MNT for Renal MNT for Renal DisordersDisorders

ND 437/537ND 437/537

Chapter 39Chapter 39

Karen White, MS, RD, LDNKaren White, MS, RD, LDN

Renal OutlineRenal Outline Functions of the kidneysFunctions of the kidneys Normal urine outputNormal urine output Nephrotic syndromeNephrotic syndrome Nephritic SyndromeNephritic Syndrome Acute renal failureAcute renal failure ESRD & Characteristics of renal failureESRD & Characteristics of renal failure Dialysis & lab values for assessment Dialysis & lab values for assessment

with ESRDwith ESRD MNTMNT Kidney stonesKidney stones

Functions of the KidneysFunctions of the Kidneys Filtration of blood: remove fluid and Filtration of blood: remove fluid and

wastes (NHwastes (NH33, urea, Cr, P, Na, K, H, urea, Cr, P, Na, K, H++,, water)water) maintain blood pressure: secrete renin maintain blood pressure: secrete renin

((in response to in response to BV BV) to stimulate the ) to stimulate the angiotensin system (vasocontstriction), angiotensin system (vasocontstriction), aldosterone (Na reabsorption) aldosterone (Na reabsorption) BP BP

secrete erythropoietin - a hormone secrete erythropoietin - a hormone needed for rbc productionneeded for rbc production

Ca-P homeostasis by activating vitamin D Ca-P homeostasis by activating vitamin D & excreting Ca & P& excreting Ca & P

FiltrationFiltrationFiltration:Filtration:1.1. filtration (into tubules)filtration (into tubules)2.2. reabsorptionreabsorption3.3. secretionsecretion

– 125 ml ultrafiltrate made 125 ml ultrafiltrate made per minuteper minute

– 124 ml reabsorbed124 ml reabsorbed– 1 ml urine per minute x 1 ml urine per minute x

60 x 24 = 1500 ml urine/d60 x 24 = 1500 ml urine/d kidneys control the kidneys control the

amount of water, amount of water, electrolyes, acid, P, & electrolyes, acid, P, & Nitrogenous wastes Nitrogenous wastes excretedexcreted

our 3L of blood is our 3L of blood is filtered over & over filtered over & over 500x/d!500x/d!

Filtration, continuedFiltration, continued Each kidney has ~ 1 million nephrons, which Each kidney has ~ 1 million nephrons, which

consist of the glomerulus connected to tubulesconsist of the glomerulus connected to tubules Glomerulus = capillary mass surrounded by a Glomerulus = capillary mass surrounded by a

membrane, Bowman’s capsule.membrane, Bowman’s capsule. Glomerulus produces 180 L ultrafiltrate/d, Glomerulus produces 180 L ultrafiltrate/d,

which the remaining tubules modify through which the remaining tubules modify through reabsorption & secretion.reabsorption & secretion.

Ultrafiltrate Ultrafiltrate blood – blood cells & proteins blood – blood cells & proteins Filtration is passive & relies on perfusion Filtration is passive & relies on perfusion

pressurepressure Tubules reabsorb most of ultrafiltrate, leaving Tubules reabsorb most of ultrafiltrate, leaving

1.5L urine/d. Reabsorption is active.1.5L urine/d. Reabsorption is active.

Urine Production - Filtration, Urine Production - Filtration, cont.cont.

Normal glomerular filtration rate (GFR) Normal glomerular filtration rate (GFR) 125ml/min125ml/min

Urine can be very dilute (50 mOsm) or Urine can be very dilute (50 mOsm) or very concentrated (1200 mOsm) very concentrated (1200 mOsm) depending on the concentration of wastes depending on the concentration of wastes in the blood and the amount of water in in the blood and the amount of water in which to dilute the wastewhich to dilute the waste

Minimum urinary volume to excrete wastes Minimum urinary volume to excrete wastes of a fixed concentration (600 mOsm) is of a fixed concentration (600 mOsm) is 500 ml!500 ml!

Urine output of < 500ml/d = oliguriaUrine output of < 500ml/d = oliguria Anuria = no urine output (< 50ml/d)Anuria = no urine output (< 50ml/d)

Glomerular DiseasesGlomerular Diseases Nephritic Syndrome Nephritic Syndrome

aka glomerulonephritisaka glomerulonephritis Nephrotic syndromeNephrotic syndrome

Both of the these Both of the these conditions are conditions are characterized by an characterized by an impairment in the impairment in the integrity of the integrity of the glomerulus, which glomerulus, which allows inappropriate allows inappropriate components to pass into components to pass into the filtrate & thus the the filtrate & thus the urine. urine.

Renal failure, in Renal failure, in contrast, is a decrease contrast, is a decrease in the ability to filter in the ability to filter blood.blood.

Nephritic Syndrome Nephritic Syndrome (glomerulonephritis)(glomerulonephritis)

inflammation of capillary loops of glomerulus.inflammation of capillary loops of glomerulus. Characterized by:Characterized by:

– hematuria - loss of glomerular barrier to blood cells, hematuria - loss of glomerular barrier to blood cells, – HTN HTN – mild mild renal fxn renal fxn

Etiology: streptococcal infection is most common.Etiology: streptococcal infection is most common. usually completely resolve (quickly), but can usually completely resolve (quickly), but can

progress to nephrotic syndrome or even ESRD.progress to nephrotic syndrome or even ESRD. MNTMNT: Na restriction with HTN. Otherwise, : Na restriction with HTN. Otherwise,

maintain good nut'l status & hope it resolves.maintain good nut'l status & hope it resolves. NO need to restrict protein or NO need to restrict protein or

potassium (K).potassium (K).

Nephrotic SyndromeNephrotic Syndrome Loss of the glomerular Loss of the glomerular

barrier to protein. (Filter's barrier to protein. (Filter's holes became too large)holes became too large)

Characterized by Characterized by proteinuria, proteinuria, hypoalbuminemia, edema hypoalbuminemia, edema & hyperlipidemia. & hyperlipidemia.

Dx by proteinuriaDx by proteinuria Etiology: diabetes, lupus, Etiology: diabetes, lupus,

amyloidosis, & other amyloidosis, & other diseases of the kidneys.diseases of the kidneys.

Can be chronic, and Can be chronic, and occasionally can progress occasionally can progress to CRF.to CRF.

MNT:MNT: goal is to goal is to replenish albumin w/o replenish albumin w/o exacerbating exacerbating proteinuria. proteinuria.

0.8 gm/kg – ¾ HBV0.8 gm/kg – ¾ HBV calories (35cal/kg+)calories (35cal/kg+) Na mildly (2400 - 3000 Na mildly (2400 - 3000

mg/d) with edema mg/d) with edema normal fluid b/c blood normal fluid b/c blood

vol vol with with albumin albumin if chronic, if chronic, saturated saturated

fat.fat. can give albumin IV.can give albumin IV.

Acute Renal Failure (ARF)Acute Renal Failure (ARF) Sudden Sudden in GFR & thus in GFR & thus ability of kidneys ability of kidneys

to excrete wastes.to excrete wastes. Can occur with oliguria or a normal urine Can occur with oliguria or a normal urine

flow!flow! DurationDuration: few days – several weeks: few days – several weeks mortalitymortality: varies greatly depending on cause: : varies greatly depending on cause:

very low with drug toxicity, up to 70% with very low with drug toxicity, up to 70% with trauma or sepsis.trauma or sepsis.

causescauses: see Box 39-1 pg. 967 (severe : see Box 39-1 pg. 967 (severe dehydration, trauma, sepsis, toxicity from dehydration, trauma, sepsis, toxicity from drugs, glomerularnephritis, obstruction d/t drugs, glomerularnephritis, obstruction d/t prostate cancer or hypertrophy, etc.)prostate cancer or hypertrophy, etc.)

ARF – typical progressionARF – typical progression1.1. Anuria or oliguriaAnuria or oliguria

2.2. RecoveryRecovery1.1. Increase in urine output, but still not Increase in urine output, but still not

filtering wastesfiltering wastes

2.2. Gradual recovery in waste filtration & Gradual recovery in waste filtration & excretionexcretion

MNT for ARFMNT for ARF protein: protein:

– oliguric phase - oliguric phase - (0.5 - 0.8) (0.5 - 0.8)– diuretic phase or dialysis - (0.8 - 1.0)diuretic phase or dialysis - (0.8 - 1.0)

calories: 30-40 cal/kg of calories: 30-40 cal/kg of drydry weight weight ((fluid fluid retentionretention))

fluid, Na, K fluid, Na, K – oliguric phase oliguric phase

fluid: output + 500ml (monitor I/O!)fluid: output + 500ml (monitor I/O!) Na 500mg - 1g (20-40 mEq) --------Na 500mg - 1g (20-40 mEq) -------- K 1200 - 2g (30-50 mEq)K 1200 - 2g (30-50 mEq)

– diuretic phase - replace losses (monitor labs; diuretic phase - replace losses (monitor labs; gradually progress to normal diet)gradually progress to normal diet)

Patients often “fed” parenterally initially when Patients often “fed” parenterally initially when N/VN/V

mEq = mg atomic wt x valenceatomic wt of Na = 23atomic wt of K = 39

Progressive Nature of Renal Progressive Nature of Renal FailureFailure

Once 2/3 - ¾ of kidney function is lost, Once 2/3 - ¾ of kidney function is lost, further loss will ensue, and ESRD is further loss will ensue, and ESRD is unavoidable.unavoidable.

Sometimes progression to ESRD is rapidSometimes progression to ESRD is rapid Other times progression can take Other times progression can take

months – years, with persons in pre-end-months – years, with persons in pre-end-stage renal disease for a long time.stage renal disease for a long time.

90% of ESRD is caused by:90% of ESRD is caused by:1.1. DMDM2.2. GlomerulonephritisGlomerulonephritis3.3. HTNHTN

Characteristics of Chronic Renal Characteristics of Chronic Renal Failure (CRF)Failure (CRF)

fluid retention (edema)fluid retention (edema) Na, K (irregular Na, K (irregular

heartbeat)heartbeat) H - acidosisH - acidosis BPBP Hct (anemia)Hct (anemia) vit D conversion vit D conversion renal osteodystrophy: renal osteodystrophy:

Calcium pulled from bones Calcium pulled from bones (b/c (b/c Ca abs & to Ca abs & to P P balance with balance with P P excretion), excretion),

Ca & P precipitate and are Ca & P precipitate and are deposited on blood deposited on blood vessels!vessels!

BUN, Cr, NHBUN, Cr, NH33 - build up - build up of Nof N22 wastes = azotemia wastes = azotemia

uremiauremia::– Malaise, weak Malaise, weak – N/V N/V – muscle cramps, itchingmuscle cramps, itching– anorexia, dysguesiaanorexia, dysguesia– neurologic/cognitive neurologic/cognitive

impairment. impairment. – Happens when BUN > Happens when BUN >

100, Cr 10-20.100, Cr 10-20. Cr > 8 qualifies for Cr > 8 qualifies for

dialysis (6 if DM)dialysis (6 if DM) Correlates with GFR < Correlates with GFR <

10 ml/min.10 ml/min.

Medical Treatment for ESRDMedical Treatment for ESRD TransplantTransplant Dialysis: Dialysis: separating separating

substances in a solution by substances in a solution by selective diffusion using selective diffusion using semi-permeable membrane.semi-permeable membrane.– HemodialysisHemodialysis– Peritoneal dialysisPeritoneal dialysis

CAPDCAPD CCPD – multiple CCPD – multiple

exchnages at night by a exchnages at night by a machine; one exchange machine; one exchange during the dayduring the day

HemodialysisHemodialysis– blood passes through semi-blood passes through semi-

permeable membrane of permeable membrane of artificial kidney & waste artificial kidney & waste produces are removed by produces are removed by diffusion. 3-5 hours 3x/wkdiffusion. 3-5 hours 3x/wk

Peritoneal dialysisPeritoneal dialysis– diffusion carries wastes from diffusion carries wastes from

the blood through the semi-the blood through the semi-permeable peritoneal permeable peritoneal membrane and into membrane and into dialysate solution that is dialysate solution that is infused into the peritoneal infused into the peritoneal cavity. The dialysate = cavity. The dialysate = sugar water. CAPD - sugar water. CAPD - exchange solution 4-5x/d exchange solution 4-5x/d everyday. More efficient but everyday. More efficient but less commonless common

Hemodialysis vs. Peritoneal Hemodialysis vs. Peritoneal dialysisdialysis

MNT for Pre-ESRD, MNT for Pre-ESRD, Hemodialysis, Peritoneal DialysisHemodialysis, Peritoneal Dialysis

MNT for Pre-ESRD, MNT for Pre-ESRD, Hemodialysis, Peritoneal DialysisHemodialysis, Peritoneal Dialysis

Pre-ESRDPre-ESRD HemodialysisHemodialysis CAPD or CCPDCAPD or CCPDProtein (g/kg)Protein (g/kg) 0.6-0.80.6-0.8 1.0-1.21.0-1.2 1.2-1.51.2-1.5

EnergyEnergy 35-4035-40 30-3530-35 25+25+(kcal/kg IBW)(kcal/kg IBW)PhosphorusPhosphorus 8-128-12 <<1717 <<1717(mg/kg IBW)(mg/kg IBW)SodiumSodium 1000-30001000-3000 2000-30002000-3000 2000-40002000-4000(mg/d)(mg/d)PotassiumPotassium UnrestrictedUnrestricted ~ 40~ 40 UnrestrictedUnrestricted(mg/kg IBW)(mg/kg IBW)FluidFluid UnrestrictedUnrestricted 500-750 +500-750 + 2000 +2000 +(ml/d)(ml/d) urine outputurine output

(1000 if anuric)(1000 if anuric)

CalciumCalcium 1200-16001200-1600 based on serumbased on serum based on serumbased on serum(mg/d)(mg/d) levellevel levellevel

In GeneralIn General most strictmost strict most liberalmost liberal

Pre-ESRDPre-ESRD HemodialysisHemodialysis CAPD or CCPDCAPD or CCPDProtein (g/kg)Protein (g/kg) 0.6-0.80.6-0.8 1.0-1.21.0-1.2 1.2-1.51.2-1.5

EnergyEnergy 35-4035-40 30-3530-35 25+25+(kcal/kg IBW)(kcal/kg IBW)PhosphorusPhosphorus 8-128-12 <<1717 <<1717(mg/kg IBW)(mg/kg IBW)SodiumSodium 1000-30001000-3000 2000-30002000-3000 2000-40002000-4000(mg/d)(mg/d)PotassiumPotassium UnrestrictedUnrestricted ~ 40~ 40 UnrestrictedUnrestricted(mg/kg IBW)(mg/kg IBW)FluidFluid UnrestrictedUnrestricted 500-750 +500-750 + 2000 +2000 +(ml/d)(ml/d) urine outputurine output

(1000 if anuric)(1000 if anuric)

CalciumCalcium 1200-16001200-1600 based on serumbased on serum based on serumbased on serum(mg/d)(mg/d) levellevel levellevel

In GeneralIn General most strictmost strict most liberalmost liberal

Monitor Patient StatusMonitor Patient Status

1.1. BP >140/90BP >140/90

2.2. EdemaEdema

3.3. Weight changesWeight changes

4.4. Urine outputUrine output

5.5. Urine analysis:Urine analysis:—AlbuminAlbumin—ProteinProtein

Monitor Patient StatusMonitor Patient Status—cont’d—cont’d

Monitor Patient StatusMonitor Patient Status—cont’d—cont’d

6. Kidney function6. Kidney function– creatinine clearancecreatinine clearance– Glomerular filtration rate (GFR)Glomerular filtration rate (GFR)

7. Blood values7. Blood values– BUN 10 to 20 mg/dl (<100 mg/dl)BUN 10 to 20 mg/dl (<100 mg/dl)– Creatinine 0.7 to 1.5 mg/dl (10-15 mg/dl)Creatinine 0.7 to 1.5 mg/dl (10-15 mg/dl)– Potassium 3.5 to 5.5 mEq/LPotassium 3.5 to 5.5 mEq/L– Phosphorus 3.0 to 4.5 mg/dlPhosphorus 3.0 to 4.5 mg/dl– Albumin 3.5-5.5 g/dlAlbumin 3.5-5.5 g/dl– Calcium 9-11 mg/dlCalcium 9-11 mg/dl

– See table 39-5 p 977-979 for more info on lab See table 39-5 p 977-979 for more info on lab valuesvalues

6. Kidney function6. Kidney function– creatinine clearancecreatinine clearance– Glomerular filtration rate (GFR)Glomerular filtration rate (GFR)

7. Blood values7. Blood values– BUN 10 to 20 mg/dl (<100 mg/dl)BUN 10 to 20 mg/dl (<100 mg/dl)– Creatinine 0.7 to 1.5 mg/dl (10-15 mg/dl)Creatinine 0.7 to 1.5 mg/dl (10-15 mg/dl)– Potassium 3.5 to 5.5 mEq/LPotassium 3.5 to 5.5 mEq/L– Phosphorus 3.0 to 4.5 mg/dlPhosphorus 3.0 to 4.5 mg/dl– Albumin 3.5-5.5 g/dlAlbumin 3.5-5.5 g/dl– Calcium 9-11 mg/dlCalcium 9-11 mg/dl

– See table 39-5 p 977-979 for more info on lab See table 39-5 p 977-979 for more info on lab valuesvalues

Kidney TransplantKidney TransplantKidney TransplantKidney Transplant1.1. Types: related donor or cadaverTypes: related donor or cadaver2.2. Posttransplant management:Posttransplant management:

CorticosteroidsCorticosteroidsCyclosporineCyclosporine

3.3. Diet while on high-dose steroids:Diet while on high-dose steroids:1.3 to 2 g/kg BW protein1.3 to 2 g/kg BW protein30 to 35 kcal/kg BW energy30 to 35 kcal/kg BW energy80 to 100 mEq Na80 to 100 mEq Na

4.4. Diet after steroids:Diet after steroids:1 g/kg BW protein1 g/kg BW proteinKcal to achieve IBWKcal to achieve IBWIndividualize Na levelIndividualize Na level

1.1. Types: related donor or cadaverTypes: related donor or cadaver2.2. Posttransplant management:Posttransplant management:

CorticosteroidsCorticosteroidsCyclosporineCyclosporine

3.3. Diet while on high-dose steroids:Diet while on high-dose steroids:1.3 to 2 g/kg BW protein1.3 to 2 g/kg BW protein30 to 35 kcal/kg BW energy30 to 35 kcal/kg BW energy80 to 100 mEq Na80 to 100 mEq Na

4.4. Diet after steroids:Diet after steroids:1 g/kg BW protein1 g/kg BW proteinKcal to achieve IBWKcal to achieve IBWIndividualize Na levelIndividualize Na level

Kidney Stones - Kidney Stones - NephrolithiasisNephrolithiasis

Kidney Stones - Kidney Stones - NephrolithiasisNephrolithiasis

1.1. Ca salts (Ca oxalate or Ca phosphate)Ca salts (Ca oxalate or Ca phosphate)2.2. Uric acidUric acid3.3. CystineCystine

Ca salts —Rx: high fluid; evaluate calcium Ca salts —Rx: high fluid; evaluate calcium from diet; may need more!from diet; may need more!

Calcium intake & kidney stones inversely Calcium intake & kidney stones inversely related!related!

low-oxalate diet may be needed low-oxalate diet may be needed (avoid (avoid rhubarb, spinach, strawberries, chocolate, rhubarb, spinach, strawberries, chocolate, wheat bran, nuts, beets & tea)wheat bran, nuts, beets & tea) Apndx 45 Apndx 45

acid-ash diet is sometimes useful but not acid-ash diet is sometimes useful but not proven totally effectiveproven totally effective

1.1. Ca salts (Ca oxalate or Ca phosphate)Ca salts (Ca oxalate or Ca phosphate)2.2. Uric acidUric acid3.3. CystineCystine

Ca salts —Rx: high fluid; evaluate calcium Ca salts —Rx: high fluid; evaluate calcium from diet; may need more!from diet; may need more!

Calcium intake & kidney stones inversely Calcium intake & kidney stones inversely related!related!

low-oxalate diet may be needed low-oxalate diet may be needed (avoid (avoid rhubarb, spinach, strawberries, chocolate, rhubarb, spinach, strawberries, chocolate, wheat bran, nuts, beets & tea)wheat bran, nuts, beets & tea) Apndx 45 Apndx 45

acid-ash diet is sometimes useful but not acid-ash diet is sometimes useful but not proven totally effectiveproven totally effective

Kidney Stones—cont’dKidney Stones—cont’dKidney Stones—cont’dKidney Stones—cont’d

4.4. Uric acid stonesUric acid stones

Alter pH of urine to more alkalineAlter pH of urine to more alkaline

Use high-alkaline-ash dietUse high-alkaline-ash diet

5.5. Cystine stones (rare)Cystine stones (rare)

4.4. Uric acid stonesUric acid stones

Alter pH of urine to more alkalineAlter pH of urine to more alkaline

Use high-alkaline-ash dietUse high-alkaline-ash diet

5.5. Cystine stones (rare)Cystine stones (rare)

Acid-Ash DietAcid-Ash Diet Increases acidity of urine (contains Increases acidity of urine (contains

chloride, phosphorus, and sulfur)chloride, phosphorus, and sulfur) Meats, cheese, grains emphasizedMeats, cheese, grains emphasized Fruits and vegetables limited Fruits and vegetables limited

(exceptions are corn, lentils, (exceptions are corn, lentils, cranberries, plums, prunes)cranberries, plums, prunes)

Alkaline-Ash DietAlkaline-Ash Diet Increases alkalinity of urine (contains Increases alkalinity of urine (contains

sodium, potassium, calcium, and sodium, potassium, calcium, and magnesium)magnesium)

Fruits and vegetables emphasized Fruits and vegetables emphasized (exceptions are corn, lentils, (exceptions are corn, lentils, cranberries, plums, prunes)cranberries, plums, prunes)

Meats and grains limitedMeats and grains limited

Pyelonephritis (UTI)Pyelonephritis (UTI) High fluid intakeHigh fluid intake Cranberry juice can decrease bacteriaCranberry juice can decrease bacteria

Foods high in potassiumFoods high in potassium Fruits and vegetablesFruits and vegetables

– potatoes, legumes, greens, oranges, potatoes, legumes, greens, oranges, banana, watermelon, dry fruits, cantaloupe, banana, watermelon, dry fruits, cantaloupe, avocadoavocado