Renal System “Kidneys - The Master Chemists of the Body”

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					Renal System
“Kidneys: The Master Chemists of the Body”
“Study of internal & external structures of the
Composition of the Renal System
Structure of the Kidneys
Vascular Structure of the Nephron
• Renal artery  Segmental artery  Lobar artery 
  Interlobar arteries  Arcuate arteries  Small
  interlobular arteries  Smaller afferent arteries 
  Capillary bed (Glomerulous)  Efferent arteriole 
  Peritubular capillaries  Interlobular vein  Arcuate
  vein  Renal vein
Tubular Structure of the Nephron
Renal Corpuscle
Specialized Cells of the Proximal
      Convoluted Tubule

• Brush boarder cells
• Large surface area allowing for reabsorption of
the filtrate into the blood stream
Key Feature: Highly permeable to water & many
 Specialized Cells of the
Descending Loop of Henle

 •Simple squamous epithelial cells that lack
 brush boarders

 •Small surface area resulting in a decrease
 in the amount of filtrate reabsorbed into the
 blood stream

 Key feature: Highly permeable to water but
 not solutes
    Ascending Loop of Henle
• Similar to those of the PCT except fewer

Key feature: Highly permeable to solutes
 (particularly sodium chloride), not permeable
  to water
  Juxtaglomerular Apparatus
• Endocrine structure that secretes the hormones
  erythropoietin and renin
Key Feature: Renin triggers angiotensin to turn into
  angiotensin I which turns to angiotensin II which
  constricts the walls of arteries to increase BP
  Erythopoietin stimulates the production of RBC when
  kidneys are exposed to low O2 concentrations
   Specialized Cells of the Late
    Distal Convoluted Tubule
• Cuboidal cells that fall into two distinct
  regions, principle cells and intercalated
• Key feature (principle cells): Permeable to
  water & solutes and regulated by
• Key feature (intercalated cells): Involved in
  the secretion of H ions for acid/base
     Specialized Cells of the
    Medullary Collecting Duct
• Cuboidal cells
• Key feature: Hormonally regulated
  permeability to water and urea
“Study of how organisms perform their vital
         Primary Functions
1. Regulates our blood volume and pressure by
   adjusting the volume of water lost and through
   releasing erythropoietin & renin
2. Regulates plasma concentration of electrolytes
3. Stabilizes blood pH by controlling the loss of
   H+ & bicarbonate
4. Conserves valuable nutrients
5. Assists liver in detoxifying poisons
           Renal Function
Step 1:

• Filtrate is produced at the renal corpuscle
  through the mechanism of filtration, has
  the same osmotic concentration as plasma
  (~300mOsm/L) excluding proteins
Step 2:

• PCT actively transports ions such as Na+,
  K+, Mg- & bicarbonate out of the tubular
  fluid and into the peritubular fluid there is
  also a continuous flow of water being
  reabsorbed into the peritubular fluid

• ~60-70% of the filtrate volume is
Step 3:

• Descending loop of Henle water moves
  into the blood stream leaving a highly
  concentrated filtrate in the bottom of the
Step 4:

• Ascending limb of Henle is impermeable to
  water but actively transports solutes
  through a mechanism which transports
  Na+/Cl- into the peritubular fluid and
  countertransports K+ into the loop of
Step 5:

• The final adjustments in the composition of the
  tubular filtrate are made in the DCT & the
  collecting system

• Reabsorption of Na+ for exchange of K+ is
  controlled by the hormone aldosterone released
  by the adrenal cortex

• DCT is the prime site of Ca2+ reabsorption
  which is regulated by circulating levels of
  parathyroid hormone & calcitrol
Step 6:

• Final adjustments in the volume and osmotic
  concentration of the filtrate occurs at the distal
  portion of the DCT & the collecting system

• Exposed to antidiuretic hormone (ADH) these
  segments become premeable to water and
  therefore water moves into the peritubular fluid

• Exposure to aldosterone causes Na+ to leave
  the tubule in exchange for K+
Step 7:

• The vasa recta absorbs solutes & water
  reabsorbed by the loop of Henle and the
  collecting ducts and thereby maintains the
  concentration gradient of the medulla
        Alterations of Renal System
  – Cystitis, “nonbacterial” cystitis, chronic pyelonephritis
Obstructive Disorders:
  – Kidney Stones, Neurogenic Bladder, Tumors (including
    bladder tumors)
Glomerular Disorders:
  – Glomerulonephritis, nephritic syndrome
Renal Failure:
  – Acute Renal Failure (ARF)
  – Chronic Renal Failure (CRF)
Acute Renal Failure
“Abrupt decline (days to weeks) in the
kidneys’ ability to filter metabolic waste
      products from the blood.”
     Renal Failure: Terminology
•   Creatinine Clearance
•   Glomerular Filtration Rate (GFR)
•   Serum Creatinine (SCr)
•   Blood Urea Nitrogen (BUN)
•   Azotemia
•   Uremia
 Alterations-Acute Renal Failure
Renal Impairment             GFR- 50mL/Min
50% of Normal                Serum Creatinine: less than 2 mg/dL
                             BUN: High normal
Renal Insufficiency          GFR 25-40mL/min
25% of Normal                Serum Creatinine: 1.5-3.0 mg/dL
                                               (mildly elevated)
                             BUN: Mild azotemia
Renal Failure                GFR < 25mL/min
< 20% of renal fcn remains   Serum Creatinine: > than 3.0 mg/dL
                             Electrolyte imbalances
End stage renal              GFR < 10 mL/min
disease (ESRD)               Creatinine and BUN: marked increase
< 10% of renal fcn remains   Electrolyte imbalances
    A R F: Clinical Manifestations:
•   Azotemia
•   Hypervolemia
•   Elevated BUN and Creatinine levels
•   Electrolytes abnormality
      ↑K+       ↓ Na +      ↑ Phosphate ↓ Ca
• Metabolic acidosis
• Hypertension
• Associated with oliguria
    – Urine output < 30ml/hr or, < 400ml/day
• Reversible if Dx and TX early
Acute Renal Failure: Classification
             Pre-renal Causes of ARF
True intravascular depletion
   Renal losses
   GI loss
   Evaporative losses
   Hypotension

Decreased effective circulating volume to
The kidneys
   CHF
   Interruption of renal
    artery flow
   Nephrotic syndrome

Impaired renal blood flow due to exogenous agents
   Drug therapy (NSAIDs, calcium channel blockers)
          Pre-renal ARF: S&S
•   Low BP
•   Dizziness
•   Dry mouth
•   ↑ HR
•   Thirst
•   Weight loss
•   Oliguria
      Intrarenal Acute Renal Failure:
          Acute Tubular Necrosis
1. „Post Ischemic‟
  •    Ischemia generates toxic oxygen free radicals and inflammatory
       mediators, which cause swelling, injury and necrosis

  •    Occurs most frequently after surgery (40-50% of cases)

  •    Also associated with sepsis, obstetric complications, severe burns,
       trauma, severe hypotension with hypovolemia.

2. „Nephrotoxic‟
  Pharmaceuticals, Radiocontrast media, Heavy metals
                 Intrinsic Causes of ARF
1.       Acute Tubular Necrosis (ATN)
     –      Renal post-ischemia Injury
     –      Toxins
     –      Nephrotoxic drugs
     –      Rhabdomyolysis

2.       Glomerular disease
     –      Systemic lups erythematosus

3.       Vascular disease
     –      Malignant hypertension

4.       Interstitial disease
     –      Allergic rxn to drugs
     –      Autoimmune disease
     –      Pyelonephritis
     –      Infiltrative disease
         Intrarenal ARF: S&S
•   High BP/ Low BP
•   Dizziness
•   ↑ HR
•   Weight gain/ Weight loss
•   Oliguria/ Diaphoresis
•   Fluid overload and Edema/ Dehydration
         Post-Renal Causes of ARF
• Upper Urinary Tract Obstructions
   –   Ureter obstructions (urethral strictures)
   –   Intratubular obstruction (crystals, stones)
   –   Tumors
   –   Intraluminal bladder mass (clot, tumor, fungus ball)

• Lower Urinary Tract Obstructions
   – Benign or malignant hypertrophy of the prostate (prostate cancer)
   – Injury
         Post Renal ARF: S&S
•   High BP
•   Dizziness
•   ↑ HR
•   Weight gain
•   Oliguria
•   Fluid overload
•   Edema
           Acute Renal Failure Stages

Oliguria         < 400 ml/day or 30 ml/hr
                 Begins 1 day after hypotensive event; lasts 1-3
                 BUN and plasma creatinine elevations
                 Oliguric patients may require dialysis
Diuresis         As renal function improves, increase in urine
                  volume is progressive
                 Monitor fluid and electrolyte imbalance …watch
                for volume depletion
Recovery        May take 3-12 months
                Approx. 30% do not recover
                Serial measurements of creatinine provide an
                  index of renal function
          Incidence of ARF
• 2-5% of all hospitalized patients
• 10-20% are critically ill
• Mortality Rate- 25% increases to 75% if
  complicated by other life threatening
• The most common reason for a patient to seek
  help for renal dysfunction is due to variations in
  voiding, pain, or changes to the urine

Historical Assessment:
• Is this new onset?
• What symptoms were noted first?
• Precipitating factors- alcoholism, hereditary traits
• General pattern of illness
                        Physical Exam
• Skin- pallor, yellow grey in colour, changes in turgor, bruises, texture (rough
   and dry skin)
• Mouth- stomatis, ammonia breath odor
• Face/Abdomen and extremities- edema, bladder distention, masses, weight
• General state of health
• Landmark at the costovertebral angle. The left kidney is rarely palpable due
   to the spleen. The lower portion of the right is sometimes palpable.
• The bladder should feel smooth and rounded
• A firm fist strike should not elicit pain to the kidneys- if there is tenderness
   this may indicate infection or polycystic kidney disease.
• The bladder is percussable after 150ml of urine in which dullness is heard
   above the suprapubic bone.
• The diaphragm is used to auscultate the abdominal aorta and renal arteries
   for bruit.
            Assessment of Pain
   Kidney Pain              Dull, continuous, costovertebral angle (CVA)
                            spreading towards the umbilicus.
   Renal or ureteral Pain   Severe, sharp, felt from the CVA to the
                            bladder and often into the ovaries or testes.

   Bladder Pain             Dull, continuous, suprapubic discomfort
                            (possibly sharp indicative of spasm).

   Urethral Pain            Burning sensation, sharp spastic pain.

   Prostatic Pain           Vague discomfort or full feeling. (possible
                            back ache).

Due to urinary organs sharing autonomic and sensory nerves with the GI
system, patients may complain of GI symptoms.
   Assessment in the Alteration of

1. Number of times that urination occurs
2. Number of times the individual rises to
   void during the night (nocturia)
3. Inability or difficulty voiding (hesitancy)
4. Amount of urine output
5. Involuntary voiding (incontinence)
Diagnostic Testing
    Measuring kidney function
            Diagnostic Tools
•   Urinalysis
•   Blood Work
•   X-ray
•   Urogram (intravenious pyelogram)
•   Ultrasound
•   Doppler
•   Scopes
•   Biopsies
               The Urinalysis
 Also called a routine UA (urinalysis)- gross and microscopic
  examination of urine to determine pH, gravity and substance

Gross Assessment- appearance and odor of the urine
Microscopic Assessment- bacteria, RBC, WBC, crystals, casts.

                            Normal Findings of Urinalysis:
                            pH- 4.5-8.0
                            Gravity-1.001 to 1.030
                            Protein- Negative
                            RBC/WBC- Negative
                            Glucose- Negative
                            Ketones- Negative
                            Nitrates- Negative
                   The Urinalysis
• Normal
    inorganic material such as NA+, Cl-, Mg+, SO4-, PO4-, and
     NH4+ and organic materials such as urea, creatinine, and uric
     acid in the urine.
• Abnormal
    RBCs, WBCs, bacteria protein, glucose, ketones

• Urinalysis involves evaluation of color, turbidity, protein,
  pH, specific gravity, sediment

• Presence of bacteria, RBCs, WBCs, casts or crystals in
  the urine sediment may indicate a renal disorder.
           Assessing Urine
• The first morning void is considered ideal
  as it has the greatest concentration and
  lowest pH (maximizing the ability to detect
  formed elements).
• A regular void (with appropriate washing of
  the genitals) is usually satisfactory.
• A midstream or catheterized specimen is
  more appropriate for culture and bacteria
Catheterization and Renal Insufficiency

   “Urinary track infections are the leading
   cause of nosocomial infections estimated
                     at 40%”
          Assessing Blood
Why assess the blood?
• Electrolyte balance
• Acid-base homeostasis
• Regulates serum concentrations of BUN
  and Creatinine
• Produce erythropoietin
Normal Blood and Serum Lab Values
Sodium     135- 145 mEq/L
Potassium   3.5- 5.3 mEq/L
Chloride    98- 106 mEq/L
BUN         10- 20mg/dL
Creatinine  60-110 umol/L (Female)
            70-120 umol/L (Male)
Phosphorus 0.8- 1.4 mmol/L
Calcium     2.0- 2.6 mmol/L
Magnesium    1.6- 2.6 mg/dL
Hemoglobin 120-140g/L (Female)
            140-160g/L (Male)
      Lab Tests for Renal Function:
              Blood Tests
• Blood Urea Nitrogen               • Serum Creatinine Level
  – Measures the concentration        – Should be a stable value
    of urea in the blood              – When creatinine levels rise
  – Urea is formed from protein         and accumulate in the
    metabolism and is elevated          plasma:
    when glomerular filtration is          Double  renal function is
    reduced                                 about half of Normal
  – BUN rises in states of                 Tripled  ~ 75% of RF is
    dehydration and acute                   lost
    chronic renal failure because
    passage through tubules is         Represents a decrease in GRF
Estimating GFR and Creatinine Clearance
GFR- Filtration rate/min at the glomerulus.
            170 x Serum Creatinine concentration^-0.999
            X age^-0.176
            X 0.762 (if female)
            X 1.18 (if race is African)
            X blood urea nitrogen concentration^-0.17
            X serum albumin concentration^-0.318
            = GRF in Adults

Creatinine Clearance- The clearance rate in mL/min of the
  waste product creatinine.

             0.55 x Length/ Serum Creatinine
     Therapeutic Fluid Challenge
250mL of 5% dextrose (or Saline) over 30min.

Increase in Output:
~ indicative of pre-renal impairment or hypovolemia.

No Increase in Output:
~ indicative of post-renal impairment.

TFC contraindicated if severe fluid overload!
    Nursing Diagnosis for ARF
1. Imbalanced Nutrition: less than body
   requirements related to anorexia,
   nausea, vomiting, unpalatable diet.

2. Risk for Infection: related to invasive

3. Anxiety: related to present status and
    unknown prognosis.
         Planning Treatment

1.   Treat the cause
2.   Prevent progression
3.   Identify complications
4.   Promote comfort through symptomatic
 Gerontological Considerations
• 20-30% decrease in size and weight of the
  kidneys between the ages of 30-90years
  (predominantly in the cortex). By 70 years old
  30-50% of the glomeruli have lost their function.
  Blood flow to and from the kidneys also
• Estrogen receptors in the urethra, bladder and
  pelvic floor decrease causing lack of elasticity.
• The prostate enlarges affecting pattern,
  retention and infection.
                          Dietary Restrictions
Fruits (other than apples, grapes, peaches, berries)
Dietary products

Sodium and Fluid:
Approx 2000mg and 500-1000mL per day


Decrease amount of cooked meats

Calcium carbonate (Tums) supplement with meals

The diet for those in kidney failure must compensate for lack of kidney function, provide adequate
    nutrition and alleviate symptoms of uremia. Diet is based on lab values.
    Commonly Used Nephrotoxic
Gentamicin         Neomycin         Streptomycin

      Sulfonamides             Vancomycin

Cocaine             Rifampin        Heavy metals

          Heroin               Lithium

NSAIDS               Quinine
     Basic Interventions for ARF
•   Vital Signs
•   Administration of fluid
•   Administration of pharmaceuticals
•   Draw blood
•   Catheterization
•   Teaching
Interventions Related to Mr. Jones
•   NPO 6-12 hours then Renal Diet
•   Fluid restriction: 500-1000mL/24hr
•   Cardiac Monitor
•   ECG 12 hours
•   Administration of pharmaceuticals *
•   Assessment of urinary output- may include 24 hour fluid
•   Assess vascular perfusion
•   D/C Maalox (Rx: Tums PRN)
•   Book Echocardiogram
•   Book dietary consultation
•   Blood Work- CBC, Routine Chemistry, Lithium Level,
                Pharmaceutical Therapy
Kayexalate (Sodium Polystyrene Sulfonate)
Action: Removes potassium from the body by exchanging sodium ions
        for potassium.
Nursing Consideration: Determine potassium levels daily.
                       Consult physician about decreasing sodium
                       intake, as drug contains 100mg of sodium.

Sodium Bicarbonate (NaHCO3)
Action: Systematic antacid.
Nursing Consideration: Monitor urinary pH as a guide to dosage.
                       Observe for reversal of metabolic acidosis

Mannitol (Osmitrol)
Action: Increases electrolyte excretion by the kidneys (Na, K, Cl)
Nursing Consideration: Monitor I&O and daily weight.
                        Monitor site for signs of inflammation.
                        Monitor for signs of electrolyte imbalance

Calcium Glucanate (Kalcinate)
Action: Calcium replacement solution
Nursing Consideration: Monitor for fall in BP during administration
                       Monitor site for signs of inflammation
                       Monitor for calcium imbalance
                Pharmaceutical Therapy
Action: Allows glucose to be utilized, decreasing the breakdown of ketones
        preventing further acidosis.
        Moves potassium into cells.
Nursing Consideration: Monitor CBG levels
                        Consult physician about abnormal results

Lasix (Ferosemide)
Action: Loop diuretic used in the treatment of congestive heart failure and
Nursing Consideration: I & O or 24 hour urine
                        Consult physician about increasing sodium
            Patient Discharge
• Continual renal damage
• Potential nephrotoxic agents
• Dietary restrictions

• Medication adherence
• Scheduled appointments
• Maintain level of activity as tolerated
     Diffusion of solutes through a semi-permeable
          membrane that separates two solutions

Goals of Dialysis

1.   Remove excess end products from blood
2.   Maintain baseline concentration of electrolytes
3.   Remove excess fluid
4.   Correct acidosis
5.   Removal of toxins
            Types of Dialysis
1. Hemodialysis

2. Peritoneal

• Dialysate contains electrolytes in varying
  concentration which prevents complete
  removal of body electrolytes

Components- Sodium, Calcium,
 Magnesium, Potassium, Chloride, Acetate,
 Lactate, Bicarbonate, Glucose, Dextrose
Care of Patients Pre-Hemodialysis
1. Medication may be held for 6-12 hours
2. Vital signs taken
3. Patient teaching- eg. NPO, amount of
   time the dialysis may take
4. Therapeutic communication
Care of Patients Post-Hemodialysis
1. Vitamins may be given post-dialysis.
2. Observe access area- hemotoma,
   bleeding, infection.
3. Monitor vital signs.
4. Monitor vascular response- capillary
   refill, pedal pulse, cyanosis.
5. Offer food as per dietary prescription.
           Patient Education
• Avoid tight clothing around access site
• Check site for adequate blood flow (buzz)
• Watch for signs of infection or bleeding
• Do not allow anyone to draw blood or conduct
  blood pressure from access extremity
• Do not sleep with pressure on extremity
• Avoid use of creams and lotions
• Keep and understand how to use “bulldog
  clamps” should tubing become disconnected
  from external shunt.
         Complex Challenges
•   Diabetes
•   Chronic Renal Failure
•   Medication Adherence
•   Transplant
•   Infection
•   Psychological adaptation
•   Urostomy
                 Chronic Renal Failure
“Slow, progressive, (months to years) irreversible loss of renal function.”
         Classification of CRF
• Classified by site of damage
  – Pre-renal CRF
     • Continuous hypoperfusion leading to kidney atrophy
     • Causes
  – Renal (intrinsic) CRF
     • Changes within the kidneys caused by chronic abnormalities
  – Post-renal CRF
     • Backpressure within the kidneys damages nephrons
     • Causes
  Stages of Chronic Renal Disease
     Stage             Description                  GFR
At Increased Risk   Risk factors for kidney   More than 90mL/min
        1               Kidney damage
                     (protein in the urine)   More than 90 mL/min
                       and Normal GFR
        2           Kidney damage and            60-89 mL/min
                    mild decrease in GFR
        3           Moderate decrease in         30-59 mL/min
        4            Severe decrease in          15-29 mL/min
        5               Kidney Failure        Less than 15 mL/min
                      (dialysis or kidney
                     transplant needed)
 C R F: Clinical Manifestations
• The clinical manifestations of CRF are:
  – GFR < 30mL/min
  – Uremia: described as a decline in renal
    function and the accumulation of toxins in the
  – Uremic symptoms can affect every organ
    system… (uremic syndrome)
   C R F: Uremia Manifestations
    System                             Manifestation
Skeletal           • Bone demineralization
cardiopulmonary • Hypertension, pericarditis, pulmonary edema
Neurologic         • Fatigue, attention deficit, peripheral neuropathy,
                     stupor, coma
Hematologic        • Anemia, bleeding, infection, suppressed immunity
Endocrine          • Retarded growth in children, osteomalacia,
                     increased goiter
Gastrointestinal   • Diarrhea, N & V, anorexia, urinous breath
Integumentary      • Pruritis, pigmentation
Reproductive       • Infertility, decreased libido, impotence, amenorrhea
CRF: Evaluation and Treatment
• Dx
  –   Hx and presenting S&S
  –   Blood values
  –   Ultrasound, intravenous pyelogram or plain x-ray films
  –   Renal biopsy confirms Dx
• Tx:
   • Dietary management
   • Sodium and fluids
   • Potassium
   • Caloric intake
   • Erythropoetin
  If CRF cannot be managed with diet, diuretic and fluid
  restrictions, then dialysis, or transplant becomes necessary.
     First successful transplant-
     Boston 1954

Criteria for Transplant:
•     Age
•     Psychological Status
•     General Health

Options for ESRD:
1.   Dialysis
2.   Transplant
3.   Death without treatment
            Nursing Management
These patients become surgical patients with surgical interventions

Discharge Post Transplant
1. Medication teaching (many medications will be taken for life).
2. Restrict activity for 2 or 3 months post transplant.
3. Weigh daily. Take temperature and blood pressure twice daily.
4. Report signs of infection.
5. Avoid strong sunlight.
6. Discuss family planning and sexuality.
7. Avoid large groups of people for 2 or 3 months post transplant.
8. Comply with dietary restrictions.
Combs, G (1998). The Vitamins: Fundamental Aspects in Nutrition and Health. 2nd ed. San Diego, CA: Academic

Davies S, Phillips L, Griffiths A, Naish P, Russell G (2000). Analysis of the effects of increasing delivered dialysis
    treatment to malnourished peritoneal dialysis patients. Kidney International 57:1743-1754. Retrieved September
    21, 2007

Dorthy, J (1992). Renal Disorders. St. Louis: Mosby.

Food and Nutrition Board, Institute of Medicine (2002). Dietary Reference Intakes for Energy, Carbohydrates, Fiber,
    Fat, Protein, and Amino Acids. Retrieved September 20, 2007 from World Wide Web:

Generation CLIK (2007). The Kidney Foundation. Retrieved September 20, 2007 from the World Wide Web:

Hamburg, J (1997) Structure and Function of the Kidney. Philadelphia: Saunders.

Hekelman, P & Carol, A (2000). Nephrology Nursing: Perspectives of Care. New York: McGraw- Hill.

Kellum, J & Palensky, P (2006). Renal Support in Acute Kidney Injury. The Lancet. Vol. 368, Iss. 9533; p. 344.
     Retrieved September 18, 2007

Lewis S, McLean H, Dirksen, S (2004). Medical-Surgical Nursing: assessment and management of clinical problems 5 th
    edition. St Louis: Mosby

Marcus, S & Zirpin, D (2007). Therapeutic Drug Monitoring of Mood Stabilizers in Renal Patients with Bipolar Disease.
    American Journal of Psychiatry. Vol. 156, Iss. 7; p. 1014 Retrieved September 19, 2007

Merck & Co. (2007). Acute Renal Failure: Merck Manual Professional. Retrieved September 18 th from the World Wide

Novel H, Daniel K, Meyer, J (2007). A concept analysis of renal supportive care: the changing world of nephrology
    Journal of Advanced Nursing Vol. 59, Iss. 6; p. 644 Retrieved September 18, 2007

Timby, B (2004). Introductory Medical Surgical Nursing 7th edition. Philadelphia: Lippincott Williams and Wilkins.