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ACUTE AND CHRONIC RENAL FAILURE
RENAL ASSESSMENT
Show slides:
1. Kidney
2. Nephron
The nephron is the functional unit of the kidney
Consists of: proximal convoluted tubule, Loop of Henle, & distal
convoluted tubule (NB: this is NB to know as medications act
on these areas)
In renal failure: the nephron may be damaged due to:
i). Ischemia
ii) exposure to nephrotoxic agents (ASA, antibiotics
(Gentamycin)
For this unit we will focus primarily on the purpose and function of the
kidney
The kidneys perform the following EXCRETORY, REGULATORY AND
ENDOCRINE FUNCTIONS for the body in order to maintain
homeostasis:
1. Rid the body of the wastes of metabolism (get rid of urea, creatinine)
2. Maintain fluid and electrolyte balance:
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1. RE FLUID BALANCE:
The kidney:
- regulates urine output; responds to hypervolemia (by ↑ urine
output: we see dilute urine);
- responds to hypovolemia (by ↓ urine output & concentrates urine)
- when there is damage, polyuria, oliguria, and anuria can result
2. RE ELECTROLYTE BALANCE:
The kidney responds to changes in electrolyte balance such as:
Hyperkalemia, Hypocalcemia, Hyperphosphatemia, Magnesemia, Hyper
and hyponatremia
3. ACTIVATES VITAMIN D:
Converts Vit D to its active metaboltye in order to facilitate absorption of
calcium from the GI tract so that the Calcium/phosphate ratio may
remain in balance
4. ACID-BASE BALANCE:
5. CONTROL BLOOD PRESSURE:
6. STIMULATE RBC PRODUCTION & PROLONG RBC LIFE:
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Assessment of Renal Function:
Assessment of renal function may be based upon blood composition, urine
composition tests, and renal clearance tests.
Blood Tests
• Blood tests of renal function include tests for plasma creatinine levels
(44 – 133 μmol/Litre)
 Blood test for blood urea nitrogen, BUN levels (1.8 – 7.1 mmol/Litre)
 Although the BUN test is widely used for screening renal malfunction,
the plasma creatinine is a more reliable indicator of renal function.
Urinalysis
Urinalysis considers physical examination, chemical examination, microscopic
examination and bacteriological examination of urine:
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PHYSICAL EXAMINATIONS consider total urine volume and
specific gravity 1.016 – 1.022
An increase in urine volume is called polyuria and is an indication of the
tubule's inability to reabsorb water. The specific gravity is an indicator of how
well the kidneys are concentrating urine
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CHEMICAL EXAMINATIONS consider the protein levels in urine.
Increases are called proteinuria, and because most of these are albumins, we
also call it albuminuria. In glomerulonephritis, the albumins originate in the
blood; in pyelonephritis, the proteins originate in the urinary tract walls.
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MICROSCOPIC EXAMINATIONS consider the number and type of
particles in urine.
These include crystalloid matter, erythrocytes, leukocytes, and casts. Casts form
within tubules when protein is present and may contain erythrocytes or
leukocytes or both.

BACTERIOLOGICAL EXAMINATIONS consider the presence,
number and kind of bacteria in urine.
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
Urine Creatinine: 124 -230 μmol/kg/day
Clearance Tests
Clearance tests help determine how efficiently the kidneys process the blood
delivered to it;
It compares the amount of a substance in blood with the amount of the same
substance in urine. Time may or may not be a factor.
The amount of substance in plasma, in urine, and urinary output rate (also a
factor that considers body surface area) are determined.
Reports indicate the amount of substance cleared per volume of blood or a
volume of blood cleared of a substance per unit time.
24 hour Creatine clearance test reflects glomerular filtration rate because
none is reabsorbed by the renal tubule system.
• Normal = 1.5 – 2.3 mL/sec
How Done? Have patient urinate at the beginning of the day. Discard specimen.
Collect the urine output for the next 24 hours.
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Assessment of the Urinary System
• Subjective Data
Important Health Information
• Past health history
• Medications
• Surgery or other treatments
Functional Health Patterns
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Health perception – health management
Nutritional – metabolic
Elimination
Activity – exercise
Sleep – rest
Cognitive – perceptual
Self-perception – self-concept
Role – relationship
Sexuality – reproductive
Coping – stress tolerance
Value – belief
• Objective Data
Physical Examination
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Inspection
Palpation
Percussion
Auscultation
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Inspection: assess for changes in the following:
Skin: pallor, yellow-grey cast, excoriation, changes in turgor
Mouth: ammonia breath odour
Face & extremities: generalized edema, peripheral edema, bladder distension,
enlarged kidneys
Abdomen: stria, abdominal contour changes
Weight: weight gain d/t edema; weight loss and muscle wasting in renal failure
General health status: fatigue, lethargy, diminished alertness
Palpation:
Palpate the kidneys just below the back parts of the rib cage (see Health
Assessment text!)
Percussion:
Assess tenderness in the flank area: normally this does not elicit pain
Auscultation:
Assess for bruit over the costovertebral angle that is formed by the rib cage and
the vertebral column (front of body); If hear a bruit (abnormal murmur), this
indicates impaired blood flow to kidneys
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