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HLT-LPN37-03 · Lesson 7 · 14 clock hours · theory

Renal and Urinary Disorders: Kidney Function, UTI, Renal Failure, and Dialysis

Objective. Students will explain nursing care priorities for patients with urinary tract infections, acute kidney injury, chronic kidney disease, and patients receiving dialysis, including monitoring intake and output and interpreting relevant laboratory values.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed clinician in the field or by a certification or approval body. It is a study draft and may contain errors. Do not use it to make decisions about any patient or medication. Always follow your instructor, your supervising professional, and current official references and regulations.

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How the Kidneys Work

The kidneys are paired organs that filter blood continuously, removing waste products and excess fluid while regulating electrolyte balance, acid-base balance, and blood pressure. Each kidney contains about one million nephrons — the functional filtering units. Blood enters the glomerulus, where filtration occurs; the filtrate then passes through the tubules, where substances are selectively reabsorbed or secreted. The end product, urine, drains through the ureters to the bladder and exits via the urethra. Healthy kidneys also produce erythropoietin, which stimulates red blood cell production, and activate vitamin D for calcium absorption.

Normal urine output is approximately 0.5 mL/kg/hour in adults. Monitoring intake and output (I&O) is one of the most important nursing responsibilities in any patient with a renal or urinary condition. Output below 30 mL/hour in an adult is a significant warning sign that must be reported.

Urinary Tract Infections (UTI)

A UTI is a bacterial infection affecting any part of the urinary tract. Lower UTIs (cystitis) involve the bladder; upper UTIs (pyelonephritis) involve the kidneys and are more serious. Common causative organisms include Escherichia coli. Risk factors include female anatomy, urinary catheterization, diabetes, and urinary stasis.

Clinical manifestations of cystitis include dysuria (painful urination), urinary frequency and urgency, cloudy or foul-smelling urine, and suprapubic discomfort. Pyelonephritis adds flank pain, fever, chills, and nausea. Older adults may present atypically with confusion or a change in mental status rather than classic urinary symptoms.

Urinalysis findings in UTI include elevated white blood cells (pyuria), presence of bacteria (bacteriuria), nitrites (from bacterial metabolism), and possibly red blood cells. A urine culture identifies the organism and guides antibiotic selection.

Nursing priorities include encouraging fluid intake (unless contraindicated), ensuring the patient completes the full antibiotic course, teaching perineal hygiene (front to back), and monitoring for signs of systemic infection. For catheterized patients, maintaining a closed drainage system and removing the catheter as soon as clinically possible are essential infection-prevention measures.

Acute Kidney Injury (AKI)

AKI is a sudden decline in kidney function, classified by cause:

Key laboratory changes in AKI include elevated blood urea nitrogen (BUN) and serum creatinine (azotemia), hyperkalemia (elevated potassium — a life-threatening concern because it causes cardiac arrhythmias), metabolic acidosis, and hyperphosphatemia. Urine output may be low (oliguria: less than 400 mL/day) or absent (anuria).

Nursing priorities: strict I&O monitoring, daily weights, cardiac monitoring for hyperkalemia, restricting potassium and fluid intake as ordered, avoiding nephrotoxic medications, and communicating changes in urine output promptly to the provider.

Chronic Kidney Disease (CKD)

CKD is a progressive, irreversible loss of kidney function over months to years, staged 1–5 based on the glomerular filtration rate (GFR). Stage 5 (GFR below 15 mL/min) is end-stage renal disease (ESRD), requiring dialysis or transplant to sustain life. Common causes include diabetes mellitus and hypertension.

As CKD progresses, the kidneys lose their ability to excrete waste and regulate electrolytes, leading to accumulating BUN and creatinine, hyperkalemia, hyperphosphatemia, metabolic acidosis, and fluid overload. Decreased erythropoietin production causes anemia (low hemoglobin). Uremia — the buildup of uremic toxins — causes fatigue, nausea, pruritus (itching), and cognitive changes.

Nursing priorities include dietary management (protein, potassium, phosphorus, and sodium restrictions; phosphate binders as ordered), monitoring blood pressure, administering erythropoiesis-stimulating agents as ordered, patient education about disease progression, and psychosocial support.

Dialysis Nursing Care

Dialysis replaces lost kidney function by removing waste products and excess fluid.

Hemodialysis (HD) passes the patient's blood through an external dialyzer (artificial kidney) using a semipermeable membrane. Access options include an arteriovenous (AV) fistula (preferred long-term access), AV graft, or temporary central venous catheter. AV fistula precautions: never take blood pressure, draw blood, or start an IV in the fistula arm. Assess the fistula by palpating for a thrill (vibration) and auscultating for a bruit (sound of blood flow); absence of either indicates a problem and must be reported immediately. During HD, monitor blood pressure, weight, and signs of disequilibrium syndrome (headache, confusion, seizure — caused by rapid fluid and solute shifts).

Peritoneal dialysis (PD) uses the patient's own peritoneum as the semipermeable membrane. Dialysate is instilled into the peritoneal cavity, allowed to dwell, then drained. Key nursing concerns include strict aseptic technique to prevent peritonitis (watch for cloudy effluent, fever, and abdominal pain) and accurate recording of dwell time and drainage volume.

Dietary restrictions for dialysis patients generally include limits on potassium (avoid bananas, oranges, potatoes), phosphorus (avoid dairy, nuts, cola), sodium, and fluid intake. Restrictions are individualized by the care team.

Psychosocial support: ESRD and dialysis impose significant lifestyle burdens — frequent treatment sessions, dietary restrictions, fatigue, and loss of independence. The LPN supports patients by listening, providing consistent care, connecting patients with social work and support groups, and reinforcing that feelings of grief and frustration are normal.

Safety Priorities

Key terms10

Glomerular Filtration Rate (GFR)A measure of how well the kidneys filter blood per minute; used to stage chronic kidney disease, with lower values indicating greater kidney impairment.
AzotemiaElevated levels of nitrogen-containing waste products (BUN and creatinine) in the blood, indicating reduced kidney excretion.
OliguriaUrine output less than 400 mL in 24 hours (or less than 30 mL/hour in adults); a key sign of acute kidney injury.
HyperkalemiaAbnormally elevated serum potassium; a life-threatening complication of kidney failure that can cause dangerous cardiac arrhythmias.
AV FistulaA surgically created connection between an artery and vein, usually in the forearm, used as the preferred long-term vascular access for hemodialysis; identified by a palpable thrill and audible bruit.
UremiaA clinical syndrome resulting from the accumulation of uremic toxins in the blood due to severely reduced kidney function; symptoms include fatigue, nausea, pruritus, and confusion.
PeritonitisInflammation or infection of the peritoneum; a serious complication of peritoneal dialysis, signaled by cloudy dialysate effluent, fever, and abdominal pain.
ErythropoietinA hormone produced by the kidneys that stimulates red blood cell production; deficiency in CKD leads to anemia.
Disequilibrium SyndromeA complication of hemodialysis caused by rapid fluid and solute shifts, manifesting as headache, confusion, nausea, or seizures during or shortly after treatment.
PyuriaThe presence of white blood cells in the urine, indicating infection or inflammation in the urinary tract.

Worked examples3

1. A patient's fluid intake for the 8-hour shift was: IV fluids 250 mL, oral fluids 180 mL, and one tube feeding flush of 60 mL. Urine output was 240 mL. Calculate fluid balance for the shift and determine whether output meets the minimum safe threshold.
  1. Step 1 — Calculate total intake: 250 mL (IV) + 180 mL (oral) + 60 mL (flush) = 490 mL intake.
  2. Step 2 — Record urine output: 240 mL output for 8 hours.
  3. Step 3 — Calculate fluid balance: 490 mL intake − 240 mL output = +250 mL (positive balance, meaning the patient retained more fluid than excreted).
  4. Step 4 — Check hourly urine rate: 240 mL ÷ 8 hours = 30 mL/hour. This is exactly at the minimum acceptable threshold (30 mL/hour). Any further drop must be reported to the provider promptly.
Answer: Fluid balance is +250 mL for the shift. Urine output is 30 mL/hour — at the lower limit of normal. The nurse should continue to monitor closely and report any decline.
2. A simulated patient's lab results show serum potassium 6.2 mEq/L and BUN 58 mg/dL. Identify whether these values are abnormal and state the clinical significance for a patient with AKI.
  1. Step 1 — Compare to normal ranges: Potassium normal range is approximately 3.5–5.0 mEq/L; BUN normal range is approximately 7–20 mg/dL.
  2. Step 2 — Potassium 6.2 mEq/L is above the upper limit — this is hyperkalemia. In AKI, the kidneys cannot excrete excess potassium.
  3. Step 3 — BUN 58 mg/dL is well above the upper limit — this indicates azotemia, meaning nitrogenous wastes are accumulating because the kidneys are not filtering adequately.
  4. Step 4 — State clinical significance: Hyperkalemia is a medical emergency because elevated potassium can cause life-threatening cardiac arrhythmias. Elevated BUN signals reduced kidney clearance and risk of uremia.
Answer: Both values are critically abnormal. Potassium 6.2 mEq/L (normal ~3.5–5.0) indicates hyperkalemia requiring immediate notification of the provider and cardiac monitoring. BUN 58 mg/dL (normal ~7–20) confirms azotemia consistent with AKI.
3. During a hemodialysis session, a patient complains of a sudden headache and appears confused. Identify the likely complication, explain why it occurs, and list two immediate nursing actions.
  1. Step 1 — Recognize the complication: Sudden headache and confusion during or after hemodialysis are classic signs of disequilibrium syndrome.
  2. Step 2 — Explain pathophysiology: Rapid removal of urea and other solutes from the blood creates an osmotic gradient; water shifts into brain cells, causing cerebral edema.
  3. Step 3 — Immediate nursing action 1: Slow or stop the dialysis treatment as directed by the dialysis nurse or provider and stay with the patient.
  4. Step 4 — Immediate nursing action 2: Notify the provider and monitor neurological status (level of consciousness, pupils, vital signs) frequently; be prepared to manage seizure activity if it develops.
Answer: Disequilibrium syndrome. Actions: slow or stop dialysis per protocol and provider order; notify the provider and monitor neurological status closely.

The math in this lesson1

Learners total 490 mL intake, find a +250 mL fluid balance, and compute 30 mL/hour urine output.
6.RP.3
Brush up in the math halls at newSchoolWorks.com:
In class: Lecture covering kidney function, urinalysis interpretation, pathophysiology and clinical manifestations of UTI, acute kidney injury (prerenal, intrarenal, postrenal), and chronic kidney disease staging; students complete a graphic organizer comparing AKI and CKD across etiology, labs, and nursing priorities. · Lab-value analysis exercise: students receive a printed set of comprehensive metabolic panels from three simulated patients at different CKD stages; they identify abnormal BUN, creatinine, potassium, phosphorus, and hemoglobin values, state clinical significance, and write two nursing interventions per patient. · Group discussion on dialysis nursing care: instructor presents hemodialysis and peritoneal dialysis with visual diagrams; students discuss AV fistula access precautions, monitoring during and after dialysis, dietary restrictions, and psychosocial support needs of patients with end-stage renal disease.
Materials: Lewis's Medical-Surgical Nursing, printed CMP lab results worksheets, urinalysis reference chart, diagrams of hemodialysis and peritoneal dialysis circuits, dietary restriction handout
Check: Students correctly identify all abnormal values on the lab analysis worksheet and state appropriate nursing actions; pass = 80% on a 15-item quiz covering renal pathophysiology, lab interpretation, and nursing interventions.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

Safe and Effective Care Environment
1. A nurse is caring for a patient with a urinary catheter. Which action is most important in preventing catheter-associated urinary tract infection (CAUTI)?
Physiological Integrity
2. A patient with acute kidney injury has a serum potassium of 6.5 mEq/L. Which assessment finding requires the most immediate nursing action?
Physiological Integrity
3. A patient receiving peritoneal dialysis reports that the drained dialysate looks cloudy rather than clear. The nurse should first:
Safe and Effective Care Environment
4. The nurse assesses a patient's hemodialysis AV fistula and cannot detect a thrill or bruit. Which action is the priority?
Health Promotion and Maintenance
5. Which dietary instruction is most appropriate for a patient with stage 4 chronic kidney disease?
Physiological Integrity
6. A patient is admitted with oliguria following three days of vomiting and poor fluid intake. This presentation is most consistent with which type of acute kidney injury?
Physiological Integrity
7. An older adult patient with a UTI presents with new onset confusion but denies dysuria or frequency. Which statement best explains this presentation?
Physiological Integrity
8. A nurse reviews lab results for a patient with chronic kidney disease and notes hemoglobin of 9.2 g/dL. The nurse understands that anemia in CKD is primarily caused by:
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