What is the best approach to managing a patient with rhabdomyolysis?

Management of Rhabdomyolysis

Immediate Fluid Resuscitation

Initiate aggressive intravenous fluid resuscitation with 0.9% normal saline at 1000 mL/hour immediately upon patient contact, as this is the single most critical intervention to prevent acute kidney injury and reduce mortality. 1

• Start IV access as soon as possible, even before extrication is complete in trauma scenarios 2
• Reduce infusion rate by at least 50% if initial resuscitation exceeds 2 hours to avoid volume overload 2, 1
• Target urine output of ≥300 mL/hour (approximately 3-5 mL/kg/hour for a 70 kg patient), which is 6-10 times higher than standard oliguria thresholds 2, 1
• Insert bladder catheter to monitor hourly urine output unless urethral injury is suspected 2

Fluid Selection

• Use 0.9% normal saline exclusively - avoid potassium-containing solutions (Lactated Ringer's, Hartmann's, Plasmalyte A) as potassium levels can increase markedly after reperfusion even with intact renal function 2, 1
• Avoid starch-based fluids due to association with increased AKI and bleeding 2

Volume Requirements Based on Severity

• Severe rhabdomyolysis (CK >15,000 IU/L): Administer >6L per day 3, 2
• Moderate rhabdomyolysis: Administer 3-6L per day 3, 2
• Early initiation is critical - delayed fluid resuscitation significantly increases AKI risk 3, 2, 4

Discontinue Causative Agents Immediately

Stop all potentially offending medications and supplements immediately upon diagnosis. 3

Medications to Discontinue

• Statins (most common drug cause, incidence 1.6 per 100,000 patient-years) 3
• Gemfibrozil (carries 10-fold higher rhabdomyolysis risk than fenofibrate) 3
• Succinylcholine in susceptible patients 3

Supplements to Discontinue

• Red yeast rice containing lovastatin 3
• Creatine monohydrate 3, 1
• Wormwood oil, licorice, Hydroxycut 3

Laboratory Monitoring Protocol

Initial Diagnostic Tests

• Total creatine kinase (CK) - not CK-MB, which lacks sensitivity/specificity for rhabdomyolysis 3
• Complete metabolic panel with potassium, calcium, phosphorus, magnesium 3
• Creatinine and BUN 3
• Urinalysis for myoglobinuria (brown urine, positive for blood without RBCs) 3
• Arterial blood gas for metabolic acidosis 3

Serial Monitoring During Treatment

• Monitor CK, creatinine, potassium, calcium, and phosphorus every 6-12 hours in severe cases until CK is declining and renal function stabilizes 3, 1
• Plasma myoglobin levels 3
• Urine pH (target approximately 6.5) 2

Timing Considerations

• CK peaks 24-120 hours after the inciting event - levels at 9 hours post-injury are likely still rising and do not represent peak values 3
• Repeat CK measurement at 24 hours if clinical suspicion remains high despite initial normal values 3
• Impact trauma from falls can elevate CK without true rhabdomyolysis, but assume true muscle breakdown until proven otherwise if levels are doubling 3

Electrolyte Management

Hyperkalemia (Life-Threatening Priority)

• Monitor potassium closely and correct emergently - hyperkalemia can precipitate fatal cardiac arrhythmias 3, 1
• Obtain ECG to identify cardiac effects of hyperkalemia 3
• Use standard hyperkalemia protocols including calcium gluconate, insulin/glucose, and albuterol 1
• Sodium bicarbonate may aid potassium reuptake into cells in life-threatening hyperkalemia 2

Calcium and Phosphorus

• Monitor calcium levels closely - large bicarbonate doses can worsen hypocalcemia by decreasing free calcium 2
• Track phosphorus levels as part of serial electrolyte monitoring 3, 1

What NOT to Use (Critical Pitfalls)

Bicarbonate for Urine Alkalinization

Do not routinely use sodium bicarbonate for urine alkalinization - current evidence shows no benefit over aggressive crystalloid resuscitation alone for preventing pigment nephropathy 2, 4

• Bicarbonate adds extra volume without proven benefit 2
• Can worsen hypocalcemia 2
• Reserve bicarbonate only for severe metabolic acidosis or life-threatening hyperkalemia as standard critical care indications 2

Mannitol

Do not routinely use mannitol - studies show little additional benefit compared to crystalloid resuscitation alone and it is potentially nephrotoxic 2, 4

• May only benefit patients with CK >30,000 IU/L, though this benefit remains undefined 2
• Contraindicated in patients with oligoanuria 2
• If used, only after adequate volume expansion is achieved 2

Loop Diuretics

• Diuresis is not recommended as primary treatment and may increase AKI risk unless adequate volume resuscitation achieved first 2
• Consider only for management of volume overload, not as primary rhabdomyolysis treatment 2

Compartment Syndrome Surveillance

Early Warning Signs

• Pain, tension, paresthesia, and paresis are early signs requiring immediate evaluation 3
• Late signs (pulselessness, pallor) indicate irreversible damage 3

Fasciotomy Indications

• Perform early fasciotomy when compartment pressure exceeds 30 mmHg 3, 1
• Also indicated when differential pressure (diastolic BP - compartment pressure) is <30 mmHg 3, 1
• Compartment syndrome can both cause and complicate rhabdomyolysis 3

Pain Management Strategy

First-Line Analgesic

• Acetaminophen 500-1000 mg (onset 15-30 minutes, maximum 4-6 grams daily) is preferred initial analgesic 3
• Avoids nephrotoxic effects particularly problematic in rhabdomyolysis patients at high AKI risk 3

Agents to Avoid

• All NSAIDs must be avoided (ibuprofen, ketoprofen, diclofenac, naproxen, mefenamic acid) due to gastrointestinal and renal toxicity 3

Severe Pain Management

• Reserve opioids for severe muscle pain unresponsive to acetaminophen 3
• Oral morphine 20-40 mg for opioid-naive patients (oral:parenteral ratio 1:2 to 1:3) 3
• In established AKI with eGFR <30 mL/min, use fentanyl or buprenorphine as safest opioid choices 3
• Provide round-the-clock dosing with rescue doses (10-15% of total daily dose) for breakthrough pain 3

Renal Replacement Therapy Indications

Initiate dialysis early for the following indications: 2, 1

• Refractory hyperkalemia despite medical management 1
• Severe metabolic acidosis 1
• Fluid overload despite conservative management 2, 1
• Persistently elevated CK levels after 4 days of adequate hydration 1

Dialysis Modality

• Intermittent hemodialysis is preferred - provides rapid potassium clearance and allows treatment of multiple patients per day on same machine 2

Duration of Treatment

Continue intravenous fluids until ALL of the following criteria are met: 1

• CK levels are declining (typically continue until <1,000 U/L) 5
• Urine output remains adequate (≥300 mL/hour) 1
• Electrolytes normalize 1
• Renal function stabilizes or improves 1

Etiology-Specific Considerations

Statin-Induced Rhabdomyolysis

• Risk factors include age, diabetes, renal impairment, cardiovascular disease, hypothyroidism, and drug interactions 3
• SLCO1B1 gene mutations increase risk 3
• Consider alternative lipid management: pravastatin, fluvastatin (minimal CYP450 metabolism), ezetimibe, PCSK9 inhibitors, or bempedoic acid 3

Exertional Rhabdomyolysis

• Novel overexertion or unaccustomed exercise volume/intensity is common trigger 3
• "High responders" reach remarkably high CK levels more quickly 3
• Consider genetic testing (RYR1, CACNA1S for malignant hyperthermia susceptibility; CPT2, PYGM, ACADM, AMPD1, VLCAD for metabolic myopathies) in recurrent cases 3

Trauma-Related Rhabdomyolysis

• Crush injuries and severe limb trauma are major risk factors 3
• Document all recreational drug use (cocaine, methamphetamine, MDMA, ketamine, heroin) 3
• Review all over-the-counter medications, herbal supplements, and performance-enhancing products 3