Chronic kidney disease

Background

• Chronic kidney disease (CKD) is defined as abnormalities in kidney structure or function present for ≥3 months with implications for health
• Affects ~37 million adults in the United States; the majority are unaware of their diagnosis
• Most common causes: diabetes mellitus (~40%), hypertension (~30%), glomerulonephritis, polycystic kidney disease
• CKD is a major independent risk factor for cardiovascular disease — most patients with CKD die of cardiovascular events, not kidney failure
• CKD patients present to the ED frequently — often for complications of CKD rather than the kidney disease itself

KDIGO Staging

Stage	eGFR (mL/min/1.73m²)	Description
G1	≥90	Normal or high (CKD if other markers of kidney damage present)
G2	60-89	Mildly decreased
G3a	45-59	Mildly to moderately decreased
G3b	30-44	Moderately to severely decreased
G4	15-29	Severely decreased
G5	<15	Kidney failure (may require dialysis or transplant)

• CKD also staged by albuminuria category: A1 (<30 mg/g), A2 (30-300 mg/g), A3 (>300 mg/g)
• Both eGFR and albuminuria predict risk of progression and cardiovascular events
• KDIGO 2024 update: Recommends creatinine-based eGFR (CKD-EPI 2021 equation without race); add cystatin C when eGFR creatinine may be inaccurate (extremes of muscle mass, amputation, cirrhosis)

Clinical Features

• Volume overload / congestive heart failure — dyspnea, edema, hypertensive emergency
• Hyperkalemia — medication-related (ACEi, ARB, SGLT2i, spironolactone, trimethoprim), dietary, missed dialysis, metabolic acidosis
• Uremic symptoms — nausea, vomiting, anorexia, fatigue, pruritus, altered mental status, seizures, pericarditis
• Infections — CKD patients are immunocompromised; UTI, pneumonia, vascular access infections, peritonitis (peritoneal dialysis)
• Acute kidney injury (AKI on CKD) — dehydration, nephrotoxins, obstruction, sepsis
• Cardiovascular events — acute coronary syndrome, stroke, peripheral vascular disease (risk 2-10× higher than general population)
• Electrolyte disorders — hyperkalemia, hyperphosphatemia, hypocalcemia, metabolic acidosis
• Anemia exacerbation — GI bleeding, erythropoietin deficiency, iron deficiency
• Dialysis access complications — thrombosed fistula/graft, access infection, dialysis catheter malfunction, steal syndrome
• Medication-related adverse effects — drug accumulation due to impaired clearance

Differential Diagnosis

When evaluating a CKD patient with acute decompensation, consider:

• AKI on CKD — reversible causes should always be sought (dehydration, obstruction, nephrotoxins, sepsis)
• Volume overload: Congestive heart failure, nephrotic syndrome, cirrhosis, medication non-compliance
• Hyperkalemia: Medication-related, dietary, missed dialysis, tissue breakdown, metabolic acidosis
• Infection/sepsis: UTI, pneumonia, dialysis access infection, peritonitis (PD patients)
• Cardiovascular: Acute coronary syndrome (CKD patients may have atypical presentations), hypertensive emergency, uremic pericarditis/tamponade
• Uremic encephalopathy: Diagnosis of exclusion — rule out other causes of AMS (hypoglycemia, stroke, sepsis, drug toxicity, electrolyte abnormalities)
• Drug accumulation/toxicity: Medications not dose-adjusted for renal function (opioids, gabapentin, antibiotics, metformin, lithium, digoxin)
• GI bleeding: Platelet dysfunction + anticoagulant use + angiodysplasia (common in CKD)

Evaluation

Workup

Standard Labs

• BMP — creatinine (compare to baseline), BUN, potassium, bicarbonate, calcium, glucose
• CBC — anemia (normocytic, from erythropoietin deficiency), platelet count
• Magnesium, phosphorus — hyperphosphatemia and hypomagnesemia are common
• VBG or ABG — assess for metabolic acidosis (non-anion gap from impaired H⁺ excretion ± anion gap from uremic toxins)
• Urinalysis — proteinuria, hematuria, casts (assess for active glomerulonephritis or UTI)
• Lactate — if concern for sepsis or tissue hypoperfusion
• Coagulation studies — if bleeding, uremic platelet dysfunction, or DIC suspected
• Troponin — chronic elevation is common in CKD (especially on dialysis); interpret in the context of symptoms and trending rather than a single value

If AKI on CKD Suspected

• Renal ultrasound — assess kidney size (small echogenic kidneys = chronic disease), hydronephrosis (obstruction), renal vein thrombosis
• Bladder scan / post-void residual — if obstruction suspected
• Fractional excretion of sodium (FENa) or FEUrea (if on diuretics) — prerenal vs. intrinsic
• Urine electrolytes, urine protein-to-creatinine ratio

Targeted

• ECG — mandatory in all CKD presentations — evaluate for hyperkalemia (peaked T waves, widened QRS, sine wave), ischemia, pericarditis (diffuse ST elevation)
• CXR — pulmonary edema, pleural effusion, pericardial effusion, pneumonia
• Blood cultures — if febrile (low threshold for blood cultures in dialysis patients and those with indwelling catheters)

Diagnosis

• CKD itself is usually an established diagnosis — the ED role is to identify acute complications and reversible causes of decompensation
• Always compare creatinine to baseline — a patient with baseline creatinine 3.0 who presents at 3.2 is very different from one presenting at 6.0
• Determine if the patient has a nephrology provider and whether they are on dialysis (and when their last session was)
• CKD is confirmed (not just diagnosed in the ED) when kidney damage or decreased function has been present for ≥3 months — a single elevated creatinine may represent AKI, not CKD

Management

Life-Threatening Emergencies

Hyperkalemia (K⁺ >5.5 mEq/L)

• ECG changes present or K⁺ >6.5:
  • Calcium gluconate 10% 10 mL (or calcium chloride via central line) IV over 2-3 min — cardiac membrane stabilization (does not lower K⁺)
  • Regular insulin 10 units IV + dextrose 25g (D50W) IV — shifts K⁺ intracellularly
  • Albuterol 10-20 mg nebulized — additional K⁺ shift
  • Sodium bicarbonate 50-100 mEq IV — if concurrent metabolic acidosis (effect on K⁺ is modest)
  • Kayexalate (sodium polystyrene sulfonate) 15-30g PO or Patiromer or Sodium zirconium cyclosilicate (Lokelma) — true K⁺ elimination (delayed onset)
  • Emergent dialysis — definitive treatment for severe/refractory hyperkalemia in CKD/ESRD
• See Hyperkalemia for full management

Uremic Pericarditis

• Friction rub + chest pain + uremia = indication for emergent dialysis
• Avoid anticoagulation (risk of hemorrhagic pericardial effusion → tamponade)
• If hemodynamic compromise → evaluate for tamponade → pericardiocentesis if indicated

Pulmonary Edema / Volume Overload

• NIV (BiPAP) for respiratory distress
• IV nitroglycerin for afterload reduction if hypertensive
• IV furosemide — CKD patients require higher doses (start 40-80mg IV for CKD G3-4; 80-200mg IV for G5/ESRD); may be ineffective in ESRD
• Emergent dialysis (ultrafiltration) if refractory to medical management or anuric
• See Congestive heart failure

Severe Metabolic Acidosis

• Sodium bicarbonate IV if pH <7.1 or bicarbonate <8-10 mEq/L with hemodynamic instability
• Dialysis for severe refractory acidosis
• Caution: sodium bicarbonate can worsen volume overload and cause hypocalcemia (ionized calcium drops as pH rises)

Medication Safety

Critical drug dosing considerations in CKD:

• NSAIDs: Avoid in CKD G3-5 — worsen renal function, cause hyperkalemia, fluid retention, GI bleeding
• Metformin: Contraindicated when eGFR <30; hold when eGFR 30-45 if acutely ill; risk of lactic acidosis
• Opioids: Morphine — avoid (active metabolite accumulates → prolonged sedation/respiratory depression); use fentanyl or hydromorphone (safer in CKD). Meperidine — avoid (normeperidine accumulation → seizures)
• Gabapentin/pregabalin: Dose reduce; accumulation causes sedation, altered mental status, myoclonus
• Antibiotics: Many require dose adjustment — particularly vancomycin (dose by levels/AUC), aminoglycosides (avoid if possible), nitrofurantoin (ineffective and neurotoxic in CKD G4-5)
• Enoxaparin: If eGFR <30, use unfractionated heparin instead, or reduce enoxaparin dose (1 mg/kg daily instead of BID) with anti-Xa monitoring
• Contrast: IV iodinated contrast can be given when clinically indicated (e.g., CT angiography for PE, stroke) — do not withhold life-saving imaging for CKD; hydrate with IV crystalloid before and after; hold metformin for 48h after contrast if eGFR <30
• ACEi/ARB: Hold during acute illness, dehydration, or AKI ("sick day rules"); do not start or uptitrate in the ED during acute presentations
• Potassium-sparing medications: Review and hold spironolactone, amiloride, triamterene, trimethoprim if hyperkalemic

Dialysis-Specific Considerations

• Determine modality (hemodialysis vs. peritoneal dialysis), schedule, and when last session occurred
• Missed dialysis: Common ED presentation; check K⁺, bicarbonate, volume status; arrange urgent dialysis
• Dialysis access:
  • Do not use an AV fistula or graft for blood draws, IV access, or blood pressure measurement
  • Do not place a blood pressure cuff on the access arm
  • Assess fistula/graft for thrill (palpable) and bruit (auscultate) — absence suggests thrombosis → vascular surgery or interventional radiology consultation
• Peritoneal dialysis peritonitis: Cloudy PD effluent + abdominal pain ± fever; send PD fluid for cell count (WBC >100/µL with >50% neutrophils), Gram stain, and culture; initiate empiric IP antibiotics (typically IP vancomycin + IP ceftazidime or gentamicin per local protocol) after consulting nephrology
• Dialysis catheter infection: Blood cultures from catheter AND peripheral site; empiric IV vancomycin + gram-negative coverage; consult nephrology regarding catheter removal vs. salvage

Disposition

Admit

• Hyperkalemia with ECG changes, K⁺ >6.5, or refractory to ED treatment
• Pulmonary edema/volume overload requiring dialysis or not responding to diuretics
• Uremic pericarditis or pericardial effusion with hemodynamic concern
• Uremic encephalopathy or severe uremic symptoms
• Severe metabolic acidosis (pH <7.2, bicarbonate <10)
• AKI on CKD with significant creatinine rise from baseline and no readily reversible cause
• Sepsis or serious infection (especially dialysis access infection, PD peritonitis)
• Need for emergent or urgent dialysis
• New diagnosis of ESRD requiring dialysis initiation

Discharge with Close Follow-Up

• Mild hyperkalemia (K⁺ 5.5-6.0, no ECG changes) corrected in ED with dietary counseling, medication adjustment, and follow-up within 24-48 hours
• Stable CKD with minor medication-related issue (dose adjustment made)
• Mild volume overload responsive to diuretic adjustment
• Ensure: Nephrology follow-up arranged, medication list reconciled, "sick day rules" reviewed (hold ACEi/ARB, metformin, NSAIDs, diuretics during acute illness/dehydration)

See Also

• Acute kidney injury
• Hyperkalemia
• Metabolic acidosis
• Congestive heart failure
• Dialysis complications
• Pericardial effusion and tamponade
• Hypertensive emergency
• Uremic encephalopathy

External Links

• KDIGO 2024 CKD Guideline (Full Text)
• MDCalc - Cockcroft-Gault Equation
• MDCalc - CKD-EPI eGFR Calculator