Refresher: How to recognize and treat exertional rhabdomyolysis

Your patients can sometimes take exercise too far.Physicians in some parts of Canada are reporting an uptick in cases of exertional rhabdomyolysis, a potentially serious condition linked to severe muscle breakdown that can lead to acute kidney injury. As high-intensity workouts, social-media fitness culture and summer heat converge, clinicians are wise to be alert to the warning signs.Earlier this year, Newfoundland and Labrador health officials issues a news release saying there had been an unusual spike in an exertion-related rhabdomyolysis. They urged people to work out in moderation and suggested social media pressure was fuelling workouts that were landing people in the ER.Following the news release, Dr. Richard Barter, clinical chief of emergency medicine for Newfoundland and Labrador Health Services in St. John's, told the Canadian Press that the health body had confirmed about 20 cases of rhabdomyolysis in eastern Newfoundland over a six-month period. That’s significantly higher than the few cases doctors would typically expect to see in a year. Most involved women between the ages of 19 and 30. Dr. Barter suggested social media and “extreme” fitness culture might be contributing factors, pointing to online trends that encourage intense workouts, high repetition counts and competitive exercise posting.Rhabdomyolysis, or rhabdo for short, is a condition in which damaged skeletal muscle breaks down and releases substances such as myoglobin, creatine phosphokinase (CPK) and electrolytes into the bloodstream. Most commonly the condition causes severe muscle pain, generalized weakness and dark, tea-coloured urine. However, presentations can vary. Additional nonspecific symptoms include fever, nausea, decreased urination and vomiting. In severe cases, this can lead to complications including acute kidney injury, electrolyte imbalances, problems with blood clotting and cardiac arrhythmias.Severe dehydration and overheating can also contribute by accelerating muscle breakdown and impairing the kidneys’ ability to clear waste products, making cases rise in hot weather. Although the recent spike involved women, according to StatPearl, rhabdo is generally more common in men. Symptoms usually develop one to three days after a muscle injury, though some people may not even notice extraordinary muscle soreness.In addition to over-exertion, rhabdomyolysis can be caused by a range of other factors, including traumatic injuries such as burns, electrocution and crush injuries, notes StatPearl— as well as genetic factors. Certain medications, including statins, antipsychotics, antidepressants and antivirals, have been linked to rhabdomyolysis, as have some non-prescribed psychoactive substances. The condition may also develop after prolonged immobility, such as when a person falls or loses consciousness and remains unable to move for an extended period.In some cases, underlying genetic, metabolic or neuromuscular disorders, including Duchenne muscular dystrophy and McArdle disease, can increase the risk.A 2025 international workshop of 21 experts called for standardized clinical guidelines for rhabdomyolysis, including clearer diagnostic thresholds and followup recommendations. The group agreed that diagnosis should involve symptoms such as severe muscle pain, weakness or swelling alongside markedly elevated creatine kinase (CK) levels. Experts also recommended using the McMahon score (assessment of risk of renal failure) to assess acute kidney injury risk. It also recommended guidance on when genetic testing may be appropriate. The workshop emphasized the need for better long-term followup, including attention to both physical and psychological effects.One panelist expert, Dr. Nicol Voermans, a Dutch neuromuscular neurologist, noted that strenuous exercise as a trigger for exertional rhabdomyolysis is particularly common among people returning to intense workouts after a break or those exposed to sudden, unfamiliar physical demands, such as military recruits. She said that while the condition can sometimes point to an underlying neuromuscular disorder, it more often occurs in otherwise healthy individuals. Dr. Voermans also highlighted research showing that elevated CK levels after intense exercise are relatively common and do not always indicate clinically significant rhabdomyolysis.Other studies presented at the workshop found exertional rhabdo was most common among young men participating in activities such as running and weightlifting, with outbreaks also reported in team sports where athletes were pushed by coaches beyond safe physical limits.Following the workshop, guidelines were developed: “A Clinical Approach to Rhabdomyolysis” outlines how to screen and treat rhabdomyolysis, offering the following recommendations (in part):Initial assessment: Suspect rhabdoEvaluate for symptoms: severe muscle pain, weakness, swelling, dark/red urine, reduced consciousness.Check vital signs: hypotension, tachycardia, body temperature > 40°C.Review history: known triggers (exercise, trauma, drugs), prior episodes, family history, comorbidities.Laboratory tests: serum creatine kinase (CK), renal function, electrolytes, urine analysis for myoglobin.Emergency room referral criteriaRefer to ER if any of the following are present:severe symptoms (muscle weakness, swelling, dark urine, reduced consciousness)abnormal vital signs (hypotension, tachycardia, fever > 40°C)no clear trigger, prior episodes, or comorbiditiesCK > 10,000 U/L (exertional) or > 5,000 U/L (non-exertional)polypharmacy or illicit drug useGenetic testingConsider genetic testing if any RHABDO features are present:recurrent episodespersistent HyperCKemia (>8 weeks)accustomed exercise (event not explained by intensity)blood CK > 50x upper limit of normaldrugs/other triggers insufficient to explain severityother family members affected or other exertional symptomsIf genetic testing is negative or inconclusive, consider further investigations (muscle MRI, biopsy, metabolic studies).ManagementInitiate aggressive IV fluids to maintain urine output (target: 300 mL/hour for first 24 hours).Monitor and correct metabolic abnormalities.Avoid nephrotoxic agents.ICU admission for severe cases or those with little/no urine output, profound acidosis or severe hyperkalemiaEliminate causative drugs/toxins.Followup and preventionrest and oral hydration for mild casesgradual return to activity after CK normalizationpatient education on avoiding triggers and recognizing symptomsspecialist referral for those with genetic/metabolic riskThe authors concluded: “At each step, it is important to distinguish the role of triggers and a possible genetic susceptibility. It is essential for physicians working at the ‘physiological’ end (sports medicine/military medicine) and those working at the clinical end of the medical spectrum (emergency medicine, internal medicine, neurology) to consider that exertional rhabdomyolysis can happen to anyone who is exposed to unaccustomed exercise and/or other triggers. The threshold, however, is much lower in patients with an underlying genetic disorder.”

Refresher: How to recognize and treat exertional rhabdomyolysis

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