chapter 48

🧠 0. EXAM-CRITICAL VOCAB (ONLY MUST-KNOW TERMS)

🧠 1. SYSTEMS MAP — BIG PICTURE OF CHAPTER 48

This is the ENTIRE chapter’s “cause → effect → complication → intervention” web.

A. NORMAL KIDNEY → WHAT HAPPENS WHEN IT FAILS

1. Normal physiology

• Filters waste (creatinine, BUN)

• Balances F/E (Na, K, Mg, Ca, Phos)

• Regulates BP (RAAS)

• Produces EPO (RBCs)

• Activates vitamin D

• Maintains acid–base balance (HCO₃⁻ reabsorption)

2. If kidney function ↓ → EVERYTHING fails

💥 ↓ GFR → waste buildup → uremia
💥 ↓ Na/H₂O regulation → overload OR dehydration
💥 ↓ K excretion → hyperkalemia → V-tach/V-fib
💥 ↓ HCO₃⁻ → metabolic acidosis
💥 ↓ EPO → anemia → fatigue, pallor, SOB
💥 ↓ Vit D → hypocalcemia → fractures
💥 ↑ phosphate → bone disease
💥 ↑ RAAS → HTN → more kidney damage

Logic-Check (Answer ONLY):

1. If GFR decreases, what happens to creatinine?

2. Why does CKD cause metabolic acidosis?

3. Why does kidney failure cause anemia?

B. FLUID AND ELECTROLYTE IMBALANCES

(Section: “Fluid & Electrolyte Imbalances in Kidney Disorders,” p. 1555)

Kidney cannot:

• Concentrate urine → dilute urine

• Excrete K⁺ → hyperkalemia

• Excrete phosphorus → hyperphosphatemia

• Reabsorb calcium → hypocalcemia

• Excrete fluid → fluid overload → crackles, edema, HTN

Hyperkalemia Cascade

Kidney failure → K accumulates → myocardium irritable → peaked T waves → widened QRS → V-fib → death

NCLEX Danger:

Logic-Check:

1. What EKG change shows dangerous hyperkalemia?

2. Why does CKD cause hypocalcemia?

C. DISORDERS THAT DAMAGE THE KIDNEY

1. Glomerular diseases

• Nephritic: INFLAMMATION

  • hematuria

  • ↓ GFR

  • mild proteinuria

  • edema

  • HTN

• Nephrotic: PERMEABILITY

  • MASSIVE proteinuria (>3.5 g/day)

  • ↓ albumin → edema everywhere

  • hyperlipidemia

Pattern:

Nephritic → active inflammation
Nephrotic → leaky basement membrane

Logic-Check:

1. Which syndrome has massive proteinuria?

2. Why does nephrotic syndrome cause edema?

D. HEREDITARY DISORDERS

Polycystic Kidney Disease

• Cysts → enlarge → compress nephrons → ↓ function

• Flank pain

• Hematuria

• HTN

• At risk for brain aneurysms

Logic-Check:

1. Why does PKD cause early HTN?

2. Why do patients with PKD have flank pain?

E. ACUTE VS CHRONIC KIDNEY FAILURE

AKI (Sudden)

• Prerenal (hypoperfusion)

• Intrarenal (ATN)

• Postrenal (obstruction)

CKD (Slow, progressive → irreversible)

• GFR < 60 for 3+ months

• Ends in ESKD (requires dialysis)

Logic-Check:

1. Which AKI is most common?

2. Which AKI has muddy brown casts?

3. What defines CKD?

F. ESRD → NEED FOR DIALYSIS

Dialysis is required when:

• K⁺ > 6.0

• Severe acidosis

• Fluid overload unresponsive to diuretics

• Uremic symptoms

• GFR < 15

Hemodialysis removes:

• K⁺

• urea/creatinine

• fluid

G. RENAL CANCER

Silent → hematuria → flank mass → weight loss
Often incidental finding.

H. RENAL TRAUMA

Most common sign: hematuria
Watch for shock, flank mass, ecchymosis.

⚡️ 2. HIGH-YIELD PATTERN RECOGNITION (THE MOST IMPORTANT SECTION)

These are the automatic pattern-recognition "cheat codes" the NCLEX EXPECTS you to know.

🔹 PATTERN 1 — ANY ↓ PERFUSION → KIDNEY FAILURE

↓ CO (HF, shock)
↓ blood flow (hypovolemia, sepsis)
→ ↓ GFR → ↑ BUN/Cr → AKI (prerenal)

NCLEX Focus:
They love asking which patient is at risk for AKI — it’s ALWAYS the low-perfusion patient.

🔹 PATTERN 2 — ANY STENOSIS OR HARDENING → ↑ PRESSURE → DAMAGE

Chronic HTN → nephrosclerosis → CKD
Atherosclerosis → renal ischemia → RAAS activation → MORE HTN

NCLEX Focus:
Uncontrolled HTN is the #1 cause of CKD after diabetes.

🔹 PATTERN 3 — ANY REGURGITATION OR LEAK → PROTEIN LOSS

Glomerular basement membrane damage →
Proteinuria →
↓ albumin →
↓ oncotic pressure →
edema

NCLEX Focus:
Nephrotic syndrome = MASSIVE protein loss + hyperlipidemia.

🔹 PATTERN 4 — ANY INFLAMMATION OF GLOMERULI → HEMATURIA

Acute Nephritic Syndrome
Chronic Glomerulonephritis
Post-strep GN
→ RBCs leak → cola-colored urine

NCLEX Focus:
Nephritic = hematuria
Nephrotic = proteinuria

🔹 PATTERN 5 — ANY OBSTRUCTION → POSTRENAL AKI

Stones
Tumors
Clots
BPH
→ urine backs up →
↑ pressure →
↓ GFR →
postrenal AKI

NCLEX Focus:
Sudden anuria = think obstruction first.

🔹 PATTERN 6 — ANY TUBULAR DAMAGE → “MUDDY BROWN CASTS”

ATN (intrarenal AKI) → hallmark finding:
muddy brown granular casts
w/ oliguria

NCLEX Focus:
Contrast dye + aminoglycosides = top causes of ATN.

🔹 PATTERN 7 — CKD = “EVERY SYSTEM FAILS”

Uremia → neuro, GI, cardiac, skin, respiratory, endocrine dysfunction

NCLEX Focus:
CKD =

• anemia

• bone disease

• acidosis

• hyperkalemia

• fluid overload

• HTN

🔹 PATTERN 8 — ANY KIDNEY FAILURE → HYPERKALEMIA

K+ > 5.0
Peaked T waves
→ give:
Calcium gluconate → insulin/D50 → albuterol → dialysis

NCLEX Focus:
Hyperkalemia = most lethal complication.

🔹 PATTERN 9 — CYSTS = PRESSURE + STRUCTURAL DAMAGE

PKD →
HTN + flank pain + enlarged kidneys + hematuria + risk of brain aneurysms

NCLEX Focus:
Screen FIRST-DEGREE RELATIVES.

🔹 PATTERN 10 — ANY UROLOGIC SURGERY → RISK OF BLEEDING + SHOCK

Kidney is extremely vascular → postop nephrectomy patient
→ watch for:

• hypotension

• tachycardia

• ↓ UO

• flank swelling

NCLEX Focus:
↓ UO after nephrectomy = CALL RAPID.

🔹 PATTERN 11 — TRANSPLANT FEVER = REJECTION

Tender graft + fever + oliguria + ↑ creatinine
= acute rejection

NCLEX Focus:
Cyclosporine/tacrolimus → nephrotoxic → need to monitor levels.

🔹 PATTERN 12 — PD VS HD PATTERNS

PD = slow, gentle
HD = fast, aggressive

PD complications = peritonitis
HD complications = hypotension, muscle cramps, disequilibrium

NCLEX Focus:
Cloudy PD effluent = peritonitis = call provider.

🔗 3. CROSS-CHAPTER CONNECTIONS

❤ Cardiac ↔ Renal

HF → ↓ CO → ↓ GFR → AKI
HTN → nephrosclerosis → CKD
CKD → hyperkalemia → dysrhythmias
ESRD → fluid overload → pulmonary edema

🩸 Hematology ↔ Renal

CKD → ↓ EPO → anemia
Uremia → platelet dysfunction → bleeding risk

🦴 Endocrine/Bone ↔ Renal

CKD → ↓ Vit D → ↓ Ca → ↑ PTH → bone breakdown
Renal osteodystrophy = fractures + bone pain

🧪 Acid–Base ↔ Renal

Kidney failure → ↓ HCO₃ reabsorption → metabolic acidosis

🧠 Neuro ↔ Renal

Uremic toxins → confusion, asterixis, seizures

🩺 Infection ↔ Renal

UTIs → pyelonephritis → chronic scarring → CKD
Peritonitis → PD complication
Immunosuppression → transplant infections

🚨 4. RED FLAG INTEGRATION LIST (MANDATORY EMERGENCIES)

Call RAPID if:

• K⁺ > 6.0

• Peaked T waves

• New confusion in CKD → uremic encephalopathy

• UO < 30 mL/hr

• No urine after kidney surgery

• Flank swelling + hypotension after renal trauma

• Cloudy PD fluid

• Pericardial friction rub (uremic pericarditis)

• Weight gain > 1 kg/day on dialysis patient

• Pulmonary edema (pink frothy sputum)

Lethal NCLEX Labs

• K⁺ > 6

• pH < 7.2

• Hgb < 7

• BUN > 100

• Cr > 6 in CKD patient

• Phos > 6

• Ca < 8 → risk for seizures

• GFR < 15 → ESKD → dialysis

Must-call provider findings

• Bloody urine (post-biopsy, post-surgery)

• Severe flank pain in PKD

• Post-op tachycardia + hypotension

• Peritoneal dialysis abdominal rigidity

• Transplant: fever + oliguria

🩺 5. NURSING PRIORITIES + INTERVENTION MAP

Top priorities for ALL renal disorders:

1. Monitor K+

2. Monitor fluid status

3. Daily weights

4. Strict I&O

5. BP control

6. Monitor for pulmonary edema

7. Renal dosing of medications

8. Prevent infection (catheters, transplant, PD)

9. Manage anemia

10. Manage bone disease

What NOT to do:

• No NSAIDs

• No contrast dye unless emergency

• No nephrotoxic antibiotics unless essential

• No mag-containing antacids

• No high-potassium foods in CKD

• No BP or blood draws on AVF arm

💉 6. DRUG / PROCEDURE / DISEASE TIE-INS

ACE inhibitors / ARBs

• ↓ proteinuria

• Protect kidneys

• BUT can ↑ creatinine + ↑ K+

• Avoid in AKI

Erythropoietin (EPO)

• Fixes anemia

• Takes weeks

• Watch for ↑ BP, ↑ clotting

Phosphate binders (sevelamer, calcium acetate)

• MUST take WITH food

• Prevent CKD bone disease

Dialysis

HD: pulls fluid FAST → risk of hypotension
PD: slower → risk of peritonitis

Transplant meds

Tacrolimus/cyclosporine → nephrotoxic
Mycophenolate → GI upset
Steroids → hyperglycemia, weight gain

✨ 7. WHAT BEGINNERS GET WRONG

🧨 Misunderstanding #1:

“Low urine output = dehydration.”
Correct: It can also be AKI or obstruction.

🧨 Misunderstanding #2:

“HTN has symptoms.”
Correct: Silent until organ damage.

🧨 Misunderstanding #3:

“CKD patients shouldn’t eat protein.”
Correct: Dialysis patients NEED higher protein.

🧨 Misunderstanding #4:

“Creatinine rises quickly.”
Correct: BUN rises faster; Cr is slower but more accurate.

🧨 Misunderstanding #5:

“All kidney pain = stones.”
Correct: Could be PKD, trauma, cancer, infection.

✨ 8. QUICK VISUAL PATTERNS / SHAPES LIST

• Nephritic = RBCs (blood)

• Nephrotic = Protein (foam)

• PKD = huge cystic kidneys

• ATN = muddy brown casts

• AKI = sudden rise in Cr

• CKD = slow, progressive, irreversible

• PD peritonitis = cloudy effluent

• Renal trauma = flank bruising

• Transplant rejection = fever + tender graft

⚡️ ULTRA-HIGH-YIELD EXAM SHEET

Memorize these:

• GFR < 60 = CKD

• GFR < 15 = ESKD

• K⁺ > 6 = emergency

• PD cloudy fluid = peritonitis

• Hematuria = nephritic

• Massive proteinuria = nephrotic

• ATN = muddy brown casts

• PKD = HTN + cysts + flank pain

• Nephrosclerosis = due to HTN

• RAAS activation = worsens HTN

• CKD diet = low K, low phos, low Na, fluid restriction

⚠ NCLEX TRAPS

• Choosing diuretics in ESRD (they don’t work)

• Giving contrast to CKD patient

• Not holding antihypertensives before dialysis

• AV fistula arm: NO BP, NO blood draws

• Thinking oliguria = fluid restriction (only if fluid overloaded)

• Treating hyperkalemia with Kayexalate FIRST (wrong — insulin + Ca first)

• Mistaking hypocalcemia for hypercalcemia in CKD

• Forgetting to check transplant med levels (tacrolimus/cyclosporine)