The causative agent of this condition can vary widely, but the pathophysiology behind it remains the same, simply put "rhabdo" is nothing more than a medical condition characterized by the breakdown of skeletal muscle tissue. This results in muscle cell proteins (myoglobin) and other products to be released systemically into the bloodstream. When this happens, the kidney suffer mightily as myoglobin is a rather large molecule that the filters within the renal system just can't handle. Tea colored urine is a key indicator that muscle breakdown is occurring somewhere.
Etiology -
The cause can be traumatic in nature. Think of direct injuries like crush injuries, severe burns, or anything related to muscle injury.... even consider something like high voltage electrocution
Excessive exercise, especially in untrained individuals, or in cases where overexertion happens in the absence of proper hydration or fluid replacement.
Muscle ischemia from conditions that reduce the blood flow to the muscles such as compartment syndrome. This can be seen on occasion in drug overdose patients who are unconscious is peculiar positions for extended time periods before being found.
Medications like statin drugs (cholesterol lowering agents) can also cause this condition in susceptible individuals. It could be during the first weeks, or it can be delayed months or years after the regimen is started. CoQ10 could be a safer alternative.
Bacterial or viral infectious process have also been known to cause rhabdomyolysis.
Genetic predispositions like enzyme deficiencies could increase someone's odds of muscle damage/breakdown as well
Pathophysiology -
When the muscle breakdown occurs, myoglobin isn't the only protein released into the system. Creatine Kinase (CK) is an enzyme found in skeletal muscle amongst other things and increases in this evident after a blood draw is another strong indicator that muscle injury is occurring. Keep in mind that hyperkalemia is also a common and dangerous finding as the electrolyte gets released from the intracellular spaces. Regardless of the mechanism, muscle injury results in a cascade of events that leads to many other electrolyte abnormalities with sodium and calcium.
Treatment -
The main goal of rhabdomyolysis treatment is to prevent kidney injury and address any underlying causes when possible. Treatment involves administering intravenous (IV) fluids to maintain adequate urine output and correcting any electrolyte imbalances. In addition, IV bicarbonate may be done in some instances to decrease the toxicity of myoglobin to the renal tubules. If compartment syndrome is the cause of rhabdomyolysis, surgical treatment with an emergency fasciotomy should be performed promptly, as IV fluid administration may result in worsening edema within the muscle compartment. Hemodialysis may be considered in individuals with low urine output, even with intensive fluid resuscitation, or who have already developed acute kidney failure.
The prognosis of rhabdomyolysis varies depending on the underlying cause. Nonetheless, most individuals can completely recover kidney function, even if they initially developed acute kidney failure.
The image above represents an improvement in the patient condition and their renal function. Note that because treatment was aimed at fixing the underlying causes and providing aggressive fluid hydration the myoglobin in the urine was gradually able to be cleared.
In our pre-hospital environment, rhabdomyolysis remains an often-underappreciated phenomenon. As a consequence, the causes are treated while the syndrome remains overlooked. It can become challenging to put all of the pieces of the clinical puzzle together, especially in the critical care transport environment, but this condition can usually be identified pretty quickly in your local ED after a few lab tests and some clinical history taking.
May 20, 2024
Author: Joshua Ishmael, MBA, MLS(ASCP)CM, NRP
Pass with PASS, LLC
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