Download Fundamentals of Nutrition

Section 3
Medical Nutrition Therapy
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Chapter 19
Diet and Renal Disease
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Objectives
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Describe, in general terms, the work of
the kidneys.
Explain why protein is restricted for
renal clients.
Explain why sodium and water are
sometimes restricted for renal clients.
Explain why potassium and
phosphorus are sometimes restricted
for renal clients.
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Kidneys
Kidneys excrete wastes, maintain volume
and composition of body fluids, and
secrete certain hormones.
They filter the blood, cleanse it of waste
products, and recycle other, usable,
substances so that the necessary
constituents of body fluids are constantly
available.
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Kidneys
One million working parts called
nephrons.
Glomerulus is the filtering unit.
The kidneys maintain both the
composition and the volume of body
fluids.
They maintain fluid balance, acid-base
balance and electrolyte balance.
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Kidneys
Waste materials sent via 2 tubes called
ureters from the kidneys to the urinary
bladder.
1.5 liters of urine excreted per day.
Waste materials include end products of
protein metabolism (urea, uric acid,
creatinine, ammonia, and sulfates), excess
water and nutrients, dead renal cells, and
toxic substances.
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Kidneys
Oliguria: urinary output less than 500
ml/day.
Kidneys unable to adequately eliminate
waste products–can result in renal failure.
Kidneys indirectly stimulate the bone
marrow to produce red blood cells.
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Types of Renal Disorders
Initially caused by infection, degenerative
changes, diabetes mellitus, cardiovascular
disorders, cysts, renal stones, trauma.
When severe, renal failure may result.
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Acute Renal Failure
Acute renal failure occurs suddenly and
may last a few days to a few weeks.
Caused by another medical problem such
as a serious burn, a crushing injury, or
cardiac arrest.
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Chronic Renal Failure
Develops slowly, number of functioning
nephrons constantly diminishing.
Uremia is a condition in which protein
wastes that should normally have been
excreted are instead circulating in the
blood.
Symptoms include nausea, headache,
coma, convulsions. Severe renal failure
will result in death unless dialysis used.
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Nephritis
Inflammatory diseases of the kidneys.
Caused by infection, degenerative
processes, or vascular disease.
Glomerulonephritis is a nephritis affecting
the capillaries in the glomeruli.
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Nephrosclerosis
Hardening of renal arteries.
Caused by arteriosclerosis and
hypertension.
Usually occurs in older people, sometimes
develops in young diabetic clients.
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Polycystic Kidney Disease
Relatively rare, hereditary disease.
Cysts form and press on the kidneys.
Kidneys enlarge and lose function.
Although people with this condition have
normal kidney function for many years,
renal failure may develop near the age of
50.
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Nephrolithiasis
Stones develop in the kidneys.
Stones classified according to their
composition–calcium oxalate, uric acid,
cystine, calcium phosphate, and
magnesium ammonium phosphate (known
as struvite).
Associated with metabolic disturbances
and immobilization of the client.
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Dietary Treatment of Renal
Disease
Extremely complicated.
Intended to reduce the amount of excretory
work demanded of the kidneys while
helping them maintain fluid, acid-base,
and electrolyte balance.
Clients with chronic renal failure may have
protein, sodium, potassium and
phosphorus restricted.
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Dietary Treatment of Renal
Disease
Sufficient calories necessary: 25 to 50
kcal per kilogram of body weight.
Energy requirements should be fulfilled by
carbohydrates and fat.
Protein increases the amount of nitrogen
waste the kidneys must handle.
Diet may limit protein to 40 grams based
on glomerular filtration rate and weight.
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Dietary Treatment of Renal
Disease
Sodium may be limited if the client tends
to retain it.
Fluids are typically restricted for renal
clients.
Calcium supplements may be prescribed.
Vitamin D may be added and phosphorus
limited, to prevent osteomalacia.
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Dietary Treatment of Renal
Disease
Potassium may be restricted in some
clients because hyperkalemia tends to
occur in end stage renal disease (ESRD).
Excess potassium can cause cardiac arrest.
Renal clients often have an increased need
for vitamins B, C, and D, and supplements
are often given.
Iron is commonly prescribed.
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Dialysis
Done be either hemodialysis or peritoneal
dialysis.
Hemodialysis requires permanent access to
the bloodstream through a fistula.
Hemodialysis is done 3 times a week for 35 hours at a time.
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Dialysis
Peritoneal dialysis makes use of the
peritoneal cavity.
Less efficient than hemodialysis.
Treatments usually last about 10 to 12
hours a day, 3 times a week.
Complications include peritonitis,
hypotension, weight gain.
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Diet During Dialysis
Dialysis clients may need additional
protein.
Amount must be carefully controlled.
A client on hemodialysis requires 1.0 to
1.2g of protein per kilogram of body
weight to make up for losses during
dialysis.
A client on peritoneal dialysis requires 1.2
to 1.5g protein per kilogram body weight.
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Diet During Dialysis
75% of this protein should be high
biological value (HBV) protein, found in
eggs, meat, fish, poultry, milk, and cheese.
Potassium is usually restricted.
A typical renal diet could be written as
“80-3-3” which means 80g protein, 3g
sodium, and 3g potassium daily.
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Diet During Dialysis
Healthy people ingest from 2,000 to 6,000
mg of potassium per day.
Daily intake allowed clients in renal failure
is 3,000 to 4,000 mg.
End stage renal disease clients intake
allowed is 1,500 to 2,500 mg per day.
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Diet After Kidney Transplant
Need for extra protein or for the restriction
of protein.
Carbohydrates and sodium may be
restricted.
Additional calcium and phosphorus may
be necessary if there was substantial bone
loss before the transplant.
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Stop and Share
A client with renal disease is on a
potassium restriction of 3,000 mg.
What recommendations would you give
the client?
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Stop and Share
Regulate intake by making careful choices.
Milk is normally restricted to ½ cup a day
because it is high in potassium.
Suggest use of potassium content charts to
select low potassium foods.
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Stop and Share
Low potassium (<
150 mg/serving)
fruits include:
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•
•
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Applesauce
Berries
Figs
Fruit cocktail
Grapes
•
•
•
•
•
•
•
Lemon, lime
Nectors
Mandarin oranges
Peaches
Pears
Plums
Rhubarb
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Dietary Treatment of Renal
Stones
Treatment varies based on type of stone.
Clients should drink lots of fluid.
Eat a well-balanced diet.
Once stones have been analyzed, specific
diet modifications may be indicated.
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Calcium Oxalate Stones
A diet low in calcium can reduce the risk
of calcium oxalate renal stones. In fact,
higher dietary calcium intake may
decrease the incidence of renal stones for
most people.
Reduce level of oxalate, which is found in
beets, wheat bran, chocolate, tea, rhubarb,
strawberries, spinach.
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Uric Acid Stones
Purine-rich foods restricted.
Purines are the end products of
nucleoprotein metabolism.
Found in meats, fish, poultry, organ meats,
anchovies, sardines, meat extracts, broths.
Usually associated with gout, GI diseases
that cause diarrhea, and malignant disease.
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Cystine Stones
Cystine is an amino acid.
Cystine stones may form when the cystine
concentration in the urine becomes
excessive because of a hereditary
metabolic disorder.
Increase fluids and recommend an
alkaline-ash diet.
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Struvite Stones
Composed of magnesium ammonium
phosphate.
Sometimes called infection stones because
they develop following urinary tract
infections caused by certain
microorganisms.
Low phosphorus diet is often prescribed.
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Considerations for the Health
Care Professional
Client with renal disease has a lifelong
challenge.
Develop a trusting relationship with the
client.
Help motivate clients to learn how to
manage their nutritional requirements and
help the dietitian assist them.
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Conclusion
Kidneys rid the body of wastes, maintain
fluid, electrolyte, and acid-base balance,
and secrete hormones.
Entire body is affected by kidney disease.
Diet therapy extremely complex.
Untreated severe kidney disease can result
in death unless client receives dialysis or
kidney transplant.
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