Running head: CASE STUDY: CHRONIC RENAL DISEASE IN A DOG
Case Study: Chronic Renal Disease in a Dog
Sarra Borne Lord
Tarleton State University
CA Nutrition and Care
VETE 4323
Dr. Mary Carpino
October 29, 2015
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CASE STUDY: CHRONIC RENAL DISEASE IN A DOG
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Case Study: Chronic Renal Disease in a Dog
Chuck is a ten-year-old, neutered male, Golden Retriever, who was presented with the
complaint of acute onset polydipsia, polyuria, and accidents in the house. Chuck has been a
patient since puppyhood and is up to date on vaccinations. Previous medical history includes a
routine neuter, two laceration repairs, and several nail trims. The owner relates that Chuck’s
appetite has decreased over the last week. For the past three years, Chuck has received the same
food in the same quantity. The last few days, Chuck has not been finishing his food and has not
been interested in treats. Chuck also appears to have less energy and is not as interested in
playing. Chuck has vomited twice in the past week.
Physical Examination:
Rectal Temperature: 100.8oF
Heart Rate: 90 beats per minute
Respiratory Rate: 24 breaths per minute
Weight: 78 pounds (decreased from 88 pounds at last exam nine months ago)
Body Condition Score: 2.5/5
Skin/Coat: muzzle white, coat dull
Oral Cavity: moderate dental tartar
Musculoskeletal: decreased range of motion in hind limbs, not painful
Gastrointestinal: Kidneys palpate small bilaterally with right smaller than left
Based on physical findings a urinalysis was ordered.
Urinalysis:
Source
Color
Turbidity
Specific Gravity
Blood
Glucose
Ketones
pH
Protein
Bilirubin
Urobilinogen
Sediment analysis
Free Catch
Pale Yellow
Clear
1.010
Negative
Negative
Negative
6.0
+++
Negative
Negative
No RBC, WBC or Crystals seen. Rare granular casts.
CASE STUDY: CHRONIC RENAL DISEASE IN A DOG
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After reviewing the urinalysis results, the veterinarian received consent to run a complete
blood count and serum chemistry with electrolytes.
CBC Parameter
RBC
HCT
HGB
MCV
MCHC
WBC
Platelets
Result
6.2
41
12.6
66.0
30.6
5.0
500
Reference Range (IDEXX)
4 .8 – 9.3 x 106/uL
38.3-56.5 %
13.4-20.7 g/dL
59 -76 fL
32.6 – 39.2 g/dL
4 – 15.5 x 103/uL
143-448 103/uL
Chemistry Parameter
BUN
Creatinine
Phosphorus
Calcium
Sodium
Potassium
Chloride
Total Protein
ALT
ALKP
Result
98 H
6.7 H
7.6 H
11.0
149
3.7
115
7.2
70
50
Reference Range
8-29 mg/dL
0.8 – 1.5 mg/dL
2.5 – 6.1 mg/dL
8.4 – 11.8 mg/dL
142 – 152 mEq/L
4.0 – 5.4 mEq/L
108 – 119 mEq/L
5.5 -7.5 g/dL
18 – 121 g/dL
5 – 160 U/L
Total Bilirubin
Cholesterol
Amylase
Glucose
0.2
320
1120
92
0.0 – 0.3 mg/dL
131 – 345 mg/dL
337 – 1469 u/l
63 – 114 mg/dL
After evaluating the information gained from the history, physical examination, and lab
results, the veterinarian makes a clinical diagnosis of renal failure. The lab results show an
elevation of the BUN or blood urea nitrogen. The BUN measures the by-products of protein
metabolism that are normally excreted by the kidneys. If the kidneys are not working correctly
and filtering out these waste products, they will build up in the blood. The lab results also show
an elevation of creatinine that is a breakdown product of muscle and a measurement of the
glomerular filtration rate of the kidneys. The kidneys are the only organs that excrete creatinine,
and if there is an increased level of creatinine in the blood, it means that kidney function is
CASE STUDY: CHRONIC RENAL DISEASE IN A DOG
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impaired. The serum phosphorus level is elevated, which occurs when the kidneys fail to excrete
excess amounts in the urine. The urine specific gravity showed that the urine is not being
concentrated, and there is too much water being excreted. There are also large quantities of
protein excreted in the urine that is an expected finding in some types of kidney disease. Finally,
the presence of granular casts in the urine indicates that the kidneys are sloughing some of the
cells that line the renal tubules. “If a cast is seen in the urine, kidney (renal) disease or
involvement exists; the presence of casts indicates kidney (renal) disease rather than lower
urinary tract disease (Ringsrud, 2001, p. 191).
The veterinarian uses the IRIS staging system to put Chuck into Early Stage III Chronic
Renal Disease. IRIS or the International Renal Interest Society was organized in 1998 with the
mission of assisting veterinary practitioners better understand, diagnose and treat renal diseases
in dogs and cats. IRIS has established internationally recognized clinical guidelines for the
staging and treatment of renal disease. Chuck meets the criteria for Stage III because his blood
creatinine is >2.8 mg/dL. However, his urine protein to creatinine ratio and his blood pressure
would need to be evaluated for proper staging.
Patients in IRIS Stage I and II may not have any clinical signs and are not yet azotemic, so
their owners do not suspect that anything is amiss. IRIS Stage I and II may be detected in
patients who receive regular senior pet evaluations if an upward trend is noticed in their blood
urea nitrogen (BUN) and creatinine levels. By IRIS Stage III, approximately 75% of renal
nephrons are non-functional, and clinical signs start to come to the fore. “With appropriate
therapies, animals can survive for long periods of time with only a small fraction of functional
renal tissue, perhaps 5 -8% in dogs and cats” (The Merck Veterinary Manual Online [Merck],
2013, p. 9).
CASE STUDY: CHRONIC RENAL DISEASE IN A DOG
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Azotemia is an increased concentration of non-protein nitrogenous compounds in the
blood as measured by elevated BUN and creatinine levels. Azotemia can be pre-renal, renal or
post-renal. Pre-renal azotemia occurs when the glomerular filtration rate (GFR) is decreased due
to a disturbance in the circulatory system such as hypovolemia or cardiac disease. In pre-renal
azotemia, the kidneys are still able to concentrate the urine as shown by a normal urine specific
gravity with no evidence of protein in the urine. Post- renal azotemia results from urinary
obstruction or rupture and clinical signs include frequent attempts to urinate with little to no
production, or a distended abdomen due to the presence of urine in the abdomen (uroabdomen).
Renal azotemia is diagnosed when the kidneys are no longer able to concentrate urine (USG
1.008 – 1.012), blood urea and creatinine levels are elevated above normal reference levels, and
there are clinical signs of polyuria (increased urination) and polydipsia (increased thirst).
The veterinarian prescribes enalapril and a prescription renal diet. There are several
manufacturers that produce prescription renal diets for dogs and cats. Hill’s Pet Nutrition
manufactures Hill’s Prescription k/d; Royal Canin manufactures Veterinary Diet Renal Support,
and Purina ProPlan Veterinary Diet manufactures NK Kidney Function. All of these foods come
in both canned and dry formulas. They are all designed to provide a reduced level of highquality protein, restricted sodium and phosphorus levels, and added B-complex vitamins.
Providing a reduced level of high-quality protein will help meet Chuck’s nutritional
requirement for protein while attempting to decrease the workload of his kidneys by avoiding
excessive nitrogenous waste. Patients with kidney disease cannot eliminate excess sodium and
fluid from the body efficiently. Excessive amounts of sodium can contribute to hypertension
(high blood pressure), and the build-up of fluid (edema). Hypertension can result in greater
damage to the kidneys, and edema can contribute to heart failure. Normal kidneys can process
CASE STUDY: CHRONIC RENAL DISEASE IN A DOG
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phosphorus, but during chronic renal disease, the damaged kidneys cannot remove phosphorus
from the bloodstream very efficiently. Excessive dietary phosphorus that isn’t excreted can start
to pull calcium out of the bones making them weaker. The increase in B-vitamins is to replace
the larger amount of water soluble vitamins excreted because of Chucks increased urinary
frequency.
In addition to a prescription renal diet, Chuck should always be allowed access to fresh
water. Pets with renal disease are at risk for dehydration because their bodies cannot concentrate
their urine output which means they are losing a large amount of water that would be retained in
a pet with normal renal function.
Chuck’s owner chooses to try Hill’s Prescription Diet k/d dry food. It has 398 kcal/cup.
Chuck weighed 88 pounds when he was healthy nine months ago. At 88 pounds, Chuck’s
resting energy requirement would be 1113 kcal/day. According to the estimated energy
requirement calculator, an average, neutered adult has a maintenance daily energy requirement
factor of 1.6. Chuck’s daily energy requirement is approximately 1780 kcal/day. He should
receive about 4.5 cups of dry k/d per day split into 2 or more meals. His owner should introduce
the Hills k/d gradually over a week’s period by slowly increasing the amount of k/d and reducing
the amount of his usual diet until he is only eating k/d. Introducing the new diet slowly will help
prevent gastrointestinal upset.
Chuck will need rechecks every four months to monitor the progression of his disease. At
each visit his physical condition and weight will be monitored, his blood values and blood
pressure will be evaluated, and drug therapy will be instituted as needed. Renal disease is not
curable; numerous steps can minimize the symptoms and slow the progression of the disease.
Chuck’s owner should monitor him for anorexia, dehydration, mouth ulcers, bad breath,
CASE STUDY: CHRONIC RENAL DISEASE IN A DOG
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increased lethargy, pale gums, vomiting, and diarrhea. Any of these can indicate a worsening of
his symptoms. Chuck’s owner should keep track of food and water consumption and watch for a
decrease in either. If Chuck is not drinking enough water, he will need additional fluids to
prevent dehydration. Monitoring his weight will ensure he is receiving enough calories to
maintain his weight at a healthy level.
CASE STUDY: CHRONIC RENAL DISEASE IN A DOG
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References
Foster, J. D. (2013, September/October). Canine chronic kidney disease: Current diagnostics and
goals for long-term management. Today’s Veterinary Practice, 21-26. Retrieved from
http://216.119.71.215/mags/1309/T1309F02.pdf
International Renal Interest Society. (2013). IRIS staging of CKD. Retrieved from
http://www.iris-kidney.com/pdf/n378.008-iris-website-staging-of-ckd-pdf.pdf
Ringsrud, K. M. (2001, April). Casts in the urine sediment. Laboratory Medicine, 32(4), 191193. Retrieved from http://www.2ndchance.info/dxme-Casts-Ringsrud2001.pdf
Rockett, J., & Christensen, C. (2010). Case studies in veterinary technology: A scenario-based
critical thinking approach. Heyburn. ID: Rockett House
The Merck Veterinary Manual Online. (2013). Renal dysfunction in small animals. Retrieved
October 29, 2015, from
http://www.merckvetmanual.com/mvm/urinary_system/noninfectious_diseases_of_the_u
rinary_system_in_small_animals/renal_dysfunction_in_small_animals.html