28/03/2026
Rhabdomyolysis — what’s actually going on
At its core, rhabdomyolysis is muscle cell death with leakage of intracellular contents into the bloodstream.
The key mechanism is energy failure. Muscle gets damaged → ATP drops → ion pumps fail → calcium floods into the cell → enzymes get activated → the cell essentially digests itself. What spills out is what causes the downstream problems, especially myoglobin, CK, and electrolytes.
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Common causes (think patterns, not lists)
Instead of memorising everything, group them:
Mechanical / physical insult
Crush injuries, prolonged immobilisation, burns, compartment syndrome, extreme exertion
Metabolic / internal issues
Genetic myopathies, mitochondrial disease, electrolyte disturbances
Drugs & toxins
Statins, alcohol, co***ne, amphetamines, some anaesthetic agents
Infections
Viral (influenza), HIV, others
Other triggers
Hyperthermia, seizures, prolonged intense activity
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Why it becomes dangerous
The big issue isn’t the muscle itself—it’s what gets released.
Myoglobin → kidneys
This is the main problem. It’s toxic to renal tubules and can lead to acute kidney injury.
Electrolytes → heart
Hyperkalaemia is the one that matters clinically → arrhythmias
Systemic effects
Metabolic acidosis, DIC in severe cases, compartment syndrome
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What you actually see clinically
It’s not always obvious.
Classic triad (but not always present):
• Muscle pain
• Weakness
• Dark urine
Other things:
• Swelling of affected muscle
• Reduced urine output if kidneys are involved
• General symptoms like nausea or fever
That dark urine is myoglobin, not blood.