Diet and Renal Disease

ObjectivesDescribe work of kidneys in general termsDiscuss common causes of renal diseaseExplain why the following are sometimes

restricted for renal clients:ProteinSodium and waterPotassium and phosphorus

KidneysExcrete wastesMaintain volume and composition of body

fluidsSynthesize and secrete certain hormones as

neededFilter blood and remove or recycle waste

products

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KidneysMaintain fluid, acid-base, and electrolyte

balanceNephrons

Working partsGlomerulus

Filtering unit

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KidneysUreters transport liquid waste materials from

kidneys to bladderWaste materials:

End products of protein metabolism, excess water and nutrients, dead renal cells, and toxic substances

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KidneysOliguria:

Urinary output less than 500 mL per dayKidneys unable to adequately eliminate waste

products Can result in renal failure

Renal DiseasesPossible causes:

Infection, degenerative changes, diabetes mellitus, cardiovascular disorders, cysts, renal stones, or trauma

Can result in renal failure

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Renal DiseasesAcute renal failure

Occurs suddenlyMay last a few days to a few weeksCan be caused by another medical problem

E.g., serious burn, crushing injury, cardiac arrest

Chronic kidney diseaseDevelops slowly with number of functioning

nephrons diminishing

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Renal DiseasesChronic kidney disease

Uremia Condition in which protein wastes not excreted

Instead, circulated in blood Symptoms:

Nausea, headache, coma, and convulsions

Severe renal failure can result in death unless dialysis used

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Renal DiseasesNephritis

Inflammatory disease of kidneysCaused by infection, degenerative processes,

or vascular diseaseGlomerulonephritis

Inflammation affecting capillaries in glomeruli

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Renal DiseasesNephrosclerosis

Hardening of renal arteriesCaused by arteriosclerosis and hypertensionUsually occurs in older clients

Sometimes develops in younger clients with diabetes

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Renal DiseasesPolycystic kidney disease

Relatively rare hereditary diseaseCysts form

Press on kidneysKidneys enlarge

Lose functionRenal failure may develop

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Renal DiseasesNephrolithiasis

Stones develop in kidneys Classified according to composition

Associated with metabolic disturbances and immobilization of client

Dietary Treatment of Renal DiseaseGoals:

Slow buildup of waste in bloodReduce work of kidneyMaintain fluid, acid-base, and electrolyte

balanceSufficient calories and protein necessary to

prevent malnutrition

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Dietary Treatment of Renal DiseaseEnergy requirements should be fulfilled by

carbohydrates and fat to spare proteinMetabolized protein increases amount of

nitrogen waste kidneys must handleProtein allowance based on glomerular

filtration rate and weight

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Dietary Treatment of Renal DiseaseSodium and fluids may be limited to prevent

edema, hypertension, and CHFCalcium and vitamin D supplements may be

prescribedPhosphorus may be limited if retained

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Dietary Treatment of Renal DiseaseHyperkalemia may occur in end-stage renal

disease (ESRD)Potassium may be restricted

Renal clients often have increased need for vitamin B, vitamin C, and vitamin DSupplements often given

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Dietary Treatment of Renal DiseaseIron commonly prescribed to treat or prevent

anemia

DialysisHemodialysis

Requires permanent access to bloodstream through fistula

Treat three times per week for three to five hours each time

Peritoneal dialysisUses peritoneal cavity for accessLess efficient than hemodialysisUsually treat three times per week for

approximately 10 to 12 hours per day(continues)

DialysisContinuous ambulatory peritoneal dialysis

(CAPD):Exchanges fluid four to five times dailyComplications:

Peritonitis, hypotension, and weight gain

Diet during DialysisMust carefully control protein intake

75 percent should be high biological valuePotassium usually restrictedTypical renal diet could be written as “80-3-

3”80 g protein, 3 g sodium, and 3 g potassium

daily

Diet after Kidney TransplantNeed for extra protein or for restriction of

proteinCarbohydrates and sodium may be restrictedAdditional calcium and phosphorus may be

necessary if substantial bone loss before transplant

Stop and ShareConsider the following scenario:

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 ShareRegulate intake by making careful choicesMilk normally restricted to ½ cup per day

High in potassiumSuggest use of potassium content charts to

select low-potassium foods

Dietary Treatment of Renal StonesVaries based on type of stoneDrink large amount of fluidEat well-balanced dietOnce stones analyzed, specific diet

modifications may be indicated

Calcium Oxalate StonesRisk factors:

Excessive animal protein intakeOxalate

Reduce level of oxalateFound in beets, wheat bran, chocolate, tea,

rhubarb, strawberries, and spinach

Uric Acid StonesRestrict purine-rich foods

Found in meats, fish, poultry, organ meats, anchovies, sardines, meat extracts, and broths

Usually associated with gout, gastrointestinal diseases that cause diarrhea, and malignant disease

Cystine StonesCaused by excessive cystine concentration in

urineDue to hereditary metabolic disorder

Increased fluids and alkaline-ash diet recommended

Struvite StonesComposed of magnesium ammonium

phosphateDevelop following urinary tract infections

caused by certain microorganismsLow-phosphorus diet often prescribed

Considerations for the Health Care Professional

Clients with renal disease have lifelong challenge

Develop trusting relationship with clientHelp motivate clients to learn how to manage

nutritional requirementsHelp dietitian assist clients

ConclusionKidneys eliminate body wastes, secrete

hormones, and maintain fluid, acid-base, and electrolyte balance

Entire body affected by kidney disease

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ConclusionDiet therapy may be extremely complexUntreated, severe kidney disease can result

in deathUnless client receives dialysis or kidney

transplant