Chapter 47: Assessment of Kidney & Urinary Function Flashcards
Functions of the Kidneys
Control BP & H2O Balance
Excrete waste products & renal clearance
Regulate electrolytes, acid-base balances, & RBC production
Secrete prostaglandins
Synthesize vitamin D to active form
Form urine
Renal Clearance
The ability of the kidneys to clear solutes from plasma
Organs of the Urinary System
Kidneys, ureters, bladder, & urethra
Kidneys
Pair of brownish-red, bean-shaped structures located retroperitoneally (behind & outside peritoneal cavity) that remove waste & extra fluid from the body
-Also critical in maintaining acid-base balance, synthesizing hormones to control BP, & stimulating the bone marrow for RBC production
Hilum
Rounded outer convex surface of the kidneys
Why is the RT kidney slightly lower than the LT kidney?
The RT kidney is slightly lower than the LT kidney due to location of the liver
What provides external protection for the kidneys?
The ribs & muscles of the abdomen & back
What provides internal protection for the kidneys?
Fat deposits (surround each kidney-> protect from jarring)
Medulla
Inner portion of the kidney
What does the medulla contain?
It contains the loops of Henle, vasa recta, & collecting ducts from the juxtamedullary nephrons
Where do the collecting ducts from both the juxtamedullary nephrons & cortical nephrons connect to?
They connect to the renal pyramids
Where do the renal pyramids drain to?
They drain to the minor calyces-> major calyces-> opens directly into the pelvis
Renal Pelvis
Beginning of the collecting system
-Composed of structures that are designed to collect & transport urine
Once the urine leaves the renal pelvis…
…the composition does NOT change
Nephrons
Structural & functional units of the kidneys responsible for urine formation
If the total number of functioning nephrons is <20% of normal, what interventions should be taken?
If the total number of functioning nephrons is <20% of normal, kidney replacement therapy is recommended
-Also if 80% is damaged
The length of a tubular component of the nephron is directly related to…
…its ability to concentrate urine
Glomerulus
Tuft of capillaries forming part of the nephron where filtration occurs
Blood Supply to the Kidneys
Blood flows through the glomerulus-> leaves via efferent arteriole & flows back to inferior vena cava via network of capillaries & veins
Bowman Capsule
Encapsulates the glomerulus & afferent & efferent arterioles
Where does the filtrate of the bowman capsule go to?
It travels to the proximal tubule-> loop of Henle-> distal tubule-> either the cortical or medullary collecting ducts
Juxtaglomerular Apparatus
Site of renin production
Renin
Works to regulate BP (increases via RAAS system)
Tubular Components of the Nephron
Bowman capsule, proximal tubule, descending & ascending limbs of the loop of Henle, & cortical & medullary collecting ducts
Ureter
Moves urine to bladder
Urothelium
Inner lining of the ureters
- Prevents reabsorption of urine
Bladder
Houses urine to be excreted & prevents urine reflux into the kidneys
Usual Capacity of Adult Bladder
400-500 mL
Micturation
Voiding or Urination
Steps of Urine Formation
1) Glomerular filtration
2) Tubular reabsorption
3) Tubular secretion
Urethra
Eliminates urine from the bladder
Antidiuretic Hormone (ADH)
AKA Vasopressin
Hormone secreted from the posterior section of the pituitary gland in response to changes in osmolality of the blood
Effect of ADH on the Renal System
1) Decreased H2O intake-> blood osmolality increases, stimulates ADH release
2) ADH acts on the kidney-> increases reabsorption of H2O & return osmolality of blood to normal
What happens to ADH secretion in response to excess water intake?
ADH secretion becomes suppressed & less H2O is reabsorbed by the kidney tubule-> diuresis
Diuresis
Increased urine volume
Osmolarity
Ratio of solute to H2O
Osmolality
Degree of dilution/concentration of urine
Aldosterone
Hormone synthesized by adrenal cortex that causes the kidney to reabsorb Na+2
Creatinine
Endogenous waste product of skeletal muscle that is filtered at the glomerulus , passed through w/ min change & excreted in urine
Glomerular Filtration Rate (GFR)
Amount of plasma filtered through the glomeruli per unit of time
As renal function declines…
… GFR & renal clearance drops
Erythropoietin
Glycoprotein from the kidney that stimulates the bone marrow to produce RBCs
Nocturia
Awakening during the night to urinate
Gerontological Considerations for Kidney & Urinary Function
GFR decreases starting between 35-45 years of age
More susceptible to acute kidney injury & CKD due to structural & physiological changes:
- Glomerulus sclerosis
- Renal vasculature sclerosis
- Decreased Blood flow & GFR
- Altered tubular function
- Acid- base imbalance
Renal reserve is decreased
More prone to develop hypernatremia & fluid volume deficit due to decreased thirst
Decreased bladder wall contractility
Vaginal & urethral tissue atrophy due to estrogen decrease
Increased risk for developing UTIs
Bacteriuria
Bacteria in the urine (bacterial count >100,000 colonies/ml: infection is present)
Dysuria
Pain or difficulty w/voiding
Urinary Frequency
Voiding more than every 3 hrs
Hematuria
Presence of RBCs in the urine
Urinary Retention
Inability to completely empty the bladder
Anuria
Decreased urine output of < 50 mL w/in 24 hrs
Enuresis
Involuntary voiding during sleep
Hesitancy
Delay, difficulty in intitiating voiding
Nursing Assessment for Kidney & Urinary Function
Healthy Hx:
- Ask about risk factors
- Previous UTIs or kidney stones
Family Hx:
- Genetically passed disorders
Ex) Polycystic kidney disease (PKD), renal cystic disease, diabetes, CAD, pulmonary HTN
- Infertility/Cystic fibrosis
- Renal carcinoma
Head-to-Toe Focus: Abdomen, suprapubic region, genitalia, lower back, & lower extremities
Palpation of kidneys is unusual (may indicate enlargement)
-Costovertebral angle, may extend to umbilicus
Physical Symptoms:
1) Pain
- Kidneys: Dull constant ache, (sudden distention of capsule: sharp, stabbing, & colicky in nature)
* Location: Costovertebral angle, may extend to umbilicus
* Associated w/ N/V
* Possible causes: acute obstruction, kidney stone
- Bladder: Dull, continuous pain that may be intense w/voiding
* Location: Suprapubic region
* Possible causes: Over distended bladder, interstitial cystitis
- Uretral: Severe, sharp, stabbing pain, colicky in nature
* Location: Costovertebral angle, flank, lower abdominal area, testis or labium
* Possible causes: Uretral stone, blood clot
2) Changes in voiding patterns or urine appearance
3) Are GI symptoms present? N/V, diarrhea, abdominal pain or discomfort
4) Unexplained anemia
Risk Factors for Chronic Kidney Disease (CKD)
Diabetes
Sickle Cell disease
Nephrotic syndrome
HTN
Lupus
Risk Factors for Renal Insufficiency
HTN
Risk Factors for Oliguria/Anuria
Benign prostatic hyperplasia/hypertrophy (BPH)
Risk Factors for Acute Kidney Injury (AKI)
Exposure to chemical
UTI
Calculi
Diabetes
Old age
Risk Factors for Urinary Tract Infections (UTI)& Incontinence
Advanced age (incomplete emptying) Spinal cord injury
Procedures: cystoscopy and catheterization
Multiple Sclerosis (MS),
Vaginal childbirth (incontinence only)
Risk Factors for Neurogenic Bladder/Retention
Diabetes,
MS
Stroke
BPH
Mass/tumor, calculi
Trauma, spinal cord injury
Risk Factors for Renal Calculi
Gout
Crohn’s
hyperparathyroidism
Ileostomy, immobilization
Cancer
Renal tubular acidosis
Granulomatous diseases
PKD
Risk Factors for Structural Trauma
Recent pelvic surgery, radiation therapy to pelvis
Pre-Procedure for Urodynamic Testing
Interview on patient’s urologic symptoms & voiding habits
During the Procedure Measures for Urodynamic Testing
Ask patient to:
- Describe sensations they felt
- Change positions (from supine to sitting up)
- Cough/ Perform Valsalva maneuver (bear down)
Anticipate inserting 1 or 2 urinary catheters: To measure bladder pressure & filling
- May have to insert another catheter in the rectum or vagina to measure abdominal pressure
- Bladder will be filled via catheter 1 or more times
Anticipate possible electrode application for electromyography
- Warn the client they may be uncomfortable initially during insertion & later during position changes
Patient Education Post-Urodynamic Testing
Patient may experience this after urinary catheter insertion:
- Frequency
- Urgency
- Dysuria
Avoid caffeinated, carbonated, & alcoholic beverages (will worsen symptoms)
- Symptoms usually decrease by the day after the procedure
Slight hematuria
- Drink fluids will help clear it
Watch for UTI signs & symptoms! Contact provider immediately if patient is experiencing:
- Fever
- Chills
- Lower back pain
- Continued dysuria & hematuria
If taking an antibiotic prior to procedure, continue use to clear infection
Normal Urine Output
1 mL/kg/ hr or 1-2 L/day
Urinalysis
Checks urine color, clarity, pH, specific gravity, & presence of proteins/cells/glucose/ ketones
Colorless to Pale Yellow Urine Color Meaning
Dilute urine due to:
- Diuretic agents
- Alcohol consumption
- Diabetes insipidus
- Glycosuria
- Excess fluid intake
- CKD
Yellow to Milk White Urine Color Meaning
Pyuria, infection, & vaginal cream
Bright Yellow Urine Color Meaning
Multiple vitamin prep
Pink to Red Urine Color Meaning
Hemoglobin breakdown
RBCs
Gross blood
Menses
Bladder/ prostate surgery
Beets & blackberries
Meds: phenytoin, rifampin, thioridazine, cascara sagrada, & senna products
Blue to Blue Green Urine Color Meaning
Dyes, methylene blue
Psuedomonas organisms
Meds: Amitryptylince HCL, triamterene
Orange to Amber Urine Color Meaning
Concentrated urine due to:
- Dehydration
- Fever
- Bile
- Excess bilirubin or carotene
- Meds: Phenazopyridine, hydrochloride, nitrofurantoin
Brown to Black Urine Color Meaning
Old RBCs
Urobilinogen
Bilirubin
Melanin
Porphyrin
Extremely concentrated urine due to:
- Dehydration
- Medications: iron prep, cascada sagrada, methyldopa
Urine Culture
Identifies which antimicrobial therapy that is best suited for particular strains
Osmolality
Measures the presence of solutes in urine
MOST ACCURATE measurement of the kidney’s ability to DILUTE & CONCENTRATE urine
Normal Urine Osmolality Range
200-800
Less is best!
Specific Gravity
Measures density compared to H2O
Normal Urine Specific Gravity Range
1.005- 1.025
Abnormally Low Specific Gravity Reading Causes
Diabetes insipidus, glomerulonephritis, & hyperhydration
Abnormally High Specific Gravity Reading Causes
Diabetes mellitus, nephritis, & dehydration
24- Hour Urine Collection
Picture of the kidney’s ability to clear solutes from plasma
- Usually measuring creatinine in urine
BUN (Blood Urea Nitrogen)
Urea is the nitrogenous end product of protein metabolism
- Test values are affected by protein intake, tissue breakdown, & fluid volume changes
Normal BUN Range
8-20 mg/dL
High levels indicate the kidneys are not filtering well
Patients > 60 years: 8-23 mg/dL
Creatinine
Creatinine is the end product of muscle energy metabolism
- Regulated & excreted via kidneys
Normal Creatine Range
Male: 0.6 -1.2 mg/ dL
Female: 0.4 -1 mg/ dL
Waste product that is not filtered appropriately in presence of renal damage
BUN to Creatinine Ratio
Evaluates hydration status
-Elevated: Hypovolemia
- Normal ratio w/ elevated BUN & creatinine: Intrinsic kidney disease
10: 1
Glomerular Filtration Rate (GFR)
Used to identify the stage of kidney disease
Stage 1 Glomerular Filtration
Possible kidney damage (e.g., protein in the urine) w/ normal kidney function
eGFR: 90 or above
Kidney Function: 90-100%
Stage 2 Glomerular Filtration
Kidney damage w/ mild loss of kidney function
eGFR: 60-89
Kidney Function: 60-89%
Stage 3a Glomerular Filtration
Mild to moderate loss of kidney function
eGFR: 45-59
Kidney Function: 45-59%
Stage 3b Glomerular Filtration
Moderate to severe loss of
kidney function
eGFR: 30-44
Kidney Function: 30-44%
Stage 4 Glomerular Filtration
Severe loss of kidney function
eGFR: 15-29
Kidney Function: 15-29%
Stage 5 Glomerular Filtration
Kidney failure
eGFR: Less than 15
Kidney Function: Less than 15
In which stages would you see a patient on dialysis?
If a patient is between stage 3b & 4, usually they would be put on dialysis.
Renal System Gerontological Considerations
GFR begins to decrease 1 point/yr
starting at age 35-40
Increased risk for AKI due to
changes of the kidney (sclerosis of
the renal tissues, decreased blood
flow or perfusion, decreasing GFR,
etc…)
About 50% of AKI cases are in
patients aged 60 and older
Increased risk for dehydration and
hypernatremia associated with a
decreased stimulation of thirst
Urological Gerontologic Considerations
Increased likelihood of nocturia
- Decreased bladder muscle tone, increased residual urine, and decreased vasopressin levels
Increased likelihood of urinary incontinence
-Many causes, but sometimes related
to mobility concerns
Older patients may begin to limit fluid intake when this happens, watch for dehydration
- Often have incomplete emptying of the bladder or urinary stasis which increase the risk of a UTI and urinary urgency
Symptoms may appear as other GI issues making diagnosis difficult
Ultrasonography
Noninvasive procedure that uses soundwaves passed into the body via transducer to detect abnormalities of internal tissues & organs
Bladder Ultrasonography
Noninvasive method of measuring urine volume in the bladder
Nursing Considerations for CT Scan & MRI
Prep:
- Teaching relaxation techniques
- Inform the patient they will be able to communicate w/staff via microphone inside the scanner
- Obtain allergy hx: shrimp, iodine, shellfish (contrast contains iodine)
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