Signs of Rhabdomyolysis in Urine

Muscle injury can release myoglobin, a pigment that may darken urine. The change may occur with severe muscle aching, swelling, tenderness or weakness after intense exertion, heat illness, a crush injury or prolonged immobility. Urine can also become dark for other reasons, including dehydration, bleeding or food and medicines, so colour is a clue rather than a diagnosis. A urine test and blood test can help clinicians identify muscle injury and check kidney function.

Stop strenuous exercise and arrange urgent medical assessment if urine becomes brown or tea-coloured after muscle pain or injury. Note the time the change began, how often you are passing urine and any trigger such as a workout, fever or fall. Avoid further exertion while waiting for advice. Do not assume that drinking large amounts quickly will solve the problem; a clinician should guide hydration after considering your symptoms and medical history.

Seek emergency care for dark urine with very little urine, severe muscle swelling, worsening weakness, fainting, confusion, vomiting or breathing difficulty. Prompt assessment is needed even if the urine returns to a lighter colour, because muscle breakdown and kidney strain may not be visible continuously. Take the name of any new medicine or supplement with you.

Could the urine colour be related to muscle breakdown? Which blood and urine tests are needed? How should I drink fluids while awaiting results? What activity, medicine or supplement should I avoid, and when is follow-up required?