What should you know about postoperative rhabdomyolysis?

Muscle cells can be injured by prolonged pressure or positioning, reduced blood flow, intense exertion, infection, medication effects, or another major stress around an operation. When muscle breaks down, proteins and electrolytes enter the blood and may affect the kidneys and heart. Symptoms can include muscle pain or swelling that seems out of proportion, marked weakness, reduced urine, or urine that looks unusually dark. Some people have few early symptoms, so clinicians may use blood and urine tests to check muscle injury and organ function when concern arises. This is different from ordinary muscle soreness after exercise, which usually follows a familiar exertion pattern and settles with recovery.

Tell the surgical or nursing team promptly about new or worsening muscle pain, swelling, weakness, reduced urine, or dark urine. Do not wait for a routine follow-up if these symptoms develop. The team may review medicines, examine the affected muscles, monitor urine output, and give fluids or other treatment based on blood-test results and kidney function. Do not start strenuous exercise, take extra supplements, or use pain medicines outside the discharge plan while the cause is being clarified. Keep the care team informed about vomiting, poor fluid intake, or any new illness.

Seek urgent medical care for severe or rapidly increasing muscle pain and swelling, new weakness, very dark urine, much less urine than usual, confusion, fainting, chest symptoms, or trouble breathing. After a procedure, also report a limb that becomes tense, numb, cold, or difficult to move. These signs can reflect muscle injury or pressure affecting circulation and nerves. If you are still in hospital, use the call system immediately; after discharge, contact emergency services or the surgical team according to local instructions.

Ask which symptoms should trigger an urgent call, whether blood or urine tests are needed, and how kidney function will be monitored. Ask whether any medicine, positioning issue, dehydration, or procedure-related event may have contributed. Before resuming exercise, ask how activity should progress and which warning signs should stop it.