Chapter 14

Kidney Functions

maintaining blood volume, excreting waste, regulation of acid-base balance, BP, calcium & phosphorous metabolism, and RBC production.

Urea

a waste by-product of protein metabolism, and these levels rise with kidney disease

support for healing

Short-term kidney disease requires nutritional _____________ rather than dietary restrictions.

nutritional restrictions

Long-term/chronic kidney disease requires _______________.

s/s of kidney stones

• sudden, intense pain located in the flank that is unrelieved by position changes.

• diaphoresis, N & V are common, and there can be blood in the urine.

s/s of end-stage kidney disease (ESKD)

fatigue, decreased alertness, anemia, decreased urination, headache, & weight loss

s/s of acute kidney injury (AKI)

• decrease urination, decreased sensation in extremities, lower extremity edema, & flank pain.

• characterized by rising blood levels of urea & other nitrogenous wastes

nephrotic syndrome

A group of symptoms that indicate your kidneys are not working properly. The key symptom is proteinuria, meaning excessive protein in the urine. It's caused by damage to the tiny blood vessels in the kidneys that filter waste and excess water from the blood. 

s/s of nephrotic syndrome

• edema & high proteinuria.

• hypoalbuminemia (blood levels of the protein albumin are lower than normal), hyperlipidemia, & blood hypercoagulation.

Nutrition Therapy for Nephrotic Syndrome

Minimize edema, proteinuria, & hyperlipidemia

• Sufficient protein & low sodium

• Low sodium diet can prevent edema and hypertension

• Cholesterol, saturated fats, and trans fats can be restricted to assist in controlling high-lipid levels

• Carbs should provide majority of the daily calories

• Replace nutrients lost in the urine (take supplements and vitamins)

• Reduce risk of renal damage & atherosclerosis

• Increase in serum albumin, decrease serum lipid levels, slow progression of kidney disease, and less edema.

• Control HTN

• Prevent protein malnutrition that can lead to muscle catabolism.

pre-renal failure

something is affecting blood supply in kidneys (could be from decreased blood volume or hypotension)

intra-renal failure

damage to the kidney itself

post-kidney failure

Occurs when there's a blockage in the urinary tract below the kidneys, preventing urine from flowing out (i.e. urea stones).

DASH Diet

• High in fruits, vegetables, whole grains, nuts, legumes, & low- fat dairy products

• Low in red & processed meats, sugar-sweetened beverages, and sweets

• Lowers BP and reduces inflammation

• Lowers risk for kidney disease

Mediterranean Diet

• Plant-based pattern - emphasizes whole grains, fruit, vegetables, nuts, legumes, and olive oil; frequent fish

• Limited amounts of red meat, processed meats, and sweets; and wine in moderation with meals

• Shown to lower the risk of 2 major risk factors for chronic kidney disease (CKD), namely cardiovascular disease

Lifestyle modifications for kidney disease

• Be physically active.

• Do not use tobacco.

• Control blood glucose levels.

• Maintain normal blood pressure.

• Maintain normal serum cholesterol.

• DASH Diet

• Mediterranean Diet

Nephritic Syndrome

• inflammation of the glomeruli, the kidney's tiny blood vessels

• s/s: edema, decrease in urine volume, proteinuria, hematuria

chronic kidney disease (CKD)

• progressive kidney damage and loss of funciton

• the kidneys are making less urine, so less fluid and fewer waste products are being removed from the body.

• When the kidneys don't filter properly, fluid builds up in the body, and electrolytes (like potassium, sodium, etc.) get out of balance.

• Because the body holds onto too much fluid, this leads to overhydration—too much water in the body tissues and bloodstream.

Risk factors for chronic kidney disease

• Diabetes, hypertension, and CVD

• Obesity, advancing age, family history

• African American, Native American, Hispanic ethnicities

Dietary recommendations/nutrition for chronic kidney disease

• Renal Meal Plan: low sodium, protein, potassium, phosphorus, and calcium

• Limit meat to 5-6 oz/day for males, 4 oz/day for females

  • Slows progression, but too little protein results in breakdown of body protein, so carefully determine protein need

  • consume 35 kcal/kg of body weight to maintain protein stores

• Restrict sodium to maintain BP.

• Restrict potassium intake to prevent hyperkalemia.

  • Risk of hyperkalemia d/t reduced urinary excretion

  • Limiting K+ intake to <3 g/day with the caveat that fruit, vegetable, & high fiber intake not be compromised.

• Calcium - 800-1000 mg/day in clients with moderate to advanced

• Limit dairy products to ½ cup a day

• Fiber- caution as most are higher in phosphorus & potassium than refined grains

• Restricting phosphorus slows progression of kidney disease.

  • Limit high-phosphorus foods (peanut butter, dried peas and beans, bran, cola, chocolate, beer, some whole grains) to one serving or less per day.

Acute Kidney Injury

• Abrupt, rapid decline in function caused by trauma, sepsis, poor perfusion, or meds, & usually is reversible.

• Can cause hyponatremia, hyperkalemia, hypocalcemia, and hyperphosphatemia.

• Fluid overload leading to pulmonary edema is a complication

Nutrition Therapy for Acute Kidney Injury

• Simple carbs, fats, oils, & low-protein starches.

• Provide nonprotein to maintain the client’s weight.

• Potassium and sodium levels in a person with kidney problems are controlled based on how much urine they’re making, what their lab results show, and how often or how well dialysis is working.

  • K+ restricted to 60-70 mEq/day when on dialysis.

  • NA+ 1-2 g/day if not on dialysis, & 2-4 g/day if on dialysis.

• Calcium requirements are less than 2,000 mg.

• Fluids restricted as ordered.

Nephrolithiasis/Renal Calculi

• Kidney stones

• The most common cause is calcium oxalate stones, which form when there's too much calcium and oxalate in the urine.

  • formation more influenced by oxalate in the system than calcium.

  • form when insoluble crystals precipitate out of urine

• Contributing factors: inadequate fluid, elevated urine pH, & excess excretion through the kidneys of oxalate, calcium, and uric acid

Risk factors for kidney stones

• Dehydration or low urine volume, UT obstruction, gout, chronic inflammation of the bowel, and intestinal bypass or ostomy surgery

Preventative nutrition for kidney stones

Avoid excessive intake of protein, NA+, calcium, & oxalates (rhubarb, spinach, beets).

Nutrition for kidney stones

• Increasing fluid, primary intervention for treatment & prevention

  • Enough to produce at least 2 L of urine per day.

• Fluid before bed bc urine concentrates at night.

  • Particularly important with cystine stones, which requires an even greater daily fluid intake.

Calcium oxalate kidney stones

• Forms due to excess calcium and oxalate in the urine, leading to crystallization and stone formation. They are the most common type of kidney stones.

• Causes:dehydration, hypercalcemia

• Avoid spinach, rhubarb, beets, nuts, chocolate, tea, wheat bran, & strawberries, high in oxalates.

• Avoid megadoses of vitamin C, which increase the amount of oxalate excreted.

Uric acid stones

Limit foods high in purines, which include lean meats, organ meats, whole grains, and legumes. Drink water at night.

Strurite Stones

• forms from bacteria

• causes: chronic UTI

cystine stones

• forms from excess cystine

• rare genetic disorder

• increase fluids for treatment

dialysis

• Protein needs increase from 06 to 1.0 g/kg before and then 1.2 to 1.5 g/kg while on ___________.

• 50% of protein intake should come from biologic sources (eggs, milk, meat, fish, poultry, soy).

• Take phosphate binders (calcium bicarbonate) when eating protein rich foods