Rhabdomyolysis: Difference between revisions

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==Background==
==Background==
[[File:PMC4065558 10.1177 1941738114522957-fig1.png|thumb|Intraoperative photograph of the left anterior compartment of the thigh. The quadriceps musculature can be seen bulging through the fascial defects.]]
*Breakdown of skeletal muscle releasing intracellular contents into the circulation
*Muscle necrosis and release of intracellular muscle constituents into the circulation
*Key toxins: myoglobin (nephrotoxic), creatine kinase (CK), potassium, phosphate, uric acid
*Recurrent episodes suggests inherited metabolic disorder
*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>
*Alcohol and drugs play a role in up to 80% of cases
*Overall mortality ~5%; higher with AKI, DIC, or [[Compartment syndrome|compartment syndrome]]


===Etiology===
==Etiology==
*[[Trauma]] or muscle compression
*Trauma / Crush injury (most common worldwide)
**[[Crush Syndrome]]
*'''Exertional''' (exercise, seizures, agitation, status epilepticus)
**Immobilization
*Drug/toxin-induced
**[[Compartment Syndrome]]
**Statins (especially with interacting drugs)
**[[Electrical injuries]]
**[[Cocaine toxicity|Cocaine]], [[Amphetamine toxicity|amphetamines]], MDMA, [[Ethanol toxicity|alcohol]]
*Nontraumatic Exertional
**[[Neuroleptic malignant syndrome|NMS]], [[Serotonin syndrome]], [[Malignant hyperthermia]]
**Exercise + hot weather
*Prolonged immobilization (found down, intraoperative)
**Exercise + [[sickle cell]]
*[[Hypokalemia]], [[Hypophosphatemia]], [[Hyponatremia]]
**Exercise + [[Hypokalemia]]
*[[Heat stroke]]
**Hyperkinetic states
*Infections (influenza, COVID-19, Legionella)
***[[Seizure]]
*Hypothermia, [[Electrical injury|electrical injuries]]
***[[delirium tremens|DTs]]
***Stimulant / [[Sympathomimetic]]<ref> O'Connor AD et al. Prevalence of Rhabdomyolysis in Sympathomimetic Toxicity: A Comparison of Stimulants. J Med. Toxicol. 2015;11(2)195-200 </ref> overdose
***[[Malignant Hyperthermia]]
***[[Neuroleptic malignant syndrome]]
*Nontraumatic Nonexertional
**Drugs and toxins
***[[Coma]] induced by [[sedative/hypnotic toxicity|sedatives]]
***[[Alcohol]]
****Coma-induced muscle compression
****Direct toxic effect
****Nutritional compromise increases risk ([[hypokalemia|hypoK]], [[hypomagnesemia|hypoMg]], [[hypophosphatemia|hypoPhos]])
***Statins
***[[Colchicine]]
***[[CO Poisoning]]
**[[Infection]]
***Viral [[myositis]] - [[influenza]], [[coxsackie]], [[EBV]], [[HSV]], [[HIV]], [[CMV]]
***Bacterial pyomyositis
***[[Septicemia]]
**Endocrine
***[[Hypothyroidism]]
**Inflammatory myopathies
***Moderate CK elevations only (rhabdomyolysis only described in case reports)
**Miscellaneous
***[[Status Asthmaticus]]
***[[Toxic shock syndrome]]
***[[Mushroom]] ingestion


==Clinical Features==
==Clinical Features==
[[File:RhabdoUrine.jpg|thumb|Urine from a person with rhabdomyolysis showing the characteristic brown discoloration as a result of myoglobinuria]]
*Classic triad: myalgias, weakness, dark urine (tea/cola-colored)
[[File:PMC2740115 1757-1626-0002-0000006479-001.png|thumb|Tea coloured with severe rhabdomyolysis]]
**Full triad present in <10% of cases
*[[Myalgia]], stiffness, [[weakness]], malaise, low-grade [[fever]], dark urine
*Muscle tenderness, swelling, and stiffness
**Musculoskeletal symptoms may be present in only half of cases
*May be asymptomatic with only lab abnormalities
*[[Nausea and vomiting]], [[abdominal pain]], [[tachycardia]] in severe cases
*Complications:
*Mental status changes secondary to urea-induced [[encephalopathy]]
**[[Hyperkalemia]] (can cause [[Cardiac dysrhythmia|cardiac dysrhythmias]]) — '''life-threatening'''
 
**[[Acute kidney injury]] (oliguria, anuria)
==Differential Diagnosis==
**[[Compartment syndrome]]
{{Extremity trauma DDX}}
**[[DIC]]
 
**Hypocalcemia (early), hypercalcemia (recovery phase)
{{Red urine DDX}}
**Metabolic acidosis


==Evaluation==
==Evaluation==
===Work-up===
*Creatine kinase (CK) — diagnostic marker
*Obtain immediate ECG (electrolyte abnormalities)
**CK >5x upper limit of normal (typically >1,000 U/L) diagnostic
*Total CK
**CK >5,000 U/L: significant risk of AKI
*[[Urinalysis]]
**Peak CK at 24-72 hours; monitor serial levels
*CBC
*Urinalysis: urine dipstick positive for "blood" but no RBCs on microscopy (myoglobinuria)
*Chemistry, including Mag, Phos
*BMP: potassium (may be severely elevated), creatinine, BUN, calcium, phosphate, bicarbonate
*Uric acid
*CBC, LDH, uric acid, coagulation studies
*[[LFTs]]
*ECG — evaluate for [[Hyperkalemia|hyperkalemia]] changes (peaked T waves, wide QRS)
*VBG, venous pH
*Consider compartment pressures if clinical concern
*[[DIC]] panel
**Coags, FSP, fibrinogen
 
===Evaluation===
*Total CK
**Most consider rhabdomyolysis if 5x or greater increase above upper limit of normal (~2000)
**Serum CK begins to rise 2-12hr after injury, peaks within 24-72hr
**Degree of CK elevation correlates with muscle injury, but NOT renal failure
*CK-MB
**May be normal or mildly elevated (<5% of total)
*Uric Acid - elevates before CK
*Myoglobinuria
**[[Urinalysis]] = +blood, no RBCs (Sn ~80%)  
**Myoglobin is cleared within 1-6hr (often see elevated CK with no myoglobinuria)
*Acute [[renal failure]]
**Creatinine increase
*Electrolyte abnormalities
**[[Hyperkalemia]]
**[[Hyperphosphatemia]]
**[[Hypocalcemia]]
**Hyperuricemia
*LFTs elevation
**Intramuscular release of AST/ALT <ref>Mayo Clin Proc 2017;92[1]:e1; J Med Toxicol 2010;6[3]:294</ref> with AST>ALT.


==Management==
==Management==
Trend:
===Aggressive IV Fluid Resuscitation===
*Volume status
*Cornerstone of treatment
*Urine pH
*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>
*Chemistry
*Target urine output 200-300 mL/hr until CK trending down and urine clears
*CK
*Monitor for fluid overload, especially in elderly and those with cardiac/renal disease
*Calcium, phosphorus
*Bicarbonate drip (150 mEq NaHCO3 in 1 L D5W) may be considered to alkalinize urine (target urine pH >6.5) — evidence is limited
*LFTs (elevation will resolve with resolving rhabdo)


===[[IV Fluids]]===
===Treat Hyperkalemia===
*Start with [[IVF]] 1-2 L/hr
*See [[Hyperkalemia]] for detailed management
*After rapid correction of fluid deficit, one method is infusing 2.5 mL/kg/hr with urine output goal of 200-300 ml/hr (2-3 cc/kg/hr)
*Calcium gluconate 10% 10 mL IV for cardiac membrane stabilization if ECG changes
*Frequently need ~10 L/day
*Insulin 10 units regular IV + D50W 50 mL IV
*[[Sodium bicarbonate]], [[Albuterol]] nebulizer, [[Kayexalate]] or patiromer
*Emergent [[Hemodialysis|dialysis]] if refractory


===[[Urinary alkalinization]]===
===Other===
*Administered as [[bicarbonate]] drip
*Treat underlying cause (cool if [[Heat stroke|hyperthermic]], correct electrolytes)
**Mix 150 mL [3 amps] of 8.4% sodium bicarbonate with 1 L D5W
*Avoid nephrotoxins (NSAIDs, contrast dye, aminoglycosides)
**Infuse at 200 mL/hour; rate is adjusted to achieve urine pH of >6.5
*[[Compartment syndrome]]: emergent fasciotomy if pressures >30 mmHg or clinical diagnosis
*Controversial; no RCT to date have demonstrated benefit
*Monitor for and treat [[DIC]] if present
*Consider if CK >5000, severe muscle injury (crush injury), rising CK AND urine pH <6.5
*Contraindications:
**Severe hypocalcemia
**Arterial pH > 7.50
**Serum bicarbonate > 30 meq/L
**Arterial pH and serum calcium should be monitored q2hr
*Discontinue alkalinization:
**Urine pH does not rise above 6.5 after 3-4hr
**Patient develops symptomatic hypocalcemia
**Arterial pH > 7.5
**Serum bicarbonate >30 meq/L
===[[Mannitol]]===
*''Mannitol administration can worsen dehydration and oliguria and although used in the past should generally be avoided''
*No RCT to date has demonstrated benefit
 
===[[Intubation]]/RSI===
*Use [[rocuronium]] due to the potential elevations in potassium that result from the rhabdomyolysis


==Disposition==
==Disposition==
*Discharge if:
*Admit patients with:
**Exertional rhabdo
**CK >5,000 U/L
**Otherwise healthy
**AKI (elevated creatinine)
**No comorbidities (heat stress, dehydration, trauma)
**[[Hyperkalemia]] or other electrolyte derangements
**Downtrending total CK
**Ongoing symptoms or rising CK
***Consider admission for CK >30,000
*Discharge may be considered for mild rhabdomyolysis (CK <5,000, normal renal function, normal K) with close follow-up and oral hydration
*Otherwise admit to monitored bed


==Complications==
==See Also==
*[[Acute Renal Failure]]
**Neither presence of myoglobinuria nor degree of CK rise is predictive of ARF
**Rare in exertional rhabdomyolysis with out presence of dehydration, heat stress, trauma
**Most commonly oliguric
*[[Hyperkalemia]]
*[[Hyperkalemia]]
**Renal function, not release of K+, is most important determinant
*[[Acute kidney injury]]
**Treat aggressively; insulin may be ineffective; may require dialysis
*[[Compartment syndrome]]
*[[Hypocalcemia]] (initial phase)
*[[Crush injury]]
**Treat only if symptomatic or severely hyperkalemic (often have rebound hypercalcemia)
*[[Heat stroke]]
*[[Hypercalcemia]] (recovery phase)
*[[Hyperphosphatemia]]
**Treat cautiously (treatment may worsen calcium precipitation in muscle)
**Consider oral phosphate binders when level >7
*[[DIC]]
**Usually resolves spontaneously within several days
*[[Compartment Syndrome]]
*Peripheral nerve injury
**Usually resolves within few days-weeks
 
 
==Medication Dosing==
*{{MedicationDose|drug=Sodium bicarbonate|dose=150 mL (3 amps) of 8.4% in 1L D5W at 200 mL/hr|route=IV drip|context=Urinary alkalinization (goal urine pH >6.5)|indication=Rhabdomyolysis|population=Adult|notes=Controversial; consider if CK >5000 and urine pH <6.5}}
 
==See Also==
*[[Crush Syndrome]]
*[[Sympathomimetic Toxicity]]
*IBCC chapter on rhabdomyolysis - https://emcrit.org/ibcc/rhabdo/


==References==
==References==
<references/>
<references/>
[[Category:Renal]]
[[Category:Renal]]
[[Category:Trauma]]
[[Category:Orthopedics]]

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

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:

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

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

See Also

References

  1. ↑ Bosch X, et al. Rhabdomyolysis and acute kidney injury. N Engl J Med. 2009;361(1):62-72. PMID 19571284.
  2. ↑ Scharman EJ, et al. Prevention of kidney injury following rhabdomyolysis: a systematic review. Ann Pharmacother. 2013;47(1):90-105. PMID 23324509.
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