Rhabdomyolysis 101: Symptoms, Causes & Treatments

Medically reviewed by Dr. Nigel

Ever considered joining a spin class or CrossFit session to find out what all the hype is about? While staying active is encouraged, it is important to listen to our body and know our limits, so that we do not end up doing our bodies more harm than good.

As reported in a local news article recently, a young fitness enthusiast was hospitalised after her first spinning class — and she is not alone. There have been multiple reports of individuals hospitalised post-workout, many of which are caused by one little-known condition — rhabdomyolysis.

Rhabdomyolysis is a serious and potentially life-threatening condition that has been reported in individuals following intense exercises such as CrossFit, spinning, marathons, and bodybuilding. 

In this article, we hope to address the lack of awareness about rhabdomyolysis amongst recreational and competitive athletes, fitness instructors, coaches, and everyone in between. Read on to learn more about the signs and symptoms of rhabdomyolysis, as well as the causes, treatment and prevention of this deadly condition.

What Is Rhabdomyolysis?

Rhabdomyolysis occurs when there is severe damage to muscle tissues, resulting in substances from inside the muscle cells leaking out into the blood. This can lead to life-threatening complications, such as:

• Kidney damage: The function of our kidneys is to filter blood and waste products out of our bodies through urine. When muscle cells are damaged, they release a protein called myoglobin into the blood. In large amounts, myoglobin can damage the kidneys and potentially lead to acute kidney failure.
• Excessive amount of salts in the blood: Muscle damage can lead to large amounts of salts such as potassium being released into our blood. This can result in problems with heart rhythm and subsequently cardiac arrest.

Causes of Rhabdomyolysis

There are several causes that result in damage to muscle tissues, including: 

• Intense exercises, especially those involving high-repetition, high-volume activities in unconditioned individuals
• Surgery or trauma
• Infections (viruses, bacteria)
• Medications (e.g. cholesterol medications called statins)
• Medical conditions (e.g. hyperthyroidism)
• Congenital (muscle problems that some people are born with)

Symptoms of Rhabdomyolysis

Many individuals may not realise that they are experiencing rhabdomyolysis after a workout as many of the common symptoms mimic that of severe muscle ache. The classic triad of symptoms includes muscle weakness, muscle pain, and red- or brown- coloured urine. However, more than half of patients may not report muscular symptoms.

Common signs of rhabdomyolysis include:

• Muscle weakness
• Muscle pain
• Red- or brown-coloured urine
• Fatigue
• Fever
• Elevated heart rate
• Nausea or vomiting
• Abdominal pain
• Confusion, reduced consciousness

Do not hesitate to visit a doctor if you experience the above symptoms, especially after vigorous exercise. Early diagnosis and treatment are key to prevent dangerous complications.

Remember: Rhabdomyolysis is a medical emergency.

Diagnosing Rhabdomyolysis

Doctors may order certain tests to diagnose rhabdomyolysis and its complications. These include:

• Blood tests 
  • Creatine kinase (CK) is a product of muscle breakdown. CK levels usually begin to rise within 2-12 hours following muscle injury and reach their peak within 24-72 hours. 
  • Electrolytes such as potassium
  • Kidney function tests to detect acute kidney injury
• Urine tests for myoglobin, a protein that is released from damaged muscles

Treatment of Rhabdomyolysis

Individuals with rhabdomyolysis are usually treated in the hospital. The mainstay of treatment involves intravenous (IV) fluids. This refers to fluids that are administered via your vein through a thin tube to flush out the harmful substances from your muscle cells. 

Further treatment may be necessary in the event of complications.

• Acute kidney injury
  • Doctors may administer medications, dietary changes, or renal replacement therapy. This refers to treatments that take over the job of the kidneys (e.g. hemodialysis – a machine that pumps blood out of the body, filters it, and returns it back to the body).

• Elevated potassium levels
  • Medications to correct the potassium levels in the blood may be required.

Prevention of Rhabdomyolysis

Whether you are a recreational or competitive athlete, here are some steps you should take to ensure rhabdomyolysis does not occur.

1. “Start low go slow” principle

This applies to the number of repetitions, duration of the session, number of sets, and intensity. For example, in strength training, one can start with lower loads of 60-70% of one repetition for a maximum of 8-12 repetitions.

2. Warm-up and cool-down

Warm-up exercises help to prevent musculoskeletal injuries by loosening the joints and increasing blood flow to the muscles. It also gradually increases the heart rate and blood circulation.

Cool-down exercises are equally crucial as it helps to reduce lactic acid buildup, reducing the risk of muscle cramps and stiffness after a workout.

3. Stay hydrated and avoid getting overheated

The risk of rhabdomyolysis increases with dehydration, thus it is vital to stay hydrated during and after the workout. Be sure to take frequent breaks in between and stay under the shade, especially if you are working outdoors under the scorching sun.

4. Avoid exercising if you are sick

5. Avoid alcohol intake prior to workout

Alcohol is a diuretic that causes you to urinate more and lose fluids. This results in dehydration, which increases the risk of muscle cell damage.

Share this article with the fitness enthusiasts in your life! Who knows when this information may come in handy — it’s always better to be well-informed.