Treatment of Rhabdomyolysis in the Elderly
Aggressive intravenous fluid resuscitation with isotonic saline is the cornerstone of rhabdomyolysis treatment in elderly patients, with immediate initiation being critical to prevent acute kidney injury, regardless of age. 1, 2, 3
Immediate Fluid Resuscitation Protocol
Begin isotonic saline (0.9% NaCl) immediately upon diagnosis, as any delay in fluid administration significantly increases the risk of acute kidney injury and worse outcomes. 1, 2, 3
Volume Requirements Based on Severity
- For severe rhabdomyolysis (CPK >15,000 IU/L): Administer >6L of intravenous fluids per day to prevent acute kidney injury and need for renal replacement therapy. 4, 1, 2
- For moderate rhabdomyolysis: Administer 3-6L of intravenous fluids per day. 4, 1, 2
- Target urine output of 300 mL/hour (approximately 3-5 mL/kg/hour for a 70 kg patient) to facilitate myoglobin clearance and prevent renal tubular obstruction. 1, 2, 3
Special Considerations for Elderly Patients
Monitor closely for fluid overload, particularly in elderly patients who commonly have cardiac or renal compromise. 1, 3 The elderly frequently present with pre-existing conditions that affect fluid tolerance, requiring careful balance between aggressive hydration and avoiding volume overload. 4
Electrolyte Monitoring and Management
Check electrolyte panels every 6-12 hours in severe cases, including plasma myoglobin, creatine phosphokinase (CPK), and potassium measurements. 4, 1, 3
Critical Electrolyte Abnormalities
- Hyperkalemia requires immediate correction, as it can precipitate life-threatening cardiac arrhythmias and pulseless electrical activity where external defibrillation may be ineffective. 1, 3
- Monitor for hypokalaemia in elderly patients, which is associated with new onset rapid ventricular rate atrial fibrillation perioperatively. 4
- Correct hypocalcemia and hyperphosphatemia promptly. 1, 3
- Assess for metabolic acidosis via arterial blood gas, which commonly occurs in severe rhabdomyolysis. 1, 3
Urine Monitoring
Place bladder catheter to monitor hourly urine output and maintain urine pH at approximately 6.5. 4, 1, 2
Medication Management
Discontinue Causative Agents
Immediately stop all medications that may contribute to rhabdomyolysis, including:
- Statins (particularly important in elderly patients who commonly take these medications). 1, 3
- Dietary supplements such as red yeast rice, creatine monohydrate, wormwood oil, licorice, and Hydroxycut. 1, 3
Avoid Nephrotoxic Medications
Do not use NSAIDs due to nephrotoxic effects. 3
Interventions NOT Recommended
Do not routinely use bicarbonate for urinary alkalinization, as current evidence does not demonstrate benefit over aggressive fluid resuscitation with crystalloids alone, and large doses can worsen hypocalcemia. 2, 5
Do not routinely use mannitol, as studies suggest little additional benefit compared to crystalloid resuscitation alone, and it is potentially nephrotoxic. 2, 5 Mannitol may only benefit patients with markedly elevated CK (>30,000 U/L), though this benefit remains undefined, and is contraindicated in patients with oligoanuria. 2
Avoid solutions with potassium (such as Ringer's lactate or Hartmann solution) because potassium levels can increase markedly after reperfusion. 2
Monitoring for Complications
Compartment Syndrome Surveillance
Maintain high suspicion for compartment syndrome, which can both cause and complicate rhabdomyolysis in elderly patients who may have fallen and been immobilized. 4, 1, 3
- Early signs: Pain, pain with passive stretch, paresthesia, and paresis. 4
- Late signs (indicating irreversible damage): Pulselessness and pallor. 4, 1
- Perform early fasciotomy when compartment pressure exceeds 30 mmHg or when differential pressure (diastolic BP – compartment pressure) is <30 mmHg. 4, 1, 3
Renal Function Monitoring
Monitor renal function through serial creatinine and BUN measurements. 1 Inadequate urine output (<300 mL/hour) suggests worsening kidney function. 1
Renal Replacement Therapy Indications
Initiate RRT if CPK remains persistently elevated despite 4 days of adequate hydration, as this indicates severe rhabdomyolysis with significant risk of irreversible kidney damage. 1, 3
Consider RRT for:
Consider discontinuation of RRT when urine output recovers adequately (>100 mL/day). 1, 3
Pain Management in Elderly Patients
Use acetaminophen as first-line analgesic, avoiding nephrotoxic NSAIDs. 3 Reserve opioids for severe muscle pain unresponsive to acetaminophen, using oral morphine for opioid-naive patients with moderate to severe pain. 3 Fentanyl or buprenorphine are the safest opioid choices in patients with acute kidney injury. 3
Critical Pitfalls to Avoid
- Delaying fluid resuscitation is the most common and dangerous error, associated with significantly higher risk of acute kidney injury and worse outcomes. 1, 2, 3, 5
- Inadequate fluid volume (using <6L/day in severe cases) may fail to prevent renal complications. 1, 3
- Failure to monitor and correct hyperkalemia can lead to pulseless electrical activity and cardiac arrest, particularly dangerous in elderly patients with pre-existing cardiac disease. 1, 3
- Missing compartment syndrome, particularly in elderly patients who have fallen and been immobilized, can result in irreversible muscle and nerve damage. 1, 3
- Assuming elderly patients require less aggressive treatment is incorrect; they require the same aggressive fluid resuscitation while monitoring more carefully for complications. 1, 2, 3