Chelsea Magro
NUTR 409
Spring 2015
Case Study #18 Chronic Kidney Disease treated with dialysis
1. Describe the physiological functions of the kidneys
The kidney is an organ in the body that maintains fluid, electrolytes and solute
balance. Nitrogenous waste and end products of protein metabolism including
ammonia, urea, uric acid, and creatinine are excreted along with electrolytes such as
potassium, phosphorus and sodium. The kidney acts like a filter and has many
nephrons that house a glomerulus that produces an ultra-filtrate substance. Renal
tubules reabsorb part of ultra-filtrate and produce urine, which is funneled and
travels into the renal pelvis and ureters. The kidney is also responsible for the
regulation of water homeostasis in the body. When there is a high concentration of
solutes and high osmolality, the kidney is stimulated to reabsorb water to help
dilute the solutes and lower the osmolality. The Kidney regulates blood pressure by
secreting rennin when blood pressure is low. Rennin stimulates the formation of
angiotenison, which is a vasoconstrictor that brings blood pressure back up.
Angiotension also stimulates aldosterone to reabsorb sodium and fluid and increase
blood pressure. The kidney produces erythropoietin, which is a hormone that
stimulates RBC synthesis. The kidney also helps convert Vitamin D to its active form.
2. What diseases/ conditions can lead to chronic kidney disease (CKD?)
Explain the relationship between diabetes and CKD
CKD is the progressive loss of renal function and the kidneys get worse and worse.
With CKD, a patient cannot regain kidney function however the disease is
manageable and progression to higher stages may be delayed. Glomerluar filtration
rate decreases with age, so as you increase in age you are at a higher risk for CKD.
Autoimmune diseases, systemic infections, urinary tract infections, kidney stones,
cancer, family history of CKD, exposure to certain drugs can all lead to CKD.
Hypertension is a risk factor for CKD as well as an African American ethnicity.
African Americans also tend to have a high risk for hypertension. American Indians
are at high risk for CKD, who also are at a high risk for diabetes. Diabetes accounts
for half of all CKD patients and is very common that patients with CKD also have
diabetes. The relationship between diabetes and CKD has to do with glucose.
Diabetic patients with elevated glucose are at risk for organ damage, including the
kidneys. If glucose levels are kept within a normal and healthy range, the chance of
kidney damage and disease is decreased. Diabetic Nephropathy is known as damage
to the blood vessels of the kidneys and the glomerulus within the nephrons of the
kidneys.
3. Outline the stages of CKD, including the distinguishing signs and symptoms
From stage 1 to 5, the kidneys are filtering less and less and severity of kidney
damage is increasing. GFR (how the blood is filtered and cleaned) decreases with
higher stages of CKD. When someone is diagnosed with CKD the stage determines
the MNT. Stages 1,2,3 have different MNT recommendations then stages 4 and 5.
Stages 1,2,3 of CKD are characterized by proteinuria (increased urine albumin) and
Azotemia(increased BUN and Cr in blood). Albumin and PAB will be low, sodium
may be normal or low due to fluid overload, and potassium and phosphorus will be
high. Edema, swelling, fluid in lungs is common from fluid overload. Changes in
color and appearance of urine, blood in the urine, making more or less urine then
normal, Nausea, vomiting, loss of appetite, difficulty swallowing, build up of waste in
the body and itchiness are the most common signs of these stages. Stages 4 and 5
are where the patient now needs dialysis and experience the most severe symptoms
such as ammonia breath, metallic taste, not wanting to eat meat or strong flavors
and itchiness. Anemia of chronic disease is also common with CKD and patients will
have low Hgb and Hct because EOP is affected. Stage 5 is characterized by uremia (a
worse form of azotemia) with out of control levels of BUN > 200 mg/dL and
creatinine at 10 10 12 mg/dL
Stage
1
2
3
4
5
Category
Kidney damage but normal or increased GFR of > 90mL/min. Normal to
increased kidney function. Usually no signs are present
Kidney damage with a mild decrease in GFR of 60-89 mL/min. Mild
decrease in kidney function.
Kidney damage with a moderate decrease in GFR of 30-59 mL/min.
Moderate decreases in kidney function.
Kidney damage with a severe decrease in GFR of 15-29mL. Severe
decrease in kidney function. Here is where characteristic symptoms of
CKD start to show such as taste changes, ammonia breath, difficulty
swallowing and numbness in extremities.
Kidney failure defined as end-stage renal disease with a GFR of
<15mL/min. Toxins build up and cause an ill feeling and treatment is
necessary. Symptoms are the most severe including swelling, muscle
cramps, fatigue, anorexia, tingling in hands/feet and changes in skin
color and pigmentation
5. What are the treatment options for stage 5 CKD? Explain the differences
between hemodialysis and peritoneal dialysis
Treatment options for end stage renal disease is intermittent dialysis or a kidney
transplant with a replacement kidney. Renal transplantation is the most preferred
method and involves surgical transplantation of a donor kidney from a living related
donor, living non-related donor or cadaver. A dialysis machine acts like an artificial
kidney, accesses the patient’s blood supply, removes it from the body and then
returns it to the body. This process filters the nitrogenous waste and protein is lost
so patients generally need more. With dialysis, you don’t loss too much fluid and
phosphorus and potassium is not removed so intake should be restricted.
Hemodialysis: is the most common form of dialysis. With this, the patient still has
the option of doing different regimens. For example, they can go to the clinic 3 days
a week for a few hours, they can do it at home for 2-3 hours or they can do it
overnight which allows more flexibility for their daytime schedule. There are
different access sights for hemodialysis and the most common are an arteriovenous
(AV) fistula or a synthetic graft.
Peritoneal dialysis: is where a catheter is surgically implanted in the abdomen and
into the peritoneal cavity. Dialysate containing a high dextrose concentration is
instilled in the peritoneum, the abdominal lining in the lower abdomen. This is
where diffusion carries waste products from the blood through the peritoneal
membrane and into the dialysate; water moves by osmosis. This fluid is then
withdrawn and discarded, and a new solution is added. Peritoneal dialysis may
either be continuous ambulatory peritoneal dialysis (CAPD), which is performed
manually by patient 24 hours a day or run 4 to 5 times a day, continuous cyclicautomatic machine (CCPD) which runs mostly overnight with one daytime cycle or
nocturnal intermittent (NIPD) which runs mostly overnight. The advantages of
peritoneal dialysis include avoidance of large fluctuations in blood chemistry, and
longer residual renal function. Even though hemodialysis is more common, a patient
can have a more normal lifestyle with peritoneal dialysis and the diet is not as
restricted. With peritoneal dialysis, there is more risk for inflammation, infection,
peritonitis, hypotension, and weight gain because of high blood sugar and dextrose
in the dialysate providing extra calories.
6. Explain the reasons for the following components of Mrs. Joaguin’s medical
nutrition therapy.
Nutrition Therapy
Rationale
35 kcal/kg
Higher energy needs to spare protein. If the patient
doesn’t get enough calories, they will use up protein
stores for energy. Want to give enough kcals so
patient is not malnourished but do not want to
exceed needs and give too much.
1.2 g protein/kg
More protein for dialysis patients to replace protein
losses during dialysis and prevent protein energy
malnutrition.
2gK
Potassium is not removed in patients with CKD so it
must be restricted
1 g phosphorus
With CKD, the kidneys do not remove excess
phosphorus. Intake must be restricted to avoid
hyperphosphatemia, which can lead to heart and
bone problems, hypocalcaemia, and calcification in
the body.
2 g Na
Restrict salt to prevent fluid overload. Salt also
makes people thirsty and will make fluid restriction
more difficult. Sodium restriction also helps to
control high blood pressure.
1000 mL fluid + urine
output
Edema and fluid overload is common in CKD patients
so we want to give them enough to replace what they
are getting rid of (output) and prevent dehydration,
but not give too much fluid. A lower blood volume
will also help lower blood pressure.
7. Calculate and interpret Mrs. Joaquin’s BMI. How does edema affect your
interpretation?
BMI= 170/3600 X 704.5 = 33.26 kg/m2
A BMI of 33 indicates Mrs. Joaquin is obese. However, since she is experiencing
edema, her weight may be inflated and she may have a BMI that is higher then her
normal value.
8. What is edema-free weight? Calculate Mrs. Joaquin’s edema-free weight
Edema-free weight is the patient’s dry weight, without any extra fluid buildup and
overload between dialysis treatments. This weight also reflects the patients
“normal” weight or usual body weight with normal kidney functions. This is the
lowest weight a patient can safely reach after dialysis without too much fluid being
removed. Mrs. Joaquin’s edema-free weight is 140 lbs, which reflects her weight
with no edema, no swelling and weight after treatment.
aBWef= BWef + [ (SBW-BWef) x 0.25 ]
Bwef= actual edema free body weight, SBW= standard body weight
aBWef = 165 + [ (65-165) X 0.25]
= 165 + [(-100) x 0.25]
= 165 + (-25)
= 140 lbs
12. What are the considerations for differences in protein requirements
among predialysis, hemodialysis, and peritoneal dialysis patients?
Patients with CKD on dialysis have more protein losses and therefore have higher
protein needs. Predialysis patient protein needs depends on GFR. A GFR >55
indicate they still have decent kidney function and require ~. 8 g/kg/d. A GFR <55
indicates they need ~ .6 g/kg/d. Hemodialysis patients need a higher amount of
protein of 1.2 g/kg/d due to losses during dialysis. Peritoneal dialysis patients need
an even higher amount of protein up to 1.5 g/kg/d. The more frequent the dialysis,
the more protein the patient needs because protein is lost in the dialysate. Protein
for CKD patients should contain a high biological value (high quality) such as
complete proteins. Complete proteins include animal proteins (poultry, fish, eggs,
may have aversion to meat flavor), soy protein, quinoa, and rice/beans.
13. Mrs. Joaquin has a PO4 restriction. Why? What foods have the highest level
of phosphorus?
Mrs. Joaquin has a phosphorus restriction because patients with CKD are not able to
remove it and it builds up in the blood as kidney failure progresses. Intake is
restricted to avoid hyperphosphatamia, which can lead to heart and bone problems,
hypocalcaemia, and calcification in the body. Phosphorus is found in processed
foods that contain phosphate highly bioavailable so almost 100% is absorbed when
consumed. For example, soda contains phosphoric acid, which is highly bioavailable.
Phosphorus is also found naturally in grains, nuts, nut butter, dried beans and peas,
meats and dairy.
14. Mrs. Joaquin tells you that one of her friends can drink only certain
amounts of liquids and wants to know if that is the case for her. What foods
are considered to be fluids? What recommendations can you make for Mrs.
Joaquin? If a patient must follow a fluid restriction, what can be done to help
reduce his or her thirst?
Foods considered as fluids include soup, yogurt, ice cream and sherbet, custards,
gelatin and jell-o, and popsicles. Mr. Joaquin should limit high sodium foods that
tend to increase thirst, only drink when thirsty from small glasses and cups, and eat
foods that quench thirst. Recommendations on how to quench thirst without
drinking a lot of fluid include chewing gum, sucking on ice chips, and consuming
high water content fruits and vegetables.
15. Several biochemical indices are used to diagnose chronic kidney disease.
One is glomerular filtration rate. What does GFR measure? What is a normal
GFR? Mrs. Joaquin’s GFR is 28 mL/min. Interpret her value
GFR is the glomerular filtration rate that measures the rate at which substances are
cleared from the plasma and used to assess kidney function. A normal GFR is
90mL/min/1.73m^2. Mrs. Joaquin has a GFR of 28 mL/min, which indicates she is in
stage 4 of CKD with severe kidney damage.
16. Evaluate Mrs. Joaquin’s chemistry report. What labs support the diagnosis
of stage 5 CKD?
Lab Test
Normal
Range
136-145
Patient
Value
130
Potassium
(mEq/L)
3.5-5.5
5.8
Phosphorus
(mg/dL)
2.3-4.7
9.5
Sodium (mEq/L)
Rationale
Low sodium indicates losses in urine or
fluid retention, which dilutes the blood.
High potassium indicates it is not
excreted through urine and
compromised filtration of the kidneys
High phosphorus indicates it is not
excreted through urine and
compromised filtration of the kidneys
Carbon dioxide
(mEq/L)
Glucose
BUN (mg/dL)
23-30
20
8-18
69
Creatinine
(mg/dL)
0.6-1.2
12
Calcium (mg/dL)
9-11
8.2
Cholesterol
(mg/dL)
TG (mg/dL)
120-199
220
35-135
200
HbA1C (%)
3.9-5.2
8.9
Protein Urea
(mg/dL)
Negative 2 +
Low CO2 indicates compromised acidbase balance from protein breakdown
High glucose indicates uncontrolled DM
High BUN indicates it is not excreted
and compromised filtration of the
kidneys
High creatinine indicates it is not
excreted and compromised filtration of
the kidneys. Can lead to muscle damage
and is reabsorbed.
Low serum calcium indicates low VIT D
and compromised kidney function to
convert VIT D to its active form
High cholesterol indicates altered lipid
metabolism
High TG indicates altered lipid
metabolism and due to diabetes and
alcohol consumption of 1 beer a day.
High levels indicate long term
uncontrolled hyperglycemia and
diabetic nephropathy as the likely cause
of CKD
High protein in the urine indicates
increased protein losses
18. Explain why the following medications were prescribed by completing the
following table.
Medication
Indications/Mechanism
Nutritional concerns
Capoten/Captopril ACE inhibitor to treat HTN and Adequate fluid intake but
kidney problems cause by
recommended to decrease
diabetes
sodium and calcium. Avoid
potassium supplements and
salt substitutes.
Erythropoietin
Hormone that stimulates RBC Most patients with kidney
production to treat anemia of
disease have anemia of
chronic disease and combat
chronic disease and given this
low Hgb and Hct.
hormone. May also need to
supplement iron, B12, or
folate.
Sodium
Antacid and alkalinizing agent Sodium concern for sodium
Bicarbonate
restricted diet
recommendation, may
increase thirst, increase
weight, lead to fluid retention,
increase blood pressure
Renal Caps
Renvela
Hectorol
Glucophage
Vitamin and mineral
supplement- water soluble
vitamins (B vitamins, folic
acid, Vitamin C) due to
increased fluid losses during
dialysis. Anorexia may cause
low dietary intake so take to
avoid malnutrition. Iron
supplementation if needed.
Phosphate binder
No recommended doses for
water soluble vitamins. Take
with juice or food. Take Fe
with vitamin C to increase
absorption.
Take with meals and avoid Ca
supplements or antacids.
Decreases Fe absorption. May
cause anorexia, N/V,
constipation
Vitamin D used to treat
Do not take with VIT D
hypocalcemia in dialysis
supplements or Mg
patients
supplements. Avoid excessive
calcium and low potassium
because this increases calcium
absorption and regulates
calcium in the blood
Also known as metformin,
May decrease weight, cause
increases the effect of insulin, anorexia, decrease folate and
lowers glucose absorption and B12 absorption
decreases hepatic glucose
production
19. What health problems have been identified in the Pima Indians through
epidemiological data? Explain what is meant by the “thrifty gene” theory. Are
the Pima at higher risk for complications of diabetes? Explain.
Pima Indians are known to have higher rates of obesity and diabetes which
increases their risk of for other associated complications including kidney disease,
eye disease and nerve damage. Half of all Pima Indians have DM and of these, almost
all are overweight or obese. The “thrifty” gene theory suggests that a genetic change
occurred in Pima Indians that allowed the population to adapt to alternating periods
of feast vs. famine. This gene helped them become more efficient at storing fat when
foods were available; so that when foods were not as widely available they could
rely on their fat stores for energy. The Pima Indians eventually adopted a lifestyle
with less physical activity and a continuous food supply but still had this protective
gene that predisposed them to developing chronic disease and making them more
susceptible to obesity, thus more susceptible to DM.
22. Why is it recommended for patients to have at least 50% of their protein
from sources that have high biological value?
Protein sources with a high biological value are high quality protein sources that
will allow the body to utilize and absorb what they are consuming instead of
breaking down their own stores. Consuming at least 50% of protein from HBV
protect and conserves body protein and minimizes urea generation. High biological
value protein sources include complete proteins containing all nine essential amino
acids, such as animal proteins, soy proteins, quinoa, hummus or a rice and beans
combination.