Rhabdomyolysis – Symptoms, Diagnosis, and Treatment
Rhabdomyolysis is a medical condition where skeletal muscle breaks down rapidly, leaking its contents into the bloodstream. When muscles are damaged, substances such as myoglobin, creatine kinase (CK), and electrolytes are released, which can affect several organs – primarily the kidneys. In severe cases, the condition can lead to acute kidney failure and requires prompt treatment.
Rhabdomyolysis can occur after, for example, extreme physical exertion, trauma, certain medications, infections, or heatstroke.
Common Symptoms of Rhabdomyolysis
Symptoms of rhabdomyolysis can vary from mild to severe. In some cases, symptoms are subtle at first.
Typical Symptoms of Rhabdomyolysis
There are three classic symptoms sometimes called the rhabdomyolysis triad:
- Muscle pain or severe muscle aching
- Muscle weakness
- Dark-colored urine (tea- or cola-colored)
Other Common Symptoms
- Muscle stiffness or swelling
- Fatigue and general malaise
- Fever
- Nausea or vomiting
- Decreased urine output
- Confusion or palpitations (due to electrolyte imbalances)
Sometimes symptoms appear quickly, but they usually arise 12–48 hours after the muscle injury.
How is Rhabdomyolysis Investigated?
If a doctor suspects rhabdomyolysis, a combination of blood tests, urine tests, and clinical examination is usually performed. The purpose of the investigation is to:
- Confirm muscle breakdown
- Assess the risk of kidney damage
- Identify the cause
Blood Tests in Rhabdomyolysis
Blood tests are the most important diagnostic method.
Key Blood Tests
Creatine Kinase (CK)
This is the most important blood test; in rhabdomyolysis, levels are often significantly elevated (often more than 5 times the normal value).
Myoglobin in the Blood
This is released from damaged muscles and can, in turn, damage the kidneys.
Electrolytes
Through blood tests, doctors also check levels of:
- Potassium
- Sodium
- Phosphate
- Calcium
If these levels are imbalanced, it can affect both the heart and kidneys.
Kidney Function
Creatinine and eGFR are two blood tests that can show if the kidneys are affected.
Urine Test
A doctor may also order a urine test to detect myoglobin in the urine. In rhabdomyolysis, the urine can become dark, often described as tea- or cola-colored. A urine dipstick may show a positive result for blood even though red blood cells are absent in the sediment. This is because myoglobin from damaged muscles is filtered through the kidneys and excreted in the urine.
Other Examinations
In some cases, additional investigations may be needed. These may include a clinical examination where the doctor assesses muscle pain, swelling, and signs of dehydration or other trauma. An ECG can also be performed to detect heart impact from high potassium levels.
Imaging
In rarer cases, imaging studies such as Magnetic Resonance Imaging (MRI) and ultrasound may be used to assess muscle damage.
Treatment of Rhabdomyolysis
Once a diagnosis of rhabdomyolysis is confirmed, treatment is initiated with the primary goal of protecting the kidneys and stopping muscle breakdown.
Common components of treatment include:
- Fluid Therapy – the most important treatment is intravenous fluids (IV drip), given to dilute myoglobin in the blood, increase urine production, and reduce the risk of kidney failure.
- Treatment of Underlying Cause – this may involve stopping a medication, treating an infection, cooling the body in case of heatstroke, or managing injuries.
- Hospital Monitoring – in some cases, repeated blood tests, monitoring of kidney function and electrolytes, and fluid tracking are required.
- Dialysis – in severe kidney failure, dialysis may sometimes become necessary, but it is relatively uncommon.