Pediatric emergency medicine trisk 2902 2902

CLINICAL PEARLS AND PITFALLS
Myoglobinuria will cause a false positive for blood on urine
dipstick testing, but microscopic analysis will not be consistent
with hematuria.
Hyperkalemia may result from both lysis of muscle cells as well as
AKI.
Hydration is the mainstay of management.
Clinical Considerations
Clinical recognition. Rhabdomyolysis is the necrosis of muscle cells
leading to introduction of intracellular contents, including myoglobin, into
the blood stream. The classic symptoms of rhabdomyolysis include
myalgias, weakness, and red or brown urine, though this triad is not always
present.
Rhabdomyolysis may be from traumatic or nontraumatic causes.
Traumatic etiologies include crush injuries, vascular occlusions, and lower
extremity compartment syndrome. Nontraumatic causes include extreme
exertion, prolonged seizure, malignant hyperthermia, DKA, hypokalemia,
hypophosphatemia, metabolic myopathies, neuroleptic malignant
syndrome, and cardiac arrest. It has also been associated with a variety of
infections, including influenza A and B, parainfluenza, coxsackievirus,
EBV, herpes simplex virus, varicella zoster, human immunodeficiency
virus, pyomyositis, necrotizing fasciitis, and sepsis. Prescription
medications, such as statins, antipsychotics, and colchicine, and illicit drugs
such as cocaine, ecstasy, and amphetamines, may cause rhabdomyolysis as
well.
AKI during rhabdomyolysis is often multifactorial, and insults include
prerenal physiology, tubular cell damage, and tubular obstruction.
Decreased intravascular volume and prerenal physiology develop secondary
to fluid sequestration within damaged muscle and intrarenal
vasoconstriction. Unlike hemoglobin, myoglobin is a monomer and is freely
filtered into the urine. Rhabdomyolysis leads to AKI through formation of

intratubular casts. Tubular cell injury results from tubular obstruction with