How should rhabdomyolysis be managed in a patient with heart failure with reduced ejection fraction to treat the muscle injury while avoiding fluid overload?

Managing Rhabdomyolysis in Patients with Heart Failure with Reduced Ejection Fraction

In patients with HFrEF who develop rhabdomyolysis, aggressive intravenous fluid resuscitation remains the cornerstone of treatment while continuing guideline-directed medical therapy (GDMT) in the absence of hemodynamic instability, using invasive hemodynamic monitoring to guide fluid administration and prevent pulmonary edema. 1

Immediate Management Priorities

Fluid Resuscitation Strategy

• Infuse fluids aggressively with more than 4 liters potentially required during the first 24-48 hours, targeting adequate tissue perfusion rather than arbitrary blood pressure goals 1
• Target adequate tissue perfusion as the principal endpoint, using clinical variables including mental status, capillary refill, urine output, and lactate clearance 1
• Perform invasive hemodynamic monitoring in patients with respiratory distress or impaired perfusion when adequacy of intracardiac filling pressures cannot be determined from clinical assessment 2, 1

Continuation of GDMT During Acute Illness

• Continue GDMT including ACE inhibitors/ARBs and beta-blockers during the acute episode unless hemodynamic instability or specific contraindications exist 1
• SGLT2 inhibitors and mineralocorticoid receptor antagonists should generally be continued as they have minimal blood pressure effects and provide ongoing benefit 3, 1
• Never discontinue GDMT for asymptomatic hypotension when perfusion is adequate; patients with adequate organ perfusion can safely tolerate systolic blood pressure 80-100 mmHg 3

Monitoring for Fluid Overload

Clinical Assessment Parameters

• Monitor for signs of fluid overload including pulmonary edema using bedside thoracic ultrasound for interstitial edema when available 1
• During fluid resuscitation, serially assess fluid intake and output measurements, vital signs, body weight, clinical signs and symptoms of systemic perfusion and congestion 2
• Monitor daily serum electrolytes, urea nitrogen, and creatinine concentrations to detect worsening renal function and electrolyte abnormalities, particularly hypokalemia and hypomagnesemia 2

Diuretic Management

• If signs of volume overload develop during fluid resuscitation, initiate intravenous loop diuretics without delay, with the initial IV dose equaling or exceeding the patient's chronic oral daily dose if already on diuretics 2
• Titrate diuretic dose based on urine output and signs of congestion to relieve symptoms and reduce extracellular fluid volume excess 2
• If diuresis is inadequate, intensify the regimen using higher loop diuretic doses, addition of a second diuretic, or continuous infusion of loop diuretics 2

Managing Renal Function During Treatment

Acceptable Changes in Renal Function

• Modest increases in creatinine (up to 30% above baseline) are acceptable and should not prompt discontinuation of ACE inhibitors/ARBs/ARNI 3
• Temporary reduction or hold if substantial renal deterioration occurs, but aggressive attempts to restore target doses should follow 3
• RAAS blockers are not nephrotoxic drugs as they only have a functional effect on renal function; they should not be withheld due to worsening renal function in most cases 4

Medication Adjustments for Renal Dysfunction

• Sacubitril/valsartan is not recommended in patients with an eGFR < 30 mL/min per 1.73 m² 5
• SGLT2 inhibitors are effective at reducing adverse cardiovascular and renal outcomes in patients with HFrEF and CKD (eGFR ≥ 25 mL/min per 1.73 m² with dapagliflozin or ≥ 20 mL/min per 1.73 m² with empagliflozin) 5, 6
• Mineralocorticoid receptor antagonist therapy should be considered in all patients with HFrEF and an eGFR ≥ 30 mL/min per 1.73 m², starting with low doses (6.25-12.5 mg daily or 12.5 mg every other day) 5

Post-Acute Management

Transition to Oral Therapy

• Transition from intravenous to oral diuretic therapy with careful attention to dosing and monitoring of electrolytes once hemodynamic stability is achieved 1
• Resume or initiate beta-blocker therapy after optimization of volume status and successful discontinuation of intravenous diuretics, vasodilators, and inotropic agents, starting at low doses only in stable patients 1

Early Follow-Up

• Early post-discharge follow-up within 7-14 days after medication changes, with monitoring of volume status, blood pressure, renal function, and electrolytes, is recommended to ensure safe uptitration and detect adverse effects 3

Common Pitfalls to Avoid

• Do not withhold GDMT for fear of worsening renal function during aggressive fluid resuscitation; the life-saving effect of RAAS blockers outweighs concerns about functional changes in renal parameters 4
• Do not give IV fluids to patients with clear signs of volume overload (orthopnea, dyspnea) without invasive hemodynamic monitoring to guide therapy 2
• Do not delay diuretic initiation if pulmonary congestion develops during fluid resuscitation for rhabdomyolysis 2
• Identify and correct reversible contributors to low blood pressure such as dehydration, infection, or acute illness before attributing hypotension to GDMT 3