8/6/2019 15B NUT-CKD

1/49

8/6/2019 15B NUT-CKD

2/49

8/6/2019 15B NUT-CKD

3/49

RENAL PHYSIOLOGY

The kidneys keep the bodys fluids,electrolytes, and organic solutes in a

healthy balance or homeostasis.

Their functional units are the millions of

nephrons in the renal cortex which filter

most constituents of the blood other than

red blood cells and protein, reabsorb

needed substances, secrete hydrogenions to maintain acid-base balance,

maintains blood pressure and secrete

wastes.

8/6/2019 15B NUT-CKD

4/49

Urine formation consists of four basic

processes:1. glomerular filtration

2. tubular reabsorption

3. tubular secretion and4. urine concentration.

Several disease conditions can interfere withthese functions.

8/6/2019 15B NUT-CKD

5/49

Inflammatory and degenerative diseases

can involve the small blood vessels andmembranes in the nephrons.

Urinary tract infections and kidney

stones can interfere with normal drainage,causing further infection and tissue

damage.

Circulatory disorders, such as

hypertension, can damage the small renal

arteries.

8/6/2019 15B NUT-CKD

6/49

8/6/2019 15B NUT-CKD

7/49

Nephrotic Syndrome

In nephrotic syndrome, an injury to theglomerular basement membrane causes

an increased glomerular permeability,

resulting in the loss of albumin and otherplasma proteins in the urine.

8/6/2019 15B NUT-CKD

8/49

Urinary protein losses greater than 3-3.5

grams per day usually indicate nephroticsyndrome.

The loss of albumin leads to edema.

Low albumin levels also trigger cholesteroland lipoprotein synthesis in the liver,

resulting in hyperlipidemia.

Q: Will you advice an increase in protein

intake in these patients?

8/6/2019 15B NUT-CKD

9/49

Protein:

High-protein diets are not recommended asthey may encourage damage to the

nephrons, leading to a progression of

renal insufficiency.Since albumin losses in nephrotic patients

are due to increased catabolism, rather

than a reduction in protein synthesis, low-

protein diets, which decrease catabolism,

may be more beneficial.

8/6/2019 15B NUT-CKD

10/49

Acute Renal Failure

Acute renal failure, manifested by oliguriaor anuria, usually occurs suddenly and is

often reversible. It is marked by a

reduction in the glomerular filtration rate

and a modification in the kidneys ability to

excrete metabolic wastes.

8/6/2019 15B NUT-CKD

11/49

Its causes can be prerenal, intrinsic, and

postrenal.Prerenal causes include severe

dehydration and circulatory collapse.

Causes intrinsic to the kidney includeacute tubular necrosis, nephrotoxicity,

vascular disorders, and acute

glomerulonephritis.

Obstructive (postrenal) causes include

benign prostatic hypertrophy and

bladder or prostate cancer.

8/6/2019 15B NUT-CKD

12/49

Diet in Acute Renal Failure

Protein: A low-protein diet (0.5-0.6 grams

per kilogram) is recommended initially.

Protein may be increased in the diet as

the glomerular filtration rate increases to

normal. If dialysis is initiated, the protein level

may be increased to 1.0-1.5 grams per

kilogram per day if necessary tocompensate for protein losses in the

dialysate.

8/6/2019 15B NUT-CKD

13/49

Diet in Acute Renal Failure

Calories: Calorie needs are generally

elevated (35-50 kilocalories per kilogram)

in order to provide positive nitrogen

balance under stressful conditions. As

protein is usually quite restricted, calorieneeds may be met by providing greater

amounts of carbohydrate and fat in the

diet.

8/6/2019 15B NUT-CKD

14/49

Sodium and Fluid: Sodium is restricted

depending on urinary excretion, edema,

serum sodium levels, and dialysis needs.

During the oliguric phase, sodium may be

restricted to 500-1000 milligrams per day,

and fluid requirements are based onreplacing losses via urine, vomitus, and

diarrhea, plus approximately 500 milliliters

per day.

8/6/2019 15B NUT-CKD

15/49

Potassium: Potassium requirements vary

depending on hemodynamic status and

the degree of hypermetabolism due to

stress, infection, or fever.

High potassium levels are treated by

dialysis or with kayexalate, an exchangeresin which substitutes sodium for

potassium in the gastrointestinal tract.

During the oliguric phase, potassium maybe restricted to 1,000 milligrams per day.

8/6/2019 15B NUT-CKD

16/49

Chronic Renal Failure

Approximately 90 percent of cases of end-stage renal disease are attributable to

diabetes mellitus, glomerulonephritis, or

hypertension.

Kidney failure results in fluid and

electrolyte imbalances, the build up of

nitrogenous wastes, and reduced ability to

produce renal hormones.

The two treatment options are trans-

plantation or dialysis.

8/6/2019 15B NUT-CKD

17/49

Mild renal insufficiency is defined as 40-80

percent of renal function. Moderate insufficiency is defined as 15-40

percent, and

severe renal insufficiency is below thesefigures.

8/6/2019 15B NUT-CKD

18/49

Diet in Chronic Renal Failure

Low-protein diets may slow the

progression of mild and moderate renal

insufficiency.

Therapeutic diets using plant sources of

protein are more effective in delaying theprogression of renal insufficiency,

compared to those using animal proteins.

Vegan (pure vegetarian) diets have beenshown to provide adequate protein.

8/6/2019 15B NUT-CKD

19/49

Dialysis Patients

Dialysis changes dietary needs. Patientsundergoing typical hemodialysis, involving

about three treatments per week, follow

diets that are restricted in protein, sodium,

potassium, phosphorus, and fluid.

Patients on continuous ambulatory

peritoneal dialysis, involving several

dialysate exchanges per day, can be moreliberal in protein, sodium, potassium, and

fluid intake.

8/6/2019 15B NUT-CKD

20/49

Sodium: Sodium intake must be modified to

prevent hypertension, congestive heartfailure, and pulmonary edema. Limiting

intake will help avoid thirst and maintain

acceptable fluid balance.

8/6/2019 15B NUT-CKD

21/49

Fluid: Fluid consumption should be

controlled to avoid congestive heartfailure, pulmonary edema, hypertension,

and swelling of the legs and feet. Fluid

allowances are 1,000-1,5000 milliliters per

day and are based on urine output andtype of dialysis.

8/6/2019 15B NUT-CKD

22/49

Protein: Protein requirements range from

1.1-1.5 grams per kilogram, depending onthe type of dialysis used and the patients

nutritional status. It is important to ensure

sufficient protein to maintain visceral

protein stores, but to avoid excesses thatcould lead the accumulation of

nitrogenous waste products in the blood

(uremia).

8/6/2019 15B NUT-CKD

23/49

Phosphorus: Kidney failure causes high

levels of phosphorus to build up in theblood and disrupts calcium/phosphorus

balance.

Elevated phosphorus levels can lead to

metastatic calcification (soft tissue

calcification), secondary hyperpara-

thyroidism, and renal osteodystrophy.

8/6/2019 15B NUT-CKD

24/49

Renal osteodystrophy.

Diseases of bone in which there is failureof normal development or abnormal

metabolism in bone which is already

mature.

Principal clinical signs are distortion and

enlargement of bones, susceptibility to

fracture, and abnormalities of gait and

posture

8/6/2019 15B NUT-CKD

25/49

Potassium: Potassium restrictions depend

on serum potassium levels, the type ofdialysis, medications, and residual renal

function. Patients on hemodialysis are

usually restricted to 2,000-3,000

milligrams per day to preventhyperkalemia between treatments.

Patients on peritoneal dialysis may follow

a more liberal dietary potassium intake, aspotassium is lost in the dialysate solution

during daily exchanges.

8/6/2019 15B NUT-CKD

26/49

Kidney Stones

About 12 percent ofAmericans develop akidney stone at some point in their lives.

Stones usually result from the

crystallization of calcium (which originally

came in foods or supplements) and

oxalate, a part of many plant foods.

Some people have a tendency to lose

excessive amounts of calcium or oxalatethrough their kidneys, and they have a

greater likelihood of a stone.

8/6/2019 15B NUT-CKD

27/49

Kidney stones can also form from uric

acid, which is a breakdown product ofprotein, or from struvite (ammonio-

magnesium phosphate) or cystine.

Nutritional steps are important in

preventing stones and can also help

prevent recurrences, which is important

given that 30-50 percent of people

diagnosed with a renal stone have arecurrence within five years.

8/6/2019 15B NUT-CKD

28/49

Preventing stones is like keeping a salt

crystal from forming in a glass of saltywater.

You can either reduce the concentration of

salt or add more water.

Epidemiologic studies have shown that

certain parts of the diet help reduce the

amount of calcium that filters into the

urine. It is a simple matter to put these factors to

work clinically.

8/6/2019 15B NUT-CKD

29/49

WHATS IN A STONE?

Calcium oxalate 72% Uric acid 23%

Ammoniomagnesium phosphate

(struvite) 5% Cystine

8/6/2019 15B NUT-CKD

30/49

The prevalence of kidney stones is three

times higher in men than women, and ishigher among Caucasians than Asians or

African Americans, for reasons that are

not clear.

They are especially likely to strike betweenthe ages of 40 and 60.

8/6/2019 15B NUT-CKD

31/49

Protective Foods

W

ater.

Water dilutes the urine and keeps calcium,oxalates, and uric acid in solution. Inresearch studies, those subjects whose

total fluid intake (from all sources) over 24hours was roughly 2.5 liters, the risk of astone was about one-third less than that ofsubjects drinking only half that much.

(They do not need to drink 2.5 liters ofwater per day; rather this is the total fluidconsumption, including juices, soups, etc.)

8/6/2019 15B NUT-CKD

32/49

High-Potassium Foods.

A study of 46,000 men conducted byHarvard University researchers found thata high potassium intake can cut the risk ofkidney stones in half.

Potassium helps the kidneys retaincalcium, rather than sending it out into theurine.

Potassium supplements are not generally

necessary. Rather, a diet including regularservings of fruits, vegetables, and beanssupplies plenty of potassium.

8/6/2019 15B NUT-CKD

33/49

Calcium. Although most stones contain

calcium, the calcium in foods does not

necessarily contribute to stones.

Calcium supplements taken between

meals may increase the risk of stones,

because about 8 percent of any extradietary calcium passes into the urine.

8/6/2019 15B NUT-CKD

34/49

8/6/2019 15B NUT-CKD

35/49

Caffeine. Caffeinated beverages reduce the

risk of stones. Caffeines diuretic effect

causes the loss of both water and calcium,

but the water loss is apparently the

predominant effect. Similarly, alcoholic

beverages are associated with a reducedrisk of kidney stones, again presumably

due to a diuretic effect. This is not a

compelling reason to drink either coffee oralcohol, but their diuretic actions do

present this advantage.

8/6/2019 15B NUT-CKD

36/49

Problem Foods

Animal Protein.Animal proteins cause calcium to be

leached from the bones and excreted in

the urine where it can form stones. Diets

rich in animal proteins also increase uric

acid excretion.

A modest increase in animal protein

intake, from less than 50 grams to 77grams per day, was associated with a 33

percent increased risk of stone formation.

8/6/2019 15B NUT-CKD

37/49

Between 1958 and the late 1960s, there

was a sharp increase in the incidence of

kidney stones in Great Britain.

During that period, there was no

substantial change in the amount of

calcium or oxalate-containing foodsconsumed. However, the consumption of

vegetables decreased, and the use of

poultry, fish, and red meat increased.Statistical analyses showed a strong

relationship between the incidence of

stones and animal protein consumption.

8/6/2019 15B NUT-CKD

38/49

Sodium. Sodium increases the passage of

calcium through the kidney and increases

the risk of stones. When people cut their

salt (sodium chloride) intake in half, they

reduce their daily need for calcium by

about 160 milligrams.

8/6/2019 15B NUT-CKD

39/49

8/6/2019 15B NUT-CKD

40/49

Sugar.

Sugar accelerates calcium losses throughthe kidney. In the Nurses Health Study,

those who consumed, on average, 60

grams or more of sugar (sucrose) per day

had a 50 percent higher risk of stones thanthose who consumed only about 20

grams.

8/6/2019 15B NUT-CKD

41/49

Climate. Kidney stones are also more

common in warm climates, presumably

because perspiration leads to dehydration

and a more concentrated urine, and

because sunlight increases the production

of vitamin D in the skin which, in turn,increases calcium absorption from the

digestive tract.

Surprisingly, oxalate-rich foods, such aschocolate, nuts, tea, and spinach, are not

associated with a higher risk of renal

stones,

8/6/2019 15B NUT-CKD

42/49

Helping Patients Avoid Kidney Stones

Encourage patients to drink plenty of wateror other fluids, staying ahead of their thirst.

Diets including generous amounts of

vegetables, fruits, and beans are rich in

potassium and very low in sodium.

8/6/2019 15B NUT-CKD

43/49

Helping Patients Avoid Kidney Stones,

contn

If you prescribe calcium supplements,

encourage patients to take them with meals,

rather than between meals.

Encourage patients to avoid animal products.

Their proteins and sodium content increase

the risk of stones.

Patients should keep salt and sugar usemodest.

8/6/2019 15B NUT-CKD

44/49

What foods are high in protein?

meat (beef, chicken, pork, turkey) fish

seafood (shrimp, scallops, clams, oysters)

eggs dairy products (milk, cheese, ice cream,

yogurt, pudding)

8/6/2019 15B NUT-CKD

45/49

8/6/2019 15B NUT-CKD

46/49

What foods are high in phosphorus?

The following foods are high inphosphorous and should be restricted.

Dairy products, including:

milk (all kinds: whole, low-fat, skim,chocolate, and buttermilk)

cheeses (all except cream cheese)

puddings and custardsyogurt

ice cream

8/6/2019 15B NUT-CKD

47/49

Foods high in sodium:

canned foods (vegetables, meats, pastameals)

processed foods (meats such as bologna,pepperoni, salami, hot dogs, sausage)

cheese dried pasta and rice mixes

soups (canned and dried)

snack foods (chips, popcorn, pretzels,cheese puffs, salted nuts, etc.)

dips, sauces, and salad dressings

8/6/2019 15B NUT-CKD

48/49

meats, chicken, turkey, and fish (especially

organ meats)

dried beans and peas, including:

black-eyes

field peas

kidney

navy

northern

pinto

lima nuts (all kinds and peanut butter)

seeds, bran, and whole grain cereals and

breads

8/6/2019 15B NUT-CKD

49/49

DONE!!