Rhabdomyolysis: Symptoms, Causes & Treatment Options

One workout can put you in hospital for five days. Not a marathon, not a crush injury — a 45-minute spin class, if it's your first.

Singapore hospitals have logged this often enough that emergency doctors now recognise the pattern on sight: a fit, otherwise healthy adult, thigh pain that's gotten worse rather than better since a class earlier in the week, and urine that's turned a colour they weren't expecting. If any part of that sounds close to what's happening to you right now, the next few sections explain exactly what to check for.

What is rhabdomyolysis?

It is derived from the Greek words rhabdos (rod-like/striated), mys (muscle), and lysin (release). It is a breakdown of skeletal muscle fiber that happens faster than your body can keep up.

The damaged muscle fibres release their contents, including a protein called myoglobin, into your bloodstream. Your kidneys have little difficulty clearing this in small amounts, but they can be overloaded when it's present in large quantities. This process of muscle tissue breakdown is what defines the condition.

It's not a new condition. It has conventionally been caused by crush injuries, severe burns, or heatstroke. What is new though is who it affects. Nowadays, an increasing number of cases seen in Singapore's emergency departments involve ordinary people doing ordinary workouts, often for the first time in a new class.

What causes rhabdomyolysis?

Rhabdomyolysis happens when your muscles are damaged and break down faster than your body can repair them.

This can happen for several reasons, including:

• Intense exercise: If you suddenly push yourself too hard during activities such as your first spin class, HIIT, CrossFit, boot camps, marathon running or heavy weightlifting, your muscles may become overwhelmed, especially if they aren't used to the intensity.
• Trauma or muscle injury: You may develop rhabdomyolysis after a crush injury, road traffic accident, major fall, severe burn or electrical injury that causes significant muscle damage.
• Long periods of immobility: If you fall, lose consciousness or are unable to move for several hours, prolonged pressure on your muscles can reduce blood flow and lead to muscle breakdown.
• Heat and dehydration: Exercising in hot or humid weather, becoming dehydrated, or developing heat exhaustion or heatstroke can increase your risk of rhabdomyolysis.
• Certain medications and substances: Some medications, including statins, antipsychotics and antidepressants, may increase your risk. Excessive alcohol use and recreational drugs such as cocaine or amphetamines can also trigger rhabdomyolysis.
• Underlying medical conditions: Certain health conditions, including severe infections, seizures, inherited muscle disorders, metabolic or mitochondrial disorders, autoimmune muscle diseases and electrolyte abnormalities, can sometimes lead to rhabdomyolysis.

In many cases, rhabdomyolysis develops because several factors occur together. For example, you might do an intense workout while dehydrated on a hot day after several months without exercising.

What are the symptoms of rhabdomyolysis?

Symptoms vary greatly in intensity and can be non-specific and can be delayed by some hours. They usually occur between 24 and 72 hours of the initial muscle injury or vigorous exercise, although the severity of the muscle injury does not always relate to the severity of the muscle soreness.

Common symptoms include

• Intense muscle pain, usually different from typical post-exercise muscle soreness and often occurs in the thighs, calves, shoulders and upper arms.
• In muscle weakness, you may have difficulty in walking up the stairs or standing to carry your hands over your head or raise your arm.
• Muscle swelling and tenderness.
• Muscle urine passing less urine than usual-this may be a sign that the kidney function is failing.
• Muscle pigment (myoglobin) passing into your urine, turning your urine dark brown, tea or cola coloured.
• Other symptoms include feeling tired, having a fever, nausea, vomiting and a general feeling of malaise.

If you experience any of these symptomss, do not put it down to "normal muscle soreness" and seek medical help immediately as prompt treatment can limit serious complications.

Is muscle pain after a workout normal or serious?

Every workout causes tiny amounts of muscle damage. This is part of how your muscles adapt and become stronger.

Normal muscle soreness usually:

✓ Appears gradually

✓ Feels like stiffness

✓ Improves each day

✓ Doesn't stop you from carrying out daily activities

✓ Doesn't change the colour of your urine

Rhabdomyolysis, however, is different.

Instead of normal adaptation, the muscle cells are breaking down faster than your body can safely manage.

Think of it this way:

Normal soreness is your muscles saying, "That was challenging."

Rhabdomyolysis is your muscles saying, "I've been pushed beyond my limits."

Recognising the difference may enable you to notice problems early, and to get help before severe complications develop.

What are the risk factors for rhabdomyolysis?

Anyone can have rhabdomyolysis, but you're at greater risk if you:

• Are new to high-intensity exercise: When you've been inactive and then suddenly join spin classes, a HIIT session, CrossFit, or boot camps, your muscles might not be conditioned to handle the sudden level of activity.
• Exercise in hot or humid conditions: High temperatures strain your muscles while dehydration makes it more difficult for your body to handle anything beyond walking.
• Get dehydrated: If you're not sipping on water throughout your workouts - especially strenuous endurance activities - it increases your chance of developing rhabdo.
• Push your body to the max: Trying to keep up with the group in a fitness class or powering through if something feels incredibly painful increases the risk of breaking down muscles.
• Have specific health conditions or use certain medications: You could be more prone to rhabdomyolysis if you have an inherited muscle disorder, a metabolic condition, or if you're taking prescribed medications such as statins.
• Do physically demanding work or training: People who work as soldiers, firefighters, athletes, and others who routinely take part in intense physical activities, especially in a warm environment, are all in this high-risk group.
• Are older and have a risk of prolonged immobility: If you were to fall and hit your head or somehow lose consciousness, being unable to move for hours can exert such pressure on your muscles that it leads to this breakdown. n your muscles can lead to rhabdomyolysis.

Speak with our Care Team today to be matched with an orthopaedic specialist who can assess your condition, explain your options, and help you plan the next steps in your treatment.

What complications can rhabdomyolysis cause?

Most people recover fully with early treatment. However, if rhabdomyolysis isn't treated promptly, it can lead to significant problems such as:

• Acute kidney injury: Damaged muscle releases myoglobin into your bloodstream which overworks and potentially damages your kidneys and may in serious cases result in kidney failure or temporary dialysis.
• Electrolyte imbalances: The breakdown of muscle cells spills potassium and other electrolytes into your blood stream which could result in heart rhythm irregularities.
• Compartment syndrome: Severe muscle swelling can increase pressure inside a muscle compartment, reducing blood flow and potentially requiring emergency surgery.
• Metabolic acidosis: Severe muscle damage can upset your body's acid-base balance, which may require medical treatment.
• Blood clotting problems (rare): In severe cases, rhabdomyolysis can affect your body's normal blood clotting process.

Early diagnosis and treatment can help prevent these complications and improve your chances of a full recovery.

How is rhabdomyolysis diagnosed?

Your doctor will start by asking about your symptoms and recent activities. They may ask questions such as:

• Have you recently started a new workout programme?
• Was there a spin class, a marathon or an endurance event in the past week?
• Have you had a fall, injury or prolonged period of immobility?
• Are you taking any medications that may affect your muscles?

Your doctor will then examine you for muscle tenderness, swelling and weakness.

Blood tests

The most important blood test measures creatine kinase (CK), an enzyme released when muscles are damaged. People with rhabdomyolysis usually have CK levels that are much higher than normal.

Your doctor will usually run a few others at the same time:

• Kidney function, because that is the organ at risk
• Electrolytes, particularly potassium, which affects heart rhythm
• Liver enzymes, which rise from muscle breakdown and can look alarming without the liver being involved
• Calcium and phosphate

Together these show how much muscle has broken down and whether anything else has been affected.

Urine tests

A urine test can detect myoglobin released from damaged muscles.

Your urine may appear dark brown, reddish-brown or cola-coloured, although some people have normal-looking urine despite significant muscle injury.

Additional tests may be recommended if your healthcare provider suspects an underlying medical condition.

How is rhabdomyolysis treated?

The treatment for rhabdomyolysis will depend on the seriousness of your condition.
For mild symptoms, you'll probably just need some monitoring, rest and drinking plenty of fluids while under the guidance of a healthcare professional.If you have a moderate to severe form, it's more likely you'll need to go to hospital.

Intravenous (IV) fluids

Intravenous fluids are at the core of your treatment and helps your body flush the myoglobin from your kidneys. IV fluids will keep your kidneys producing urine and prevent them from getting damaged. Depending on the severity of your condition, you may receive IV fluids for one to three days or longer.

Monitoring

When in hospital, you'll be carefully watched by your health team to check your creatine kinase levels (CK), your electrolytes, how much urine you are passing and your kidney function.

They may also check your heart rhythm to catch potential complications before they happen and shape your treatment.

Treating the underlying cause

As you're being treated, the team will also treat the underlying reason for your rhabdomyolysis, whether that's through stopping strenous exercise, dealing with heatstroke, a common cold or a flu, reversing an imbalance of electrolytes or looking at certain drugs that might be helping cause the problem.

Dialysis

Most people recover without needing dialysis. However, if severe kidney injury develops, temporary dialysis may be required until your kidneys recover.

How can you lower your risk? (collapsible block)

While you can't prevent every case of rhabdomyolysis, there are simple steps you can take to lower your risk, especially if you're starting a new exercise routine.

Increase intensity gradually:

If you're trying a new workout, don't aim to keep up with the most experienced participants.

Allow your muscles time to adapt over several weeks.

Make sure to drink your water: You should be well hydrated before, in the course of and after any exercise, more so when you are putting in long hours or the weather is hot and humid.

Pay attention to what your body is telling you: Some fatigue is to be expected, but dizziness, an unusual lack of strength or anything in the way of severe muscle pain is not. At the first sign that something is amiss, put a halt to the session and allow for some recovery.

Take time to recover: If you are just starting out, do not plan on back to back days of hard work. Rest is part of the process of building up and will keep you from injury.

Tell your instructor if you're a beginner: And if you are new to a boot camp, HIIT or spin class, don’t hesitate to tell the instructor. They can make the necessary adjustments to the resistance or number of reps and offer you a few extra rest breaks to ensure you are training in a safe manner.

Be mindful not to let the group dictate how you go about things: A room full of energy is infectious, but your routine has to be in keeping with your own fitness level and not that of others. Consistent effort is what brings results, not overexerting yourself in one sitting. 

Can rhabdomyolysis be prevented?

Not every case can be prevented, but you can significantly reduce your risk by exercising sensibly.

Remember these simple steps:

• Start slowly if you're new to exercise.
• Warm up before and cool down afterwards.
• Stay hydrated.
• Avoid exercising intensely when you're ill or severely sleep-deprived.
• Take regular breaks during prolonged activity.
• Avoid pushing through severe pain.
• Follow your healthcare provider's advice if you have an underlying medical condition or take medications that affect your muscles.

Exercise remains one of the best things you can do for your health. The goal isn't to avoid challenging workouts – it's to build up to them safely.

When should you see a healthcare provider?

Seek medical attention as soon as possible if you experience:

• Severe muscle pain that keeps getting worse
• Muscle swelling or tightness
• Significant weakness
• Difficulty walking
• Dark brown or cola-coloured urine
• Passing very little urine
• Fever, confusion or feeling very unwell after intense exercise

Early treatment can reduce the risk of kidney injury and other serious complications.

If you're unsure whether your symptoms are normal, it's safer to get checked than to wait.

Not sure which specialist to see?

Health in Asia (HiA) helps you connect with experienced orthopaedic specialists in Singapore. Whether you need an initial assessment, a second opinion, or further investigations, HiA makes it easier to find and book appointments with suitable specialists based on your needs.

If you're unsure whether your condition requires medical attention, speak with our Care Team on WhatsApp for personalised guidance and help finding the right specialist.