NCLEX-RN® Renal and Urinary Disorders: AKI, CKD, Dialysis, UTI, and Catheters

Kidney and urinary system content for the NCLEX-RN®: distinguishing AKI from CKD, hemodialysis vs. peritoneal dialysis, UTI nursing care, and catheter safety.

The big picture

Renal and urinary conditions account for a consistent portion of NCLEX-RN® Physiological Integrity questions. The kidneys regulate fluid balance, electrolytes, acid-base status, blood pressure, and red blood cell production — so kidney disease causes widespread complications. This guide covers acute kidney injury, chronic kidney disease, dialysis, urinary tract infection, and catheter care.

Acute kidney injury (AKI)

AKI is a sudden decline in kidney function over hours to days, leading to accumulation of waste products (creatinine, BUN) and electrolyte disturbances. Formerly called acute renal failure (ARF).

Three types of AKI — NCLEX® distinguishes all three

NCLEX® tip: Pre-renal AKI is the most common and most reversible. If the problem is "not enough blood getting to the kidneys," fix the blood flow — give fluids (for dehydration/hemorrhage) or treat the cardiac problem. Do not give fluid to a patient who is oliguric from heart failure — that makes it worse.

Phases of AKI (acute tubular necrosis pattern)

1. Onset phase: Injury occurs; urine output begins to fall
2. Oliguric phase: Urine output < 400 mL/day; electrolyte imbalances peak; lasts 1–2 weeks
3. Diuretic phase: Urine output rebounds (may reach 3–5 L/day); hypovolemia and hypokalemia risk
4. Recovery phase: GFR gradually returns; may take months

Priority lab values in AKI

Nursing priorities in AKI

1. Monitor urine output precisely — hourly catheterized output is the gold standard
2. Fluid management: Oliguric phase = fluid restriction; diuretic phase = monitor for dehydration
3. Electrolyte management: Restrict potassium and phosphorus in the diet; monitor for EKG changes from hyperkalemia
4. Medication safety: Avoid or dose-adjust nephrotoxic medications (NSAIDs, aminoglycosides, contrast dye, ACE inhibitors)
5. Skin and oral hygiene: Uremia causes pruritus and oral frost (urea crystals); provide skin and mouth care

Hyperkalemia in AKI — the most dangerous complication

Signs: muscle weakness, areflexia, paresthesias, peaked T waves on EKG → widening QRS → ventricular fibrillation.

Emergency treatment order:

1. Calcium gluconate IV — stabilises the cardiac membrane immediately (onset: minutes)
2. Regular insulin + dextrose IV — drives K⁺ into cells (most reliable temporising shift; preferred over bicarb as second step)
3. Sodium bicarbonate IV — drives K⁺ into cells; now reserved for severe metabolic acidosis only, no longer routinely second-line
4. Patiromer (Veltassa) or sodium zirconium cyclosilicate / Lokelma — preferred newer K⁺-binding agents for elimination; Kayexalate (sodium polystyrene sulfonate) is being phased out due to risk of colonic necrosis
5. Dialysis — definitive removal if medical management fails

Chronic kidney disease (CKD)

CKD is a progressive, irreversible loss of kidney function over months to years. The leading causes are diabetes mellitus and hypertension.

Stages by GFR

Systemic complications of CKD — NCLEX® loves this

CKD diet — priority teaching for NCLEX®

Medications in CKD

• Erythropoietin (EPO/darbepoetin): Treats anemia; monitor BP (EPO raises it); check hemoglobin regularly
• Phosphate binders (calcium carbonate, sevelamer): Take with meals (not before or after) — binds dietary phosphate in the gut
• Calcitriol (active vitamin D): Replaces what failing kidneys cannot make; corrects bone disease
• Calcium supplements: Given if Ca²⁺ is low; monitor closely — if phosphate is high, giving calcium can cause calcification

Dialysis

Hemodialysis (HD) vs. peritoneal dialysis (PD)

AV fistula nursing care — heavily tested

An arteriovenous (AV) fistula is the preferred long-term vascular access for hemodialysis.

• Before each use: Auscultate for a bruit (rushing sound) and palpate for a thrill (vibration) — these confirm patency
• If bruit or thrill is absent: report to provider immediately — the fistula may be clotted
• Never: Take blood pressure, draw blood, or insert IV in the fistula arm
• Teach patient: Avoid tight clothing, jewelry, or sleeping on the fistula arm; report any swelling, redness, warmth, or pain

Peritoneal dialysis: recognizing peritonitis

Peritonitis is the most serious complication of PD. Signs:

• Cloudy dialysate effluent (first and most reliable sign)
• Abdominal pain, tenderness, rebound tenderness
• Fever, nausea
• Action: Notify provider, collect effluent specimen for culture, prepare for IV/IP antibiotics

Urinary tract infection (UTI)

Signs and symptoms

NCLEX® alert: Older adults with UTI often do not have classic symptoms — they present with sudden onset of confusion (delirium), falls, decreased urine output, or behavior change. Any unexplained mental status change in an older adult should prompt urinalysis.

Nursing interventions

1. Obtain urine culture before antibiotics (culture first, treat second)
2. Administer antibiotics as ordered — first-line agents for uncomplicated cystitis are nitrofurantoin and trimethoprim-sulfamethoxazole (TMP-SMX); fluoroquinolones (ciprofloxacin) are no longer recommended as first-line for uncomplicated UTI due to collateral resistance concerns
3. Encourage fluids (2–3 L/day unless contraindicated) to flush bacteria
4. Phenazopyridine (Pyridium): Urinary analgesic — teaches patient that urine will turn orange/red; does NOT treat infection
5. Teach perineal hygiene: wipe front to back; void after intercourse

UTI prevention teaching

• Wipe front to back after toileting
• Void after sexual intercourse
• Drink adequate fluids (6–8 glasses/day)
• Avoid bubble baths, harsh soaps near the urethra
• Avoid holding urine for long periods
• Cranberry products may reduce adhesion of bacteria (evidence limited; not a replacement for treatment)

Urinary catheter care

Types of catheters

CAUTI prevention — what NCLEX® tests

Catheter-associated UTI (CAUTI) is a national patient safety priority.

Prevention bundle:

• Use catheters only when necessary — remove as soon as possible
• Maintain a closed drainage system (never disconnect)
• Keep drainage bag below bladder level at all times (prevents backflow)
• Do not allow the bag to touch the floor
• Clean the urethral meatus with soap and water during daily hygiene; no antiseptic scrubs needed
• Secure the catheter to prevent pulling (traction on the bladder neck causes trauma)
• Hand hygiene before and after any contact with the catheter system

Catheter troubleshooting

NCLEX® clinical judgment focus

For renal questions, the priority is usually one of:

1. Fluid balance — is the patient overloaded or depleted? Check for edema, lung sounds, daily weight
2. Electrolytes — hyperkalemia is the most dangerous; identify EKG changes; prepare for treatment
3. Medication safety — what is safe to give with reduced GFR?
4. Access care — fistula bruit/thrill, peritoneal catheter site, Foley patency

Common NCLEX® traps:

• Giving a NSAID to someone with AKI or CKD — NSAIDs reduce renal blood flow and worsen function
• Not restricting potassium in an oliguric AKI patient — hyperkalemia is lethal
• Ignoring cloudy PD effluent — this is peritonitis until proven otherwise
• Checking BP in a fistula arm — never acceptable

FAQ

What is the difference between AKI and CKD on NCLEX®?

AKI is sudden (hours to days) and potentially reversible if the cause is corrected. CKD is gradual (months to years) and irreversible — the goal is to slow progression. AKI presents with rising creatinine, oliguria, and electrolyte shifts over a short period. CKD presents with systemic complications (anemia, bone disease, hypertension) that develop slowly.

Why is potassium so dangerous in kidney disease?

The kidneys are the primary route for potassium excretion. When GFR drops (AKI or advanced CKD), potassium accumulates. Hyperkalemia destabilizes the cardiac membrane — peaked T waves progress to wide QRS and ventricular fibrillation. This is one of the most common causes of cardiac arrest in dialysis patients who miss treatment.

What is the most reliable sign of peritonitis in PD?

Cloudy dialysate effluent — before abdominal pain or fever develop. Patients on PD are taught to inspect every bag of effluent. Any cloudiness must be reported and cultured immediately.

When does an AV fistula take to mature?

A new fistula requires a minimum of 6 weeks to mature before use for dialysis — and often takes 2–3 months for reliable maturation. During this time, patients are taught to exercise the arm (squeeze a rubber ball) to develop the vessel. A maturing fistula may feel warm and pulsatile — that is normal.

What is the significance of CVA tenderness?

Costovertebral angle (CVA) tenderness — pain on percussion at the junction of the 12th rib and spine — indicates inflammation or infection in the kidney itself (pyelonephritis or renal abscess). This distinguishes upper UTI (pyelonephritis) from lower UTI (cystitis), which does not cause CVA tenderness.

Key takeaways

• AKI: Pre-renal = low flow, fix with fluids. Intra-renal = direct damage, manage complications. Post-renal = obstruction, relieve it. Hyperkalemia is the most dangerous complication.
• CKD: Restrict K⁺, phosphate, sodium, and fluid. EPO for anemia. Phosphate binders with meals. Stages 1–5 by GFR.
• Dialysis: AV fistula — always check bruit and thrill; never use that arm for BP/IV. PD — cloudy effluent = peritonitis.
• UTI: Culture before antibiotics. Older adults present with confusion. Wipe front to back.
• Catheters: CAUTI prevention — remove ASAP, closed system, bag below bladder, clean meatus daily.

Sources: NCSBN NCLEX-RN® 2023 Test Plan; CDC CAUTI Prevention Guidelines; National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Kidney Disease Resources.

See also:

• Electrolytes Made Simple
• NCLEX-RN® Lab Values Guide
• NCLEX-RN® Nutrition Guide
• NCLEX-RN® Pharmacology Guide
• Reduction of Risk Potential: Lab Values & Diagnostics

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