EVER experienced escalating prolonged muscle pain, followed by passing dark-coloured urine days after a session of strenuous exercise?
These are among symptoms of rhabdomyolysis, a serious condition where your skeletal muscle tissue breaks down rapidly, releasing proteins called myoglobin that can be harmful if released in large quantities into the bloodstream.
If left untreated, it could lead to acute kidney failure, says Sunway Medical Centre consultant physician, nephrologist and transplant nephrologist Dr Ng Eng Khim.
He said patients with rhabdomyolysis would normally experience escalating muscle soreness about 48 hours after conducting strenuous exercises, before experiencing muscle weakness.
“When muscle weakness kicks in to the point you may not be able to squat or even stand up, followed by cola-coloured or dark tea-coloured urine – those are your first warning signs.
“Once this happens, you should seek medical advice immediately.
“If left unattended, a decline in urine volume signals that the kidneys are failing,” he told StarMetro at Sunway Medical Centre, Bandar Sunway, Selangor.
According to Dr Ng, rhabdomyolysis has become more common among enthusiasts of extreme sports such as spin cycling and high-intensity interval training (HIIT).
“In the past, rhabdomyolysis happened more often on those whose muscles are injured during natural disasters or accidents.
“The trend has now shifted towards extreme sports enthusiasts,” he said.
“The patients often engage in intense exercises despite their muscles not conditioned to do so, making them very prone to muscle injury.
“Other factors that could lead to this condition are dehydration, not having sufficient meals before exercising and sudden change of lifestyle from sedentary to high-intensity exercises.”
He explained that when muscles are overexerted, they break down and release a large amount of myoglobin into the bloodstream.
“Myoglobin stores oxygen inside muscle cells, but when it is released in excessive amounts as a result of muscle injury, it can block the tubules inside your kidneys, causing kidney failure.
“If patients come in early, we can hydrate them to make them produce as much urine as possible to flush out the myoglobin and prevent kidney failure.”
He further explained that doctors will also observe the patients’ levels of creatine kinase – an enzyme found mainly in skeletal muscles, heart and brain that generates energy and is released after muscle injury.
“The monitoring will be done until the enzyme falls to a safe level.
“The normal creatine kinase level is 200 units per litre or below.
“However, there was a case of a patient with 500,000 units per litre, but fortunately that patient did not develop kidney failure as he sought medical attention early.”
Dr Ng said most patients seek help as soon as they notice the passing of dark-coloured urine, hence the progression to kidney failure due to this condition remains rare.
He issued a strong reminder against attempting to self-treat when experiencing rhabdomyolysis symptoms.
“Patients should not try to suppress their muscle pain through painkillers, especially if the symptoms last for more than two days.
“If pain relief is needed, always consult a doctor.”
When asked about whether patients can return to strenuous exercise after they are recovered, Dr Ng said it is best to opt for less demanding activities in the early stages of recovery.
“If you have suffered from rhabdomyolysis, it means that your muscles are not strong enough for that level of exertion.
“So, start with easier activities such as walking or low-resistance training and gradually rebuild your endurance,” he said.
He also urged fitness enthusiasts to engage with a certified trainer for professional advice on any new sports they participate in, to help them understand their limitations and progress safely without risking their health.
