MNT for Renal Disorders

1
MNT for Renal Disorders

• ND 437/537
• Chapter 39
• Karen White, MS, RD, LDN

2
Renal Outline

• Functions of the kidneys
• Normal urine output
• Nephrotic syndrome
• Nephritic Syndrome
• Acute renal failure
• ESRD Characteristics of renal failure
• Dialysis lab values for assessment with ESRD
• MNT
• Kidney stones

3
Functions of the Kidneys

• Filtration of blood remove fluid and wastes
  (NH3, urea, Cr, P, Na, K, H, water)
• maintain blood pressure secrete renin (in
  response to ? BV) to stimulate the angiotensin
  system (vasocontstriction), ? aldosterone (Na
  reabsorption) ? ? BP
• secrete erythropoietin - a hormone needed for rbc
  production
• Ca-P homeostasis by activating vitamin D
  excreting Ca P

4
Filtration

• Filtration
• filtration (into tubules)
• reabsorption
• secretion
• 125 ml ultrafiltrate made per minute
• 124 ml reabsorbed
• 1 ml urine per minute x 60 x 24 1500 ml urine/d
• kidneys control the amount of water, electrolyes,
  acid, P, Nitrogenous wastes excreted
• our 3L of blood is filtered over over 500x/d!

5
Filtration, continued

• Each kidney has 1 million nephrons, which
  consist of the glomerulus connected to tubules
• Glomerulus capillary mass surrounded by a
  membrane, Bowmans capsule.
• Glomerulus produces 180 L ultrafiltrate/d, which
  the remaining tubules modify through reabsorption
  secretion.
• Ultrafiltrate ? blood blood cells proteins
• Filtration is passive relies on perfusion
  pressure
• Tubules reabsorb most of ultrafiltrate, leaving
  1.5L urine/d. Reabsorption is active.

6
Urine Production - Filtration, cont.

• Normal glomerular filtration rate (GFR) 125ml/min
• Urine can be very dilute (50 mOsm) or very
  concentrated (1200 mOsm) depending on the
  concentration of wastes in the blood and the
  amount of water in which to dilute the waste
• Minimum urinary volume to excrete wastes of a
  fixed concentration (600 mOsm) is 500 ml!
• Urine output of lt 500ml/d oliguria
• Anuria no urine output (lt 50ml/d)

7
Glomerular Diseases

• Nephritic Syndrome aka glomerulonephritis
• Nephrotic syndrome

• Both of the these conditions are characterized by
  an impairment in the integrity of the glomerulus,
  which allows inappropriate components to pass
  into the filtrate thus the urine.
• Renal failure, in contrast, is a decrease in the
  ability to filter blood.

8
Nephritic Syndrome (glomerulonephritis)

• inflammation of capillary loops of glomerulus.
• Characterized by
• hematuria - loss of glomerular barrier to blood
  cells,
• HTN
• mild ? renal fxn
• Etiology streptococcal infection is most
  common.
• usually completely resolve (quickly), but can
  progress to nephrotic syndrome or even ESRD.
• MNT Na restriction with HTN. Otherwise,
  maintain good nut'l status hope it resolves.
  NO need to restrict protein or potassium (K).

9
Nephrotic Syndrome

• Loss of the glomerular barrier to protein.
  (Filter's holes became too large)
• Characterized by proteinuria, hypoalbuminemia,
  edema hyperlipidemia.
• Dx by proteinuria
• Etiology diabetes, lupus, amyloidosis, other
  diseases of the kidneys.
• Can be chronic, and occasionally can progress to
  CRF.

• MNT goal is to replenish albumin w/o
  exacerbating proteinuria.
• 0.8 gm/kg ¾ HBV
• ? calories (35cal/kg)
• ? Na mildly (2400 - 3000 mg/d) with edema
• normal fluid b/c blood vol ? with ? albumin
• if chronic, ? saturated fat.
• can give albumin IV.

10
Acute Renal Failure (ARF)

• Sudden ?? in GFR thus ?? ability of kidneys to
  excrete wastes.
• Can occur with oliguria or a normal urine flow!
• Duration few days several weeks
• mortality varies greatly depending on cause
  very low with drug toxicity, up to 70 with
  trauma or sepsis.
• causes see Box 39-1 pg. 967 (severe
  dehydration, trauma, sepsis, toxicity from drugs,
  glomerularnephritis, obstruction d/t prostate
  cancer or hypertrophy, etc.)

11
ARF typical progression

• Anuria or oliguria
• Recovery
• Increase in urine output, but still not filtering
  wastes
• Gradual recovery in waste filtration excretion

12
MNT for ARF

• protein
• oliguric phase - ? (0.5 - 0.8)
• diuretic phase or dialysis - (0.8 - 1.0)
• calories 30-40 cal/kg of dry weight (fluid
  retention)
• fluid, Na, K
• oliguric phase ?
• fluid output 500ml (monitor I/O!)
• Na 500mg - 1g (20-40 mEq) --------?
• K 1200 - 2g (30-50 mEq)
• diuretic phase - replace losses (monitor labs
  gradually progress to normal diet)
• Patients often fed parenterally initially when
  N/V

mEq mg ? atomic wt x valence atomic wt of Na
23 atomic wt of K 39
13
Progressive Nature of Renal Failure

• Once 2/3 - ¾ of kidney function is lost, further
  loss will ensue, and ESRD is unavoidable.
• Sometimes progression to ESRD is rapid
• Other times progression can take months years,
  with persons in pre-end-stage renal disease for a
  long time.
• 90 of ESRD is caused by
• DM
• Glomerulonephritis
• HTN

14
Characteristics of Chronic Renal Failure (CRF)

• fluid retention (edema)
• ? Na, K (irregular heartbeat)
• ? H - acidosis
• ? BP
• ? Hct (anemia)
• ? vit D conversion
• renal osteodystrophy Calcium pulled from bones
  (b/c ? Ca abs to? P balance with ? P
  excretion),
• Ca P precipitate and are deposited on blood
  vessels!
• ? BUN, Cr, NH3 - build up of N2 wastes
  azotemia ?

• uremia
• Malaise, weak
• N/V
• muscle cramps, itching
• anorexia, dysguesia
• neurologic/cognitive impairment.
• Happens when BUN gt 100, Cr 10-20.
• Cr gt 8 qualifies for dialysis (6 if DM)
• Correlates with GFR lt 10 ml/min.

15
Medical Treatment for ESRD

• Transplant
• Dialysis separating substances in a solution by
  selective diffusion using semi-permeable
  membrane.
• Hemodialysis
• Peritoneal dialysis
• CAPD
• CCPD multiple exchnages at night by a machine
  one exchange during the day

• Hemodialysis
• blood passes through semi-permeable membrane of
  artificial kidney waste produces are removed by
  diffusion. 3-5 hours 3x/wk
• Peritoneal dialysis
• diffusion carries wastes from the blood through
  the semi-permeable peritoneal membrane and into
  dialysate solution that is infused into the
  peritoneal cavity. The dialysate sugar water.
  CAPD - exchange solution 4-5x/d everyday. More
  efficient but less common

16
Hemodialysis vs. Peritoneal dialysis
17
MNT for Pre-ESRD, Hemodialysis, Peritoneal
Dialysis

• Pre-ESRD Hemodialysis CAPD or CCPD
• Protein (g/kg) 0.6-0.8 1.0-1.2 1.2-1.5
• Energy 35-40 30-35 25
• (kcal/kg IBW)
• Phosphorus 8-12 lt17 lt17
• (mg/kg IBW)
• Sodium 1000-3000 2000-3000 2000-4000
• (mg/d)
• Potassium Unrestricted 40 Unrestricted
• (mg/kg IBW)
• Fluid Unrestricted 500-750 2000
• (ml/d) urine output
• (1000 if anuric)
• Calcium 1200-1600 based on serum based on serum
• (mg/d) level level
• In General most strict most liberal

18
Monitor Patient Status

• 1. BP gt140/90
• 2. Edema
• 3. Weight changes
• 4. Urine output
• 5. Urine analysis
• Albumin
• Protein

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Monitor Patient Statuscontd

• 6. Kidney function
• creatinine clearance
• Glomerular filtration rate (GFR)
• 7. Blood values
• BUN 10 to 20 mg/dl (lt100 mg/dl)
• Creatinine 0.7 to 1.5 mg/dl (10-15 mg/dl)
• Potassium 3.5 to 5.5 mEq/L
• Phosphorus 3.0 to 4.5 mg/dl
• Albumin 3.5-5.5 g/dl
• Calcium 9-11 mg/dl
• See table 39-5 p 977-979 for more info on lab
  values

20
Kidney Transplant

• 1. Types related donor or cadaver
• 2. Posttransplant management
• Corticosteroids
• Cyclosporine
• 3. Diet while on high-dose steroids
• 1.3 to 2 g/kg BW protein
• 30 to 35 kcal/kg BW energy
• 80 to 100 mEq Na
• 4. Diet after steroids
• 1 g/kg BW protein
• Kcal to achieve IBW
• Individualize Na level

21
Kidney Stones - Nephrolithiasis

• Ca salts (Ca oxalate or Ca phosphate)
• Uric acid
• Cystine
• Ca salts Rx high fluid evaluate calcium from
  diet may need more!
• Calcium intake kidney stones inversely related!
• low-oxalate diet may be needed (avoid rhubarb,
  spinach, strawberries, chocolate, wheat bran,
  nuts, beets tea) Apndx 45
• acid-ash diet is sometimes useful but not proven
  totally effective

22
Kidney Stonescontd

• 4. Uric acid stones
• Alter pH of urine to more alkaline
• Use high-alkaline-ash diet
• 5. Cystine stones (rare)

23
Acid-Ash Diet

• Increases acidity of urine (contains chloride,
  phosphorus, and sulfur)
• Meats, cheese, grains emphasized
• Fruits and vegetables limited (exceptions are
  corn, lentils, cranberries, plums, prunes)

24
Alkaline-Ash Diet

• Increases alkalinity of urine (contains sodium,
  potassium, calcium, and magnesium)
• Fruits and vegetables emphasized (exceptions are
  corn, lentils, cranberries, plums, prunes)
• Meats and grains limited

25
Pyelonephritis (UTI)

• High fluid intake
• Cranberry juice can decrease bacteria

26
Foods high in potassium

• Fruits and vegetables
• potatoes, legumes, greens, oranges, banana,
  watermelon, dry fruits, cantaloupe, avocado