Kidney Function Overview

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Questions and Answers

What is a common symptom of the condition affecting children aged 6 months to 5 years as described?

Hepatic failure

Cyanosis

Pulmonary edema (correct)

Chronic cough

What type of therapy involves the movement of fluid and molecules across a semi-permeable membrane?

Osmosis therapy

Renal replacement therapy

Dialysis (correct)

Diffusion therapy

What is a potential complication during acute renal failure?

Hyperkalemia (correct)

Hypoglycemia

Osteoporosis

Hyperlipidemia

Which dietary restrictions are typically recommended for patients undergoing hemodialysis?

Restricted protein, phosphate, potassium, and fluids Signup and view all the answers

What is a characteristic of hemodialysis?

It circulates blood through a filter Signup and view all the answers

Which of the following renal function tests evaluates the ability of the kidneys to concentrate solutes in urine?

Urine specific gravity Signup and view all the answers

What is the primary extracellular ion regulated by aldosterone?

Sodium Signup and view all the answers

Which condition stimulates the production of erythropoietin?

Decreased oxygen in renal blood flow Signup and view all the answers

What regulates the reabsorption of bicarbonate ions in the kidneys?

Acid-base balance mechanisms Signup and view all the answers

What is the normal range for blood urea nitrogen (BUN) in adults?

2.5 – 7 mmol/L Signup and view all the answers

How does low renal artery pressure affect blood pressure?

Stimulates release of renin and aldosterone Signup and view all the answers

Which metabolic waste product is an indicator of kidney function and relates to muscle metabolism?

Creatinine Signup and view all the answers

What is the consequence of decreased kidney function related to Vitamin D?

Decreased calcium absorption Signup and view all the answers

What is the normal range for specific gravity in urine?

1.010 to 1.025 Signup and view all the answers

Which phase of Acute Kidney Injury (AKI) is characterized by a severe decrease in urine output?

Oliguric phase Signup and view all the answers

What lab value is commonly elevated in chronic renal failure?

Creatinine Signup and view all the answers

Which of the following is NOT a cause of prerenal acute kidney injury?

Nephrotoxic agents Signup and view all the answers

During which phase of AKI is the urine output expected to gradually increase?

Diuretic phase Signup and view all the answers

What is a potential complication related to chronic renal failure?

Hypertension Signup and view all the answers

What is the minimum urine output per hour that indicates normal kidney function?

0.5 mL/kg/hour Signup and view all the answers

What type of diagnostic study involves evaluating the kidneys using energy-based imaging?

Nuclear scans Signup and view all the answers

Which of the following is a primary nursing intervention during the oliguric phase of AKI?

Monitoring daily weight Signup and view all the answers

Which electrolyte is expected to be elevated in kidney failure due to decreased excretion?

Potassium Signup and view all the answers

What is the impact of acute renal failure on blood pH levels?

Decrease due to acid buildup Signup and view all the answers

Which assessment finding would indicate fluid retention in a patient with renal failure?

Weight gain Signup and view all the answers

What is the primary focus in patient education for individuals with renal failure?

Understand dietary restrictions Signup and view all the answers

In which phase of acute kidney injury is metabolic acidosis most likely to occur?

Oliguric phase Signup and view all the answers

What complication is associated with acute renal failure that can lead to fluid accumulation around the heart?

Pericarditis Signup and view all the answers

Which treatment option for acute renal failure involves the continuous removal of waste products through a machine?

Continuous renal replacement therapy Signup and view all the answers

What is a significant risk factor for developing end-stage renal disease (ESRD) following acute renal failure in children?

Infection Signup and view all the answers

Which of the following is a common clinical manifestation in children with acute renal failure?

Oliguric or anuric state Signup and view all the answers

What is the primary mechanism through which hemodialysis removes excess waste and fluid from the blood?

Diffusion Signup and view all the answers

Which of the following dietary restrictions is typically enforced for patients undergoing hemodialysis?

Limited phosphate Signup and view all the answers

What is the most common cause of prerenal acute kidney injury?

Dehydration and hypovolemia Signup and view all the answers

Which phase of acute kidney injury typically results in an abrupt decrease in urine output?

Oliguric phase Signup and view all the answers

What is the primary function of the kidneys regarding blood pressure?

Release of renin Signup and view all the answers

What significant change occurs during the diuretic phase of acute kidney injury?

Gradual increase in urine output Signup and view all the answers

Which metabolic waste product is considered an end product of muscle metabolism and an indicator of kidney function?

Creatinine Signup and view all the answers

Which lab values are expected to increase in chronic renal failure?

Creatinine, potassium, and serum BUN Signup and view all the answers

How do the kidneys maintain acid-base balance in the body?

Through selective reabsorption of bicarbonate ions Signup and view all the answers

What is the primary nursing intervention during the oliguric phase of acute kidney injury?

Limit fluid intake to 600 mL/day plus output Signup and view all the answers

What hormone produced by the kidneys stimulates the production of red blood cells in the bone marrow?

Erythropoietin Signup and view all the answers

What indicates fluid retention in a patient with renal failure?

Increased abdominal girth Signup and view all the answers

Which electrolyte is primarily maintained by aldosterone and plays a crucial role in extracellular fluid balance?

Sodium Signup and view all the answers

During the recovery phase of acute kidney injury, what is a key factor influencing recovery?

The severity of renal failure Signup and view all the answers

What is a common nursing diagnosis for a patient experiencing excess fluid volume due to acute renal failure?

Imbalanced nutrition: less than body requirements Signup and view all the answers

What is the normal urinary pH range that indicates proper kidney function?

7.35 - 7.45 Signup and view all the answers

What happens to urine concentration when the body is dehydrated?

Urine becomes more concentrated Signup and view all the answers

Which assessment finding suggests metabolic acidosis in a patient with acute kidney injury?

Elevated serum potassium levels Signup and view all the answers

In children, which factor is most commonly associated with the development of acute renal failure?

Dehydration or poor perfusion Signup and view all the answers

Which mechanism increases sodium retention in response to low blood pressure?

Renin-angiotensin mechanism Signup and view all the answers

What effect does an increase in bicarbonate reabsorption by the kidneys have on blood pH?

Makes it more alkaline Signup and view all the answers

Study Notes

Kidney Function

Primary functions:
- Removal of metabolic wastes
- Fluid balance
- Electrolyte balance
- Acid-base regulation
- Blood pressure control
- Hormone production
Metabolic wastes:
- Urea:
  - End product of protein metabolism
  - Measured as BUN (Blood Urea Nitrogen)
  - Normal adult range: 2.5 – 7 mmol/L
  - Normal pediatric range: 3.2 – 6.4 mmol/L (age and gender dependent)
- Creatinine:
  - End product of muscle metabolism
  - Indicator of kidney function
  - Normal ranges vary by age and gender
  - Increases with age
Fluid balance:
- Kidney regulates urine concentration (dilute or concentrate) in response to blood osmolarity changes
- Plays a role in maintaining arterial blood pressure
- Dehydration increases blood osmolarity, leading to ADH release, which increases water reabsorption
Electrolyte balance:
- Sodium:
  - Primary extracellular ion
  - Regulated by aldosterone, angiotensin II, and renin
  - Renin release stimulated by decreased renal perfusion or low renal artery pressure
  - Increased sodium retention leads to increased water retention
- Potassium:
  - Primary intracellular ion
- Calcium and magnesium:
  - Also regulated by the kidneys
Acid-base regulation:
- Through selective secretion of hydrogen ions and reabsorption of bicarbonate ions
- Bicarbonate ions are filtered in the glomerulus and reabsorbed in the renal tubules
- Normal pH range: 7.35 - 7.45
- Healthy kidneys excrete 70 mEq of acid per day until urine pH reaches 4.5
- Excess acid is bound to chemical buffers (phosphate and ammonia)
- Phosphate is filtered in the glomerulus
- Ammonia is produced by renal tubule cells
- This allows more acid to be excreted without lowering urine pH
Blood pressure control:
- Decreased renal perfusion or low renal artery pressure stimulates renin, aldosterone, and ADH (anti-diuretic hormone) release.
- Leads to vasoconstriction, increasing blood pressure.
Hormone production:
- Erythropoietin:
  - Stimulates bone marrow to produce red blood cells
  - Released in response to low blood oxygen levels in renal blood flow
  - Deficiency leads to anemia
- Vitamin D:
  - Activated by the kidney
  - Impaired kidney function leads to decreased calcium absorption.

Renal Function Tests

Urine osmolality: Evaluates the kidney's ability to concentrate solutes in urine.
Specific gravity: Evaluates the kidney's ability to concentrate solutes in urine. Normal range is 1.010 to 1.025.
Creatinine clearance: Measures the rate at which creatinine is cleared from the blood.

Diagnostic Studies

Urinalysis and urine culture
Renal function tests
Ultrasonography
CT and MRI
Nuclear scans
Intravenous urography, retrograde pyelography, cystography, renal angiography
Endoscopic procedures
Biopsies

Renal Failure (Acute Kidney Injury)

Definition: Occurs when the kidneys cannot remove waste or perform regulatory functions.
A systemic disorder with various causes.
Acute renal failure: Reversible syndrome characterized by decreased glomerular filtration rate (GFR) and oliguria.
Chronic renal failure (ESRD): Progressive, irreversible deterioration of renal function leading to azotemia.
AKI: Abrupt decrease (within 48 hours) in kidney function.
- Characterized by increased creatinine, decreased urine output.
- Reflects a spectrum of kidney injury.

Consequences of Kidney Damage

Increased creatinine and urea levels in the blood.
Acid buildup in blood, decreasing serum bicarbonate levels and pH.
Sodium retention and increased serum potassium levels.
Renin release leads to increased blood pressure.
Decreased red blood cell production (anemia) leading to fatigue, shortness of breath, and dizziness.
Decreased calcium absorption.

Signs and Symptoms

Fluid retention: Weight gain, peripheral and pulmonary edema, increased blood pressure.
Electrolyte imbalances:
- Hyperkalemia: Can lead to cardiac arrhythmias.
- Hyponatremia: Can lead to weakness, lethargy, confusion.
- Hypokalemia: Can lead to fatigue, weakness, leg cramps.
Anemia:
- Fatigue, weakness, shortness of breath.
Metabolic acidosis: Dyspnea, lethargy, confusion.
Uremic symptoms: Nausea, vomiting, fatigue, confusion.

Causes of Acute Renal Failure

Hypovolemia: Dehydration.
Hypotension: Low blood pressure.
Reduced cardiac output and heart failure: The heart cannot pump enough blood to the kidneys.
Obstruction of the kidney or lower urinary tract: Blockage in the urinary tract.
Obstruction of renal arteries or veins: Blockage in the blood supply to the kidneys.
Nephrotoxic agents: Toxins that damage the kidneys.
Injury: Trauma, burns, and other injuries.

Causes Based on Location of Damage

Prerenal (most common - 70%): Factors outside the kidneys that reduce renal blood flow, leading to decreased GFR.
- Causes: Hypovolemia, decreased cardiac output, decreased peripheral vascular resistance, blocked renal artery, medications (NSAIDs, ACE inhibitors).
Intrarenal (25% of cases): Damage to renal tissue.
- Causes: Glomerulonephritis, burns, crush injuries, severe transfusion reactions, acute tubular necrosis related to nephrotoxins (NSAIDs, acetaminophen), ischemia, toxemia in pregnancy.
Postrenal: Mechanical obstruction of urine outflow, causing backflow into the renal pelvis.
- Causes: Prostatic hyperplasia, prostate cancer, strictures, calculi formations, blood clots.
- High incidence among the elderly.

Chronic Renal Failure (ESRD)

Characterized by changes in lab values:
- Increased creatinine, potassium, serum BUN
- Decreased pH

Phases of AKI

Initiation period: Initial insult to the kidneys.
Oliguric phase: Decreased GFR, typically occurs within 1-7 days after injury and lasts 10-20 days.
- Markedly decreased urine output.
- Increased serum concentration of substances normally excreted by kidneys.
- Longer duration is associated with a poorer prognosis.
Diuretic phase: Gradual increase in urine output (1-5 L/day), lasts 1-3 weeks.
Recovery phase: Lasts 1-2 weeks but can take up to 1 year.
- Lab values return to normal limits.
- Recovery depends on the individual’s overall health, severity of renal failure, cause of failure, and any complications.
- Can lead to chronic kidney disease.

Nursing Process

Assessment:
- Fluid status:
  - Intake and output monitoring is crucial.
  - In oliguric phase, fluid restriction may be necessary.
- Nutritional status:
  - Consult a dietitian to ensure adequate intake and adjust dietary restrictions (protein, potassium, sodium, phosphate, fluids).
- Patient knowledge:
  - Assess understanding of renal failure and its implications.
- Activity tolerance:
  - Monitor patient's ability to perform daily activities.
- Self-esteem:
  - Address potential body image concerns and psychosocial issues.
- Potential complications:
  - Monitor for signs and symptoms of hyperkalemia, pericarditis, pericardial effusion, pericardial tamponade, hypertension, anemia, bone disease, and metastatic calcifications.
Diagnosis:
- Excess fluid volume
- Imbalanced nutrition
- Deficient knowledge
- Risk for situational low self-esteem
Planning:
- Goals:
  - Maintain ideal body weight with no excess fluid.
  - Ensure adequate nutritional intake.
  - Increase patient knowledge regarding renal failure.
  - Promote patient participation in activities within their tolerance.
  - Improve self-esteem.
  - Prevent complications.
- Nursing actions:
  - Accurate intake and output monitoring throughout all phases of AKI.
  - Fluid restriction in oliguric phase (typically 600 mL/day plus previous 24-hour output).
  - Education regarding fluid restrictions.
  - Assistance with coping with fluid restrictions.
  - Frequent oral hygiene to promote self-esteem.
  - Daily weight monitoring at the same time each day.
  - Vital sign monitoring, particularly blood pressure and edema assessment.
  - Nutritional monitoring and consultation with a dietitian (high carb, low potassium, sodium, protein, phosphate, and fluid restriction).
  - Monitor laboratory values for electrolyte imbalances and other abnormalities.
  - Assess for infections.

ARF in Children

Most common causes: Dehydration or poor perfusion (trauma, crush injuries, low blood pressure, fever).
Prerenal: Related to diarrhea, vomiting, surgery, and trauma.
Oliguria: Less than 1 mL/kg/hr.
Treatment and nursing actions similar to adults.
Fluid restrictions: 400 mL/day plus 24-hour output (weight-dependent).

Hemolytic Uremic Syndrome (HUS) in Children

Also known as thrombotic thrombocytopenic purpura (TTP) in adults or Hamburger disease.
Acute renal disease characterized by:
- Acute renal failure often triggered by E.coli infection.
- Hemolytic anemia: Red blood cells are destroyed faster than they can be created.
- Thrombocytopenia: Low platelet count.
Typically affects children 6 months to 5 years.
Often follows acute GI or upper respiratory tract infections.
Signs and symptoms: Oliguria or anuria, seizures, stupor, pulmonary edema.
May last 1-2 weeks.
5% mortality rate; 10% develop ESRD.

Collaborative Problems and Potential Complications

Hyperkalemia: High potassium levels can lead to cardiac arrhythmias.
Pericarditis: Inflammation of the pericardium, the sac surrounding the heart.
Pericardial effusion: Accumulation of fluid in the pericardium.
Pericardial tamponade: Compression of the heart due to excessive fluid in the pericardium.
Hypertension: High blood pressure.
Anemia: Low red blood cell count.
Bone disease and metastatic calcifications: Due to altered calcium and phosphate metabolism.

Treatment Options for Acute Renal Failure

Hemodialysis: Rapid removal of fluid, urea, creatinine, and potassium.
- Blood is circulated through a filter.
- Requires vascular access (central line, arteriovenous fistula, or graft).
- Typically performed 3 times per week for 4 hours each session.
- Requires dietary restrictions (protein, phosphate, potassium, fluids).
- Medications may be required (antihypertensives, phosphate binders, vitamins).
Continuous renal replacement therapies (CCRT): A type of dialysis that can be used for patients who are critically ill or unstable.

Dialysis

Definition: Uses a semi-permeable membrane to separate two solutions, enabling the movement of fluid and molecules.
- Osmosis: Movement of water from an area of low solute concentration to an area of high solute concentration.
- Diffusion: Movement of molecules or ions from a region of higher concentration to a region of lower concentration.

Hemodialysis

Rapid removal of fluid, urea, creatinine, and potassium.
Blood is circulated through a filter.
Requires vascular access (central line, arteriovenous fistula, or graft).
Patients are typically hooked up to a machine for 4 hours, 3 times per week.
Dietary restrictions: Protein, phosphate, potassium, and fluid intake.
Medications: Antihypertensives, phosphate binders, vitamins.

Note:

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Kidney Functions

Metabolic waste removal: The kidneys filter waste products from the blood, including urea (from protein breakdown), creatinine (from muscle metabolism)
Fluid balance: Regulates fluid levels by concentrating or diluting urine based on blood osmolality. Increased osmolality triggers ADH (antidiuretic hormone) for water reabsorption, leading to concentrated urine.
Electrolyte balance: Controls electrolyte levels like sodium (regulated by aldosterone, angiotensin II, and renin), potassium, calcium, and magnesium.
Acid-base regulation: Maintains blood pH by selectively excreting hydrogen ions and reabsorbing bicarbonate ions. Kidneys can excrete up to 70 mEq of acid per day, assisted by phosphate and ammonia buffers.
Blood pressure control: Decreased renal perfusion triggers renin, aldosterone, and ADH release, resulting in vasoconstriction and increased blood pressure.
Hormone production: Produces erythropoietin, stimulating red blood cell production, and activates vitamin D for calcium absorption.

Renal Failure

Acute Kidney Injury (AKI): Sudden decrease in kidney function within 48 hours.
- Characterized by increased creatinine and decreased urine output (oliguria).
- Is usually reversible.
- Causes: Hypovolemia, hypotension, reduced cardiac output, obstruction in the kidney or urinary tract, nephrotoxic agents, injuries.
Chronic Renal Failure (ESRD): Progressive, irreversible deterioration of kidney function leading to azotemia (severe waste buildup in the blood).
- Signs: Increased creatinine and urea, decreased pH, electrolyte imbalances (hyperkalemia, hyponatremia), hypertension, anemia, and decreased calcium absorption.

Acute Renal Failure (AKI)

Phases:
- Initiation Phase: The initial insult to the kidneys.
- Oliguric Phase: Decreased glomerular filtration rate (GFR) leading to reduced urine output (usually 1-7 days after injury).
  - Increased serum concentrations of substances normally excreted by kidneys.
  - Can last 10-20 days.
- Diuretic Phase: Gradual increase in urine output (1-5 L/day).
  - Monitor for electrolyte imbalances (hyponatremia, hypokalemia).
- Recovery Phase: Lab values return to normal (can take 1-2 weeks, up to a year).
  - Recovery influenced by overall health, severity of AKI, and complications.
  - Can progress to Chronic Kidney Disease.

Diagnostic Studies

Urinalysis and urine culture: Evaluate urine components for abnormalities.
Renal function tests: Assess kidney function (creatinine, BUN, creatinine clearance).
Ultrasonography: Visualize the kidneys and urinary tract.
CT and MRI: Provide detailed images of the kidneys and surrounding structures.
Nuclear scans: Use radioactive material to assess kidney function.
Intravenous urography, retrograde pyelography, cystography, renal angiography: Imaging techniques to visualize the kidneys, ureters, and bladder.
Endoscopic procedures: Visualize the inside of the urinary tract.
Biopsies: Obtain tissue samples for diagnosis.

Treatment Options for Acute Renal Failure

Hemodialysis: Rapid removal of fluids, urea, creatinine, and potassium.
- Blood circulated through a filter.
- Requires a vascular access (central line, arteriovenous fistula, or graft).
- Performed 3 times a week, typically for 4 hours each session.
- Requires dietary restrictions (protein, phosphate, potassium, fluids).
Continuous Renal Replacement Therapies (CCRT): Continuous method of blood filtering for patients with unstable hemodynamics.

Hemolytic Uremic Syndrome (HUS)

An acute renal disease in children (6 months to 5 years).
- Usually follows a gastrointestinal or respiratory infection.
- Characterized by:
  - Acute renal failure
  - Hemolytic anemia
  - Thrombocytopenia
- Signs: Oliguria, anuria, seizures, stupor, pulmonary edema.
- Can lead to end-stage renal disease in 10% of cases.

Nursing Considerations

Fluid Status: Monitor intake and output, restrict fluids (especially during oliguric phase), and assess for edema.
Nutritional Status: Consult with a dietitian for appropriate dietary restrictions (low potassium, sodium, phosphate, high carbohydrates, protein restrictions may be necessary).
Patient Knowledge: Educate patients and families about renal failure, treatment options, and self-care.
Activity Tolerance: Assess activity level and provide appropriate interventions for fatigue.
Self-Esteem: Address potential issues related to body image, sexual function, and fluid restrictions.
Potential Complications: Monitor for hyperkalemia, pericarditis, hypertension, anemia, and bone disease.

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Description

This quiz covers the essential functions of the kidneys, including waste removal, fluid and electrolyte balance, and hormone production. Explore how the kidneys regulate blood pressure and maintain acid-base balance through various metabolic processes. Test your knowledge on key concepts such as urea, creatinine, and urine concentration.