NCLEX Renal & Urinary Nursing Review: AKI, CKD, Dialysis & UTIs

Renal content shows up on the NCLEX far more often than its share of nursing school lecture hours would suggest, and there is a reason for that: the kidneys touch almost everything the exam cares about. Fluid balance, electrolytes, acid–base status, blood pressure, medication safety, and lab interpretation all run through renal function. If you understand what the kidney does and what happens when it stops doing it, a large block of questions becomes answerable from reasoning instead of recall. This review covers the renal and urinary concepts that come up most, framed the way the NCLEX frames them — as nursing priorities, not pathophysiology trivia.

Start with what the kidney actually does

Nearly every renal question is a consequence of one of these five jobs failing. Learn the jobs, and you can predict the findings instead of memorizing them:

• Excretes nitrogenous waste — so failure raises BUN and creatinine.
• Regulates fluid volume — so failure brings edema, weight gain, crackles, hypertension, and jugular venous distention.
• Balances electrolytes — so failure brings hyperkalemia, hyperphosphatemia, hypocalcemia, and sodium disturbances.
• Maintains acid–base balance by excreting hydrogen ions and reclaiming bicarbonate — so failure causes metabolic acidosis.
• Secretes hormones — erythropoietin (failure → anemia), renin (blood pressure control), and the enzyme that activates vitamin D (failure → poor calcium absorption and bone disease).

When a question gives you a patient with kidney disease and asks which finding to report, walk that list. The answer is almost always the one with the fastest path to harm — which, in renal patients, is usually potassium.

Renal labs and assessment data worth knowing cold

Reference ranges differ slightly between laboratories, so always read the values a question gives you against the range it provides. These are the commonly taught adult ranges:

• BUN: roughly 10–20 mg/dL. Rises with kidney injury, but also with dehydration, GI bleeding, and high protein intake — it is not kidney-specific.
• Creatinine: roughly 0.6–1.2 mg/dL. More specific to kidney function because it comes from muscle breakdown at a fairly steady rate.
• Potassium: 3.5–5.0 mEq/L. The single most dangerous renal lab.
• Sodium: 135–145 mEq/L · calcium: about 9.0–10.5 mg/dL · phosphorus: about 3.0–4.5 mg/dL.
• GFR: an estimate of filtration. Normal is generally described as 90 mL/min/1.73 m² or above; chronic kidney disease is staged as GFR falls, with stage 5 (under 15) the point at which dialysis or transplant is usually discussed.
• Urine specific gravity: about 1.005–1.030. High suggests concentrated urine (dehydration); fixed low values suggest the kidney has lost its ability to concentrate.
• Urine output: adults should make at least 0.5 mL/kg/hour. Oliguria is commonly defined as less than 400 mL in 24 hours.

Two bedside assessments outrank all of these on the NCLEX: daily weight (same scale, same time, same clothing — 1 kg of weight change is roughly 1 L of fluid) and strict intake and output. If an answer choice offers either one, read it carefully. For a wider drill on interpreting values, see our guide to NCLEX lab values you must memorize.

Acute kidney injury: classify it, then treat the cause

Acute kidney injury (AKI) is a sudden drop in kidney function, and the NCLEX expects you to sort it into one of three categories, because the nursing priority changes with each:

• Prerenal — a perfusion problem. Hypovolemia, hemorrhage, shock, heart failure, or sepsis. The kidney tissue is intact; it is simply not getting blood. Priority: restore volume and perfusion.
• Intrarenal (intrinsic) — damage to the kidney tissue itself, classically from nephrotoxic medications, IV contrast, prolonged ischemia, rhabdomyolysis, or glomerular disease. Priority: stop the offending agent.
• Postrenal — obstruction below the kidney. Benign prostatic hyperplasia, stones, tumors, or a blocked catheter. Priority: relieve the obstruction — and yes, checking a kinked or occluded catheter is a legitimate first action.

AKI is classically described in phases: onset, an oliguric phase (output falls, potassium and waste products climb), a diuretic phase (large urine volumes, with the new risk now being dehydration and electrolyte loss), and a recovery phase. A favorite test point: in the diuretic phase the patient is not out of danger — they can become hypovolemic and hypokalemic quickly.

Know the common nephrotoxins well enough to flag them: aminoglycoside antibiotics, vancomycin, NSAIDs, and iodinated contrast media. In a patient with an elevated creatinine, questioning a scheduled contrast study or an NSAID order is appropriate nursing judgment.

Chronic kidney disease: the predictable cluster

Chronic kidney disease (CKD) is progressive and largely irreversible, and the leading causes in the United States are diabetes and hypertension — which is why blood pressure and glucose control dominate the teaching answers. The findings cluster predictably:

• Anemia from low erythropoietin — treated with erythropoiesis-stimulating agents and iron, monitored by hemoglobin.
• Hyperphosphatemia with hypocalcemia, driving secondary hyperparathyroidism and bone disease. Phosphate binders are given with meals so they bind dietary phosphorus.
• Metabolic acidosis — expect a low bicarbonate and compensatory deep, rapid respirations. Our acid–base and ABG interpretation guide walks through reading those gases.
• Fluid overload and hypertension — hence fluid restriction, sodium restriction, and daily weights.
• Uremia — fatigue, nausea, pruritus, altered mental status, and in late disease a pericardial friction rub, which is an urgent finding.

Diet questions reward one habit: ask what the kidney can no longer excrete. CKD diets are generally low in sodium, potassium, phosphorus, and (before dialysis) protein. Foods flagged as high potassium on exams include bananas, oranges and orange juice, potatoes, tomatoes, avocados, and salt substitutes — salt substitutes are potassium chloride, which makes them a classic wrong answer for a renal patient.

Dialysis nursing care and access safety

Dialysis items are high yield because they are mostly about protecting the access and monitoring volume.

Hemodialysis. With an arteriovenous fistula or graft, the extremity rules are absolute: no blood pressure cuffs, no venipunctures, no IV lines, and no constricting clothing on that arm. Assess for a palpable thrill and an audible bruit; absence of either suggests clotting and is reported immediately. Weigh the patient before and after treatment to quantify fluid removed, and watch for hypotension, cramping, and dizziness from removing fluid too fast. Many antihypertensives and water-soluble medications are held until after dialysis — verify the specific order rather than assuming.

Peritoneal dialysis. Warm the dialysate (never in a microwave), use strict sterile technique at the catheter, and measure outflow against inflow. Normal effluent is clear or pale yellow; cloudy drainage is the hallmark of peritonitis and the finding to report. If outflow is sluggish, reposition the patient, check for kinks, and assess for constipation before escalating.

Hyperkalemia: the renal emergency to recognize first

If a renal question includes a potassium level, read it before anything else. Hyperkalemia can cause lethal arrhythmias, and the classic early ECG change taught for it is peaked (tall, tented) T waves, with widening QRS complexes as it worsens.

1. Stabilize the heart — IV calcium gluconate protects the myocardium without lowering potassium.
2. Shift potassium into cells — regular insulin with dextrose; sometimes a beta-agonist or sodium bicarbonate in acidosis.
3. Remove it from the body — a potassium-binding agent given by the GI route, or dialysis, which is definitive.

Also notice what raises potassium: potassium-sparing diuretics such as spironolactone, ACE inhibitors and ARBs, salt substitutes, and stored blood. Loop diuretics such as furosemide do the opposite and cause hypokalemia. Our fluid and electrolytes review drills these patterns in more depth.

Urinary tract problems: infection, stones, retention, and catheters

Urinary tract infection. Typical findings are dysuria, urgency, frequency, and suprapubic discomfort. In older adults, new confusion or a functional decline may be the presenting sign — an extremely common exam point. Infection that reaches the kidney (pyelonephritis) adds fever, chills, and flank or costovertebral angle tenderness, and is treated far more aggressively. Teaching centers on completing the full antibiotic course, adequate fluid intake, voiding when the urge occurs, voiding after intercourse, and front-to-back perineal hygiene.

Renal calculi. Expect sudden, severe, colicky flank pain that may radiate to the groin, often with hematuria, nausea, and restlessness. Nursing care is pain control, fluids unless contraindicated, ambulation, and straining all urine so a passed stone can be analyzed — the analysis determines the prevention plan.

Retention and catheters. Suspect retention with a distended, tender bladder, frequent small voids, or no output; a bladder scan for post-void residual is the non-invasive assessment. For an indwelling catheter: keep the drainage bag below bladder level and off the floor, maintain a closed system, secure the tubing, avoid dependent loops, perform routine perineal care, and remove the catheter as early as possible — duration is the biggest driver of catheter-associated infection.

How to answer renal questions under pressure

• Convert the pathology into a kidney job that failed. Most findings fall out of that single step.
• Scan for potassium, then airway and breathing. Hyperkalemia and fluid overload with crackles are the renal findings that kill fastest.
• In “which patient do you see first” items, pick change over severity. A new or worsening finding outranks a chronic abnormal one.
• Treat weight and intake/output as high-value data in any fluid-balance scenario.
• Check the medication list for nephrotoxins and potassium raisers before choosing an intervention.
• Assess before you act unless the question presents an emergency. Checking a kinked catheter or scanning for residual urine is often the correct first response.

Next step: practice with rationales

Renal content rewards repetition because the same handful of relationships get tested from many angles. Work through question sets, read the rationale on every item — including the ones you answered correctly — and keep a running list of the relationships that trip you up, such as which diuretic moves potassium which direction. Then spend your remaining study time on that list rather than re-reading the whole chapter.