Hyperkalemia - Nephrology Lectures 2025

🚰 FIRST CATHETER = FOLEY CATHETER (Not Central Line!)

🔑 Clinical Decision Point

If NO EKG changes AND able to establish urine output → May avoid hemodialysis

Therefore: Foley catheter is the FIRST catheter to place in hyperkalemia, not a central line for dialysis access.

✅ Foley First When:

No EKG changes present
Hyperkalemia unexplained
Clinical suspicion of obstruction
Trying to avoid dialysis
ANY bladder scan >300mL

⚡ Central Line When:

EKG changes present
K+ >7.5 mEq/L
Symptomatic hyperkalemia
Failed medical management
Anuric or dialysis-dependent

🚨 Emergency Protocol: STABILIZE → FOLEY → SHIFT → REMOVE

1 STABILIZE MEMBRANE: Calcium Gluconate 30mL IV (or CaCl₂ 10mL if central line)
• Onset: 1-3 minutes • Duration: 30-60 minutes • NO effect on K+ levels • ONLY if EKG changes present

2 FOLEY CATHETER: Especially if no EKG changes - may prevent need for dialysis
• May reduce K+ 0.8-1.1 mEq/L in 4-6 hrs • Can prevent need for dialysis • Check bladder scan • Post-void residual >100mL

3 SHIFT INTRACELLULAR: Insulin (most reliable) + Albuterol (variable response)
• Insulin 10U IV + D50 25g IV (90% response rate, K+ ↓ 0.6-1.2 mEq/L)
• Albuterol 10-20mg neb (60-80% respond, K+ ↓ 0.5-1.0 mEq/L)
• Synergistic effects when combined • Monitor glucose hourly × 6hrs
• If respiratory acidosis: Improve ventilation (each 0.1 pH ↑ = 0.6 mEq/L K+ ↓)

4 REMOVE POTASSIUM: Lokelma 10g PO IMMEDIATELY (don't wait!)
• Give ASAP, don't wait 1-2 hours • Onset: 1 hour, K+ ↓ 0.4 mEq/L @ 1hr, 0.7 mEq/L @ 4hrs • Works in small intestine

💊 LOKELMA: Give IMMEDIATELY, Don't Wait!

⏰ Timing is Critical

Common Mistake: Waiting 1-2 hours after insulin/albuterol to give Lokelma

Correct Approach: Give Lokelma IMMEDIATELY with other treatments

✅ Why Give ASAP:

1-hour onset means earlier benefit
Synergistic with shifting agents
Prevents K+ rebound after insulin wears off
Provides sustained K+ removal
May prevent need for dialysis

🚫 Lokelma Won't Work If:

Bowel obstruction (works in small intestine)
Severe gastroparesis
Recent bowel surgery
Inability to take PO medications
Ileus or severe constipation

🧠 Mechanism: Small Intestine Action

Lokelma (sodium zirconium cyclosilicate) works primarily in the small intestine by exchanging sodium and hydrogen for potassium. This is why it won't work in bowel obstruction - the medication must reach the small intestine to be effective.

🔍 Comprehensive Etiology: Why Is K+ High?

📋 Systematic Approach to Hyperkalemia Causes

💀 Cellular Death/Lysis

Massive K+ Release from Cells

Rhabdomyolysis: Muscle cell breakdown
• CPK >1000, myoglobin in urine • Check for dark/coca-cola urine
Tumor Lysis Syndrome: Oncology emergency
• Chemotherapy initiation • High LDH, uric acid, phosphate
Gut Ischemia: Intestinal cell death
• Mesenteric ischemia • Often with severe acidosis
Massive Hemolysis: RBC destruction
• Check LDH, haptoglobin, indirect bilirubin
Compartment Syndrome: Muscle necrosis
• Trauma, prolonged immobilization
Massive Burns: Tissue destruction
• >20% body surface area • Peak K+ at 24-48 hours
Malignant Hyperthermia: Anesthesia emergency
• Succinylcholine trigger • Hyperthermia + rigidity

🫘 Renal Causes

Impaired K+ Excretion

RAASi Blockade: Most common cause
• ACE inhibitors, ARBs, spironolactone • Aldosterone receptor antagonists
Low Distal Sodium Delivery: Volume depletion
• Dehydration reduces distal Na+ delivery • Less K+ exchange in collecting duct
AKI/CKD: Reduced nephron mass
• eGFR <30: high risk • Oliguria/anuria
Type 4 RTA: Hypoaldosteronism
• Diabetes, NSAIDs, heparin • Normal anion gap acidosis
Calcineurin Inhibitors: Tacrolimus, cyclosporine
• Impairs distal K+ secretion
Trimethoprim/Pentamidine: ENaC blockade
• Blocks sodium channels in collecting duct
Gordon Syndrome: Pseudohypoaldosteronism type II
• Thiazide-sensitive hypertension + hyperkalemia

🏥 Endocrine Disorders

Hormonal Dysregulation

Addison's Disease: Primary adrenal insufficiency
• Low cortisol AND aldosterone • Hyperpigmentation, hypotension
Congenital Adrenal Hyperplasia: 21-hydroxylase deficiency
• Salt-wasting crisis in newborns • Virilization
Hypoaldosteronism: Selective mineralocorticoid deficiency
• Diabetes, HIV, elderly • Normal cortisol
Hyporeninism: Low renin state
• Diabetic nephropathy • NSAIDs, β-blockers

🔬 Pseudohyperkalemia

Falsely Elevated Lab Values

Hemolysis: Most common pseudo-cause
• Check hemolysis index • Repeat with careful draw
Thrombocytosis: Platelet clumping
• PLT >1,000,000 • Use heparinized tube
Extreme Leukocytosis: WBC breakdown
• WBC >100,000 • Leukemia, lymphoma
Fist Clenching: During phlebotomy
• Muscle contraction releases K+
Difficult Draw: Prolonged tourniquet
• Cellular release from ischemia
Hereditary Spherocytosis: Fragile RBCs
• Family history, spherocytes on smear
Stored Blood: Transfusion-related
• Blood >7 days old • Massive transfusion protocol

📈 Increased K+ Intake

Salt Substitutes: KCl instead of NaCl
• "NoSalt", "Morton Salt Substitute"
IV Potassium: Iatrogenic
• High-dose K+ replacement
High-K+ Foods: Usually not sole cause
• Bananas, oranges, potatoes in CKD
Blood Transfusions: Especially massive
• Each unit contains ~5-7 mEq K+
Herbal Supplements: Noni juice, alfalfa
• Often overlooked in history

🔄 Transcellular Shifts

Acidosis: K+ shifts out of cells
• Each 0.1 pH ↓ = ~0.6 mEq/L K+ ↑
Insulin Deficiency: DKA
• Total body K+ often low despite high serum
β-blocker Overdose: Impaired cellular uptake
Hypertonicity: Water shifts out
• Hyperglycemia, mannitol
Succinylcholine: Depolarizing paralytic
• Especially in burn/trauma patients
Digitalis Toxicity: Na-K-ATPase inhibition
• Check digoxin level • Avoid calcium if suspected
Intense Exercise: Muscle K+ release
• Heat stroke, dehydration • Usually transient

🧬 Genetic/Congenital

Hereditary Disorders

Hyperkalemic Periodic Paralysis: Sodium channel mutations
• Episodes triggered by K+ intake, cold, rest after exercise
Pseudohypoaldosteronism Type I: Mineralocorticoid resistance
• Autosomal recessive • Salt wasting, failure to thrive
Pseudohypoaldosteronism Type II: Gordon syndrome
• Thiazide-sensitive hypertension + hyperkalemia
Sickle Cell Disease: Renal tubular dysfunction
• Type 4 RTA pattern • Chronic hemolysis

💊 Additional Medications

Often Overlooked Drug Causes

Heparin (UFH/LMWH): Aldosterone suppression
• Usually after 4+ days • Check aldosterone level
NSAIDs: Multiple mechanisms
• Reduced renin, prostaglandin inhibition • Type 4 RTA
Immunosuppressants: Beyond calcineurin inhibitors
• Sirolimus, everolimus
α-agonists: Clonidine, methyldopa
• Central sympathetic suppression
Mannitol: Hyperosmolar-induced shift
• Especially in neuro ICU patients

🚨 Critical Care Causes

ICU-Specific Scenarios

Massive Tissue Trauma: Crush injuries
• Earthquake victims • Prolonged entrapment
Reperfusion Injury: After ischemia
• Tourniquet release • Revascularization procedures
Ventilator-Associated: Respiratory acidosis
• Acute CO2 retention • Check ABG
Post-Cardiac Arrest: Cellular injury
• Global hypoxic-ischemic injury

🚨 HIGH-YIELD Clinical Correlations

Volume Depletion + RAASi:
Classic combo - dehydration ↓ distal Na+ delivery + ACE-I blocks aldosterone = severe hyperkalemia

Pseudohyperkalemia Clues:
Normal ECG + extreme K+ (>8) + no symptoms = likely false positive

Rhabdomyolysis Triad:
Hyperkalemia + AKI + dark urine = check CPK, treat aggressively

Addison's Disease Clues:
Hyperkalemia + hyponatremia + hypotension + hyperpigmentation

Gordon Syndrome:
Hyperkalemia + hypertension + normal GFR = think thiazide trial

Digitalis Toxicity Alert:
Hyperkalemia + dig toxicity = NO CALCIUM (causes "stone heart")

📊 EKG Manifestations of Hyperkalemia

1. Mild Hyperkalemia

5.5-6.0 mEq/L

Early manifestations include tall, peaked T waves, best visualized in precordial leads. QT interval may shorten slightly. Often asymptomatic but requires monitoring.

• T wave height >5mm limb leads, >10mm precordial leads • Narrow base • First ECG change

🎯 Calcium Success Marker: QRS narrowing is the primary indicator of membrane stabilization, NOT T wave flattening

2. Moderate Hyperkalemia

6.1-7.0 mEq/L

Progression to PR interval prolongation and diminished P wave amplitude. QRS complex begins to widen as conduction velocity decreases. ST segment depression may be present.

• PR >200ms • P wave amplitude decreased • QRS begins widening • ST depression

3. Severe Hyperkalemia

7.0-8.0 mEq/L

Absence of P waves, marked QRS widening resembling bundle branch block or sine wave pattern. Heart blocks may occur. These changes represent pre-terminal rhythms requiring immediate intervention.

• No visible P waves • QRS >120ms • Bundle branch block pattern • Sine wave emerging

4. Critical Hyperkalemia

>8.0 mEq/L

Terminal wide QRS complexes merging with T waves creating sine wave pattern. Ventricular fibrillation or asystole may follow without immediate treatment.

• Sine wave pattern • QRS-T wave fusion • VFib/asystole risk • LIFE-THREATENING

🔍 Diagnostic Workup

📋 Essential Labs

Repeat K+: Confirm result, rule out hemolysis
BMP: Check BUN/Cr, bicarb, glucose
Magnesium: Often overlooked contributor
ABG: If acidosis suspected
CPK: If rhabdomyolysis suspected

⚡ Immediate Assessment

12-Lead ECG: Look for peaked T waves
Bladder Scan: Check for retention FIRST
Cardiac Monitor: Continuous rhythm monitoring
Vital Signs: Blood pressure, heart rate
Muscle Strength: Weakness, paralysis
Reflexes: Diminished or absent

🔍 Etiology Investigation

Medication Review: ACE-I, ARB, K+ sparing diuretics
Kidney Function: AKI, CKD assessment
Endocrine: Adrenal insufficiency, hypoaldosteronism
Tissue Breakdown: Rhabdomyolysis, tumor lysis
GI Function: Bowel obstruction (affects Lokelma)
Dietary History: Salt substitutes, supplements

💊 Treatment Mechanisms & Timing

🛡️ Membrane Stabilization

Calcium (No K+ Effect)

Calcium Gluconate: 30mL IV (peripheral OK) - 9% elemental Ca
Calcium Chloride: 10mL IV (central line only) - 27% elemental Ca
⚡ KEY: CaCl₂ has 3× MORE elemental calcium than gluconate
Success Marker: QRS narrowing (not T wave flattening)
Onset: 1-3 minutes
Duration: 30-60 minutes
Mechanism: Stabilizes cardiac membrane
Caution: Avoid in digoxin toxicity

🎯 Clinical Pearl: Monitor for QRS narrowing as the primary indicator of calcium effectiveness. T wave changes are less reliable and occur later.

🔄 Potassium Shifting

Evidence-Based Intracellular Shifting

📊 Evidence Summary: Insulin is most reliable; albuterol variable; bicarbonate controversial unless severe acidosis

Insulin + Glucose: MOST RELIABLE
• K+ ↓: 0.6-1.2 mEq/L • Onset: 15-30 min • Duration: 4-6 hrs • ~90% response rate
• Standard: 10U regular insulin IV + 25g dextrose (if glucose <250)
Albuterol: VARIABLE effectiveness
• K+ ↓: 0.5-1.0 mEq/L • Onset: 30-60 min • Duration: 2-4 hrs • Only 60-80% respond
• Dose: 10-20mg nebulized • Higher doses (20mg) more effective
• Less reliable in ESRD patients • Use as adjunct to insulin
Sodium Bicarbonate: CONTROVERSIAL - Limited evidence
• Only effective if severe metabolic acidosis (pH <7.1-7.2)
• Minimal effect in normal pH • May cause volume overload, alkalosis
• Dose: 50-100 mEq IV if pH <7.1 • Avoid in mild acidosis
Respiratory Acidosis Treatment: Address underlying cause
• Mechanical ventilation: ↑ minute ventilation, ↓ PCO₂
• Each 0.1 pH ↑ = ~0.6 mEq/L K+ ↓ • Treat airway obstruction, respiratory depression
• BiPAP/CPAP for acute respiratory failure • Bronchodilators if indicated

🎯 Clinical Evidence & Recommendations:

First-Line (Grade A):
• Insulin + glucose combo
• Most predictable response
• Works in all patient populations

Second-Line (Grade B):
• Albuterol as adjunct
• Bicarbonate only if pH <7.1
• Treat respiratory acidosis

⚡ Synergistic Effect: Insulin + albuterol together more effective than either alone (additive K+ reduction)

🗑️ Potassium Removal

Eliminates K+ from Body

Lokelma: 10g PO IMMEDIATELY (don't wait!)
Patiromer: Once daily dosing
Hemodialysis: Most effective for severe cases
Lokelma onset: 1 hour (small intestine)
Dialysis: 1 mEq/L in 60 min
Note: Foley catheter first if no EKG changes

🆚 Potassium Binder Comparison: New Generation vs Traditional

Parameter	Lokelma (SZC)	Veltassa (Patiromer)	Kayexalate (SPS)
FDA Approval	2018	2015	1950s
Exchange Ion	Sodium + Hydrogen	Calcium	Sodium
Site of Action	Small intestine	Colon	Colon
Onset of Action	1 hour (0.4 mEq/L)	~7 hours	~2 hours
Dosing Frequency	TID loading, then daily	Once daily	Every 6-8 hours
Bowel Obstruction	Won't work	May still work (colon)	May still work (colon)
Major Side Effects	Edema, fluid retention	Hypomagnesemia	Colonic necrosis risk
Clinical Use	Acute & chronic (give ASAP)	Chronic management	Acute (use with caution)

⚖️ Dialysis vs Conservative Management Decision

The choice between aggressive intervention (dialysis) and conservative management depends critically on EKG changes and ability to establish urine output:

🚰 Conservative Management

When appropriate:

No EKG changes
K+ 5.5-7.0 mEq/L
Able to establish UOP
No severe symptoms

Start with: Foley catheter

🏥 Aggressive Management

When needed:

ANY EKG changes
K+ >7.5 mEq/L
Anuric/oliguric
Severe symptoms

Prepare for: Emergent dialysis

Key Point: Many cases of hyperkalemia can be managed without dialysis if treated early and aggressively with Foley catheter placement, Lokelma, and shifting agents.

🚰 Urinary Obstruction: The Great Mimicker

Often overlooked but rapidly reversible cause that can prevent the need for dialysis

5-10%

of AKI cases in ED

22%

of AKI in men >60

0.8-1.1

mEq/L reduction in 4-6 hrs

800+

mL retention = significant improvement

Clinical Pearl: Relief of obstruction alone can be more effective than insulin-glucose therapy and may completely avoid the need for dialysis. Always perform bladder scan in unexplained hyperkalemia.

⚠️ Common Pitfalls & Evidence-Based Corrections

🚫 Avoid These Mistakes

Central line first: Place Foley BEFORE central line if no EKG changes
Delaying Lokelma: Give IMMEDIATELY, don't wait 1-2 hours
Bicarbonate routine use: Only effective if pH <7.1-7.2
Expecting albuterol to work: Only 60-80% respond (vs 90% for insulin)
Missing respiratory acidosis: Treat underlying ventilation issues
Calcium in Digitalis Toxicity: Can precipitate "stone heart"
Insulin without Dextrose: Risk of severe hypoglycemia

👀 Monitor Closely

Urine Output: After Foley placement
QRS Width: Calcium success = QRS narrowing (not T waves)
Glucose: Hourly × 6h after insulin (90% respond)
Albuterol Response: Only 60-80% will respond
Respiratory Status: If acidosis present, treat underlying cause
Potassium: Every 2-4 hours initially
ECG: Continuous monitoring if changes present

✅ Evidence-Based Success

Insulin + Glucose: Most reliable shifting agent (Grade A evidence)
QRS Narrowing: Primary indicator of calcium effectiveness
K+ Reduction >0.5 mEq/L: Within 1 hour of treatment
Bicarbonate Response: Only if severe acidosis (pH <7.1)
Respiratory Improvement: Each 0.1 pH ↑ = 0.6 mEq/L K+ ↓
Urine Output >0.5 mL/kg/hr: After Foley placement
Avoided Dialysis: Conservative management successful

🧮 Enhanced Hyperkalemia Calculator

Comprehensive Treatment Protocol Calculator

Serum K+ (mEq/L): 6.2

Patient Weight (kg): 70

ECG Changes:

Bladder Scan (mL): 150

Kidney Function:

Clinical Symptoms:

Suspected Etiology:

Calculating comprehensive treatment protocol...

📚 Verified Sources

Phase 2 audit (electrolytes-K-hypoNa-Reference_Check.md) flagged this file as having zero formal citations. Verified PubMed anchors below for the major drug-treatment claims (Lokelma, Patiromer, Kayexalate, insulin/dextrose, albuterol). Specific Lokelma onset values (0.4 mEq/L @ 1hr / 0.7 @ 4hr) and Foley reduction (0.8-1.1 mEq/L) precision claims remain at the FDA-label / clinical-convention level rather than primary-RCT-published data. [Bibliography added 2026-05-03]

Sterns RH, Grieff M, Bernstein PL. Treatment of hyperkalemia: something old, something new. Kidney Int. 2016;89(3):546-554. PMID: 26880450. — Comprehensive review of hyperkalemia treatment mechanisms; insulin/dextrose, albuterol, calcium, bicarbonate, binders.
Anker SD, Kosiborod M, Zannad F, et al; HARMONIZE Investigators. Maintenance of serum potassium with sodium zirconium cyclosilicate (ZS-9) in heart failure patients: results from a phase 3 randomized, double-blind, placebo-controlled trial. Eur J Heart Fail. 2015;17(10):1050-1056. PMID: 26011677. — HARMONIZE phase 3 — Lokelma (ZS-9) median time to normalization 2.2 hours; sustains normokalemia for 28 days while RAASi continued.
Weir MR, Bakris GL, Bushinsky DA, et al; OPAL-HK Investigators. Patiromer in patients with kidney disease and hyperkalemia receiving RAAS inhibitors. N Engl J Med. 2015;372(3):211-221. PMID: 25415805. — Patiromer pivotal trial; effective at 4-week treatment; supports continued RAASi use in CKD with hyperkalemia.
Bushinsky DA, Williams GH, Pitt B, et al. Patiromer induces rapid and sustained potassium lowering in patients with chronic kidney disease and hyperkalemia. Kidney Int. 2015;88(6):1427-1433. PMID: 26352299. — Patiromer onset of action — median time to K+ normalization approximately 7 hours.
Allon M, Copkney C. Albuterol and insulin for treatment of hyperkalemia in hemodialysis patients. Kidney Int. 1990;38(5):869-872. PMID: 2266671. — Foundational HD-population data on insulin (K+ ↓ 0.65 mEq/L at 60 min) and albuterol (K+ ↓ approximately 0.6 mEq/L); approximately 30% of ESRD patients are albuterol non-responders.
Adrogué HJ, Madias NE. Changes in plasma potassium concentration during acute acid-base disturbances. Am J Med. 1981;71(3):456-467. PMID: 7025622. — Foundational paper on the pH-K+ relationship; in-vivo correlation closer to 0.2-0.4 mEq/L per 0.1 pH unit shift in metabolic acidosis (NOT the 0.6 widely-quoted teaching upper bound).
Sterns RH, Grieff M, Bernstein PL. Treatment of hyperkalemia: something old, something new. Kidney Int. 2016;89(3):546-554. PMID: 26880450. — Already cited as ref 1; also covers Kayexalate colonic necrosis safety signal and FDA black-box context.

Phase 2 note: Lokelma "0.4 mEq/L @ 1hr / 0.7 @ 4hrs" and Foley "0.8-1.1 mEq/L reduction in 4-6 hrs" precision values cannot be sourced to a single primary RCT. The Lokelma values are FDA-label-derived; the Foley reduction is clinical-observation territory without a randomized comparator. Direction is correct; precision is overstated. The "Each 0.1 pH ↑ = 0.6 mEq/L K+ ↓" rule is the published upper bound (Adrogué 1981); the typical effect is closer to 0.2-0.4. Insulin "90% response rate" is at the high end of published estimates from small HD-specific studies; direction correct.

🎯 Enhanced Key Learning Points

🚰 Foley First Principle

First catheter = Foley (not central line)
If no EKG changes, establish UOP first
May prevent need for dialysis
Check bladder scan in all cases

💊 Lokelma Timing

Give IMMEDIATELY, don't wait
Works in small intestine
Won't work in bowel obstruction
1-hour onset for K+ reduction

⚡ Emergency Priorities

EKG changes = immediate calcium
CaCl₂ has 3× MORE elemental Ca than gluconate
QRS narrowing = calcium success (not T waves)
Stabilize → Foley → Shift → Remove
Continuous cardiac monitoring
Don't wait for labs to treat severe cases

🔍 Etiology Recognition

Cellular death: Rhabdo, tumor lysis, gut ischemia
Renal: RAASi blockade, volume depletion, CKD
Endocrine: Addison's disease, CAH
Pseudohyperkalemia: Hemolysis, thrombocytosis
Genetic: Hyperkalemic periodic paralysis
Critical care: Burns, reperfusion injury

⚡ Hyperkalemia