CSR Medical Nutrition Therapy for Renal Conditions 3 — Questions and Answers
Question 1: A CKD stage 3b patient with metabolic acidosis has a serum bicarbonate of 19 mEq/L. Which dietary approach can help correct this?
- Increase dietary protein to buffer acid load
- Increase intake of fruits and vegetables to provide alkali (Correct answer)
- Restrict fluid to concentrate bicarbonate in the blood
- Eliminate all grains to reduce acid production
Correct answer: Increase intake of fruits and vegetables to provide alkali
Fruits and vegetables have an alkaline ash effect and can increase serum bicarbonate, helping correct metabolic acidosis in CKD.
Question 2: Which form of vitamin D requires activation by the kidney and is therefore deficient in patients with advanced CKD?
- Ergocalciferol (vitamin D2)
- Cholecalciferol (vitamin D3)
- 25-hydroxyvitamin D (calcidiol)
- 1,25-dihydroxyvitamin D (calcitriol) (Correct answer)
Correct answer: 1,25-dihydroxyvitamin D (calcitriol)
The kidney converts 25-OH vitamin D to the active form calcitriol (1,25-dihydroxyvitamin D), which is deficient when renal function is impaired.
Question 3: A hemodialysis patient with secondary hyperparathyroidism has elevated PTH, normal calcium, and elevated phosphorus. What is the most appropriate initial nutritional intervention?
- Increase calcium-containing foods to suppress PTH
- Reduce dietary phosphorus and review phosphate binder adherence (Correct answer)
- Increase vitamin D food sources to normalize PTH
- Restrict protein to reduce phosphorus intake indirectly
Correct answer: Reduce dietary phosphorus and review phosphate binder adherence
Elevated phosphorus drives secondary HPT, so reducing dietary phosphorus and optimizing binder adherence is the priority nutritional intervention.
Question 4: A CKD patient taking calcium carbonate as a phosphate binder is found to have hypercalcemia. What dietary counseling change is most appropriate?
- Increase dietary phosphorus to bind the excess calcium
- Limit calcium-rich foods and discuss non-calcium binder alternatives with the care team (Correct answer)
- Stop all dairy products and add vitamin D supplementation
- Increase fluid intake to dilute serum calcium
Correct answer: Limit calcium-rich foods and discuss non-calcium binder alternatives with the care team
Hypercalcemia in a patient on calcium-based binders warrants limiting high-calcium foods and flagging the need for non-calcium binder consideration.
Question 5: Which biomarker is the BEST indicator of long-term protein-energy nutritional status in a hemodialysis patient, given its long half-life?
- Serum prealbumin (transthyretin)
- Serum albumin (Correct answer)
- Serum transferrin
- C-reactive protein (CRP)
Correct answer: Serum albumin
Serum albumin, with a half-life of about 20 days, reflects long-term nutritional status and remains the most widely used marker in dialysis patients.
Question 6: A peritoneal dialysis patient has a PET (peritoneal equilibration test) showing high transport. How does this affect nutritional needs?
- Greater glucose absorption occurs, increasing risk of hyperglycemia and obesity (Correct answer)
- Less protein is lost into the dialysate, reducing protein requirements
- Fluid removal is more efficient, allowing liberalized fluid intake
- Phosphorus clearance is higher, reducing dietary phosphorus restriction needs
Correct answer: Greater glucose absorption occurs, increasing risk of hyperglycemia and obesity
High transporters absorb more glucose from the dialysate, increasing caloric intake and risk of hyperglycemia, dyslipidemia, and weight gain.
Question 7: What is the recommended daily fluid allowance calculation typically used for anuric hemodialysis patients?
- 1500 mL per day regardless of residual renal function
- 500–750 mL/day plus any measured urine output (Correct answer)
- Equal to interdialytic weight gain goal of less than 1 kg
- Based solely on thirst sensation and body weight
Correct answer: 500–750 mL/day plus any measured urine output
Fluid is typically restricted to 500–750 mL/day (insensible losses) plus any residual urine output in anuric HD patients.
CSR Medical Nutrition Therapy for Renal Conditions 3
A CKD stage 3b patient with metabolic acidosis has a serum bicarbonate of 19 mEq/L.
Which dietary approach can help correct this?