Rhabdomyolysis: Difference between revisions
(Major rewrite: IV fluid targets, hyperkalemia management, etiology, CK thresholds, peer-reviewed references) |
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==Background== | ==Background== | ||
*Breakdown of skeletal muscle releasing intracellular contents into the circulation | *Breakdown of skeletal muscle releasing intracellular contents into the circulation | ||
*Key toxins: | *Key toxins: myoglobin (nephrotoxic), creatine kinase (CK), potassium, phosphate, uric acid | ||
* | *Acute kidney injury (AKI) occurs in 15-40% of cases<ref name="bosch">Bosch X, et al. Rhabdomyolysis and acute kidney injury. ''N Engl J Med''. 2009;361(1):62-72. PMID 19571284.</ref> | ||
*Overall mortality ~5%; higher with AKI, DIC, or [[Compartment syndrome|compartment syndrome]] | *Overall mortality ~5%; higher with AKI, DIC, or [[Compartment syndrome|compartment syndrome]] | ||
==Etiology== | ==Etiology== | ||
* | *Trauma / Crush injury (most common worldwide) | ||
*'''Exertional''' (exercise, seizures, agitation, status epilepticus) | *'''Exertional''' (exercise, seizures, agitation, status epilepticus) | ||
* | *Drug/toxin-induced | ||
**Statins (especially with interacting drugs) | **Statins (especially with interacting drugs) | ||
**[[Cocaine toxicity|Cocaine]], [[Amphetamine toxicity|amphetamines]], MDMA, [[Ethanol toxicity|alcohol]] | **[[Cocaine toxicity|Cocaine]], [[Amphetamine toxicity|amphetamines]], MDMA, [[Ethanol toxicity|alcohol]] | ||
**[[Neuroleptic malignant syndrome|NMS]], [[Serotonin syndrome]], [[Malignant hyperthermia]] | **[[Neuroleptic malignant syndrome|NMS]], [[Serotonin syndrome]], [[Malignant hyperthermia]] | ||
* | *Prolonged immobilization (found down, intraoperative) | ||
*[[Hypokalemia]], [[Hypophosphatemia]], [[Hyponatremia]] | *[[Hypokalemia]], [[Hypophosphatemia]], [[Hyponatremia]] | ||
*[[Heat stroke]] | *[[Heat stroke]] | ||
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==Clinical Features== | ==Clinical Features== | ||
*Classic triad: | *Classic triad: myalgias, weakness, dark urine (tea/cola-colored) | ||
**Full triad present in <10% of cases | **Full triad present in <10% of cases | ||
*Muscle tenderness, swelling, and stiffness | *Muscle tenderness, swelling, and stiffness | ||
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==Evaluation== | ==Evaluation== | ||
* | *Creatine kinase (CK) — diagnostic marker | ||
**CK >5x upper limit of normal (typically >1,000 U/L) diagnostic | **CK >5x upper limit of normal (typically >1,000 U/L) diagnostic | ||
**CK >5,000 U/L: significant risk of AKI | **CK >5,000 U/L: significant risk of AKI | ||
**Peak CK at 24-72 hours; monitor serial levels | **Peak CK at 24-72 hours; monitor serial levels | ||
* | *Urinalysis: urine dipstick positive for "blood" but no RBCs on microscopy (myoglobinuria) | ||
* | *BMP: potassium (may be severely elevated), creatinine, BUN, calcium, phosphate, bicarbonate | ||
* | *CBC, LDH, uric acid, coagulation studies | ||
* | *ECG — evaluate for [[Hyperkalemia|hyperkalemia]] changes (peaked T waves, wide QRS) | ||
*Consider compartment pressures if clinical concern | *Consider compartment pressures if clinical concern | ||
==Management== | ==Management== | ||
===Aggressive IV Fluid Resuscitation=== | ===Aggressive IV Fluid Resuscitation=== | ||
* | *Cornerstone of treatment | ||
* | *Normal saline at 200-300 mL/hr (or 1-2 L/hr initially if severely hypovolemic)<ref name="scharman">Scharman EJ, et al. Prevention of kidney injury following rhabdomyolysis: a systematic review. ''Ann Pharmacother''. 2013;47(1):90-105. PMID 23324509.</ref> | ||
*Target urine output | *Target urine output 200-300 mL/hr until CK trending down and urine clears | ||
*Monitor for fluid overload, especially in elderly and those with cardiac/renal disease | *Monitor for fluid overload, especially in elderly and those with cardiac/renal disease | ||
*Bicarbonate drip (150 mEq NaHCO3 in 1 L D5W) may be considered to alkalinize urine (target urine pH >6.5) — evidence is limited | *Bicarbonate drip (150 mEq NaHCO3 in 1 L D5W) may be considered to alkalinize urine (target urine pH >6.5) — evidence is limited | ||
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===Treat Hyperkalemia=== | ===Treat Hyperkalemia=== | ||
*See [[Hyperkalemia]] for detailed management | *See [[Hyperkalemia]] for detailed management | ||
* | *Calcium gluconate 10% 10 mL IV for cardiac membrane stabilization if ECG changes | ||
* | *Insulin 10 units regular IV + D50W 50 mL IV | ||
*[[Sodium bicarbonate]], [[Albuterol]] nebulizer, [[Kayexalate]] or patiromer | *[[Sodium bicarbonate]], [[Albuterol]] nebulizer, [[Kayexalate]] or patiromer | ||
*Emergent [[Hemodialysis|dialysis]] if refractory | *Emergent [[Hemodialysis|dialysis]] if refractory | ||
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==Disposition== | ==Disposition== | ||
* | *Admit patients with: | ||
**CK >5,000 U/L | **CK >5,000 U/L | ||
**AKI (elevated creatinine) | **AKI (elevated creatinine) | ||
Latest revision as of 09:31, 22 March 2026
Background
- Breakdown of skeletal muscle releasing intracellular contents into the circulation
- Key toxins: myoglobin (nephrotoxic), creatine kinase (CK), potassium, phosphate, uric acid
- Acute kidney injury (AKI) occurs in 15-40% of cases[1]
- Overall mortality ~5%; higher with AKI, DIC, or compartment syndrome
Etiology
- Trauma / Crush injury (most common worldwide)
- Exertional (exercise, seizures, agitation, status epilepticus)
- Drug/toxin-induced
- Statins (especially with interacting drugs)
- Cocaine, amphetamines, MDMA, alcohol
- NMS, Serotonin syndrome, Malignant hyperthermia
- Prolonged immobilization (found down, intraoperative)
- Hypokalemia, Hypophosphatemia, Hyponatremia
- Heat stroke
- Infections (influenza, COVID-19, Legionella)
- Hypothermia, electrical injuries
Clinical Features
- Classic triad: myalgias, weakness, dark urine (tea/cola-colored)
- Full triad present in <10% of cases
- Muscle tenderness, swelling, and stiffness
- May be asymptomatic with only lab abnormalities
- Complications:
- Hyperkalemia (can cause cardiac dysrhythmias) — life-threatening
- Acute kidney injury (oliguria, anuria)
- Compartment syndrome
- DIC
- Hypocalcemia (early), hypercalcemia (recovery phase)
- Metabolic acidosis
Evaluation
- Creatine kinase (CK) — diagnostic marker
- CK >5x upper limit of normal (typically >1,000 U/L) diagnostic
- CK >5,000 U/L: significant risk of AKI
- Peak CK at 24-72 hours; monitor serial levels
- Urinalysis: urine dipstick positive for "blood" but no RBCs on microscopy (myoglobinuria)
- BMP: potassium (may be severely elevated), creatinine, BUN, calcium, phosphate, bicarbonate
- CBC, LDH, uric acid, coagulation studies
- ECG — evaluate for hyperkalemia changes (peaked T waves, wide QRS)
- Consider compartment pressures if clinical concern
Management
Aggressive IV Fluid Resuscitation
- Cornerstone of treatment
- Normal saline at 200-300 mL/hr (or 1-2 L/hr initially if severely hypovolemic)[2]
- Target urine output 200-300 mL/hr until CK trending down and urine clears
- Monitor for fluid overload, especially in elderly and those with cardiac/renal disease
- Bicarbonate drip (150 mEq NaHCO3 in 1 L D5W) may be considered to alkalinize urine (target urine pH >6.5) — evidence is limited
Treat Hyperkalemia
- See Hyperkalemia for detailed management
- Calcium gluconate 10% 10 mL IV for cardiac membrane stabilization if ECG changes
- Insulin 10 units regular IV + D50W 50 mL IV
- Sodium bicarbonate, Albuterol nebulizer, Kayexalate or patiromer
- Emergent dialysis if refractory
Other
- Treat underlying cause (cool if hyperthermic, correct electrolytes)
- Avoid nephrotoxins (NSAIDs, contrast dye, aminoglycosides)
- Compartment syndrome: emergent fasciotomy if pressures >30 mmHg or clinical diagnosis
- Monitor for and treat DIC if present
Disposition
- Admit patients with:
- CK >5,000 U/L
- AKI (elevated creatinine)
- Hyperkalemia or other electrolyte derangements
- Ongoing symptoms or rising CK
- Discharge may be considered for mild rhabdomyolysis (CK <5,000, normal renal function, normal K) with close follow-up and oral hydration