Is forced alkaline diuresis recommended for a patient with rhabdomyolysis and myoglobinuria?

Forced Alkaline Diuresis in Rhabdomyolysis with Myoglobinuria

Forced alkaline diuresis is NOT recommended for patients with rhabdomyolysis and myoglobinuria, as current evidence shows no benefit over aggressive crystalloid resuscitation alone in preventing acute kidney injury or reducing the need for dialysis. 1, 2

Primary Treatment: Aggressive Crystalloid Resuscitation

The cornerstone of management is aggressive intravenous fluid resuscitation with isotonic saline (0.9% NaCl), not urinary alkalization. 1, 3

Fluid administration protocol based on severity:

• Severe rhabdomyolysis (CK >15,000 IU/L): Administer >6L of IV fluids per day 4, 1, 3
• Moderate rhabdomyolysis: Administer 3-6L of IV fluids per day 4, 1, 3
• Target urine output: ≥300 mL/hour (approximately 3-5 mL/kg/hour for a 70 kg patient) to ensure adequate myoglobin clearance 1, 3

Early initiation is critical—delayed fluid resuscitation significantly increases the risk of acute kidney injury. 4, 1, 3

Why Bicarbonate (Alkaline Diuresis) Is Not Recommended

The Kidney International guideline explicitly states that current evidence does not demonstrate benefit of active alkalization over aggressive fluid resuscitation in preventing pigment nephropathy. 1

Specific risks of bicarbonate administration:

• Worsens hypocalcemia by decreasing free calcium levels, which is already a concern in rhabdomyolysis 1
• Adds extra volume without proven benefit 1
• No improvement in outcomes: The Eastern Association for the Surgery of Trauma meta-analysis found that bicarbonate did not improve the incidence of acute kidney injury or need for dialysis 2

The quality of evidence is very low (mostly retrospective studies), but the consistent finding across studies is that bicarbonate provides no additional benefit beyond crystalloid resuscitation. 2

Fluid Type Selection

Use isotonic saline (0.9% NaCl) for initial resuscitation. 1, 3

Avoid these fluids:

• Potassium-containing solutions (Lactated Ringer's, Hartmann's solution, Plasmalyte A) because potassium levels can increase markedly after reperfusion, even with intact renal function 1
• Starch-based fluids due to association with increased rates of acute kidney injury 1

Monitoring Parameters

Essential monitoring includes:

• Plasma myoglobin, CK, and potassium levels with repeated bioassessments 4, 1, 3
• Hourly urine output via bladder catheterization 1, 3
• Electrolyte panels every 6-12 hours in severe cases 3
• Urine pH (should be maintained at approximately 6.5) 1

Notably, myoglobin has faster elimination kinetics than CK (average time to 50% reduction: 12 hours for myoglobin vs. 42 hours for CK), suggesting that serum myoglobin level, rather than CK, should guide therapy. 5

Other Interventions NOT Recommended

Mannitol: Do not routinely use mannitol, as studies suggest little additional benefit compared to crystalloid resuscitation alone, and it is potentially nephrotoxic. 1 Mannitol may only benefit patients with markedly elevated CK (>30,000 U/L), though this benefit remains undefined, and it is contraindicated in patients with oligoanuria. 1

Critical Pitfalls to Avoid

• Delaying fluid resuscitation is the most significant error—start isotonic saline immediately upon diagnosis 3
• Using bicarbonate based on outdated protocols from older literature (such as the 1991 case report 6 describing forced mannitol-alkaline diuresis)—this approach has been superseded by higher-quality evidence showing no benefit 2
• Inadequate fluid volume that fails to achieve target urine output of ≥300 mL/hour 1, 3
• Missing hyperkalemia, which can precipitate cardiac arrhythmias and arrest—correct immediately 3

Historical Context

While older case reports described the use of forced mannitol-alkaline diuresis 6, the 2022 systematic review and meta-analysis from the Eastern Association for the Surgery of Trauma provides the most recent and highest-quality evidence, demonstrating that aggressive IVFR alone decreases acute renal failure and need for dialysis, while bicarbonate does not. 2 This represents a clear evolution in the standard of care away from alkalization strategies.