Med-Surg · Renal / Fluid & Electrolytes
Acute Kidney Injury & Chronic Kidney Disease
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Prepared for Pass the Shift (owner: Kristina, RN). Always follow your facility’s protocols, provider orders, and current drug references.
1. Overview and Pathophysiology
is a sudden drop in kidney function over hours to days, with rising creatinine and/or oliguria. Classify by cause:
| Type | Mechanism | Examples |
|---|---|---|
| Prerenal | Low perfusion to kidneys | Hypovolemia, HF, sepsis, NSAIDs/ACE inhibitors in low-flow states |
| Intrarenal (intrinsic) | Direct kidney damage | Acute tubular necrosis (ischemia, contrast, aminoglycosides), glomerulonephritis |
| Postrenal | Obstruction of urine outflow | Stones, BPH, tumors, blocked catheter |
is lasting kidney damage or eGFR < 60 for ≥ 3 months. Staging uses eGFR (G1–G5) and albuminuria. ESRD usually means dialysis or transplant is needed (often G5).
Kidneys regulate fluid, electrolytes, acid–base, erythropoietin, and vitamin D activation—so CKD produces anemia, bone-mineral disorders, acidosis, and volume overload.
2. Causes and Risk Factors
- AKI: shock, major surgery, nephrotoxins (aminoglycosides, amphotericin, NSAIDs, iodinated contrast), rhabdomyolysis, obstruction
- CKD: diabetes and hypertension (top causes), glomerulonephritis, polycystic kidney disease, recurrent AKI, autoimmune disease
- Risks for faster decline: uncontrolled BP/glucose, smoking, high-protein load as directed against renal plan, missed dialysis
3. Signs and Symptoms
- Oliguria (< 0.5 mL/kg/hr or < 30 mL/hr commonly taught), anuria, dark urine
- Fluid overload: edema, weight gain, hypertension, pulmonary crackles
- Uremia: fatigue, anorexia, nausea, pruritus, uremic frost (late), confusion, pericarditis risk
- Electrolyte effects: hyperkalemia, hyperphosphatemia, hypocalcemia
- Anemia symptoms: pallor, activity intolerance
- Dialysis access problems: loss of thrill/bruit, infection, steal syndrome
4. Diagnostics and Labs
Lab reference ranges vary by laboratory. Always use your facility’s ranges.
| Test | Typical reference | Nursing relevance |
|---|---|---|
| Creatinine | ~0.6–1.2 mg/dL | Best routine marker of GFR change |
| BUN | ~10–20 mg/dL | Also rises with dehydration/GI bleed |
| eGFR | > 90 typical young adult | CKD staging |
| K⁺ / Na⁺ / Ca²⁺ / Phos / HCO₃⁻ | See F&E guide | Daily threats in AKI/CKD |
| CBC | — | Anemia of CKD |
| PTH | Lab-dependent | Secondary hyperparathyroidism |
| UA, FeNa, urine eosinophils | — | Help classify AKI cause |
| Renal ultrasound | — | Size, obstruction |
5. Priority Nursing Assessments
- Strict I&O, daily weight, BP, edema, lung sounds
- Telemetry if hyperkalemic
- Nephrotoxic med review; contrast exposure
- AV fistula/graft: thrill (palpate) and bruit (listen) every shift; no BP/IV/venipuncture on that arm
- Peritoneal dialysis: effluent clarity (cloudy → peritonitis until proven otherwise)
- Mental status, pruritus, bleeding tendency (uremic platelets)
6. Priority Nursing Interventions
- Treat reversible causes (fluids for prerenal if ordered; relieve obstruction)
- Avoid/adjust nephrotoxins per pharmacy; hold metformin around contrast per protocol
- Hyperkalemia emergency pathway (see F&E guide)
- Fluid and diet restrictions as ordered (Na, K, phos, fluid; protein per renal dietitian)
- Prepare for renal replacement therapy when indicated (AEIOU mnemonic often taught: Acidosis, Electrolytes, Intoxicants, Overload, Uremia)
- Infection control for catheters; sterile PD technique teaching
- ESA administration and iron as ordered for anemia; phosphate binders with meals
7. Medications
| Class / examples | Role | Nursing considerations |
|---|---|---|
| Loop diuretics | Volume removal if residual function | Monitor K⁺ and ototoxicity |
| Phosphate binders (sevelamer, calcium acetate) | Lower phos | Give with food; separate from some meds |
| ESAs (epoetin, darbepoetin) | Anemia of CKD | Monitor Hb; thrombosis/HTN risk if overcorrected |
| Potassium binders | Chronic or subacute hyperkalemia | Not a substitute for emergency care |
| Sodium bicarbonate | Metabolic acidosis | Follow labs |
| Antihypertensives (often ACEi/ARB early CKD) | Slow progression | Watch K⁺ and creatinine; may be held in AKI |
| Vitamin D analogs / calcimimetics | CKD–MBD | Calcium monitoring |
| Immunosuppressants | Post-transplant | Infection teaching |
8. Patient Education
- Daily weights; report gain per care team thresholds
- Diet restrictions with dietitian support; labels for K⁺/Na⁺/phos
- Fistula care: no tight jewelry, no BP cuff, report loss of thrill, keep site clean
- PD: sterile exchanges, recognize cloudy fluid/abdominal pain/fever
- Medication timing around dialysis (many antihypertensives held pre-HD per order)
- Vaccines as recommended (hepatitis B, influenza, pneumococcal)
9. Complications
- Hyperkalemia → cardiac arrest
- Pulmonary edema, hypertensive emergency
- Uremic encephalopathy / pericarditis
- Infection (access, peritonitis, hepatitis exposure historically)
- Dialysis disequilibrium (rare with first treatments)—headache, seizures
- Mineral bone disease, calciphylaxis (severe)
10. Memory Aids
- “Pre / Intra / Post” for AKI location
- “No BP, sticks, or IVs on the fistula arm”
- “Cloudy bag = call” for PD peritonitis
- “AEIOU” indications for dialysis
- “Binders with bites” (phosphate binders with meals)
11. NCLEX-Style Practice Questions
1. Appropriate care for a left-arm AV fistula includes:
A. BP measurements in the left arm each shift
B. Palpating for a thrill and auscultating for a bruit
C. Starting an IV in the left forearm for antibiotics
D. Applying a tight compression dressing over the fistula
Answer: B. Thrill/bruit confirm patency. Compression and needle sticks threaten the access.
2. A client with AKI from gastroenteritis is hypotensive with rising creatinine. Which AKI type is most likely?
A. Postrenal
B. Prerenal
C. Intrinsic from stones
D. Chronic only
Answer: B. Hypovolemia/hypotension reduces renal perfusion → prerenal AKI (may progress to ATN if untreated).
3. Priority action for K⁺ 6.9 with peaked T waves in a dialysis client?
A. Give oral potassium supplements
B. Cardiac monitor, notify provider, anticipate emergency treatments / urgent dialysis
C. Encourage salt substitutes
D. Ambulate to lower potassium
Answer: B. This is a cardiac emergency until potassium is lowered safely.
4. Which finding after peritoneal dialysis exchange needs immediate reporting?
A. Clear yellow effluent
B. Cloudy effluent with abdominal pain
C. Mild fullness during dwell
D. Slightly lower BP after fluid removal
Answer: B. Cloudy effluent suggests peritonitis.
5. Why are phosphate binders given with meals?
A. They taste better with food
B. They bind dietary phosphorus in the gut
C. They only work on an empty stomach
D. They replace insulin
Answer: B. Binding dietary phosphorus requires presence in the GI tract with food.
References
Kidney Disease: Improving Global Outcomes (KDIGO). (2024). KDIGO clinical practice guideline for the evaluation and management of chronic kidney disease. https://kdigo.org/
MedlinePlus. (n.d.). Chronic kidney disease. National Library of Medicine. Retrieved October 15, 2026, from https://medlineplus.gov/chronickidneydisease.html
MedlinePlus. (n.d.). Acute kidney injury. National Library of Medicine. Retrieved October 15, 2026, from https://medlineplus.gov/acytekidneyinjury.html
National Council of State Boards of Nursing. (2026). 2026 NCLEX-RN test plan. https://www.nclex.com/test-plans.page
Goyal, A., Daneshpajouhnejad, P., Hashmi, M. F., & Bashir, K. (2023). Acute kidney injury. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK441896/