, requiring supplementation.

11. Describe the nutrition management of a renal transplant recipient over the long term?

Long term renal transplant MNY consists of a low fat diet with moderate protein intake (1g/kg/day). Moderate kcal intake to maintain a healthy body weight with regular exercise. Generally fluid and sodium restrictions are not necessary. Based on lab values, calcium and iron supplementation may be recommended.

Reference for questions 10 and 11:

Hark L., Darwin D., and Morrison G. Medical Nutrition and Disease: A Case-Based Approach, 5th. Ed. Philadelphia, PA: Wiley-Blackwell; 2014: 407-8.

12.  What are these medications and what is their use?

a. Epogen = synthetic form of erythropoietin to manage anemia; given during dialysis; response to dose takes 2-6 weeks

b. Rocaltrol = oral active form of vitamin D necessary for ESRD

c. Kayexalate (polystyrene sulfonate) = used to reduce high levels of serum potassium.

d. Phoslo (calcium acetate) = phosphate binder necessary to reduce Phos levels in the blood

e. Renagel (cationic polymer) = phosphate binder to reduce Phos levels in the blood

f. Tums (calcium carbonate) = phosphate binder if taken with meals; calcium supplement if taken between meals

g. Niferex 150/NuIron (polysaccharide-iron complex) = iron supplementation, which helps form new red blood cells

h. Nephrocaps/Nephrovite/NephplexRx (vitamin B complex with vitamin C) = used to replenish vitamin B and C deficiency common in renal failure

i. Azathioprine/Imuran (immunosuppressant) = used after a kidney transplant to help prevent the body from rejecting the new organ

13. List some herbs pre-dialysis or dialysis patients might try to improve their condition. What are the risks of taking these herbs?

Supplementation with complimentary or alternative medicine (CAMs) has become popular for CKD patients. St. John’s Wort is a common CAM is known to interfere with the bioavailability of cyclosporine and tacrolimus and cause kidney transplant rejection. Fish oil has shown to have positive effects with CKD, but may interfere with anticoagulant medications. Bulking agents, such as flax seed require large amounts of fluid intake and should be used with caution if a patient is on a fluid restricted diet. Noni juice is a popular supplement that should be avoided by CKD patients due to the high potassium content. Finally, most supplements are not approved by the FDA so patients should always talk to their doctor before taking them.

Hark L., Darwin D., and Morrison G. Medical Nutrition and Disease: A Case-Based Approach, 5th. Ed. Philadelphia, PA: Wiley-Blackwell; 2014: 408.


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