Pediatric Rhabdomyolysis Treatment & Management

The inciting cause of rhabdomyolysis must be identified and corrected.^[34] Expansion of extracellular volume is the cornerstone of treatment. Other supportive measures include correction of electrolyte imbalances.^{[6, 35]} No randomized trials of fluid repletion regimens in any age-group have been done.^[7] Few studies on these treatments in children are available.^[8]

Aggressive and early hydration with isotonic sodium chloride solution is important for the prevention of pigment-associated renal failure. The composition of repletion fluid is controversial and may also include sodium bicarbonate. Initial fluid use in young children has been recommended at 20 mL/kg and 1-2 L/h in adolescents. Subsequent hydration 2-3 times maintenance may be sufficient.^{[8, 36]}

Insert a Foley catheter for careful monitoring of urine output. Obtain an ECG to monitor effects of hyperkalemia and other electrolyte disturbances. Alkalinization of urine is believed to be helpful and is based on the observation that acidic urine is necessary to cause acute tubular necrosis (ATN). Some authorities believe that aggressive hydration sufficiently causes a solute diuresis that alkalinizes the urine. Mannitol is often used to induce diuresis in adult patients. Its efficacy has not been adequately compared with that of aggressive hydration regimens.^{[11, 37, 7]}

Sodium bicarbonate is used with care to prevent metabolic acidosis because it may potentiate hypocalcemia. Intravenous bicarbonate concentration is often adjusted to achieve a urine pH level of more than 6.5. This level of alkalinization inhibits precipitation of myoglobin and hemoglobin in the tubules.

Ferrihemate and globin are the breakdown products of myoglobin when pH levels fall to less than 5.6. Ferrihemate is one of the agents responsible for ATN. It contains iron, a transition element, which is free to accept and donate electrons. This results in the generation of free radicals, which cause direct renal cell injury. Heme-proteins may also affect nitrous oxide (NO), endothelin receptors, and cytokines.^[11]

Frequently monitor serum electrolyte levels, urine pH levels, and acid-base status. Metabolic abnormalities should also be addressed. Treat hyperkalemia by administering insulin and glucose, a nebulized beta agonist, and a potassium exchange resin. These measures transiently shift potassium from extracellular to intracellular compartments.^{[8, 33]}

Correct hypocalcemia only if the patient has cardiac dysrhythmias or seizures. Calcium may combine with phosphate, forming a metastatic calcification, often intramuscularly. Control hyperphosphatemia using alkaline diuresis. Hypercalcemia may develop during the recovery phase.

If urine output is adequate, consider the use of diuretics such as mannitol (in adults) and furosemide. Mannitol, acting as an osmotic diuretic, is thought to increase urinary flow and reduce myoglobin cast obstruction in renal tubules.^[6]

Dialysis may be required in patients with oliguric renal failure, persistent hyperkalemia, other electrolyte abnormalities, pulmonary edema, congestive heart failure, and persistent metabolic acidosis.

The role of free-radical scavengers and antioxidants in rhabdomyolysis (eg, pentoxifylline, vitamin E and vitamin C) has been studied in animal models of ischemia-reperfusion injuries. Controlled studies evaluating the efficacy of these agents have not been performed, and their clinical use remains unclear.^{[11, 7]}

Surgical care may be necessary, depending on the cause of rhabdomyolysis.^[6] Measure compartment pressures and perform a fasciotomy if pressures are high (>30 mm Hg). Limb fractures may require surgical and orthopedic treatment.^[38]

The following consultations may be indicated:

• Consult a nephrologist for patients who have significant rhabdomyolysis, show evidence of renal failure, or require dialysis.
• Consult a neurologist for patients with status epilepticus or newly onset seizures.
• Consult an orthopedic surgeon for patients with a limb fracture or compartment syndrome.
• Notify the poison control center in cases of overdose or snake/insect envenomation.
• Consult a rheumatologist for patients with suspected inflammatory myopathies, systemic lupus erythematosus, or sarcoidosis.
• Consult a geneticist and metabolism specialist for patients with genetic or metabolic abnormalities. Diagnosis of inborn errors of metabolism and prompt metabolic interventions may be life saving.

Dietary modification may help to reduce the symptoms associated with some of the metabolic disorders and inborn errors of metabolism.^[9] Dietary supplementation with glucose or fructose may decrease the pain and fatigue associated with phosphorylase deficiency. The muscle pain and myoglobinuria due to carnitine palmityl transferase deficiency may be reduced with frequent meals and a low-fat, high-carbohydrate diet. Substitution of medium-chained triglycerides may also be helpful. Dietary modification does not seem to change the muscle symptoms of phosphofructokinase deficiency or phosphoglycerate mutase deficiency.

Strenuous activities (eg, competitive sports) should be avoided if they cause recurrent myalgias, myopathy, or rhabdomyolysis.^[9] Children and adolescents with recurrent rhabdomyolysis related to exertion require further medical evaluation.

High-school coaches and trainers must ensure proper hydration and maintain fluid balance during practice sessions and games. Signs and symptoms of heat exhaustion must be evaluated in a timely fashion during hot and humid conditions.^[15]

Alcohol abuse should be stopped. Use of narcotics and sedative hypnotics should be avoided, and inciting prescribed medications must be stopped.