Adult 2 Unit 2

Kidney and Urinary Systems

Provides hormones involved in: 

• red blood cell production

• bone metabolism 

• Control of blood pressure

Regulates fluid and electrolytes

Removes wastes  

Structures

• Kidneys

• Ureters

• Bladder

• Urethra 

Diagnostic Studies

• Urinalysis and urine culture

• Renal function tests (refer to Table 48-5)

• Ultrasonography

• CT and MRI

• Nuclear scans

• Endoscopic procedures

• Biopsies

• IV urography 

• Retrograde pyelography

• Cystography

• Renal angiography

The KDIGO Clinical Practice Guideline for AKI (2024) defines AKI (Acute Kidney Injury) as:

Increase in serum creatinine by 0.3 mg/dL or more within 48 hours

OR

Increase in serum creatinine to 1.5 or more times (50% or more) the patient’s baseline, which is known or presumed to have occurred within the prior 7 days

OR

Urine output less than 0.5 mL/kg/h for greater than 6 hours

AKI / ARF

1368-1373

Acute renal failure can have many etiologies 

Characterized by a sudden onset and rapid decline of renal function

Almost a complete loss of function in a period of hours to days

Kidneys unable to remove metabolic wastes

Cannot perform regulatory functions

Substances accumulate

Disruptions in both endocrine and metabolic functions

Fluid, electrolyte and acid-base problems develop

Acute vs Chronic 

• Acute –

  • lethargic, ill, dry skin & mucous membranes, central nervous symptom s/s, decreased GFR of sudden onset (GFR- 125mL/min/1.73m²)

• Chronic –

  • progressive, irreversible loss of function, eventually affects other organ systems leading to end-stage renal disease (ESRD)

Acute Kidney Injury

• Characterized by a rapid loss of kidney function. 

  • Rise in serum creatinine level and/or a reduction in urine output. 

  • Serum creatinine: 0.6-1.2 mg/dL (male)  0.4-1.0 mg/dL (female) 

  • Can develop over hours or days

Acute Renal Failure

• Risk Factors

  • Hx of HTN, DM

  • Recent use/exposure to nephrotoxic agents, heavy metals or organic solvents

  • Recent severe hypotensive episode

  • Presence of tumor or obstruction

  • Recent infections

  • Idiopathic / unknown

• Wide range of possibly life threatening metabolic issues

• Metabolic acidosis

• Fluid / electrolyte imbalances

Effects of Aging on Urinary System/Gerontologic Considerations

• Between ages 30 and 90

  • Size and weight of kidneys decrease 20% to 30% 

• By seventh decade

  • Loss of 30% to 50% of glomerular function

• Atherosclerosis accelerates decrease of renal size with age

• Physiologic changes

  • Loss Between ages 30 and 90

  • Size and weight of kidneys decrease 20% to 30% 

• By seventh decade

  • Loss of 30% to 50% of glomerular function

• Atherosclerosis accelerates decrease of renal size with ageof elasticity and muscle support

  • Decreased renal blood flow

    • Results in decreased GFR

  • Altered hormonal levels result in

    • Decreased ability to concentrate urine

    • Altered excretion of water, sodium, potassium, and acid

  • Prostate enlargement

Gerontologic Considerations

• More susceptible to AKI

  • Dehydration due to polypharmacy- diuretics & laxatives

  • Illness and immobility

  • Hypotension

  • Aminoglycoside therapy

  • Obstructive disorders

  • Surgery

  • Infection

• Under normal conditions, the aging kidney is able to maintain homeostasis. 

• However, after abrupt changes in blood volume, acid load, or other insults, the kidney may not be able to function effectively because much of its reserve has been lost.

Categories of ARF

Chart 49-4

Causes: Prerenal, Intrarenal, Postrenal

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Prerenal Causes

• Volume depletion

  • Hemorrhage, overuse of diuretics, excessive GI losses (vomiting, diarrhea), severe dehydration 

• Impaired cardiac function

  • Heart failure, MI, cardiogenic shock, valve disease, damage to renal artery

• Vasodilation

  • Medications, anaphylaxis, sepsis

Intrarenal Causes

• Prolonged renal ischemia

  • Myoglobinuria (burns, massive trauma, injuries involving a large amount of muscle damage); hemoglobinuria 

• Nephrotoxic agents

  • Aminoglycosides antibiotics , NSAIDS, radiopaque contrast agents

• Infection

  • Pyelonephritis, glomerulonephritis, etc. (e. coli, various bacteria, fungi, protozoan or viral causes)

Intrarenal Failure

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Postrenal Causes

• Obstruction in flow of urine from ureters to external urethral opening

  • Urolithiasis (stones), blood clots or stricture

  • Tumors (prostate, ovarian or cervical or colon cancer)

  • Bladder dysfunction 

  • Obstruction (benign prostatic hyperplasia, obstructed indwelling urinary catheter, ureteral obstructions)

  • Trauma 

Obstructions to urine outflow

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Obstructions to urine outflow

Obstruction

• Increased pressure in kidney structures

Pressures interfere with function

• Can’t filter or regulate wastes / fluids

Tissue injury occurs

• GFR decreases

Hydronephrosis

• Kidney Failure

Acute Kidney Injury Progression

AKI may progress through phases: oliguric, diuretic, and recovery.

When a patient does not recover from AKI, then CKD may develop.

Oliguria

UOP < 400 mL/day

Minimum amount of urine required to rid the body of waste products is 400 mL/day

Anuria: 

UOP < 50 mL/day

Uremia:

Excess of urea and other nitrogenous wastes in blood

Azotemia

Abnormal concentration of nitrogenous wastes in blood

Diagnostics

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Urine Studies

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Radio-contrast induced nephropathy

• Contrast-induced nephropathy

  • Some contrast agents can result in nephrotoxic injury

  • Major cause of hospital acquired ARF

• Identify patients at risk before procedures

• Baseline Cr > 2.0 mg/Dl = high risk

• Recommendations

  • pre-procedure hydration may be considered

  • Use of other diagnostic procedures - ultrasound

• Client receiving metformin 

  • Should be held 48 hours prior and post procedure to decrease risk of lactic acidosis* 

    • Follow your institution’s policy. Guidelines and opinions vary

Phases of AKI / ARF

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Oliguric Phase

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Oliguric Phase: Clinical Manifestations

• Fluid overload

  • Contributes to heart failure, pulmonary edema, pericardial or pleural effusions

• Elevated BUN, CR

• Neuro symptoms

  • Fatigue, difficulty concentrating, seizures, stupor, coma

• Hypermagnesemia

  • Kidneys cannot excrete magnesium

• Hypocalcemia:

  • Kidneys cannot produce the active component of vit D in order to absorb calcium through GI tract

• Hyperphosphatemia

  • Low calcium = high phosphorus

• Metabolic acidosis

  • Impaired kidney cannot excrete hydrogen ions

  • Serum bicarbonate  decreases

    • Existing levels depleted attempting to buffer acids

    • Also production is affected

  • Severe acidosis develops

• Kussmaul respirations

Diuretic Phase: Clinical Manifestations

• Begin to see increases in UOP 

  • 1 to 3 L (can get up to 5 L / a day!) 

  • Glomerular filtration is recovering

  • Improvement in ability to excrete wastes

  • BUT – can’t concentrate urine

• Lab values begin to normalize

• Uremic symptoms may still be present

• Volume may reach normal or elevated levels

• At risk for excess fluid loss

• Monitor for:

  • Hyponatremia

  • Hypokalemia

  • Dehydration

Recovery Phase

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AKI Complications

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Prevention of AKI/ARF

AKI Medical Management

Pharmacologic Therapy 

• Loop Diuretics

  • Furosemide or bumetanide may be prescribed to promote diuresis. 

  • Help remove excess fluid and manage fluid overload. 

  • May increase urine output but do not repair kidney damage. 

• IV Fluids and Volume Replacement

  • IV fluids may restore kidney perfusion in patients with prerenal AKI caused by hypovolemia. 

  • Blood products may be administered when volume or blood replacement is indicated. 

  • Albumin may be prescribed when hypovolemia is caused by low protein levels. 

• Medication Safety

  • Discontinue medications that are toxic to the kidneys. 

  • Adjust medication dosages according to kidney function or creatinine clearance. 

  • Avoid radiographic contrast when possible.

Nutritional Therapy 

AKI increases metabolism and tissue breakdown, placing patients at high risk for malnutrition. Nausea and vomiting may further reduce nutritional intake.

• Monitor weight daily. 

• Weight loss may indicate that calorie intake is below the patient’s needs. 

• Weight gain, failure to lose weight, or hypertension may indicate fluid retention. 

• Provide a high-protein, high-calorie diet. 

• Individualize nutrition based on the cause of AKI, degree of tissue breakdown, kidney replacement therapy, other health conditions, and nutritional status. 

• Include a renal dietitian as an essential member of the healthcare team.

Nutritional Therapy

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Nutritional imbalances in AKI

• Caused by nausea, vomiting, inadequate dietary intake

• Impaired glucose use and protein synthesis

• Increased tissue catabolism

Weight monitoring

• Daily weight checks are essential

• Loss of 0.2–0.5 kg (0.5–1 lb) per day may indicate negative nitrogen balance (caloric intake < requirements)

• Weight gain, no weight loss, or development of hypertension may indicate fluid retention

Nutritional support considerations

• Based on: underlying cause of AKI, catabolic response, type/frequency of renal replacement therapy (RRT), comorbidities, and nutritional status

• Protein replacement is individualized to maximize benefit and minimize uremic symptoms

Dietary approach

• High-carbohydrate meals to spare protein for growth/tissue healing

• Restrict sodium, potassium, and phosphorus-containing foods (e.g., bananas, citrus fruits/juices, dairy products)

Phases of AKI

How long they last

• Oliguric phase: lasts 10–14 days

• Diuretic phase: urine output increases, signals beginning of recovery phase

Fluid and electrolyte management

• Guided by blood chemistry results and daily weights

• Replace sodium, potassium, and water as needed, avoiding over- or underhydration

Post-diuretic phase

• High-protein, high-calorie diet

• Gradual return to normal activities

Focused Renal Assessment

• Physical (cardiopulmonary, renal and overall hemodynamic status)

• Previous renal problem history

• Recent use of nephrotoxic substances

• Recent exposure to heavy metals or organic solvents

• Hypotensive episode of > 25 minutes

• Tumors or clots in renal area

• Presence of infection

Nursing Assessment

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Nursing Assessment

• Pulmonary 

  • Assess for signs of circulatory overload.

• Cardiac 

  • Assess for signs of decreased cardiac output

  • Auscultate heart sounds for presence of third heart sound (could indicate heart failure)

Nursing Diagnoses and Collaborative Problem

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Nursing Interventions - AKI

• Monitor fluid / electrolytes

  • I’s and O’s (include all emesis, drainage, stools)

  • Lab values

  • S/sx of hyperkalemia (cardiac* and musculoskeletal systems)

  • Weigh daily

• Monitor heart rhythms, serum electrolytes

• Monitor s/sx metabolic acidosis

• If peripheral edema is present, move the patient gently and reposition often.

• Give oral and IV fluids as prescribed BUT administer IV medications in least amount of fluid possible.

• Administer medications (e.g., diuretics) as prescribed.

  • Diuretic therapy requires close supervision because reduced blood volume can result in inadequate renal perfusion.

•  Client may require renal replacement therapy if indicated.

  • Therapy clears the body of excess fluid and waste products. Renal replacement therapy may be needed to clear solutes, and dehydration should be treated.

Nursing Interventions: Hyperkalemia

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Treatment Options for Renal Failure

• Hemodialysis

• Peritoneal dialysis

• Continuous renal replacement therapies (CCRT)

Renal Replacement Therapy (RRT)

Alternative or adjunctive method for treating ARF

Means by which uremic toxins and fluids are removed

Acid–base status/electrolytes adjusted slowly and continuously 

Renal Replacement Therapy (RRT)

Indications

• Volume overload

• Elevated serum potassium level

• Metabolic acidosis 

• BUN level > 120 mg/dL (43 mmol/L)

• Significant change in mental status

• Pericarditis, pericardial effusion, or cardiac tamponade

Evaluation - AKI

• The expected outcomes are that the patient with AKI will

  • Regain and maintain normal fluid and electrolyte balance

  • Adhere to the treatment regimen

  • Experience no complications

  • Have complete recovery

Health Promotion - AKI

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Urolithiasis and Nephrolithiasis

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• Urolithiasis refers to stones anywhere in the urinary tract. 

• Nephrolithiasis refers specifically to kidney stones. 

• Stones may develop in one or both kidneys and vary greatly in size. 

• Kidney stones are common and frequently recur. 

Urolithiasis and Nephrolithiasis

How Stones Form 

• Stones develop when substances in the urine become highly concentrated and form crystals. Common substances include:

  • Calcium oxalate 

  • Calcium phosphate 

  • Uric acid 

  • Calcium-based stones are the most common.

Urolithiasis and Nephrolithiasis

Major Risk Factors 

• Dehydration 

• Urinary tract infections 

• Urinary stasis 

• Immobility 

• High blood or urine calcium 

• Abnormal urinary tract anatomy 

• Gout or metabolic disorders 

• Inflammatory bowel disease, ileostomy, or bowel resection 

• Certain medications and supplements

Types of Stones 

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Urolithiasis and Nephrolithiasis

Clinical Manifestations 

• Deep aching pain in the costovertebral or flank area 

• Hematuria and sometimes pyuria 

• Pain radiating toward the bladder, genitalia, or thigh 

• Urinary frequency or urgency with only a small amount of urine passed 

• Nausea, vomiting, diarrhea, or abdominal discomfort 

• Fever and chills if infection is present 

• Renal colic causes sudden, severe flank pain with costovertebral tenderness, nausea, and vomiting.

• Ureteral colic causes severe, wave-like pain that radiates to the thigh or genital area. Blood may appear in the urine as the stone irritates the urinary tract.

• Bladder stones may cause irritation, UTI, hematuria, or urinary retention.

Urolithiasis and Nephrolithiasis

Assessment and Diagnostic Findings 

• Urinalysis: Checks for blood, infection, crystals, and other abnormalities. 

• Imaging: May include kidney, ureter, and bladder x-rays; noncontrast CT; or abdominal ultrasound. 

• Blood tests: Evaluate substances associated with stone formation. 

• 24-hour urine collection: Measures calcium, uric acid, creatinine, sodium, urine pH, and total urine volume. 

• Health history: Reviews diet, medications, and family history of kidney stones. 

• Stone analysis: Determines the stone’s chemical composition and may identify the underlying metabolic disorder. 

Urolithiasis and Nephrolithiasis

Medical Management 

Treatment goals are to:

• Remove or help the stone pass 

• Relieve pain and obstruction 

• Treat infection 

• Prevent kidney damage 

• Identify the stone type and prevent recurrence 

General Management

• Administer opioids or NSAIDs for renal colic. 

• NSAIDs also decrease prostaglandins, swelling, and ureteral pressure. 

• Encourage fluids unless contraindicated by vomiting, heart failure, or fluid restrictions. 

• Recommend 8–10 glasses of water daily and a urine output greater than 2 L/day.

Nutritional and Medications by Stone Type 

• Calcium stones: Liberal fluids; calcium restriction may be recommended for certain patients. Thiazide diuretics may reduce urinary calcium. 

• Uric acid stones: Follow a low-purine diet and avoid foods such as organ meats, shellfish, anchovies, asparagus, and mushrooms. Allopurinol may lower uric acid and reduce stone size. 

• Cystine stones: Increase fluids, follow a low-protein diet, and alkalinize the urine with potassium alkali salts. 

• Oxalate stones: Increase fluids and limit high-oxalate foods, including spinach, Swiss chard, chocolate, peanuts, and pecans. 

Urolithiasis and Nephrolithiasis

Interventional Procedures 

• Ureteroscopy

• Extracorporeal shock wave lithotripsy 

• Percutaneous stone removal

Urolithiasis and Nephrolithiasis

Surgical Management 

• Nephrolithotomy

• Urterolithotomy

• Cystotomy 

• Pyelolithotomy 

• Nephrectomy

Ureteroscopy

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Percutaneous Nephrolithotomy

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Patient Education for Renal Calculi

Nursing Interventions for Renal Calculi

• Assess

  • Pain 

  • n/v/d

  • Abd Distention 

  • UTI

  • Obstruction

  • Strain urine  

• Increase fluid intake

• Monitor I/O

• Monitor for infection 

• Sudden increase in pain 

• VS

• Patient education