Rhabdomyolysis (rhabdo) is caused by skeletal muscle injury, when muscles die and their contents are released into the bloodstream. About 26,000 cases of rhabdo are reported in the US each year, and it’s often associated with over-exertion, since athletes and novice gym-goers can end up with the condition after working out too hard. Rhabdo can also be caused by heat stroke, infection, trauma to the muscle (such as a crush injury), metabolic disorders, drug and alcohol use, and some medications (mainly statins) - anything that causes injury to the muscle can result in rhabdo.
The release of muscle contents (myoglobin - the protein that stores oxygen) into the bloodstream causes kidney damage, or even complete kidney failure when it’s left untreated.
Signs and Symptoms
There are some general signs and symptoms of rhabdo; however, in some cases, a patient may not see any signs and symptoms (about half of all cases don’t have any muscle-related signs and symptoms).
The main symptoms is muscle pain, particularly when it’s a result of over-exertion or another type of obvious muscle injury. Rhabdo can present with a “classic triad” of pain in the shoulders, thighs, and lower back, muscle weakness and problems moving extremities, and dark red (bloody looking) or brown urine. Those who experienced rhabdo as a result of exercising too hard reported feeling overly exhausted, sore, and with bloating on the stomach and extremities.
Signs of rhabdo also include:
- Pain the abdomen
- Nausea and/or vomiting
- Confusion or loss of consciousness
Rhabdo can cause high levels of potassium in the blood, which causes an irregular heartbeat (leading to cardiac arrest) and kidney damage - occurring in up to half of all patients diagnosed with rhabdo. Compartment syndrome can occur after the patient has received fluids, and the resulting compression of nerves, blood vessels, and muscles can result in lasting damage to the tissues and blood flow problems.
Since rhabdo is the result of myoglobin in the bloodstream that eventually makes it into urine, doctors can check for rhabdo by testing urine and blood for myoglobin. They can also test blood for creatine kinase (which is an enzyme released in the blood from the muscle breakdown).
A full medical history is also taken in the diagnosis of rhabdo, along with a physical exam. When the cause of rhabdo could be related to trauma, radiography, CTs, or MRIs may be utilized to better view the injury site.
Rhabdo causes kidney damage and dehydration, so the most important thing is fluid resuscitation. IV fluids will be started that contain bicarbonate to flush out the myoglobin from the kidneys. Depending on the level of kidney damage, bicarbonate medications and diuretics (which make the body flush out water and salt) can be prescribed to help keep the kidneys working. IV fluids will also help bring down high potassium levels (hyperkalemia) present in the blood and bring up low calcium levels (hypocalcemia).
If kidney damage or failure has occurred, dialysis may be required. Dialysis works by removing blood from the body, cleaning it to remove waste, then putting it back in the body.
Since the muscles are damaged, taking the time to recover and hydrate is very important. At-home treatment includes resting the body and drinking lots of clear fluids. If the rhabdo was a result of a metabolic disorder, dietary modifications may help prevent a recurrence of rhabdo.
Staying well-hydrated, particularly during exercise and when out in the heat, can help prevent rhabdo from occurring. If rhabdo is suspected, going to the hospital for immediate treatment is the best course of action to avoid permanent damage to the kidneys.
Sources and More Information
Healthline, “Rhabdomyolysis: Causes, Symptoms, And Diagnosis” https://www.healthline.com/health/rhabdomyolysis#causes
MedicineNet, “Rhabdomyolysis” https://www.medicinenet.com/rhabdomyolysis/article.htm#rhabdomyolysis_facts
Medscape, “Rhabdomyolysis” https://emedicine.medscape.com/article/1007814-overview
WedMD, “Rhabdomyolysis” https://www.webmd.com/a-to-z-guides/rhabdomyolysis-symptoms-causes-treatments#1
Women’s Health, “I Got Rhabdo and It Nearly Destroyed My Body” by Melanie Pace as told to Kristen Domonell, https://www.womenshealthmag.com/fitness/a19983278/rhabdomyolysis/
Jenny Ewen, BA, EMT